MSK - OMG - SCURRED - DIES. Flashcards

1
Q

what are tight junctions composed of?

A
  • occludins / claudins

- prevent paracellular solute movement

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2
Q

what are cadherins?

A

Ca2+ dependent adhesion proteins –> found in adherins junction & connects actin cytoskeletons of adjacent cells

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3
Q

what is the significance of cadherins?

A

loss of E-cadherin –> metastasis

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4
Q

what is the disease associated w/ autoantibodies against desmosomes?

A

pemphigus vulgaris

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5
Q

what are desmosomes?

A

structural support via keratin interactions

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6
Q

what are integrins?

A

membrane proteins binding to collagen / laminin in BM –> maintain “BM integrity)

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7
Q

what is the significance of an abnormal passive abduction test (Valgus)

A

MCL injury

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8
Q

significance of an abnormal passive adduction? (varus)

A

LCL injury

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9
Q

mcmurray test

A

pain on external rotation –> medial meniscus

pain on internal rotation –> lateral meniscus

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10
Q

unhappy triad

A

-ACl
MCL
medial meniscus injury

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11
Q

where do you inject to relieve delivery pain?

A

pudendal nerve –> ischial spine

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12
Q

rotator cuff muscles (4)

A

1) supraspinatus
2) infraspintaus
3) teres minor (axillary nerve)
4) subscapularis

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13
Q

supraspinatus function

A

abducts arm

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14
Q

infraspintaus function

A

laterally rotates arm

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15
Q

teres minor function

A

adducts / laterally rotates arm

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16
Q

subscapularis function

A

medially rotates / adducts arm

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17
Q

where is scaphoid found and why is ti prone to avascular necrosis?

A
  • anatomical snuff box
  • most commoonly fractured carpal bone
  • avascular necrosis b/c: retrograde blood supply
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18
Q

what are the wrist bones / describe what is seen on xray?

A
So Long To Pinky, Here Comes The Thumb
Scaphoid
Lunate
Triquetrum
Pisiform
Hamate
Capitate
Trapezoid
Trapezium

Trapezium / trapezoid overlap on the base of the thumb. Capitate is the largest, well differentiated bone on the 1st row.
Scaphoid is the biggest bone on the bottom row (right next to distal radius)

Triquetrum/pisiform overlap

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19
Q

what nerve runs adjacent to the hook of the hamate?

A

ulnar nerve

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20
Q

guyon canal syndrome?

A

compression of the ulnar nerve

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21
Q

erbs palsy injury

A

tear of upper trunks C5-C6 roots

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22
Q

examples of erb palsy injuries:

A

infants: lateral traction on neck during delivery
adults: trauma

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23
Q

functional deficits from erb’s palsy

A

1) deltoid/supraspinatus = no abduction (arm hangs loose)
2) infraspinatus = no lateral rotation (arm rotated medially)
3) biceps = no flexion / supination (arm pronated + extended

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24
Q

klumpke palsy injury + causes

A

tear of lower trunk: C8-T1

1) infants: upward force during delivery
2) adults: trauma: grabbing tree to break a fall

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25
Q

klumpke deficits

A

intrinsic hand muscles: lumbricals, interossei, thenar, hypothenar –>
1) total CLAW hand: unable to flex MCP, unable to extend DIP / PIP

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26
Q

thoracic outlet syndrome

A

compression of lower trunk / subclavian vessels

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27
Q

typical injury causing thoracic outlet syndrome

A

cervical rib injury / pancoast tumor

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28
Q

deficits in thoracic outlet syndrome

A

intrinsic hand muscles:

1) lumbricals
2) interossei
3) thenar
4) hypothenar

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29
Q

thoracic outlet syndrome presentation

A

atrophy of intrinsic hand muscles: ischemia, pain, edema due to vascular compression

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30
Q

winged scapula injury / causes

A

axillary node dissection / stab wounds –> long thoracic nerve

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31
Q

deficit on winged scapula

A

serratus anterior: inability to anchor scapula –> cannot abduct arm above horizontal

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32
Q

axillary (C5-C6) cause of injury

A

cause: fractured surgical neck of humerus (or anterior humerus dislocation)

