Anatomical Position

When an organism is in its typical anatomical position, positional descriptive state are offered to show regions and features.

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Key Takeaways

Key PointsIn traditional anatomical position, the limbs space placed similarly to the supine position imposed on cadavers during autopsy.The anatomical place of the skull is the Frankfurt plane. In this position, the lower margins the the orbitals (eye sockets), the lower margin that the orbits, and also the top margins that the ear canals (poria) lie in the same horizontal plane.Because pets can readjust orientation v respect to your environments and appendages can readjust position with respect come the body, positional descriptive terms refer to the organism just in its standard anatomical place to stop confusion.Key Termsappendage: A limb of the body.supine: lying on the back, reclined.anatomical position: The standard place in i beg your pardon the human body is standing through feet together, arms to the side, and also head, eyes, and also palms encountering forward.

The need for Standardization

Standard anatomical position is the body orientation provided when explicate an organism’s anatomy. Standardization is important to stop confusion since most organisms deserve to take on plenty of different positions the may adjust the family member placement that organs. Every descriptions describe the biology in its conventional anatomical position, even when the organism’s appendages room in one more position. Thus, the conventional anatomical position gives a “gold standard” when comparing the anatomy of different members the the exact same species.


Relative location in the anatomical position: many terms are offered to explain relative location on the body. Cranial refers to functions closer come the head, while caudal advert to attributes closer to the feet. The former of the body is described as anterior or ventral, while the earlier is referred to as posterior or dorsal. Proximal and also distal explain relative position on the limbs. Proximal describes a function that is closer to the torso, when distal describes a feature that is closer come the fingers/toes. Medial and lateral refer to position relative come the midline, i beg your pardon is a vertical line attracted through the facility of the forehead, down v the belly button to the floor. Medial suggests a function is closer come this line, when lateral indicates attributes further native this line.

Standard Anatomical place in Humans

The traditional anatomical place is agreed top top by the international medical community. In this position, a human being is standing upright v the lower limbs with each other or contempt apart, feet flat on the floor and facing forward, top limbs in ~ the sides with the palms facing forward and also thumbs pointing far from the body, and head and also eyes directed right ahead. In addition, the arms space usually put slightly apart from the human body so that the hands perform not touch the sides. The positions of the limbs, specifically the arms, have important implications because that directional state in those appendages.

The basis because that the traditional anatomical position in humans comes from the supine position offered for analyzing human cadavers throughout autopsies. Dissection that cadavers was one of the major ways humans learned around anatomy transparent history, which has exponentially influenced the ways whereby anatomical expertise has developed into the scientific ar of today.


Standard anatomical position: The areas of the human body in standard anatomical position, in i m sorry the body is erect.

In humans, the typical anatomical position of the skull is referred to as the Frankfurt plane. In this position, the orbitales (eye sockets), reduced margins of the orbits, and also the poria (ear canal upper margins) every lie in the exact same horizontal plane. This orientation represents the position of the skull if the subject were stand upright and looking straight ahead.

It is essential to keep in mind that all anatomical explanation are based upon the traditional anatomical place unless otherwise stated.

Directional Terms

Positional terms give precise descriptions the anatomical relationship and allow for consistency as soon as referencing anatomical positions.

Learning Objectives

Identify the anatomical terms that specify the person body in space

Key Takeaways

Key PointsDescriptions the directional terms include: a) premium (head) and also inferior (caudal), b) anterior and also posterior, c) lateral and medial, d) deep and also superficial, e) proximal and also distal, and also f) dorsal and also ventral.Directional terms carry out comparison the anatomical position by compare the areas of different structures in the body.Key Termsdirectional terms: Directional terms room words provided to define the place of an anatomical structure by compare its place to other structures in ~ the human body or in ~ the orientation that the human body itself.

