Musculoskeletal Flashcards
Multinucleated giant cells residing in Howship lacunae
Osteoclasts
Backbone of bone matrix is made up of
type I collagen
Woven bone
Collagen is deposited randomly (fetus, growth plates)
Lamellar bone
Collagen is deposited in an orderly fashion
Osteogenesis Imperfecta
deficiency in synthesis of type I collagen
blue sclera, small misshapen yellow teeth, deafness
Osteogenesis Imperfecta
Type I (Osteogenesis Imperfecta Tarda)
acquired mutation, mild
most common form, fractures in early childhood, XR shows old Fx
Type II (Osteogenesis Imperfecta Congenita)
rare inherited, Fx & bone malformations at birth
Death in osteoporosis pt is likely d/t
pneumonia and PE
Osteoporosis
imbalance between bone resportion and formation ↑porosity of bones
2 Types of Osteoporosis
age-related (low osteoblast Fx)
postmenopausal (high osteoclast Fx)
Osteoporosis S/S
fractures of the distal forearm, vertebrae or proximal femur, compression microfractures, lumbar lordosis, kyphoscoliosis
Osteoporosis Histology
excessive but proportional reduction in both mineral and matrix phases of bone
Osteopetrosis
osteoclast dysfunction and diffuse skeletal sclerosis
Osteopetrosis defect
defect in carbonic anhydrase II –> blocked matrix solubilization and resorption
Erlenmeyer flask deformity
Osteopetrosis
Malignant Osteopetrosis S/S
HSM d/t extramedullary hematopoiesis, mild cranial nerve deficits
Paget Disease (Osteitis Deformans)
hereditary disease of osteoclast dysfunction and matrix madness (high osteoclast Fx -> burn-out -> high osteoblast Fx)
Paget Disease (Osteitis Deformans) cause
fifth decade, may be d/t paramyxoviruses
Paget Disease (Osteitis Deformans) affects
long bones, pelvis, spine, skull, with bone becoming thick, soft, and porous
Paget Disease (Osteitis Deformans) Histology
mosaic pattern of lamellar bone
thick porous skull
Paget Disease
Paget Disease
Leonine facies (leontiasis ossea), skull invagination (platybasia), and femur bowing
Increased hat size
Paget Disease
Paget Disease bone findings
light, soft, porous, ossified, sclerotic bone
Paget Disease
increased risk for osteosarcoma
Rickets & Osteomalacia
vitamin D deficiency or disturbance in Vit D metabolism
rosary bead formation at costochondral jxn
Rickets
Long standing hyperparathyroidism can lead to
osteitis fibrosa cystica
Osteonecrosis
ischemia → infarction of bone and marrow
Causes of Osteonecrosis
fracture, thrombosis, embolism, blood vessel injury, ↑intraosseous pressure
Medullary infarcts
infarcts of cancellous bone and marrow, but NOT cortex (SILENT)
Subchondral infarcts
involve bony plates and epiphysis, but spare the cartilage
Osteomyelitis
hematogenous spread, majority of cases are d/t S. aureus
Osteomyelitis IN A SICKLE CELL pt
Salmonella
Osteomyelitis Histology
Bone fragment becomes devitalized and necrotic (sequestrum) + sleeve of reactive bone at periphery (involucrum)
Tuberculous osteomyelitis often involves
thoracic/lumbar spine (Pott’s disease)
Tuberculous osteomyelitis
miliary TB
Osteoma
benign bone tumor, face, Gardner Syndrome
Osteoid Osteoma S/S
painful tumors, release PGE2, pain relieved by aspirin
Osteoid Osteoma Histo
radiolucent nidus surrounded by densely sclerotic bone
Osteoid Osteoma affects
femur & tibia
Osteoblastoma S/S
dull, achy pain that does NOT respond to salicylates
most common PRIMARY malignancy of bone
Osteosarcoma
most osteosarcomas arise in
long bones (near knee)
Osteosarcoma genetic link
associated with p53 and RB mutations
Osetochondroma
cartilage capped outgrowth near epiphyseal growth plate of long tubular bones
Chondroma
benign hamartomatous tumors composed of hyaline cartilage
Ollier disease
multiple endochondromas
Chondroma typically affect
females, occur in 3rd-4th decade of life, metaphyses
Fibrous Cortical Defect and Non-ossifying Fibroma
extremely common congenital defects in up to 50% of children older than age 2, b/l, multiple, most spontaneously regress
Fibrous Cortical Defect and Non-ossifying Fibroma Histo
fibroblasts in pinwheel pattern
Fibrosarcoma and Malignant Fibrous Histiocytoma Histo
malignant fibroblasts in “herringbone” pattern
Ewing Sarcoma
highly malignant small round cell tumor, neural origin
McCune Albright Syndrome
Fibrous Dysplasia
Giant Cell Tumor (Osteoclastomas)
“soap bubble” appearance, aggressive benign, epiphyseal
Myositis Ossificans
develop in athletic young adult in high contact sport following trauma; usually found in subcutis or muscle of proximal extremity
Dupuytren contracture
palmar fibromatosis
Peyronie disease
Penile fibromatosis
rhabdomyosarcoma
most common variant is embryonal rhabdomyosarcoma
