approximately 90 degree angle to long axis of the bone
across the bone at an angle
results from rotational forces: "S" shaped winding fracture
entire thickness of the bone disrupted
cortex buckles or cracks, but continuity not completely disrupted; more common in children. Also known as greenstick fractures
fractures in which the bone is broken into just 2 pieces
severe fracture in which multiple bone fragments are present
an external wound leads to the fracture; also known as a compound fracture; infections are much more likely
encased by tissue; not open
the result of repeated stresses like in sports and the military
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
healing slower than expected: 3-12 months
improper position of healed bone fragments
failed to heal within 4-6 months
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).
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.
resolves (disappears) when patient bends to the affected side & on forward flexion
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
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:
-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
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.
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.
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
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.
- 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.