Navigating Anatomy through Language

Directional state provide an exact descriptions that a structure’s location. They permit a description of anatomical place by comparing ar relative to various other structures or in ~ the rest of the body. Standard anatomical terms for direction include:

Superior and also inferior (cranial and caudal) are used when introduce to components of the human body which space toward an end of the body. Superior frameworks are toward the head (cranial) while worse (caudal) structures are toward the feet. Examples encompass the superior and also inferior vena cava, which carry deoxygenated blood far from the head (superior) and from the lower body (inferior) to the heart.Anterior and posterior are sometimes used in place of superior and also inferior, respectively. These words are used an ext often for animal anatomy and also rarely and only with very specific meaning in human being anatomy. Anterior describes the next of the structure facing up in the traditional anatomical place while posterior describes the bottom side. For example, the pituitary gland has an anterior and posterior side, every of which secretes different varieties of hormones.Dorsal and ventral are occasionally used in place of anterior and posterior, respectively. Dorsal means the back side or top side, while ventral method the frontal or lower side. This are mainly used with pet anatomy, yet can be used in person anatomy as long as they room describing the side of one appendage. One instance is the dorsal fin in fish, uncovered on the upper side that the fish’s body.Lateral is offered to describe anything closer to the sides of the human body (toward the arms, in the typical anatomical position), while medial is offered to define anything toward the middle of the body. In general, countless structures that the human being body room bilateral and symmetrical with the middle of the body, such as the lungs or the arms.Deep refers to structures closer to the interior center of the body. For example, skeletal in one appendage are situated deeper than the muscles. Superficial is provided to describe structures that space closer to the exterior surface of the body. Because that example, the outer layers that skin are superficial to deeper great of skin.Proximal and also Distal explain one suggest relative to another. Proximal refers to a allude closer to the reference suggest while distal refers to a point farther away. When describing appendages, the proximal finish of the appendage associate the appendage come the body, if the distal finish is away from the body.

Diagram of anatomical terms: Directional axes in a tetrapod.

Key Takeaways

Key PointsRegional terms explain the various parts of the body by the structures and also functions the a certain region. The most basic regional terms are the axial and appendicular regions.Axes use directional state to define the location and also orientation the a details region.The directional hatchet lateral is provided to explain structures divided by a left-to-right axis.Key Termsventral: ~ above the front side of the person body or the matching surface of one animal, typically the lower surface.posterior: Nearer the caudal finish of the human body in quadrupeds or the dorsal finish in bipeds.axis: A line in between two points that is offered to offer direction come an anatomical region.

Regional terms in Anatomy

Regional terms explain anatomy by splitting the components of the human body into different regions that contain structures that are associated in similar functions. Two primary terms are offered to describe the key regions of the body:

The Axial an ar makes increase the key axis of the human being body and includes the head, neck, chest, and trunk.The Appendicular region makes up the parts of the person body that attach to the axial region. This includes the limbs and appendages.

These room the two straightforward categories of local terms; however, numerous other terms are supplied to define smaller regions within the axial and appendicular regions. For example, the brachial an ar consists the the eight as a part of the appendicular region, when the abdominal an ar consists of the abdomen as a smaller component of the axial region.

The abdominal region is subdivided into even smaller regions based on different functions of teams of organs and tissues in that region. If a human being is experiencing pain in one part of the abdominal muscle region, climate the smaller local divisions can assist determine the organs connected in the trouble to far better treat symptoms.

Axes define Relative Positions

Another an approach for describing an ar An axis supplies a directly line in between two components of the body to describe a region of the body with straight direction. For example, blood can be stated to flowin a proximal or distal direction through a region significant by the axis. The X, Y, and Z axes of the Cartesian coordinate system are used define the specific location of one axis in typical anatomical position.

Many varieties of axes deserve to give local direction. Any pair of corresponding directional terms can be linked to form an axis (such together proximal-distal for an appendage).

The Dorsoventral axis (DV axis) is formed by the connection of the dorsal and ventral points of a region. The region between the ship (ventral) and ago (dorsal) is often defined by a DV axis.The Anterioposterior axis (AP axis) is the axis developed by the link of the anterior (top) and posterior (bottom) ends of a region. The AP axis of a an ar is by definition perpendicular to the DV axis and vice-versa.The Left-to-right axis is the axis connecting the left and also right hand sides of a region. That is supplied to define the lateral sides of a region, i m sorry in people are frequently symmetrical approximately the center of the body. It is perpendicular to both the DV and also AP axes.

