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Anatomy_Gray. Fig. 5.75 Superficial fascia. A. Lateral view. B. Anterior view. Membranous layerof superficial fasciaAnterior superior iliac spineAttachment of membranouslayer of superficial fasciato fascia lata of thigh Posterior margin ofperineal membrane Fused to posterior margin ofperineal membraneMuscles of abdominal wallInguinal ligamentFascia lata of thighPubic tubercleAB Fig. 5.76 Pudendal nerve. A. In men. B. In women. S2S3S4Obturator internus muscleInferior rectal nerveDorsal nerve of penisSacrospinous ligamentCoccygeus muscleLevator animusclePerineal nervePosterior scrotal nervePudendal nervePudendal canal infascia of obturator internusMotor branches to skeletal muscle in urogenital triangleA Dorsal nerve of clitorisPosterior labial nerveMotor branchesInferior rectal nervePudendal nervePerineal nerveB Fig. 5.77 Arteries in the perineum.


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Anatomy_Gray. Dorsal nerve of clitorisPosterior labial nerveMotor branchesInferior rectal nervePudendal nervePerineal nerveB Fig. 5.77 Arteries in the perineum. Internal iliac arteryInternal pudendal arteryInferior rectal arteryInternal pudendal arteryin fascia of obturator internusDorsal artery of penis(dorsal artery of clitoris in women)Perineal arteryPosterior scrotal artery(posterior labial artery in women)Artery of bulb of penis (artery of vestibular bulb in women)Artery to bulbUrethral arteryDeep artery of penis(deep artery of clitoris in women) Fig. 5.78 Perineal veins. Internal pudendal veinInferior rectal veinProstatic plexus of veins(vesical plexus in women)Posterior scrotal vein (or posterior labial vein in women)Deep dorsal vein (or deep dorsal vein of clitoris in women) Fig. 5.79 Lymphatic drainage of the perineum.


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Anatomy_Gray. Fig. 5.79 Lymphatic drainage of the perineum. Thoracic ductLymph from testisLILateral aortic(lumbar) nodesExternal iliac nodesSuperficial inguinal nodesLymph fromsuperficial tissues ofpenis and scrotum(clitoris and labia majorain women)Deep inguinal nodesInguinal ligamentTestisLymph from glans penis(glans clitoris, labia minora,and lower part of vaginain women)Pre-aortic nodes Fig. 5.80 Lateral view of the pelvic area with the position of the skeletal features indicated. The orientation of the pelvic inlet, urogenital triangle, and anal triangle is also shown. A. In a woman. B. In a man. Plane of pelvic inletPlane of urogenital trianglePlane of anal triangleTuberculum of iliac crestHigh point of iliac crestPosterior superior iliac spineAnterior superior iliac spinePubic tubercleAB


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Anatomy_Gray. Plane of pelvic inletPlane of urogenital trianglePlane of anal triangleTuberculum of iliac crestHigh point of iliac crestPosterior superior iliac spineAnterior superior iliac spinePubic tubercleAB Fig. 5.81 Anterior view of the pelvic area. A. In a woman showing the position of the pubic symphysis. B. In a man showing the position of the pubic tubercle, pubic symphysis, and anterior superior iliac spine. Fig. 5.82 Inferior view of the perineum in the lithotomy position. Boundaries, subdivisions, and palpable landmarks are indicated. A. In a man. B. In a woman. Fig. 5.83 Anal triangle with the anal aperture and position of the ischio-anal fossae indicated. A. In a man. B. In a woman. Anal triangleBIschial tuberosityIschial tuberosityPosition of perineal bodyPosition of ischio-anal fossaPosition of ischio-anal fossaCoccyxAnal apertureAnal triangleAIschial tuberosityPosition of perineal bodyPosition of ischio-anal fossaPosition of ischio-anal fossaCoccyxLabium minusAnal aperture


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Anatomy_Gray. Fig. 5.84 Structures in the urogenital triangle of a woman. A. Inferior view of the urogenital triangle of a woman with major features indicated. B. Inferior view of the vestibule. The labia minora have been pulled apart to open the vestibule. Also indicated are the glans clitoris, the clitoral hood, and the frenulum of the clitoris. C. Inferior view of the vestibule showing the urethral and vaginal orifices and the hymen. The labia minora have been pulled further apart than in Figure 5.84B. D. Inferior view of the vestibule with the left labium minus pulled to the side to show the regions of the vestibule into which the greater vestibular and para-urethral glands open. E. View through the vaginal canal of the cervix. F. Inferior view of the urogenital triangle of a woman with the erectile tissues of the clitoris and vestibule and the greater vestibular glands indicated with overlays.


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Anatomy_Gray. ABCDGlans clitorisGlans clitorisGlans clitorisFrenulumof clitorisVestibuleSkin overlyingbody of clitorisLabiumminusPosteriorcommissure(overliesperineal body)Labium minusLabium majusPrepuce (hood) of clitorisVaginal opening(introitus)Vaginal opening External urethral orificeExternal urethral orificeRemnants of hymenFourchetteArea of opening of the duct of the para-urethralglandArea of opening of the duct of the greater vestibular gland EFSkin overlying body of clitorisCervixExternalcervical osPosteriorfornixAnteriorfornixGlans clitorisBody of clitoris (unattached parts of corpora cavernosa)Bulb of vestibuleGreater vestibular glandMons pubisCrus clitoris (attached part of corpus cavernosum) Fig. 5.85 Structures in the urogenital triangle of a man. A. Inferior view. B. Ventral surface of the body of the penis. C. Anterior view of the glans penis showing the urethral opening. D. Lateral view of the body of the penis and glans.


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Anatomy_Gray. C. Anterior view of the glans penis showing the urethral opening. D. Lateral view of the body of the penis and glans. E. Inferior view of the urogenital triangle of a man with the erectile tissues of the penis indicated with overlays. Position of perineal bodyABBody of penisVentral surface of body of penisGlans penisGlans penisTestisTestisIschial tuberosityFrenulumRapheEpididymis, vas deferens,vessels, nerves, and lymphatics CDorsal surface ofbody of penisUrethral orificeNeck of glansGlans penisPrepuceCorona of glansPosition of perineal bodyEBody of penis (unattached parts of corpus spongiosum and corpora cavernosa)Bulb of penis (attached part of corpus spongiosum)Crus of penis (attached part of corpus cavernosum)Glans penis D Fig. 5.86 Left testicular venogram demonstrating the pampiniform plexus of veins. Fig. 5.87 Sagittal computed tomogram demonstrating a pelvic kidney.


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Anatomy_Gray. Fig. 5.86 Left testicular venogram demonstrating the pampiniform plexus of veins. Fig. 5.87 Sagittal computed tomogram demonstrating a pelvic kidney. eFig. 5.88 Digital subtraction aorto-iliac angiogram. A. Normal circulation pattern. B. Occluded left common iliac artery. eFig. 5.89 Sagittal MRI of the pelvic cavity. A. Measurement of a fibroid before the uterine artery embolization. B. Measurement of a fibroid 6 months after the embolization. The size of the fibroid has decreased. BA56.3 mm46.1 mm Table 5.1 Muscles of the pelvic walls Table 5.2 Muscles of the pelvic diaphragm Table 5.3 Muscles within the deep perineal pouch Table 5.4 Branches of the sacral and coccygeal plexuses (spinal segments in parentheses do not consistently participate) Table 5.5 Muscles of the anal triangle Table 5.6 Muscles of the superficial perineal pouch In the clinic


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Anatomy_Gray. Table 5.5 Muscles of the anal triangle Table 5.6 Muscles of the superficial perineal pouch In the clinic In certain diseases (e.g., leukemia), a sample of bone marrow must be obtained to assess the stage and severity of the problem. The iliac crest is often used for such bone marrow biopsies. The iliac crest lies close to the surface and is easily palpated. A bone marrow biopsy is performed by injecting anesthetic in the skin and passing a cutting needle through the cortical bone of the iliac crest. The bone marrow is aspirated and viewed under a microscope. Samples of cortical bone can also be obtained in this way to provide information about bone metabolism. In the clinic


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Anatomy_Gray. In the clinic The pelvis can be viewed as a series of anatomical rings. There are three bony rings and four fibro-osseous rings. The major bony pelvic ring consists of parts of the sacrum, ilium, and pubis, which forms the pelvic inlet. Two smaller subsidiary rings are the obturator foramina. The greater and lesser sciatic foramina formed by the greater and lesser sciatic notches and the sacrospinous and sacrotuberous ligaments form the four fibro-osseous rings. The rings, which are predominantly bony (i.e., the pelvic inlet and the obturator foramina), are brittle rings. It is not possible to break one side of the ring without breaking the other side of the ring, which in clinical terms means that if a fracture is demonstrated on one side, a second fracture should always be suspected. Fractures of the pelvis may occur in isolation; however, they usually occur in trauma patients and warrant special mention.


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Anatomy_Gray. Fractures of the pelvis may occur in isolation; however, they usually occur in trauma patients and warrant special mention. Owing to the large bony surfaces of the pelvis, a fracture produces an area of bone that can bleed significantly. A large hematoma may be produced, which can compress organs such as the bladder and the ureters. This blood loss may occur rapidly, reducing the circulating blood volume and, unless this is replaced, the patient will become hypovolemic and shock will develop. Pelvic fractures may also disrupt the contents of the pelvis, leading to urethral disruption, potential bowel rupture, and nerve damage. In the clinic Common problems with the sacro-iliac joints


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Anatomy_Gray. Pelvic fractures may also disrupt the contents of the pelvis, leading to urethral disruption, potential bowel rupture, and nerve damage. In the clinic Common problems with the sacro-iliac joints As with many weight-bearing joints, degenerative changes may occur with the sacro-iliac joints and cause pain and discomfort in the region. In addition, disorders associated with the major histocompatibility complex antigen HLA-B27, such as ankylosing spondylitis, psoriatic arthritis, inflammatory arthritis associated with inflammatory bowel disease, and reactive arthritis (the group referred to as seronegative spondyloarthropathies), can produce specific inflammatory changes within these joints. In the clinic


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Anatomy_Gray. In the clinic Transverse and sagittal measurements of a woman’s pelvic inlet and outlet can help in predicting the likelihood of a successful vaginal delivery. These measurements include: the sagittal inlet (between the promontory and the top of the pubic symphysis), the maximum transverse diameter of the inlet, the bispinous outlet (the distance between ischial spines), and the sagittal outlet (the distance between the tip of the coccyx and the inferior margin of the pubic symphysis). These measurements can be obtained using magnetic resonance imaging, which carries no radiation risk for the fetus or mother (Fig. 5.33). In the clinic


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Anatomy_Gray. These measurements can be obtained using magnetic resonance imaging, which carries no radiation risk for the fetus or mother (Fig. 5.33). In the clinic At the beginning of defecation, closure of the larynx stabilizes the diaphragm and intraabdominal pressure is increased by contraction of abdominal wall muscles. As defecation proceeds, the puborectalis muscle surrounding the anorectal junction relaxes, which straightens the anorectal angle. Both the internal and the external anal sphincters also relax to allow feces to move through the anal canal. Normally, the puborectal sling maintains an angle of about 90° between the rectum and the anal canal and acts as a “pinch valve” to prevent defecation. When the puborectalis muscle relaxes, the anorectal angle increases to about 130° to 140°.


