Musculoskeletal Flashcards Preview

Boards > Musculoskeletal > Flashcards

Flashcards in Musculoskeletal Deck (102)
Loading flashcards...
0

What are the muscles of the thenar & hypothenar eminences?

Both are OAF
Thenar:
Opponens pollicis
Adbuctor pollicis brevis/Adductor pollicis
Flexor policis brevis

Hypothenar:
Opponens digiti minimi
Abductor digiti minimi brevis
Flexor digiti minimi brevis

1

What nerve is affected by this injury?
Fibular neck fracture

Trauma to the lateral leg can cause common peroneal damage. Sensory deficit would be anterolateral leg & dorsum of foot.

TIPPED:
Tibial inverts & plantar flexes, Peroneal everts & dorsiflexes

2

What nerve is affected by this injury?
Knee trauma

Tibial nerve can be injured in knee trauma. Sensory deficit would be the sole of the foot. The most important thing to assess with knee dislocation or trauma is the popliteal artery. It is easily injured & can lead to amputation.

TIPPED:
Tibial inverts & plantar flexes

3

What nerves could be affected by this injury?
Posterior hip dislocation

Superior gluteal --> Trendelenberg sign

Inferior gluteal --> Can't rise from a seat or climb stairs.

4

What nerve is affected by this injury?
Anterior hip dislocation

Obturator nerve

Motor: Thigh adduction deficit
Sensory: Medial thigh deficit

5

What nerve is affected by this injury?
Pelvic fracture

Femoral n. is common

Motor defcicit: Thigh flexion & leg extension
Sensory deficit: Anterior thigh & medial leg

6

What are the types of fibers in skeletal muscle?

Type I & Type II

"1 slow red ox"

Type 1 are slow twitch
Red due to myoglobin & mitochondria
Oxidative phosphorylation

7

How does NO cause smooth muscle relaxation?

NO --> ^Guanylate cyclase activity --> ^cGMP --> myosin light chain phosphatase (MLCP) --> relaxation

8

What are the two types of bone formation & where do they occur?

Endochondral ossification:
Bones of axial & appendicular skeleton
Cartilaginous model made first by chondrocytes. Then osteoblasts/clasts --> woven bone --> lamellar bone

Membranous ossification:
Skullcap & facial bones
Woven bone --> lamellar bone (no cartilage)

9

How does estrogen affect bone metabolism?

Inhibits apoptosis in osteoblasts
Induces apoptosis in osteoclasts

10

What causes achondroplasia?

Autosomal dominant activating mutation in FGFR3 --> inhibits chondrocyte proliferation --> impaired endochondral ossification

*** >80% of mutations are spontaneous

11

What is seen in osteoporosis?

Trabecular (spongy) bone loses mass & interconnections
Normal lab values
Abnormal DEXA scan
Pathologic fractures

12

What type of fractures are seen in Osteoporosis?

Femoral neck fracture
Vertebral crush fracture
Distal radius fracture

13

What are the types of osteoporosis?

Type I = postmenopausal

Type II = senile (men & women >70y)

14

What causes osteopetrosis?
What is seen?

Mutations impair osteoclasts' ability to form acidic environment required for resorption. Common cause is mutated carbonic anhydrase type 2.

Symptoms:
Pancytopenia
Extramedullary hematopoiesis
Dense bones on X-ray with no medulla
Cranial nerve impingement --> focal deficits
Type II renal tubular acidosis (if carbonic anhydrase def.)

15

What is seen histologically with osteomalacia/rickets?

Vit. D deficiency --> impaired mineralization of osteoid

16

What is seen with osteomalacia & rickets?

^PTH, ^Alk Phos, decreased Ca2+ & Phosphate
Osteomalacia - pathologic fractures

Rickets:
Pigeon-breast deformity
Rachitic rosary
Frontal bossing
Bowing of legs (if ambulatory)

17

What is seen with Osteitis fibrosa cystica?

^Alkaline phosphatase (the only abnormal lab)
Hearing loss
Lion face
Mosaic/woven pattern of bone
Fractures
^ Hat size

Increased risk for osteosarcoma & high output CHF.

18

What is seen in McCune-Albright Syndrome?

Polyostotic fibrous dysplasia (bone replaced with fibrous tissue)
Precocious puberty
Cafe-au-lait spots

19

Where on the bone are the various primary cancers typically found?

Giant cell tumor (osteoclastoma) - Epiphysis
Osteosarcoma & Osteochondroma - Metaphysis
Ewing's & Chondrosarcoma - Diaphysis

Chondrosarcoma is typically intramedullary.

20

How does a giant cell tumor (osteoclastoma) present?

Soap bubble appearance on x-ray
Located at the epiphysis (knee)
Spindle cells with multinucleate giant cells
20-40y

21

How does an Osteochondroma present?

Mature bone with cartilaginous cap (looks like little bone)
Found on metaphysis
Males under 25y
^Risk of chondrosarcoma

22

What risk factors are associated with osteosarcoma?

Familial retinoblastoma
Paget's disease of the bone
Radiation
Bone infarcts

23

What is seen with osteosarcoma?

Codman's triangle (elevation of periosteum)
Sunburst x-ray
Found at metaphysis of long bones (knee)
Male teenagers

24

What mutation is seen in Ewing's Sarcoma?

t(11;22)

11+22 = 33 (Patrick Ewing's number)

25

What is seen with Ewing's sarcoma?

Seen in males <15y
Anaplastic small blue cell tumor (from neuroectoderm)
Onion skin appearance

Aggressive with early mets but responds well to chemo.

26

What is seen with chondrosarcoma?

Found in axial or proximal skeleton
Men 30-60y
Mass within the medullary cavity (diaphysis)

27

With bone tumors, what does the response to aspirin mean?

Responds to aspirin ---> osteoid osteoma
Does not respond --> osteoblastoma

28

What metastases are osteolytic?
Osteoblastic?

Osteoblastic = Prostate cancer

Osteolytic = BLT w/ Ketchup & Mustard

Breast (lytic/blastic)
Lung
Thyroid
Kidney
Multiple myeloma

29

What joint findings are seen in osteoarthritis?

Subchondral cysts
Osteophytes (bone spurs)
Eburnation (polished bone)
Heberden's nodes (DIP); Bouchard's nodes (PIP)