Different Directional AP Axes in 3 Body segment of a Horse: Axis (A) (in red) reflects the AP axis of the tail, (B) shows the AP axis of the neck, and also (C) mirrors the AP axis of the head.

Axes give an ext clarity and detail because that describing the ar of an anatomical region. They are generally used in both zoology and human anatomy, and can be paired through body planes to provide even more detail to anatomical direction, region, and location.

Body Planes and Sections

There are three straightforward reference planes offered in anatomy: the sagittal plane, the coronal plane, and the transverse plane.

Key Takeaways

Key PointsA coronal or frontal airplane divides the body right into dorsal and ventral (back and front, or posterior and anterior) portions.A transverse plane, also known as an axial airplane or cross-section, divides the body right into cranial and also caudal (head and tail) portions.A sagittal airplane divides the body into sinister and also dexter (left and also right) portions.Body planes have several provides within the anatomy field, including in medical imaging, explanation of body motion, and embryology.Key Termscoronal plane: any type of vertical airplane that divides the body into anterior and also posterior (belly and back) sections.transverse plane: Any airplane that divides the body into superior and inferior parts, approximately perpendicular to the spine.sagittal plane: any type of imaginary aircraft parallel to the median plane.

What are Body Planes?

Body airplane are hypothetical geometric planes used to divide the body right into sections. Lock are frequently used in both human and zoological anatomy to explain the ar or direction that bodily structures. Recommendation planes space the traditional planes offered in anatomical terminology and include:

The sagittal plane (lateral or Y-Z plane) divides the body into sinister and dexter (left and right) sides. The midsagittal (median) plane is in the midline through the center of the body, and also all various other sagittal planes room parallel to it.The coronal plane (frontal or Y-X plane) divides the body into dorsal and ventral (back and front) portions. It likewise separates the anterior and posterior portions.The transverse aircraft (axial or X-Z plane) divides the body into superior and inferior (head and tail) portions. The is frequently a horizontal plane through the center of the body and also is parallel come the ground.

While these are the major reference planes of the body, various other planes are frequently used in relation to this three. A longitudinal aircraft is any plane perpendicular come the transverse plane, if parasaggital planes space parallel come the saggital plane.The coronal plane, the sagittal plane, and the parasaggital airplane are examples of longitudinalplanes.


Anatomical airplane in a Human: There room three basic planes in zoological anatomy: sagittal, coronal, and transverse. A person in the anatomical position, can be described using a coordinate device with the Z-axis going from front come back, the X-axis going indigenous left to right, and the Y-axis going from approximately down.

Applications of body Planes

Medical imaging approaches such as sonography, CT scans, MRI scans, or pets scans are one of the primary applications of human body planes. Through imaging a patience in standard anatomical position, a radiologist can construct an X-Y-Z axis approximately the patience to use body planes to the images. The planes deserve to then be supplied to identify and locate the location of the patient’s inner organs. Separation, personal, instance organs can additionally be divided by plane to help identify smaller sized structures within the organ.

Body planes are offered to define anatomical activity in the X-Y-Z coordinate device that the human body moves through. An anatomist could model a limb’s variety of movement by measuring i m sorry planes the limb have the right to move through and how far it is able come travel.

Anatomical readjust during embryological advance is additionally described and measured v body planes. Because that example, throughout human embryonic breakthrough the coronal plane is horizontal, but becomes vertical as the embryo creates into a fetus. In compare embryology, body planes administer a basis for comparing the ways in which different varieties of organisms construct anatomically in ~ the womb.

Key Takeaways

Key PointsThe dorsal cavity has the primary organs the the worried system, including the brain and spinal cord.The diaphragm is a sheet of muscle the separates the thoracic cavity indigenous the abdominal cavity.Special membrane tissues surround the body cavities, such together the meninges that the dorsal cavity and also the mesothelium that the ventral cavity.The mesothelium is composed of the pleura that the lungs, the pericardium the the heart, and also the peritoneum that the abdominopelvic cavity.Key Termsabdominoplevic cavity: The ventral body chamber that contains the abdominal muscle cavity (primarily digestive system) and the pelvic cavity (primarily reproductive system).dorsal cavity: The cavity in the earlier of the body that contains the cranial and also vertebral cavities, which house the mind and spinal cord respectively.Thoracic Cavity: The ventral human body chamber that has the pericardial cavity (the heart) and also the pleural cavity (the lungs).