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Anatomy_Gray. The fatty tissue of the ischio-anal fossa allows for changes in the position and size of the anal canal and anus during defecation. During evacuation, the anorectal junction moves down and back and the pelvic floor usually descends slightly. During defecation, the circular muscles of the rectal wall undergo a wave of contraction to push feces toward the anus. As feces emerge from the anus, the longitudinal muscles of the rectum and levator ani bring the anal canal back up, the feces are expelled, and the anus and rectum return to their normal positions. A magnetic resonance defecating proctogram is a fairly new imaging technique that allows assessment of different phases of defecation, including rectal function and behavior of the pelvic floor musculature during this process. It is useful in detecting pelvic organ abnormal descent/prolapse during dynamic scanning and potential formation of cystocele or rectocele (Fig. 5.35). In the clinic


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Anatomy_Gray. In the clinic During childbirth the perineal body may be stretched and torn. Traditionally it was felt that if a perineal tear is likely, the obstetrician may proceed with an episiotomy. This is a procedure in which an incision is made in the perineal body to allow the head of the fetus to pass through the vagina. There are two types of episiotomies: a median episiotomy cuts through the perineal body, while a mediolateral episiotomy is an incision 45° from the midline. The maternal benefits of this procedure have been thought to be less traumatic to the perineum and to result in decreased pelvic floor dysfunction after childbirth. However, more recent evidence suggests that an episiotomy should not be performed routinely. Review of data has failed to show a decrease in pelvic floor damage with routine use of episiotomies. In the clinic


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Anatomy_Gray. In the clinic A digital rectal examination (DRE) is performed by placing the gloved and lubricated index finger into the rectum through the anus. The anal mucosa can be palpated for abnormal masses, and in women, the posterior wall of the vagina and the cervix can be palpated. In men, the prostate can be evaluated for any extraneous nodules or masses. In many instances the digital rectal examination may be followed by proctoscopy or colonoscopy. An ultrasound probe may be placed into the rectum to assess the gynecological structures in females and the prostate in the male before performing a prostatic biopsy. A digital rectal examination also allows detection of fresh or altered blood in the rectum in patients with acute gastrointestinal bleeding or chronic anemia. In the clinic Carcinoma of the colon and rectum


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Anatomy_Gray. In the clinic Carcinoma of the colon and rectum Carcinoma of the colon and rectum (colorectum) is a common and often lethal disease. Recent advances in surgery, radiotherapy, and chemotherapy have only slightly improved 5-year survival rates. The biological behavior of tumors of the colon and rectum is relatively predictable. Most of the tumors develop from benign polyps, some of which undergo malignant change. The overall prognosis is related to: the degree of tumor penetration through the bowel wall, the presence or absence of lymphatic dissemination, and the presence or absence of systemic metastases.


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Anatomy_Gray. Given the position of the colon and rectum in the abdominopelvic cavity and its proximity to other organs, it is extremely important to accurately stage colorectal tumors; a tumor in the pelvis, for example, could invade the uterus or bladder. Assessing whether or not spread has occurred usually involves computed tomography (assessment for distal metastases) and magnetic resonance imaging (local staging). Endoscopic ultrasound (EUS) is also used in some instances for local staging of rectal cancer. In the clinic Iatrogenic injury of the ureters


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Anatomy_Gray. Ureters can be injured during various surgeries within the abdomen and pelvis as they lie close to the dissection planes. The most common surgeries that can result in ureteric injury are total abdominal hysterectomy and bilateral salpingo-oophorectomy (removal of the uterus, fallopian tubes and ovaries), laparoscopic vaginal hysterectomy, laparoscopic anterior resection of the rectum, and open left hemicolectomy. At increased risk of ureteric injury are patients with a bulky tumor (uterine, colonic, rectal) and those with a history of previous operations or pelvic irradiation, all of which make dissection of tissues more difficult. During surgery, the ureter can be crushed, cut open, devascularized, or avulsed. It can also be injured during cryoablation or electric cauterization to control intraoperative bleeding. Ureters can also undergo trauma during the course of ureteroscopy, a procedure where a small endoscope is introduced through the urethra and urinary bladder into one of the


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Anatomy_Gray. intraoperative bleeding. Ureters can also undergo trauma during the course of ureteroscopy, a procedure where a small endoscope is introduced through the urethra and urinary bladder into one of the ureters to treat stones or tumors of the ureter (usually due to a tear or electrocauterization).


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Anatomy_Gray. Ureteric injury leads to high morbidity due to infection and in most severe cases to renal impairment. The prognosis is improved when the diagnosis is made intraoperatively and the ureter is repaired immediately. Delayed diagnosis leads to urine leakage and contamination of the abdominal and pelvic cavity, development of sepsis, and in the case of injury near the vagina, a uretero-vaginal fistula can develop. When the diagnosis is made postoperatively, sometimes diversion of urine flow is required and percutaneous nephrostomy is performed. In the clinic


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Anatomy_Gray. In the clinic In some patients, small calculi (stones) form in the kidneys. These may pass down the ureter, causing ureteric obstruction, and into the bladder (Fig. 5.43), where insoluble salts further precipitate on these small calculi to form larger calculi. Often, these patients develop (or may already have) problems with bladder emptying, which leaves residual urine in the bladder. This urine may become infected, which alters the pH of the urine, permitting further precipitation of insoluble salts. If small enough, the stones may be removed via a transurethral route using specialized instruments. If the stones are too big, it may be necessary to make a suprapubic incision and enter the bladder retroperitoneally to remove them. In the clinic


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Anatomy_Gray. If the stones are too big, it may be necessary to make a suprapubic incision and enter the bladder retroperitoneally to remove them. In the clinic In certain instances it is necessary to catheterize the bladder through the anterior abdominal wall. For example, when the prostate is markedly enlarged and it is impossible to pass a urethral catheter, a suprapubic catheter may be placed. The bladder is a retroperitoneal structure and when full lies adjacent to the anterior abdominal wall. Ultrasound visualization of the bladder may be useful in assessing the size of this structure and, importantly, differentiating this structure from other potential abdominal masses. The procedure of suprapubic catheterization is straightforward and involves the passage of a small catheter on a needle in the midline approximately 2 cm above the pubic symphysis. The catheter passes easily into the bladder without compromise of other structures and permits free drainage. In the clinic


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Anatomy_Gray. In the clinic Bladder cancer (Fig. 5.44) is the most common tumor of the urinary tract and is usually a disease of the sixth and seventh decades, although there is an increasing trend for younger patients to develop this disease. Approximately one-third of bladder tumors are multifocal; fortunately, two-thirds are superficial tumors and amenable to local treatment. Bladder tumors may spread through the bladder wall and invade local structures, including the rectum, uterus (in women), and lateral walls of the pelvic cavity. Prostatic involvement is not uncommon in male patients. The disease spreads via the internal iliac lymph nodes. Spread to distant metastatic sites rarely includes the lung. Large bladder tumors may produce complications, including invasion and obstruction of the ureters. Ureteric obstruction can then obstruct the kidneys and induce kidney failure. Moreover, bladder tumors can invade other structures of the pelvic cavity.


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Anatomy_Gray. Treatment for early-stage tumors includes local resection with preservation of the bladder. Diffuse tumors may be treated with local chemotherapy; more extensive tumors may require radical surgical removal of the bladder (cystectomy) and, in men, the prostate (prostatectomy). Bladder reconstruction (formation of so-called neobladder) is performed in patients after cystectomy using part of a bowel, most commonly the ileum. In the clinic The relatively short length of the urethra in women makes them more susceptible than men to bladder infection. The primary symptom of urinary tract infection in women is usually inflammation of the bladder (cystitis). The infection can be controlled in most instances by oral antibiotics and resolves without complication. In children under 1 year of age, infection from the bladder may spread via the ureters to the kidneys, where it can produce renal damage and ultimately lead to renal failure. Early diagnosis and treatment are necessary.


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Anatomy_Gray. In the clinic Urethral catheterization is often performed to drain urine from a patient’s bladder when the patient is unable to micturate. When inserting urinary catheters, it is important to appreciate the gender anatomy of the patient. In men: The spongy urethra is surrounded by the erectile tissue of the bulb of the penis immediately inferior to the deep perineal pouch. The wall of this short segment of urethra is relatively thin and angles superiorly to pass through the deep perineal pouch; at this position the urethra is vulnerable to damage, notably during cystoscopy. The membranous part of the urethra runs superiorly as it passes through the deep perineal pouch. The prostatic part of the urethra takes a slight concave curve anteriorly as it passes through the prostate gland.


