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bone and joint trauma, alteration is bone structure, bone infections, bone tumors, diseases of skeletal muscles, other disorders


broken bone

transverse fracture

approximately 90 degree angle to long axis of the bone

oblique fracture

across the bone at an angle

spiral fracture

results from rotational forces: "S" shaped winding fracture

complete fracture

entire thickness of the bone disrupted

incomplete fracture

cortex buckles or cracks, but continuity not completely disrupted; more common in children. Also known as greenstick fractures

simple fracture

fractures in which the bone is broken into just 2 pieces

comminuted fracture

severe fracture in which multiple bone fragments are present

open fracture

an external wound leads to the fracture; also known as a compound fracture; infections are much more likely

closed fracture

encased by tissue; not open

stress fracture

the result of repeated stresses like in sports and the military

compression fracture

a crushing of bone, common in vertebral bodies

treatment of fracture

casting, open reduction-external fixation, open reduction-internal fixation

open reduction-external fixation

placement of pins connected to an external frame

open reduction-internal fixation

screws, pins, etc. placed internal surgically; can speed up healing and early mobility

delayed union

healing slower than expected: 3-12 months


improper position of healed bone fragments


failed to heal within 4-6 months

compartment syndrome

high pressure in a muscle compartment (an enclosed fascial space) reducing capillary pressure below what is necessary for tissue viability. (The blood can't get in.)
1- classified as acute, chronic, crush
2- 30-40 mm Hg pressure enough to compromise muscle microcirulation
3- Symptoms—pain out of proportion to the injury, paralysis, paresthesia, pallor, pulselessness (the 5 P's).

Neurovascular injury

may be due to the initial injury or the treatment


bones displaced to extent that articulating surfaces lose contact.


bones displaced to extent that articulating surfaces lose contact, except articulating surfaces partially lose contact.


lateral curvature of the spine: S- or C- shaped deformity.
(1) 75-85% of cases idiopathic
(2) Occurs in 5% of children, with half of them requiring treatment—most of these female.

Non-structural scoliosis

resolves (disappears) when patient bends to the affected side & on forward flexion

Structural scoliosis

fails to correct itself on forced bending against the curvature or forward flexion. More serious, requires intensive therapy & probably surgery.


-the most common metabolic bone disease.
-Occurs in 1 in 2 females and 1 in 5 men older than age 60.
-65,000 women DIE of hip fractures in the US each year
-Estimated cost of osteoporosis yearly in US is $13 billion!
-The rate of bone resorption outpaces bone formation, with cancellous bone lost faster than cortical bone.

Rickets & osteomalacia

characterized by delayed mineralization of newly formed bone matrix with resulting soft osteopenic bone. All bones affected, but weight-bearing bones tend to collapse.


Vitamin D deficiency common, which prevents maintenance of normal Ca2+ and PO4- levels. Also common:
(1) Genu valgum—knock knees
(2) Genu varum—bow legs
(3) Kyphosis


due to either decreased intestinal absorption of Ca2+, increased urinary excretion , loss of Ca2+ or PO during pregnancy or lactation, malabsorption, or any combination

Paget disease (osteitis deformans

-Affects 3% of people > 50 years old in US.
-Clinical—pain & deformity of the affected bone due to excessive bone remodeling.


-bacterial bone infection. Very difficult to treat, requiring LONG courses of IV antibiotics.
-ii) Organisms may reach bone via: Bloodstream, Adjacent tissues, Direct introduction of the organisms into bone—like in open fractures.
-Take particular care with human bites!
-In hematogenous bone infections, skin, sinuses, ear, and teeth are common primary sites. Also, GI, GU, and respiratory systems are possible.
Age-related bony involvement:
-kids—long bones
-adults—spine, pelvis, smaller bones like the feet.


area of devitalized bone that can serve as a reservoir of bacteria.


layer of new bone formed by osteoblasts around infected bone in an effort to isolate the infection


can also infect bone, most commonly the vertebral column: Potts disease


the most common (non-metastatic) bone tumor.
-50% of all benign bone tumors
-Hereditary, usually in people < 30 years of age

Osteoid osteoma

painful! but benign
- Most common in cortex of tibia or femur.
- Usually in people 10-20 years of age.

Giant cell tumor

benign, but aggressive, can transform into sarcomas. Painful

Osteosarcoma (osteogenic sarcoma)

the most common primary bone malignancy. Highly malignant.
- Develops in 2 age groups: children to 30 and adults 60-70 years of age. Average age at diagnosis is 15.
- Growth typically rapid & destructive, so pain intense;
- Lungs are frequently the site of metastasis


cartilage-forming malignancy, usually in adults.

Ewing sarcoma

highly malignant, rapidly metastasizing bone cancer, most commonly found in children.
- Because they often appear systemically ill with fever, anemia, leukocytosis, and increased sed rate, it can be confused with osteomyelitis.

Multiple myeloma

represents about 1% of all cancers; actually a plasma cell cancer.
- Bone pain is the most common symptom—making this a really miserable disease.
- Discussed more fully in week #3

Muscular dystrophy

a group of disorders of progressive muscle degeneration.

Duchenne muscular dystrophy

the most common & severe
- X-linked recessive (so obviously only affects males)
- Muscle cells deficient in dystrophin (a muscular protein); which weakens the cell membrane, allowing extracellular fluid to leak into the cell.
- Clinical— Calf muscle enlarge as muscle fibers degenerate & fat cells infiltrate muscles. Frequent falls present by age 5-6; wheelchair by 12-14; survival > 20 rare. These kids stand up by "walking" their hands up their legs in the Gower's maneuver.

Becker muscular dystrophy

milder than Duchenne, with wheelchair requirement delayed until age 30 or so.

Fascioscapulohumeral muscular dystrophy

autosomal dominant; affects shoulder girdle & face; rare; normal lifespan possible.

Myasthenia gravis

autoimmune disorder
- Most common in women ages 20-30, but men occasionally afflicted.
- Weakness usually begins with ocular & cranial muscles, may spread to limb muscles.
- Thymectomy may be helpful.
- Treat with cholinergic medications

Acetylcholine receptor antibodies

block action of the neuromuscular junction.

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