By the broadest definition, a human body cavity is any type of fluid-filled an are in a multicellular organism. However, the term usually refers to the space where interior organs develop, located between the skin and also the external lining of the gut cavity.”The person body cavity,” generally refers come the ventral body cavity since it is by much the largest one in volume. Blood vessels room not considered cavities but may be organized within cavities. Most cavities administer room for the offal to readjust to transforms in the organism’s position. Lock usually includes protective membranes and also sometimes skeleton that defend the organs.

Anatomical terminology for body cavities: Humans have actually multiple body cavities, consisting of the cranial cavity, the vertebral cavity, the thoracic cavity (containing the pericardial cavity and also the pleural cavity), the ab cavity, and also the pelvic cavity. In mammals, the diaphragm separates the thoracic cavity indigenous the abdominal muscle cavity.


The dorsal cavity is a continuous cavity located on the dorsal side of the body. It residences the offal of the upper central nervous system, including the mind and the spinal cord. The meninges is a multi-layered membrane within the dorsal cavity the envelops and also protects the brain and spinal cord.


The cranial cavity is the anterior section of the dorsal cavity consist of of the room inside the skull. This cavity has the brain, the meninges of the brain, and also cerebrospinal fluid.


The vertebral cavity is the posterior section of the dorsal cavity and also contains the frameworks within the vertebral column. These incorporate the spinal cord, the meninges of the spinal cord, and the fluid-filled spaces between them. This is the many narrow of every body cavities, sometimes defined as threadlike.


The ventral cavity, the interior space in the prior of the body, consists of many different organ systems. The organs in ~ the ventral cavity are likewise called viscera. The ventral cavity has actually anterior and also posterior portions separated by the diaphragm, a sheet of bones muscle uncovered beneath the lungs.


The thoracic cavity is the anterior ventral body cavity uncovered within the rib cage in the torso. It houses the primary organs of the cardiovascular and respiratory systems, such as the heart and also lungs, but additionally includes offal from other systems, such together the esophagus and the thymus gland. The thoracic cavity is lined by two varieties of mesothelium, a form of membrane organization that lines the ventral cavity: the pleura lining of the lungs, and the pericadium lining the the heart.


The abdominoplevic cavity is the posterior ventral human body cavity discovered beneath the thoracic cavity and diaphragm. That is generally divided into the abdominal and pelvic cavities. The ab cavity is not had within bone and also houses numerous organs the the digestive and renal systems, and also some guts of the endocrine system, such together the adrenal glands. The pelvic cavity is had within the pelvis and houses the bladder and also reproductive system. The abdominopelvic cavity is inside wall by a type of mesothelium referred to as the peritoneum.

Key Takeaways

Key PointsThe abdominopelvic cavity can be subdivided into four quadrants and nine areas.The quadrants space labeled by location: the best upper, best lower, left upper, and also left reduced quadrants.The nine areas are smaller than the 4 abdominopelvic quadrants and include the best hypochondriac, right lumbar, best illiac, epigastric, umbilical, hypogastric (or pubic), left hypochondriac, left lumbar, and also left illiac divisions.The perineum is sometimes taken into consideration to be the tenth division.The function of the abdominal muscle divisions is come describe local anatomy in the abdomen, and also to help clinicians identify which organ and tissues are affiliated in a an illness based ~ above which regions experience pain.Key Termsleft upper quadrant: The left top quadrant is the location of the left portion of the liver, the larger section of the stomach, the pancreas, left kidney, spleen, portions of the transverse and descending colon, and parts the the small intestine.Right upper quadrant: The appropriate upper quadrant contains the right portion of the liver, gallbladder, best kidney, a small portion of the stomach, portions of the ascending and also transverse colon, and parts the the little intestine.left reduced quadrant: The left reduced quadrant homes the bulk of the small intestine, several of the large intestine, the left female reproductive organs, and also the left ureter.nine divisions: An alternate system for splitting the abdominopelvic cavity into regions.right reduced quadrant: In the right reduced quadrant sit the cecum, appendix, component of the tiny intestines, the best female reproductive organs, and the best ureter.