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Anatomy_Gray. The prostatic part of the urethra takes a slight concave curve anteriorly as it passes through the prostate gland. In women, it is much simpler to pass catheters and cystoscopes because the urethra is short and straight. Urine may therefore be readily drained from a distended bladder without significant concern for urethral rupture. Occasionally, it is impossible to pass any form of instrumentation through the urethra to drain the bladder, usually because there is a urethral stricture or prostatic enlargement. In such cases, an ultrasound of the lower abdomen will demonstrate a full bladder (Fig. 5.46) behind the anterior abdominal wall. A suprapubic catheter may be inserted into the bladder with minimal trauma through a small incision under local anesthetic. In the clinic


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Anatomy_Gray. In the clinic Tumors of the testis account for a small percentage of malignancies in men. However, they generally occur in younger patients (between 20 and 40 years of age). When diagnosed at an early stage, most of these tumors are curable by surgery and chemotherapy. Early diagnosis of testicular tumors is extremely important. Abnormal lumps can be detected by palpation, and diagnosis can be made using ultrasound. Simple ultrasound scanning can reveal the extent of the local tumor, usually at an early stage. Surgical removal of the malignant testis is often carried out using an inguinal approach. The testis is not usually removed through a scrotal incision, because it is possible to spread tumor cells into the subcutaneous tissues of the scrotum, which has a different lymphatic drainage than the testis. In the clinic


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Anatomy_Gray. Interrupted descent of testis leads to an empty scrotal sac and abnormal location of the testis, which can lie anywhere along the usual route of descent. Most commonly the testis is present in the inguinal canal, where it can be palpated. This condition is usually diagnosed at birth or within the first year of life. A higher incidence of ectopic (undescended) testis occurs in premature births (30%) than in term births (3–5%). Normally, the ectopic testis can complete its descent within the first 3 months after a child is born; therefore watchful waiting is recommended for the first couple of months. A specialist referral is usually made at 6 months if the testis is still absent from the scrotal sac. It is crucial to make the diagnosis early so that an appropriate management plan can be initiated to avoid or reduce the risk of complications such as testicular malignancy, subfertility or infertility, testicular torsion, and inguinal hernia (due to patent processus vaginalis). If


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Anatomy_Gray. be initiated to avoid or reduce the risk of complications such as testicular malignancy, subfertility or infertility, testicular torsion, and inguinal hernia (due to patent processus vaginalis). If surgical correction is required, the ectopic testis is moved from the inguinal canal into the scrotum (orchiopexy). During mobilization of the testis, dissection of tissues must be performed carefully to avoid injuring the ilioinguinal nerve adjacent to the spermatic cord. At the time of orchiopexy, the patent processus vaginalis is closed and any inguinal hernia, if present, is repaired.


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Anatomy_Gray. In the clinic The ductus deferens transports spermatozoa from the tail of the epididymis in the scrotum to the ejaculatory duct in the pelvic cavity. Because it has a thick smooth muscle wall, it can be easily palpated in the spermatic cord between the testes and the superficial inguinal ring. Also, because it can be accessed through skin and superficial fascia, it is amenable to surgical dissection and surgical division. When this is carried out bilaterally (vasectomy), the patient is rendered sterile—this is a useful method for male contraception. In the clinic


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Anatomy_Gray. In the clinic Prostate cancer is one of the most commonly diagnosed malignancies in men, and often the disease is advanced at diagnosis. Prostate cancer typically occurs in the peripheral zone of the prostate (see Fig. 5.48) and is relatively asymptomatic. In many cases, it is diagnosed by a digital rectal examination (DRE) (Fig. 5.49A) and by blood tests, which include serum acid phosphatase and serum prostate-specific antigen (PSA). In rectal exams, the tumorous prostate feels “rock” hard. The diagnosis is usually made by obtaining a number of biopsies of the prostate. Ultrasound is used during the biopsy procedure to image the prostate for the purpose of taking measurements and for needle placement. Ultrasound can also be used to aid planning radiotherapy by placing special metal markers, called fiducials, under direct ultrasound guidance, through the rectal wall into or near the tumor. This allows maximization of the radiation dose to the tumor while protecting healthy tissue.


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Anatomy_Gray. Benign prostatic hypertrophy is a disease of the prostate that occurs with increasing age in most men (Fig. 5.49B). It generally involves the more central regions of the prostate (see Fig. 5.48), which gradually enlarge. The prostate feels “bulky” on DRE. Owing to the more central hypertrophic change of the prostate, the urethra is compressed, and a urinary outflow obstruction develops in a number of patients. With time, the bladder may become hypertrophied in response to the urinary outflow obstruction. In some male patients, the obstruction becomes so severe that urine cannot be passed and transurethral or suprapubic catheterization is necessary. Despite being a benign disease, benign prostatic hypertrophy can therefore have a marked effect on the daily lives of many patients. In the clinic


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Anatomy_Gray. In the clinic Ovarian cancer remains one of the major challenges in oncology. The ovaries contain numerous cell types, all of which can undergo malignant change and require different imaging and treatment protocols and ultimately have different prognoses. Ovarian tumors most commonly originate from the ovarian surface (germinal) epithelium that is continuous at a sharp transition zone with the peritoneum of the mesovarium. Many factors have been linked with the development of ovarian tumors, including a strong family history. Ovarian cancer may occur at any age, but more typically it occurs in older women.


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Anatomy_Gray. Many factors have been linked with the development of ovarian tumors, including a strong family history. Ovarian cancer may occur at any age, but more typically it occurs in older women. Cancer of the ovaries may spread via the blood and lymphatics, and frequently metastasizes directly into the peritoneal cavity. Such direct peritoneal cavity spread allows the passage of tumor cells along the paracolic gutters and over the liver from where this disease may disseminate easily. Unfortunately, many patients already have metastatic and diffuse disease (Fig. 5.52) at the time of diagnosis. In the clinic Imaging the ovary


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Anatomy_Gray. In the clinic Imaging the ovary The ovaries can be visualized using ultrasound. If the patient drinks enough water, the bladder becomes enlarged and full. This fluid-filled cavity provides an excellent acoustic window, behind which the uterus and ovaries may be identified by transabdominal scanning with ultrasound. This technique also allows obstetricians and technicians to view a fetus and record its growth throughout pregnancy. Some patients are not suitable for transabdominal scanning, in which case a probe may be passed into the vagina, permitting close visualization of the uterus, the contents of the recto-uterine pouch (pouch of Douglas), and the ovaries. The ovaries can also be visualized laparoscopically. Many countries have introduced screening programs for cervical cancer where women are regularly called for smear tests. In the clinic


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Anatomy_Gray. In the clinic A hysterectomy is the surgical removal of the uterus. This is usually complete excision of the body, fundus, and cervix of the uterus, though occasionally the cervix may be left in situ. In some instances the uterine (fallopian) tubes and ovaries are removed as well. This procedure is called a total abdominal hysterectomy and bilateral salpingo-oophorectomy. Hysterectomy, oophorectomy, and salpingo-oophorectomy may be performed in patients who have reproductive malignancy, such as uterine, cervical, and ovarian cancers. Other indications include a strong family history of reproductive disorders, endometriosis, and excessive bleeding. Occasionally the uterus may need to be removed postpartum because of excessive postpartum bleeding.


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Anatomy_Gray. A hysterectomy is performed through a transverse suprapubic incision (Pfannenstiel’s incision). During the procedure tremendous care is taken to identify the distal ureters and to ligate the nearby uterine arteries without damage to the ureters. In the clinic After ovulation, the unfertilized egg is gathered by the fimbriae of the uterine tube. The egg passes into the uterine tube where it is normally fertilized in the ampulla. The zygote then begins development and passes into the uterine cavity where it implants in the uterine wall. A simple and effective method of birth control is to surgically ligate (clip) the uterine tubes, preventing spermatozoa from reaching the ovum. This simple short procedure is performed under general anesthetic. A small laparoscope is passed into the peritoneal cavity and special equipment is used to identify the tubes. In the clinic Carcinoma of the cervix and uterus


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Anatomy_Gray. In the clinic Carcinoma of the cervix and uterus Carcinoma of the cervix (Fig. 5.56) and uterus is a common disease. Diagnosis is by inspection, cytology (examination of the cervical cells), imaging, biopsy, and dilation and curettage (D&C) of the uterus. Carcinoma of the cervix and uterus may be treated by local resection, removal of the uterus (hysterectomy), and adjuvant chemotherapy. The tumor spreads via lymphatics to the internal and common iliac lymph nodes. Many countries have introduced screening programs for cervical cancer where women are regularly called for smear tests. The age of women included in the screening population varies depending on the country. In the clinic The recto-uterine pouch


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Anatomy_Gray. In the clinic The recto-uterine pouch The recto-uterine pouch (pouch of Douglas) is an extremely important clinical region situated between the rectum and uterus. When the patient is in the supine position, the recto-uterine pouch is the lowest portion of the abdominopelvic cavity and is a site where infection and fluids typically collect. It is impossible to palpate this region transabdominally, but it can be examined by transvaginal and transrectal digital palpation. If an abscess is suspected, it may be drained through the vagina or the rectum without necessitating transabdominal surgery. In the clinic


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Anatomy_Gray. Pudendal block anesthesia is performed to relieve the pain associated with childbirth. Although the use of this procedure is less common since the widespread adoption of epidural anesthesia, it provides an excellent option for women who have a contraindication to neuraxial anesthesia (e.g., spinal anatomy, low platelets, too close to delivery). Pudendal blocks are also used for certain types of chronic pelvic pain and in some rectal or urological procedures. The injection is usually given where the pudendal nerve crosses the lateral aspect of the sacrospinous ligament near its attachment to the ischial spine. During childbirth, a finger inserted into the vagina can palpate the ischial spine. The needle is passed transcutaneously to the medial aspect of the ischial spine and around the sacrospinous ligament. Infiltration is performed and the perineum is anesthetized. Pudendal nerve blocks can also be performed with imaging guidance (using fluoroscopy, computed tomography, or


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Anatomy_Gray. the sacrospinous ligament. Infiltration is performed and the perineum is anesthetized. Pudendal nerve blocks can also be performed with imaging guidance (using fluoroscopy, computed tomography, or ultrasound) to localize the nerve rather than relying purely on anatomical landmarks.


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Anatomy_Gray. In the clinic It may be necessary to perform radical surgery to cure cancer of the prostate. To do this, the prostate and its attachments around the base of the bladder, including the seminal vesicles, must be removed en masse. Parts of the inferior hypogastric plexus in this region give rise to nerves that innervate the erectile tissues of the penis. Impotence may occur if these nerves cannot be or are not preserved during removal of the prostate. For the same reasons, women may experience sexual dysfunction if similar nerves are damaged during pelvic surgery, for example, during a total hysterectomy. In the clinic


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Anatomy_Gray. In the clinic This is a new and innovative way of performing radical prostatectomy in patients with prostate cancer. The patient is placed on an operating table near a so-called patient unit consisting of a high-resolution camera and three arms containing microsurgical instruments. The surgeon operates the robot from a computer console and views the surgical field on a monitor as magnified 3D images. The operator usually makes a number of incisions between 1 cm to 2 cm wide through which the camera and surgical instruments are inserted into the pelvis. The surgeon’s hand movements are filtered and translated by the robot into very fine and precise movements of the microtools. This markedly increases the precision of prostate removal and reduces the risk of nerve damage and potential development of postsurgical erectile dysfunction. In the clinic Abscesses in the ischio-anal fossae


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Anatomy_Gray. In the clinic Abscesses in the ischio-anal fossae The anal mucosa is particularly vulnerable to injury and may be easily torn by hard feces. Occasionally, patients develop inflammation and infection of the anal canal (sinuses or crypts). This infection can spread between the sphincters, producing intersphincteric fistulas. The infection can tract superiorly into the pelvic cavity or laterally into the ischio-anal fossae. In the clinic


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Anatomy_Gray. In the clinic A hemorrhoid is an engorgement of the venous plexus at or inside the anal sphincter. It is a common complaint and has prevalence of approximately 4% in the United States. Hemorrhoids have a slight genetic predisposition; however, straining during bowel movements, obesity, and sedentary lifestyle can also produce hemorrhoids. The symptoms include irritation, pain, and swelling. Hemorrhoids occurring at the anal verge (distal boundary of the anal canal) are typically called external hemorrhoids. Internal hemorrhoids occur inside the rectum and have a tendency to bleed. Prolapsed hemorrhoids are internal hemorrhoids that pass outside the anal canal and form lumps, which may undergo thrombosis and become painful.


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Anatomy_Gray. There are many treatments for hemorrhoids, which include ligation above the pectinate (dentate) line using simple rubber bands or surgical excision. Surgery to this region is not without complications and care must be taken to preserve the internal anal sphincter. In the back of every physician’s mind is the concern that the rectal bleeding or symptoms may not be attributable to hemorrhoids. Therefore, excluding a tumor within the bowel is as important as treating the hemorrhoids. In the clinic Emission and ejaculation of semen In men, emission is the formation of semen, and ejaculation is the expulsion of semen from the penis.


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Anatomy_Gray. In the clinic Emission and ejaculation of semen In men, emission is the formation of semen, and ejaculation is the expulsion of semen from the penis. Although erection of the penis is a vascular event generated by parasympathetic nerves from spinal levels S2–S4, the formation of semen in the urethra is caused by the contraction of smooth muscle of the ducts and glands of the reproductive system that is innervated by the sympathetic part of the visceral nervous system. Ejaculation of semen from the penis is through the action of skeletal muscles innervated by somatic motor nerves.


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Anatomy_Gray. Smooth muscle in the duct system of the male reproductive tract and in the accessory glands is innervated by sympathetic fibers from the lower thoracic and upper lumbar spinal levels (T12, L1,2). The fibers pass into the prevertebral plexus and are then distributed to target tissues. Semen is formed as luminal contents from the ducts (epididymis, ductus deferens, ampulla of the ductus deferens) and glands (prostate, seminal vesicles) are moved into the urethra at the base of the penis by the contraction of smooth muscle in the walls of the structures.


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Anatomy_Gray. Pulsatile emission of semen from the penis is generated by the reflex contraction of the bulbospongiosus muscle that forces semen from the base of the penis and out of the external urethral meatus. Bulbospongiosus muscle is innervated by somatic motor fibers carried in the pudendal nerve (S2–S4). Contraction of the internal urethral sphincter and periurethral smooth muscle, innervated by the sympathetic part of the visceral nervous system, prevents retrograde ejaculation into the bladder. In the clinic


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Anatomy_Gray. Erectile dysfunction (ED) is a complex condition in which men are unable to initiate or maintain penile erection. When this affects erections during sleep, and with self-stimulation as well as with a partner, vascular and/or nerve impairment is present. This generalized type of ED increases with age and is recognized as a risk factor for coronary artery disease. It is frequently associated with cardiovascular disease, diabetes, and neurological conditions including Parkinson’s disease, spinal cord injuries, multiple sclerosis, and as nerve damage from pelvic surgeries or radiation for pelvic malignancies. Low testosterone states can impair erections and consistently prevent sleep-induced erections. Medications including serotonin reuptake inhibitors (SSRIs), thiazides and anti-androgens can also underlie ED. When only partnered erections are problematic, psychological factors underlie the dysfunction—the normal erections from sleep confirming healthy vascular and neurological


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Anatomy_Gray. can also underlie ED. When only partnered erections are problematic, psychological factors underlie the dysfunction—the normal erections from sleep confirming healthy vascular and neurological function. Most cases of ED are multifactorial in etiology, and all markedly lessen quality of life and a person’s well-being and can lead to depression and low self-esteem as well as emotional and social isolation.


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Anatomy_Gray. Delayed (or absent) ejaculation can result from nerve damage in conditions such as diabetes, Parkinson’s disease, spinal cord injuries, multiple sclerosis, complications after major pelvic surgeries and pelvic irradiation. Ejaculation is absent after radical prostatectomy for prostate cancer (which also removes the seminal vesicles), but orgasm is still possible as the pudendal nerve is spared. SSRIs, neuroleptics, alcohol, and recreational drugs (marijuana, cocaine, and heroin) often delay orgasm and therefore ejaculation, as in health the two coincide (even though the nerves involved are different).


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Anatomy_Gray. Because erectile tissues in the clitoris have similar innervation and blood supply to the penis, vulvar swelling is likely compromised by the same conditions that cause ED in men. However, it appears that this is a rare cause of female sexual dysfunction. Reduced clitoral swelling is rarely symptomatic. Note that phosphodiesterase type 5 (PDE5) inhibitors (sildenafil) do not improve female sexual dysfunction even in conditions such as diabetes. Research confirms that otherwise healthy women with complaints of low sexual arousal have a physiologically normal increase in genital congestion in response to visual sexual stimuli, even though they do not find the stimuli mentally sexually arousing. Loss of genital sexual sensitivity from somatic nerve damage from multiple sclerosis or diabetes can be highly symptomatic and preclude orgasm. Medications preventing orgasm in men can also affect women. In the clinic Urethral rupture may occur at a series of well-defined anatomical points.


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Anatomy_Gray. In the clinic Urethral rupture may occur at a series of well-defined anatomical points. The commonest injury is a rupture of the proximal spongy urethra below the perineal membrane. The urethra is usually torn when structures of the perineum are caught between a hard object (e.g., a steel beam or crossbar of a bicycle) and the inferior pubic arch. Urine escapes through the rupture into the superficial perineal pouch and descends into the scrotum and up onto the anterior abdominal wall deep to the superficial fascia. In association with severe pelvic fractures, urethral rupture may occur at the prostatomembranous junction above the deep perineal pouch. The urine will extravasate into the true pelvis.


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Anatomy_Gray. In association with severe pelvic fractures, urethral rupture may occur at the prostatomembranous junction above the deep perineal pouch. The urine will extravasate into the true pelvis. The worst and most serious urethral rupture is related to serious pelvic injuries where there is complete disruption of the puboprostatic ligaments. The prostate is dislocated superiorly not only by the ligamentous disruption but also by the extensive hematoma formed within the true pelvis. The diagnosis can be made by palpating the elevated prostate during a digital rectal examination.


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Anatomy_Gray. A 25-year-old man visited his family physician because he had a “dragging feeling” in the left side of his scrotum. He was otherwise healthy and had no other symptoms. During examination, the physician palpated the left testis, which was normal, although he noted soft nodular swelling around the superior aspect of the testes and the epididymis. In his clinical notes, he described these findings as a “bag of worms” (Fig. 5.86). The bag of worms was a varicocele. The venous drainage of the testis is via the pampiniform plexus of veins that runs within the spermatic cord. A varicocele is a collection of dilated veins that arise from the pampiniform plexus. In many ways, they are similar to varicose veins that develop in the legs. Typically, the patient complains of a dragging feeling in the scrotum and around the testis, which is usually worse toward the end of the day. The family physician recommended surgical treatment, with a recommendation for surgery through an inguinal incision.


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Anatomy_Gray. The family physician recommended surgical treatment, with a recommendation for surgery through an inguinal incision. A simple surgical technique divides the skin around the inguinal ligament. The aponeurosis of the external oblique muscle is divided in the anterior abdominal wall to display the spermatic cord. Careful inspection of the spermatic cord reveals the veins, which are surgically ligated. Another option is to embolize the varicocele. In this technique, a small catheter is placed via the right femoral vein. The catheter is advanced along the external iliac vein and the common iliac vein and into the inferior vena cava. The catheter is then positioned in the left renal vein, and a venogram is performed to demonstrate the origin of the left testicular vein. The catheter is advanced down the left testicular vein into the veins of the inguinal canal and the pampiniform plexus. Metal coils to occlude the vessels are injected, and the catheter is withdrawn.


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Anatomy_Gray. The patient asked how blood would drain from the testis after the operation. Although the major veins of the testis had been occluded, small collateral veins running within the scrotum and around the outer aspect of the spermatic cord permitted drainage without recurrence of the varicocele. A young woman visited her family practitioner because she had mild upper abdominal pain. An ultrasound demonstrated gallstones within the gallbladder, which explained the patient’s pain. However, when the technician assessed the pelvis, she noted a mass behind the bladder, which had sonographic findings similar to a kidney (Fig. 5.87). What did the sonographer do next? Having demonstrated this pelvic mass behind the bladder, the sonographer assessed both kidneys. The patient had a normal right kidney. However, the left kidney could not be found in its usual place. The technician diagnosed a pelvic kidney.


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Anatomy_Gray. A pelvic kidney can be explained by the embryology. The kidneys develop from a complex series of structures that originate adjacent to the bladder within the fetal pelvis. As development proceeds and the functions of the various parts of the developing kidneys change, they attain a superior position in the upper abdomen adjacent to the abdominal aorta and inferior vena cava, on the posterior abdominal wall. A developmental arrest or complication may prevent the kidney from obtaining its usual position. Fortunately, it is unusual for patients to have any symptoms relating to a pelvic kidney. This patient had no symptoms attributable to the pelvic kidney and she was discharged.


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Anatomy_Gray. This patient had no symptoms attributable to the pelvic kidney and she was discharged. A 19-year-old woman presented to the emergency department with a 36-hour history of lower abdominal pain that was sharp and initially intermittent, later becoming constant and severe. The patient also reported feeling nauseated and vomited once in the ER. She did not have diarrhea and had opened her bowels normally 8 hours before admission. She had no symptoms of dysuria. She was afebrile, slightly tachycardic at 95/min, and had a normal blood pressure. Blood results showed mild leukocytosis of 11.6 x 109/L and normal renal and liver function tests. She reported being sexually active with a long-term partner. She was never pregnant, and the urine pregnancy test on admission was negative.


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Anatomy_Gray. On physical examination there was tenderness in the right iliac fossa with guarding. On vaginal examination a tender mass in the right adnexal region was felt. The patient subsequently underwent a transvaginal ultrasound examination for evaluation of adnexal pathology. The scan showed a markedly enlarged right ovary measuring up to 8 cm in long axis with echogenic stroma and peripherally distributed follicles. There was no internal vascularity when color Doppler was applied. A small amount of free fluid was seen in the pouch of Douglas. The diagnosis of ovarian torsion was made.