Anatomists and medical personnel division the abdominopelvic cavity into smaller regions to facilitate study and discussion. These departments are regularly used to categorize the individual abdominal organs by their location and role and are provided by clinicians to assist diagnose the resource of ab pain and also determine proper treatment. The most typical divisions for the abdominopelvic an ar are the four quadrants and also nine regions.

Abdominal nine divisions (a) and quadrant regions (b): The abdomen is subdivided into four quadrants and nine areas.

Abdominal four Quadrants

The abdominopelvic an ar can be separated into 4 quadrants. This quadrants are characterized by the intersection the the saggital airplane with the umbilical airplane (the transverse plane through the navel). Clinicians use these areas to identify the organs and also tissues that may be bring about pain or discomfort in that region.

Right top Quadrant

The right upper quadrant has the right section of the liver, the gallbladder, ideal kidney, a small portion of the stomach, the duodenum, the head that the pancreas, sections of the ascending and transverse colon, and parts of little intestine. Pain in this an ar is connected with infection and inflammation in the gallbladder and liver or peptic ulcers in the stomach.

Left top Quadrant

The left upper quadrant is the location of the left part of the liver, part of the stomach, the pancreas, left kidney, spleen, sections of the transverse and also descending colon, and parts of the little intestine. Pain in this an ar is associated with malrotation of the intestine and colon.

Right lower Quadrant

In the right lower quadrant sit the cecum, appendix, component of the small intestines, the right half of the female reproductive system, and the best ureter. Pains in this an ar is most commonly linked with appendicitis.

Left lower Quadrant

The left reduced quadrant dwellings the bulk of the little intestine, few of the big intestine, the left fifty percent of the female reproductive system, and the left ureter. Pains in this an ar is generally associated with colitis (inflammation of the large intestine) as well as pelvic inflammatory disease and ovarian cysts in females.

Abdominal ripe Divisions

The nine divisions of the abdominopelvic region are smaller sized than the four quadrants, allowing for a much more detailed discussion. These divisions are marked by 2 parasagittal and two transverse airplane centered approximately the navel. Most organs are component of lot of regions, consisting of the gallbladder, duodenum, stomach, kidneys, spleen, small intestine and colon. The perineum (the area beneath the hypogastric region at the bottom the the pelvic cavity) is sometimes taken into consideration to it is in a tenth division in this system.

Right Hypochondriac

The ideal hypochondriac region contains the right section of the liver, the gallbladder, the best kidney, and parts that the tiny intestine.

Left Hypochondriac

The left hypochondriac region contains component of the spleen, the left kidney, component of the stomach, the pancreas, and also parts the the colon.


The epigastric (above stomach) region contains the bulk of the stomach, component of the liver, component of the pancreas, part of the duodenum, part of the spleen, and the adrenal glands. This an ar pushes out when the diaphragm contracts during breathing.

Right Lumbar

The right lumbar an ar consists that the gallbladder, the right kidney, component of the liver, and also the ascending colon.

Left Lumbar

The left lumbar region consists of the descending colon, the left kidney, and part of the spleen.


The umbilical an ar contains the umbilicus (navel), and also many parts of the small intestine, together as component of the duodenum, the jejunum, and the illeum. It additionally contains the transverse colon (the section in between the ascending and descending colons) and also the bottom sections of both the left and right kidney.

Right Iliac

The best iliac an ar contains the appendix, cecum, and the best iliac fossa. The is likewise commonly described as the appropriate inguinal region. Ache in this area is generally connected with appendicitis.

Left Iliac

The left illiac region contains part of the diminish colon, the sigmoid colon, and also the best illiac fossa. That is additionally commonly called the left inguinal region.

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The hypogastric region (below the stomach) contains the organs approximately the pubic bone. These incorporate bladder, component of the sigmoid colon, the anus, and also many guts of the reproductive system, such together the uterus and also ovaries in females and also the prostate in males.