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Anatomy_Gray. Ovarian torsion is the twisting of an ovary on its suspensory ligament, which contains arterial, venous, and lymphatic vessels (forming so-called vascular pedicle), leading to a compromised blood supply. Initially, the venous and lymphatic circulation is compromised, resulting in ovarian edema and enlargement. The arterial flow is maintained longer due to thicker and less compressible arterial walls. Prolonged torsion leads to increased internal ovarian pressure that eventually results in arterial thrombosis, ischemia of the ovarian tissue, and necrosis. If the correct diagnosis and treatment are delayed, the patient may develop generalized sepsis. The symptoms are nonspecific, making the diagnosis of ovarian torsion challenging. There is often no significant past medical history.


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Anatomy_Gray. The symptoms are nonspecific, making the diagnosis of ovarian torsion challenging. There is often no significant past medical history. At surgery, the right ovary was hemorrhagic and necrotic with the pedicle twisted 360 degrees. The left ovary was normal in appearance. Right-sided salpingo-oophorectomy was performed, and histopathological examination confirmed completely necrotic ovary without any residual normal ovarian tissue. The patient made a quick recovery after surgical intervention. Ovarian torsion is encountered in women of all ages, but those of reproductive age have much higher prevalence. Torsion of a normal ovary is uncommon and is seen more frequently in adolescent population, with elongated pelvic ligaments, fallopian tube spasm, or more mobile fallopian tubes or mesosalpinx cited as contributing factors.


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Anatomy_Gray. A young man developed pain in his right gluteal region, in the posterior aspect of the thigh and around the posterior and lateral aspects of the leg. On further questioning, he reported that the pain also radiated over the lateral part of the foot, particularly around the lateral malleolus. The areas of pain correspond to dermatomes L4 to S3 nerves. Over the following weeks, the patient began to develop muscular weakness, predominantly footdrop. These findings are consistent with loss of the motor function and sensory change in the common fibular nerve, which is a branch of the sciatic nerve in the lower limb. A computed tomography (CT) scan of the abdomen and pelvis revealed a mass in the posterior aspect of the right side of the pelvis. The mass was anterior to the piriformis muscle and adjacent to the rectum.


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Anatomy_Gray. On the anterior belly of the piriformis muscle, the sciatic nerve is formed from the roots of L4 to S3 nerves. The mass in the patient’s pelvis compressed this nerve, producing his sensory and motor dysfunction. During surgery, the mass was found to be a benign nerve tumor and was excised. This patient had no long-standing neurological deficit. A 65-year-old man was examined by a surgical intern because he had a history of buttock pain and impotence. On examination he had a reduced peripheral pulse on the left foot compared to the right. On direct questioning, the patient revealed that he experienced severe left-sided buttock pain after walking 100 yards. After a short period of rest, he could walk another 100 yards before the same symptoms recurred. He also noticed that over the past year he was unable to obtain an erection. He smoked heavily and was on no other drugs or treatment.


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Anatomy_Gray. He smoked heavily and was on no other drugs or treatment. The pain in the left buttock is ischemic in nature. He gives a typical history relating to lack of blood flow to the muscles. A similar finding is present when muscular branches of the femoral artery are occluded or stenosed. Such patients develop similar (ischemic) pain in the calf muscles called intermittent claudication. How does the blood get to the gluteal muscles? Blood arrives at the aortic bifurcation and then passes into the common iliac arteries, which divide into the internal and external iliac vessels. The internal iliac artery then divides into anterior and posterior divisions, which in turn give rise to vessels that leave the pelvis by passing through the greater sciatic foramen and supply the gluteal muscles. The internal pudendal artery also arises from the anterior division of the internal iliac artery and supplies the penis.


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Anatomy_Gray. The patient’s symptoms occur on the left side, suggesting that an obstruction exists on that side only. Because the patient’s symptoms occur on the left side only, the lesion is likely in the left common iliac artery (eFig. 5.88) and is preventing blood flow into the external and internal iliac arteries on the left side. “How will I be treated?” asked the patient. The patient was asked to stop smoking and begin regular exercise. Other treatment options include unblocking the lesion by ballooning the blockage to reopen the vessels or by a surgical bypass graft. Stopping smoking and regular exercise improved the patient’s walking distance. The patient underwent the less invasive procedure of ballooning the vessel (angioplasty) and as a result he was able to walk unhindered and to have an erection.


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Anatomy_Gray. A 50-year-old woman was admitted to hospital for surgical resection of the uterus (hysterectomy) for cancer. The surgeon was also going to remove all the pelvic lymph nodes and carry out a bilateral salpingo-oophorectomy (removal of uterine tubes and ovaries). The patient was prepared for this procedure and underwent routine surgery. Twenty-five hours after surgery, it was noted that the patient had passed no urine and her abdomen was expanding. An ultrasound scan demonstrated a considerable amount of fluid within the abdomen. Fluid withdrawn from the abdomen was tested and found to be urine. It was postulated that this patient’s ureters had been damaged during the surgery.


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Anatomy_Gray. It was postulated that this patient’s ureters had been damaged during the surgery. The pelvic part of the ureter courses posteroinferiorly and external to the parietal peritoneum on the lateral wall of the pelvis anterior to the internal iliac artery. It continues in its course to a point approximately 2 cm superior to the ischial spine and then passes anteromedially and superior to the levator ani muscles. Importantly, the ureter closely adheres to the peritoneum. The only structure that passes between the ureter and the peritoneum in men is the ductus deferens. In women, however, as the ureter descends on the pelvic wall, it passes under the uterine artery. The ureter continues close to the lateral fornix of the vagina, especially on the left, and enters the posterosuperior angle of the bladder. It was at this point that the ureter was inadvertently damaged.


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Anatomy_Gray. It was at this point that the ureter was inadvertently damaged. Knowing the anatomy and recognizing the possibility of ureteric damage enabled the surgeons to reestablish continuity of the ureter surgically. The patient was hospitalized a few days longer than expected and made an uneventful recovery. A 25-year-old woman was admitted to the emergency department with a complaint of pain in her right iliac fossa. The pain had developed rapidly over approximately 40 minutes and was associated with cramps and vomiting. The surgical intern made an initial diagnosis of appendicitis.


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Anatomy_Gray. The typical history for appendicitis is a central abdominal, colicky (intermittent waxing and waning) pain, which over a period of hours localizes to become a constant pain in the right iliac fossa. The central colicky pain is typical for a poorly localized visceral type of pain. As the parietal peritoneum becomes inflamed, the pain becomes localized. Although this patient does have right iliac fossa pain, the history is not typical for appendicitis (although it must be remembered that patients may not always have a classical history for appendicitis). The surgical intern asked a more senior colleague for an opinion.


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Anatomy_Gray. The surgical intern asked a more senior colleague for an opinion. The senior colleague considered other anatomical structures that lie within the right iliac fossa as a potential cause of pain. These include the appendix, the cecum, and the small bowel. Musculoskeletal pain and referred pain could also be potential causes. In women, pain may also arise from the ovary, fallopian tube, and uterus. In a young patient, diseases of these organs are rare. Infection and pelvic inflammatory disease may occur in the younger patient and need to be considered. The patient gave no history of these disorders.


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Anatomy_Gray. The patient gave no history of these disorders. Upon further questioning, however, the patient revealed that her last menstrual period was 6 weeks before this examination. The senior physician realized that a potential cause of the abdominal pain was a pregnancy outside the uterus (ectopic pregnancy). The patient was rushed for an abdominal ultrasound, which revealed no fetus or sac in the uterus. She was also noted to have a positive pregnancy test. The patient underwent surgery and was found to have a ruptured fallopian tube caused by an ectopic pregnancy. Whenever a patient has apparent pelvic pain, it is important to consider the gender-related anatomical differences. Ectopic pregnancy should always be considered in women of childbearing age.


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Anatomy_Gray. Whenever a patient has apparent pelvic pain, it is important to consider the gender-related anatomical differences. Ectopic pregnancy should always be considered in women of childbearing age. A 35-year-old woman visited her family practitioner because she had a “bloating” feeling and an increase in abdominal girth. The family practitioner examined the lower abdomen, which revealed a mass that extended from the superior pubic rami to the level of the umbilicus. The superior margin of the mass was easily palpated, but the inferior margin appeared to be less well defined. This patient has a pelvic mass. When examining a patient in the supine position, the observer should uncover the whole of the abdomen.


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Anatomy_Gray. This patient has a pelvic mass. When examining a patient in the supine position, the observer should uncover the whole of the abdomen. Inspection revealed a bulge in the lower abdomen to the level of the umbilicus. Palpation revealed a hard and slightly irregular mass with well-defined superior and lateral borders and a less well-defined inferior border, giving the impression that the mass continued into the pelvis. The lesion was dull to percussion. Auscultation did not reveal any abnormal sounds. The doctor pondered which structures this mass may be arising from. When examining the pelvis, it is important to remember the sex differences. Common to both men and women are the rectum, bowel, bladder, and musculature. Certain pathological states are also common to both sexes, including the development of pelvic abscesses and fluid collections.


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Anatomy_Gray. In men, the prostate cannot be palpated transabdominally, and it is extremely rare for it to enlarge to such an extent in benign diseases. Aggressive prostate cancer can spread throughout the whole of the pelvis, although this is often associated with bowel obstruction and severe bladder symptoms. In women, a number of organs can develop large masses, including the ovaries (solid and cystic tumors), the embryological remnants within the broad ligaments, and the uterus (pregnancy and fibroids). The physician asked further questions. It is always important to establish whether the patient is pregnant (occasionally, pregnancy may come as a surprise to the patient).


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Anatomy_Gray. The physician asked further questions. It is always important to establish whether the patient is pregnant (occasionally, pregnancy may come as a surprise to the patient). This patient’s pregnancy test was negative. After the patient emptied her bladder, there was no change in the mass. The physician thought the mass might be a common benign tumor of the uterus (fibroid). To establish the diagnosis, he obtained an ultrasound scan of the pelvis, which confirmed that the mass stemmed from the uterus. The patient was referred to a gynecologist, and after a long discussion regarding her symptomatology, fertility, and risks, the surgeon and the patient agreed that a hysterectomy (surgical removal of the uterus) would be an appropriate course of therapy. The patient sought a series of opinions from other gynecologists, all of whom agreed that surgery was the appropriate option. The fibroid was removed with no complications.


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Anatomy_Gray. The patient sought a series of opinions from other gynecologists, all of whom agreed that surgery was the appropriate option. The fibroid was removed with no complications. A 52-year-old woman was referred to a gynecologist. Magnetic resonance imaging (MRI) indicated the presence of uterine fibroids. After a long discussion regarding her symptomatology, fertility, and risks, she was offered the choice between a hysterectomy (surgical removal of the uterus) or uterine artery embolization. A uterine artery embolization is a procedure where an interventional radiologist uses a catheter to inject small particles into the uterine arteries. This reduces the blood supply to the fibroids and causes them to shrink. The patient opted for the uterine artery embolization. An MRI performed 6 months after the embolization procedure showed a favorable reduction in the size of the uterine fibroids (eFig. 5.89). 524.e2 524.e1 Conceptual Overview • Relationship to Other Regions


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Anatomy_Gray. 524.e2 524.e1 Conceptual Overview • Relationship to Other Regions Fig. 5.10, cont’d Fig. 5.36, cont’d Fig. 5.45, cont’d Fig. 5.47, cont’d Fig. 5.59, cont’d Table 5.4 Branches of the sacral and coccygeal plexuses (spinal segments in parentheses do not consistently participate)—cont’d Fig. 5.63, cont’d Fig. 5.65, cont’d Fig. 5.76, cont’d Surface Anatomy • How to Define the Margins of the Perineum Surface Anatomy • Identification of Structures in the Anal Triangle Surface Anatomy • Identification of Structures in the Urogenital Triangle of Men Fig. 5.84, cont’d Surface Anatomy • Identification of Structures in the Urogenital Triangle of Men Fig. 5.85, cont’d Posterior compartment of leg 615 Lateral compartment of leg 622 Anterior compartment of leg 624 Tarsal tunnel, retinacula, and arrangement of major structures at the ankle 642 Arches of the foot 644 Fibrous sheaths of toes 645 Avoiding the sciatic nerve 659 Finding the femoral artery in the femoral


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Anatomy_Gray. Arches of the foot 644 Fibrous sheaths of toes 645 Avoiding the sciatic nerve 659 Finding the femoral artery in the femoral Identifying structures around the knee 660 Visualizing the contents of the popliteal fossa 662 Finding the tarsal tunnel—the gateway to the foot 663 Identifying tendons around the ankle and in the foot 664 Finding the dorsalis pedis artery 665 Approximating the position of the plantar arterial arch 665


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Anatomy_Gray. Finding the dorsalis pedis artery 665 Approximating the position of the plantar arterial arch 665 The lower limb is directly anchored to the axial skeleton by a sacroiliac joint and by strong ligaments, which link the pelvic bone to the sacrum. It is separated from the abdomen, back, and perineum by a continuous line (Fig. 6.1), which: joins the pubic tubercle with the anterior superior iliac spine (position of the inguinal ligament) and then continues along the iliac crest to the posterior superior iliac spine to separate the lower limb from the anterior and lateral abdominal walls; passes between the posterior superior iliac spine and along the dorsolateral surface of the sacrum to the coccyx to separate the lower limb from the muscles of the back; and joins the medial margin of the sacrotuberous ligament, the ischial tuberosity, the ischiopubic ramus, and the pubic symphysis to separate the lower limb from the perineum.


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Anatomy_Gray. The lower limb is divided into the gluteal region, thigh, leg, and foot on the basis of major joints, component bones, and superficial landmarks (Fig. 6.2): The gluteal region is posterolateral and between the iliac crest and the fold of skin (gluteal fold) that defines the lower limit of the buttocks. Anteriorly, the thigh is between the inguinal ligament and the knee joint—the hip joint is just inferior to the middle third of the inguinal ligament, and the posterior thigh is between the gluteal fold and the knee. The leg is between the knee and ankle joint. The foot is distal to the ankle joint. The femoral triangle and popliteal fossa, as well as the posteromedial side of the ankle, are important areas of transition through which structures pass between regions (Fig. 6.3).


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Anatomy_Gray. The femoral triangle and popliteal fossa, as well as the posteromedial side of the ankle, are important areas of transition through which structures pass between regions (Fig. 6.3). The femoral triangle is a pyramid-shaped depression formed by muscles in the proximal regions of the thigh and by the inguinal ligament, which forms the base of the triangle. The major blood supply and one of the nerves of the limb (femoral nerve) enter into the thigh from the abdomen by passing under the inguinal ligament and into the femoral triangle. The popliteal fossa is posterior to the knee joint and is a diamond-shaped region formed by muscles of the thigh and leg. Major vessels and nerves pass between the thigh and leg through the popliteal fossa.


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Anatomy_Gray. Most nerves, vessels, and flexor tendons that pass between the leg and foot pass through a series of canals (collectively termed the tarsal tunnel) on the posteromedial side of the ankle. The canals are formed by adjacent bones and a flexor retinaculum, which holds the tendons in position. Support the body weight A major function of the lower limb is to support the weight of the body with minimal expenditure of energy. When standing erect, the center of gravity is anterior to the edge of the SII vertebra in the pelvis (Fig. 6.4). The vertical line through the center of gravity is slightly posterior to the hip joints, anterior to the knee and ankle joints, and directly over the almost circular support base formed by the feet on the ground and holds the knee and hip joints in extension.


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Anatomy_Gray. The organization of ligaments at the hip and knee joints, together with the shape of the articular surfaces, particularly at the knee, facilitates “locking” of these joints into position when standing, thereby reducing the muscular energy required to maintain a standing position. A second major function of the lower limbs is to move the body through space. This involves the integration of movements at all joints in the lower limb to position the foot on the ground and to move the body over the foot. Movements at the hip joint are flexion, extension, abduction, adduction, medial and lateral rotation, and circumduction (Fig. 6.5). The knee and ankle joints are primarily hinge joints. Movements at the knee are mainly flexion and extension (Fig. 6.6A). Movements at the ankle are dorsiflexion (movement of the dorsal side of the foot toward the leg) and plantarflexion (Fig. 6.6B).


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Anatomy_Gray. During walking, many anatomical features of the lower limbs contribute to minimizing fluctuations in the body’s center of gravity and thereby reduce the amount of energy needed to maintain locomotion and produce a smooth, efficient gait (Fig. 6.7). They include pelvic tilt in the coronal plane, pelvic rotation in the transverse plane, movement of the knees toward the midline, flexion of the knees, and complex interactions between the hip, knee, and ankle. As a result, during walking, the body’s center of gravity normally fluctuates only 5 cm in both vertical and lateral directions. The bones of the gluteal region and the thigh are the pelvic bone and the femur (Fig. 6.8). The large ball and socket joint between these two bones is the hip joint.


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Anatomy_Gray. The bones of the gluteal region and the thigh are the pelvic bone and the femur (Fig. 6.8). The large ball and socket joint between these two bones is the hip joint. The femur is the bone of the thigh. At its distal end, its major weight-bearing articulation is with the tibia, but it also articulates anteriorly with the patella (knee cap). The patella is the largest sesamoid bone in the body and is embedded in the quadriceps femoris tendon. The joint between the femur and tibia is the principal articulation of the knee joint, but the joint between the patella and femur shares the same articular cavity. Although the main movements at the knee are flexion and extension, the knee joint also allows the femur to rotate on the tibia. This rotation contributes to “locking” of the knee when fully extended, particularly when standing. The leg contains two bones: The tibia is medial in position, is larger than the laterally positioned fibula, and is the weight-bearing bone.


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Anatomy_Gray. The leg contains two bones: The tibia is medial in position, is larger than the laterally positioned fibula, and is the weight-bearing bone. The fibula does not take part in the knee joint and forms only the most lateral part of the ankle joint—proximally, it forms a small synovial joint (superior tibiofibular joint) with the inferolateral surface of the head of the tibia. The tibia and fibula are linked along their lengths by an interosseous membrane, and at their distal ends by a fibrous inferior tibiofibular joint, and little movement occurs between them. The distal surfaces of the tibia and fibula together form a deep recess. The ankle joint is formed by this recess and part of one of the tarsal bones of the foot (talus), which projects into the recess. The ankle is most stable when dorsiflexed.


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Anatomy_Gray. The bones of the foot consist of the tarsal bones, the metatarsals, and the phalanges (Fig. 6.9). There are seven tarsal bones, which are organized in two rows with an intermediate bone between the two rows on the medial side. Inversion and eversion of the foot, or turning the sole of the foot inward and outward, respectively, occur at joints between the tarsal bones. The tarsal bones articulate with the metatarsals at tarsometatarsal joints, which allow only limited sliding movements. Independent movements of the metatarsals are restricted by deep transverse metatarsal ligaments, which effectively link together the distal heads of the bones at the metatarsophalangeal joints. There is a metatarsal for each of the five digits, and each digit has three phalanges except for the great toe (digit I), which has only two. The metatarsophalangeal joints allow flexion, extension, abduction, and adduction of the digits, but the range of movement is more restricted than in the hand.


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Anatomy_Gray. The metatarsophalangeal joints allow flexion, extension, abduction, and adduction of the digits, but the range of movement is more restricted than in the hand. The interphalangeal joints are hinge joints and allow flexion and extension. The bones of the foot are not organized in a single plane so that they lie flat on the ground. Rather, the metatarsals and tarsals form longitudinal and transverse arches (Fig. 6.10). The longitudinal arch is highest on the medial side of the foot. The arches are flexible in nature and are supported by muscles and ligaments. They absorb and transmit forces during walking and standing. Muscles of the gluteal region consist predominantly of extensors, rotators, and abductors of the hip joint (Fig. 6.11). In addition to moving the thigh on a fixed pelvis, these muscles also control the movement of the pelvis relative to the limb bearing the body’s weight (weight-bearing or stance limb) while the other limb swings forward (swing limb) during walking.


Anatomy_Gray

Anatomy_Gray. Major flexor muscles of the hip (iliopsoas—psoas major and iliacus) do not originate in the gluteal region or the thigh. Instead, they are attached to the posterior abdominal wall and descend through the gap between the inguinal ligament and pelvic bone to attach to the proximal end of the femur (Fig. 6.12). Muscles in the thigh and leg are separated into three compartments by layers of fascia, bones, and ligaments (Fig. 6.13). In the thigh, there are medial (adductor), anterior (extensor), and posterior (flexor) compartments: Most muscles in the medial compartment act mainly on the hip joint. The large muscles (hamstrings) in the posterior compartment act on the hip (extension) and knee (flexion) because they attach to both the pelvis and bones of the leg. Muscles in the anterior compartment (quadriceps femoris) predominantly extend the knee. Muscles in the leg are divided into lateral (fibular), anterior, and posterior compartments:


Anatomy_Gray

Anatomy_Gray. Muscles in the anterior compartment (quadriceps femoris) predominantly extend the knee. Muscles in the leg are divided into lateral (fibular), anterior, and posterior compartments: Muscles in the lateral compartment predominantly evert the foot. Muscles in the anterior compartment dorsiflex the foot and extend the digits. Muscles in the posterior compartment plantarflex the foot and flex the digits; one of the muscles can also flex the knee because it attaches superiorly to the femur. Specific muscles in each of the three compartments in the leg also provide dynamic support for the arches of the foot. Muscles found entirely in the foot (intrinsic muscles) modify the forces produced by tendons entering the toes from the leg and provide dynamic support for the longitudinal arches of the foot when walking, particularly when levering the body forward on the stance limb just before toe-off.


Anatomy_Gray

Anatomy_Gray. Unlike in the upper limb where most structures pass between the neck and limb through a single axillary inlet, in the lower limb, there are four major entry and exit points between the lower limb and the abdomen, pelvis, and perineum (Fig. 6.14). These are: the gap between the inguinal ligament and pelvic bone, the greater sciatic foramen, the obturator canal (at the top of the obturator foramen), and the lesser sciatic foramen. The lower limb communicates directly with the abdomen through a gap between the pelvic bone and the inguinal ligament (Fig. 6.14). Structures passing though this gap include: muscles—psoas major, iliacus, and pectineus; nerves—femoral and femoral branch of the genitofemoral nerves, and the lateral cutaneous nerve of the thigh; vessels—femoral artery and vein; and lymphatics.


Anatomy_Gray

Anatomy_Gray. This gap between the pelvic bone and the inguinal ligament is a weak area in the abdominal wall and often associated with abnormal protrusion of the abdominal cavity and contents into the thigh (femoral hernia). This type of hernia usually occurs where the lymphatic vessels pass through the gap (the femoral canal). Structures within the pelvis communicate with the lower limb through two major apertures (Fig. 6.14). Posteriorly, structures communicate with the gluteal region through the greater sciatic foramen and include: a muscle—piriformis; nerves—sciatic, superior and inferior gluteal, and pudendal nerves; and vessels—superior and inferior gluteal arteries and veins, and the internal pudendal artery. The sciatic nerve is the largest peripheral nerve of the body and is the major nerve of the lower limb.


Anatomy_Gray

Anatomy_Gray. The sciatic nerve is the largest peripheral nerve of the body and is the major nerve of the lower limb. Anteriorly, the obturator nerve and vessels pass between the pelvis and thigh through the obturator canal. This canal is formed between bone at the top of the obturator foramen and the obturator membrane, which closes most of the foramen during life. Structures pass between the perineum and gluteal region through the lesser sciatic foramen (Fig. 6.14). The most important with respect to the lower limb is the tendon of the obturator internus muscle. The nerve and artery of the perineum (the internal pudendal artery and pudendal nerve) pass out of the pelvis through the greater sciatic foramen into the gluteal region and then immediately pass around the ischial spine and sacrospinous ligament and through the lesser sciatic foramen to enter the perineum. Innervation is by lumbar and sacral


Anatomy_Gray

Anatomy_Gray. Innervation is by lumbar and sacral Somatic motor and general sensory innervation of the lower limb is by peripheral nerves emanating from the lumbar and sacral plexuses on the posterior abdominal and pelvic walls. These plexuses are formed by the anterior rami of L1 to L3 and most of L4 (lumbar plexus) and L4 to S5 (sacral plexus).


Anatomy_Gray

Anatomy_Gray. Nerves originating from the lumbar and sacral plexuses and entering the lower limb carry fibers from spinal cord levels L1 to S3 (Fig. 6.15). Nerves from lower sacral segments innervate the perineum. Terminal nerves exit the abdomen and pelvis through a number of apertures and foramina and enter the limb. As a consequence of this innervation, lumbar and upper sacral nerves are tested clinically by examining the lower limb. In addition, clinical signs (such as pain, pins-and-needles sensations, paresthesia, and fascicular muscle twitching) resulting from any disorder affecting these spinal nerves (e.g., herniated intervertebral disc in the lumbar region) appear in the lower limb.


Anatomy_Gray

Anatomy_Gray. Dermatomes in the lower limb are shown in Fig. 6.16. Regions that can be tested for sensation and are reasonably autonomous (have minimal overlap) are: over the inguinal ligament—L1, lateral side of the thigh—L2, lower medial side of the thigh—L3, medial side of the great toe (digit I)—L4, medial side of digit II—L5, little toe (digit V)—S1, back of the thigh—S2, and skin over the gluteal fold—S3. The dermatomes of S4 and S5 are tested in the perineum. Selected joint movements are used to test myotomes (Fig. 6.17). For example: Flexion of the hip is controlled primarily by L1 and L2. Extension of the knee is controlled mainly by L3 and L4. Knee flexion is controlled mainly by L5 to S2. Plantarflexion of the foot is controlled predominantly by S1 and S2. Adduction of the digits is controlled by S2 and S3. In an unconscious patient, both somatic sensory and somatic motor functions of spinal cord levels can be tested using tendon reflexes:


Anatomy_Gray

Anatomy_Gray. Adduction of the digits is controlled by S2 and S3. In an unconscious patient, both somatic sensory and somatic motor functions of spinal cord levels can be tested using tendon reflexes: A tap on the patellar ligament at the knee tests predominantly L3 and L4. A tendon tap on the calcaneal tendon posterior to the ankle (tendon of gastrocnemius and soleus) tests S1 and S2. Each of the major muscle groups or compartments in the lower limb is innervated primarily by one or more of the major nerves that originate from the lumbar and sacral plexuses (Fig. 6.18): Large muscles in the gluteal region are innervated by the superior and inferior gluteal nerves. Most muscles in the anterior compartment of the thigh are innervated by the femoral nerve (except the tensor fasciae latae, which are innervated by the superior gluteal nerve).


Anatomy_Gray

Anatomy_Gray. Most muscles in the anterior compartment of the thigh are innervated by the femoral nerve (except the tensor fasciae latae, which are innervated by the superior gluteal nerve). Most muscles in the medial compartment are innervated mainly by the obturator nerve (except the pectineus, which is innervated by the femoral nerve, and part of the adductor magnus, which is innervated by the tibial division of the sciatic nerve). Most muscles in the posterior compartment of the thigh and the leg and in the sole of the foot are innervated by the tibial part of the sciatic nerve (except the short head of the biceps femoris in the posterior thigh, which is innervated by the common fibular division of the sciatic nerve). The anterior and lateral compartments of the leg and muscles associated with the dorsal surface of the foot are innervated by the common fibular part of the sciatic nerve.


Anatomy_Gray

Anatomy_Gray. The anterior and lateral compartments of the leg and muscles associated with the dorsal surface of the foot are innervated by the common fibular part of the sciatic nerve. In addition to innervating major muscle groups, each of the major peripheral nerves originating from the lumbar and sacral plexuses carries general sensory information from patches of skin (Fig. 6.19). Sensation from these areas can be used to test for peripheral nerve lesions: The femoral nerve innervates skin on the anterior thigh, medial side of the leg, and medial side of the ankle. The obturator nerve innervates the medial side of the thigh. The tibial part of the sciatic nerve innervates the lateral side of the ankle and foot. The common fibular nerve innervates the lateral side of the leg and the dorsum of the foot. Nerves related to bone


Anatomy_Gray

Anatomy_Gray. The common fibular nerve innervates the lateral side of the leg and the dorsum of the foot. Nerves related to bone The common fibular branch of the sciatic nerve curves laterally around the neck of the fibula when passing from the popliteal fossa into the leg (Fig. 6.20). The nerve can be rolled against bone just distal to the attachment of biceps femoris to the head of the fibula. In this location, the nerve can be damaged by impact injuries, fractures to the bone, or leg casts that are placed too high. Large veins embedded in the subcutaneous (superficial) fascia of the lower limb (Fig. 6.21) often become distended (varicose). These vessels can also be used for vascular transplantation. The most important superficial veins are the great and small saphenous veins, which originate from the medial and lateral sides, respectively, of a dorsal venous arch in the foot.


Anatomy_Gray

Anatomy_Gray. The most important superficial veins are the great and small saphenous veins, which originate from the medial and lateral sides, respectively, of a dorsal venous arch in the foot. The great saphenous vein passes up the medial side of the leg, knee, and thigh to pass through an opening in deep fascia covering the femoral triangle and join with the femoral vein. The small saphenous vein passes behind the distal end of the fibula (lateral malleolus) and up the back of the leg to penetrate deep fascia and join the popliteal vein posterior to the knee. The external surfaces of the pelvic bones, sacrum, and coccyx are predominantly the regions of the pelvis associated with the lower limb, although some muscles do originate from the deep or internal surfaces of these bones and from the deep surfaces of the lumbar vertebrae, above (Fig. 6.22).


Anatomy_Gray

Anatomy_Gray. Each pelvic bone is formed by three bones (ilium, ischium, and pubis), which fuse during childhood. The ilium is superior and the pubis and ischium are anteroinferior and posteroinferior, respectively. The ilium articulates with the sacrum. The pelvic bone is further anchored to the end of the vertebral column (sacrum and coccyx) by the sacrotuberous and sacrospinous ligaments, which attach to a tuberosity and spine on the ischium. The outer surface of the ilium, and the adjacent surfaces of the sacrum, coccyx, and sacrotuberous ligament are associated with the gluteal region of the lower limb and provide extensive muscle attachment. The ischial tuberosity provides attachment for many of the muscles in the posterior compartment of the thigh, and the ischiopubic ramus and body of the pubis are associated mainly with muscles in the medial compartment of the thigh. The head of the femur articulates with the acetabulum on the lateral surface of the pelvic bone.


Anatomy_Gray

Anatomy_Gray. The upper fan-shaped part of the ilium is associated on its inner side with the abdomen and on its outer side with the lower limb. The top of this region is the iliac crest, which ends anteriorly as the anterior superior iliac spine and posteriorly as the posterior superior iliac spine. A prominent lateral expansion of the crest just posterior to the anterior superior iliac spine is the tuberculum of the iliac crest. The anterior inferior iliac spine is on the anterior margin of the ilium, and below this, where the ilium fuses with the pubis, is a raised area of bone (the iliopubic eminence). The gluteal surface of the ilium faces posterolaterally and lies below the iliac crest. It is marked by three curved lines (inferior, anterior, and posterior gluteal lines), which divide the surface into four regions:


Anatomy_Gray

Anatomy_Gray. The inferior gluteal line originates just superior to the anterior inferior iliac spine and curves inferiorly across the bone to end near the posterior margin of the acetabulum—the rectus femoris muscle attaches to the anterior inferior iliac spine and to a roughened patch of bone between the superior margin of the acetabulum and the inferior gluteal line. The anterior gluteal line originates from the lateral margin of the iliac crest between the anterior superior iliac spine and the tuberculum of the iliac crest, and arches inferiorly across the ilium to disappear just superior to the upper margin of the greater sciatic foramen—the gluteus minimus muscle originates from between the inferior and anterior gluteal lines.


Anatomy_Gray

Anatomy_Gray. The posterior gluteal line descends almost vertically from the iliac crest to a position near the posterior inferior iliac spine—the gluteus medius muscle attaches to bone between the anterior and posterior gluteal lines, and the gluteus maximus muscle attaches posterior to the posterior gluteal line. The ischial tuberosity is posteroinferior to the acetabulum and is associated mainly with the hamstring muscles of the posterior thigh (Fig. 6.23). It is divided into upper and lower areas by a transverse line. The upper area of the ischial tuberosity is oriented vertically and is further subdivided into two parts by an oblique line, which descends, from medial to lateral, across the surface: The more medial part of the upper area is for the attachment of the combined origin of the semitendinosus muscle and the long head of the biceps femoris muscle. The lateral part is for the attachment of the semimembranosus muscle.


Anatomy_Gray

Anatomy_Gray. The lateral part is for the attachment of the semimembranosus muscle. The lower area of the ischial tuberosity is oriented horizontally and is divided into medial and lateral regions by a ridge of bone: The lateral region provides attachment for part of the adductor magnus muscle. The medial part faces inferiorly and is covered by connective tissue and by a bursa. When sitting, this medial part supports the body weight. The sacrotuberous ligament is attached to a sharp ridge on the medial margin of the ischial tuberosity. The external surfaces of the ischiopubic ramus anterior to the ischial tuberosity and the body of the pubis provide attachment for muscles of the medial compartment of the thigh (Fig. 6.23). These muscles include the adductor longus, adductor brevis, adductor magnus, pectineus, and gracilis.


Anatomy_Gray

Anatomy_Gray. The large cup-shaped acetabulum for articulation with the head of the femur is on the lateral surface of the pelvic bone in the region where the ilium, pubis, and ischium fuse (Fig. 6.24). The margin of the acetabulum is marked inferiorly by a prominent notch (acetabular notch). The wall of the acetabulum consists of nonarticular and articular parts: The nonarticular part is rough and forms a shallow circular depression (the acetabular fossa) in central and inferior parts of the acetabular floor—the acetabular notch is continuous with the acetabular fossa. The articular surface is broad and surrounds the anterior, superior, and posterior margins of the acetabular fossa. The smooth crescent-shaped articular surface (the lunate surface) is broadest superiorly where most of the body’s weight is transmitted through the pelvis to the femur. The lunate surface is deficient inferiorly at the acetabular notch.


Anatomy_Gray

Anatomy_Gray. The acetabular fossa provides attachment for the ligament of the head of the femur, whereas blood vessels and nerves pass through the acetabular notch. The femur is the bone of the thigh and the longest bone in the body. Its proximal end is characterized by a head and neck, and two large projections (the greater and lesser trochanters) on the upper part of the shaft (Fig. 6.26). The head of the femur is spherical and articulates with the acetabulum of the pelvic bone. It is characterized by a nonarticular pit (fovea) on its medial surface for the attachment of the ligament of the head. The neck of the femur is a cylindrical strut of bone that connects the head to the shaft of the femur. It projects superomedially from the shaft at an angle of approximately 125°, and projects slightly forward. The orientation of the neck relative to the shaft increases the range of movement of the hip joint.


Anatomy_Gray

Anatomy_Gray. The upper part of the shaft of the femur bears a greater and lesser trochanter, which are attachment sites for muscles that move the hip joint. The greater trochanter extends superiorly from the shaft of the femur just lateral to the region where the shaft joins the neck of the femur (Fig. 6.26). It continues posteriorly where its medial surface is deeply grooved to form the trochanteric fossa. The lateral wall of this fossa bears a distinct oval depression for attachment of the obturator externus muscle. The greater trochanter has an elongate ridge on its anterolateral surface for attachment of the gluteus minimus and a similar ridge more posteriorly on its lateral surface for attachment of the gluteus medius. Between these two points, the greater trochanter is palpable.


Anatomy_Gray

Anatomy_Gray. On the medial side of the superior aspect of the greater trochanter and just above the trochanteric fossa is a small impression for attachment of the obturator internus and its associated gemelli muscles, and immediately above and behind this feature is an impression on the margin of the trochanter for attachment of the piriformis muscle. The lesser trochanter is smaller than the greater trochanter and has a blunt conical shape. It projects posteromedially from the shaft of the femur just inferior to the junction with the neck (Fig. 6.26). It is the attachment site for the combined tendons of psoas major and iliacus muscles. Extending between the two trochanters and separating the shaft from the neck of the femur are the intertrochanteric line and intertrochanteric crest.


Anatomy_Gray

Anatomy_Gray. Extending between the two trochanters and separating the shaft from the neck of the femur are the intertrochanteric line and intertrochanteric crest. The intertrochanteric line is a ridge of bone on the anterior surface of the upper margin of the shaft that descends medially from a tubercle on the anterior surface of the base of the greater trochanter to a position just anterior to the base of the lesser trochanter (Fig. 6.26). It is continuous with the pectineal line (spiral line), which curves medially under the lesser trochanter and around the shaft of the femur to merge with the medial margin of the linea aspera on the posterior aspect of the femur.


Anatomy_Gray

Anatomy_Gray. The intertrochanteric crest is on the posterior surface of the femur and descends medially across the bone from the posterior margin of the greater trochanter to the base of the lesser trochanter (Fig. 6.26). It is a broad smooth ridge of bone with a prominent tubercle (the quadrate tubercle) on its upper half, which provides attachment for the quadratus femoris muscle. Shaft of the femur The shaft of the femur descends from lateral to medial in the coronal plane at an angle of 7° from the vertical axis (Fig. 6.27). The distal end of the femur is therefore closer to the midline than the upper end of the shaft. The middle third of the shaft of the femur is triangular in shape with smooth lateral and medial margins between anterior, lateral (posterolateral), and medial (posteromedial) surfaces. The posterior margin is broad and forms a prominent raised crest (the linea aspera).


Anatomy_Gray

Anatomy_Gray. The linea aspera is a major site of muscle attachment in the thigh. In the proximal third of the femur, the medial and lateral margins of the linea aspera diverge and continue superiorly as the pectineal line and gluteal tuberosity, respectively (Fig. 6.27): The pectineal line curves anteriorly under the lesser trochanter and joins the intertrochanteric line. The gluteal tuberosity is a broad linear roughening that curves laterally to the base of the greater trochanter. The gluteus maximus muscle is attached to the gluteal tuberosity. The triangular area enclosed by the pectineal line, the gluteal tuberosity, and the intertrochanteric crest is the posterior surface of the proximal end of the femur.


Anatomy_Gray

Anatomy_Gray. The triangular area enclosed by the pectineal line, the gluteal tuberosity, and the intertrochanteric crest is the posterior surface of the proximal end of the femur. The hip joint is a synovial articulation between the head of the femur and the acetabulum of the pelvic bone (Fig. 6.30A). The joint is a multiaxial ball and socket joint designed for stability and weight-bearing at the expense of mobility. Movements at the joint include flexion, extension, abduction, adduction, medial and lateral rotation, and circumduction. When considering the effects of muscle action on the hip joint, the long neck of the femur and the angulation of the neck on the shaft of the femur must be borne in mind. For example, medial and lateral rotation of the femur involves muscles that move the greater trochanter forward and backward, respectively, relative to the acetabulum (Fig. 6.30B).


Anatomy_Gray

Anatomy_Gray. The articular surfaces of the hip joint are: the spherical head of the femur, and the lunate surface of the acetabulum of the pelvic bone. The acetabulum almost entirely encompasses the hemispherical head of the femur and contributes substantially to joint stability. The nonarticular acetabular fossa contains loose connective tissue. The lunate surface is covered by hyaline cartilage and is broadest superiorly. Except for the fovea, the head of the femur is also covered by hyaline cartilage. The rim of the acetabulum is raised slightly by a fibrocartilaginous collar (the acetabular labrum). Inferiorly, the labrum bridges across the acetabular notch as the transverse acetabular ligament and converts the notch into a foramen (Fig. 6.31A).


Anatomy_Gray

Anatomy_Gray. The ligament of the head of the femur is a flat band of delicate connective tissue that attaches at one end to the fovea on the head of the femur and at the other end to the acetabular fossa, transverse acetabular ligament, and margins of the acetabular notch (Fig. 6.31B). It carries a small branch of the obturator artery, which contributes to the blood supply of the head of the femur. The synovial membrane attaches to the margins of the articular surfaces of the femur and acetabulum, forms a tubular covering around the ligament of the head of the femur, and lines the fibrous membrane of the joint (Figs. 6.31B and 6.32). From its attachment to the margin of the head of the femur, the synovial membrane covers the neck of the femur before reflecting onto the fibrous membrane (Fig. 6.32).


Anatomy_Gray

Anatomy_Gray. The fibrous membrane that encloses the hip joint is strong and generally thick. Medially, it is attached to the margin of the acetabulum, the transverse acetabular ligament, and the adjacent margin of the obturator foramen (Fig. 6.33A). Laterally, it is attached to the intertrochanteric line on the anterior aspect of the femur and to the neck of the femur just proximal to the intertrochanteric crest on the posterior surface. Three ligaments reinforce the external surface of the fibrous membrane and stabilize the joint: the iliofemoral, pubofemoral, and ischiofemoral ligaments.


Anatomy_Gray

Anatomy_Gray. Three ligaments reinforce the external surface of the fibrous membrane and stabilize the joint: the iliofemoral, pubofemoral, and ischiofemoral ligaments. The iliofemoral ligament is anterior to the hip joint and is triangular shaped (Fig. 6.33B). Its apex is attached to the ilium between the anterior inferior iliac spine and the margin of the acetabulum and its base is attached along the intertrochanteric line of the femur. Parts of the ligament attached above and below the intertrochanteric line are thicker than the part attached to the central part of the line. This results in the ligament having a Y appearance. The pubofemoral ligament is anteroinferior to the hip joint (Fig. 6.33B). It is also triangular in shape, with its base attached medially to the iliopubic eminence, adjacent bone, and obturator membrane. Laterally, it blends with the fibrous membrane and with the deep surface of the iliofemoral ligament.