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33
Q

axillary presentation

A

1) flattened deltoid
2) loss of arm abduction at shoulder (>15 degrees)
3) loss of sensation over deltoid muscle / lateral arm

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34
Q

musculocutaneous (C5-C7) causes of injury

A

upper trunk compression

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35
Q

musculocutaneous presentation

A

1) loss of forearm flexion / supination

2) loss of snsation over the lateral forearm

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36
Q

radial nerve (C5-T1) causes of injury (2)

A

1) midshaft fracture of humerus

2) compression of axilla

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37
Q

radial nerve presentation

A

1) wrist drop (loss of extension along elbow, wrist, fingers)
2) dec. grip strength (limited action of flexors)
3) loss of sensation over posterior arm / forearm + dorsal hand

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38
Q

median (C5-T1) causes of injury (2)

A

1) supracondylar fracture of humerus (Proximal)

2) carpal tunnel syndrome via wrist laceration (distal)

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39
Q

median nerve presentation

A

“ape hand” / “pope’s blessing

1) loss of wrist / lateral finger flexion, thumb opposition, 2/3 lumbricals
2) loss of sensation over thenar eminence

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40
Q

ulnar nerve (C8-T1) causes of injury (2)

A

1) fracture of medial epicondyle of humerus –> HAHA FUNNY BONE (proximal)
2) hook of hamage (distal)

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41
Q

ulnar deficit presentation

A

Ulnar claw on digit extension

1) if proximal: radial deviation
2) loss of wrist / medial finger flexion, abduction/adduction
3) loss of sensation over medial 1.5 fingers, including hypothenar eminence

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42
Q

what nerve deficit best defines clawing?

A

distal median / ulnar nerves

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43
Q

when do proximal ulnar / median lesions present?

A

voluntary flexion of the digits

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44
Q

thenar muscles are controlled by?

A

median OAF:
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis

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45
Q

hypothenar muscles are controlled by?

A

ulnar nerve

Opponens digit minimi
Abductor digit minimi
Flexor digit minim

46
Q

what are the functions of the thenar / hypothenar muscles?

A

Oppose
Abduct
Flex

(OAF)

47
Q

DAB

A

dorsals ABduct

48
Q

PAD

A

Palmars ADduct

49
Q

causes of obturator nerve injury

A

pelvic surgery

50
Q

obturator nerve presentation (L2-L4)

A

dec. thigh sensation (medially) + dec. adduction

51
Q

femoral nerve injury (L2-L4)

A

pelvic fracture

52
Q

presentation of femoral nerve injury

A

dec. thigh flexion / leg extension

53
Q

common peroneal nerve (L4-S2) cause of injury

A

1) trauma / compression of the Lateral Leg

2) fibular neck fracture

54
Q

common peroneal nerve presentation

A

foot drop: inverted / plantarflexed at rest, loss of eversion + dorsiflexion
sensation loss: dorsum of foot

55
Q

tibial (L4-S2) cause of injury:

A

knee trauma

1) proximal lesion = baker cyst
2) distal lesion = tarsal tunnel syndrome

56
Q

superior gluteal (L4-S1) cause of injury

A

1) posterior hip dislocation

2) polio

57
Q

presentation of superior gluteal injury

A

1) trendelenburg sign/gait: weight-bearing leg cannot abduct and maintain pelvic alignment
* lesion is contralateral to the side of the hip that drops

58
Q

inferior gluteal injury (L5-S2)

A

posterior hip dislocation

59
Q

inferior gluteal injury presentation

A

1) difficulty climbing stairs / rising from seated position

2) loss of hip extension (due to deficit in the maximus

60
Q

mnemonic for peroneal nerve

A

PED: peroneal EVERTS and DORSIFLEXES.

injury = foot dropPED

61
Q

mnemonic for tibial nerve

A

TIP: Tibial Inverts & Plantarflexes;

injury = no TIP toes

62
Q

where does the sciatic nerve run and how does it split?

A

posterior thigh –> common peroneal + tibial

63
Q

long thoracic nerve is paired with what artery?

A

lateral thoracic

64
Q

surgical neck of the humerus has what nerve / artery?

A

-axillary nerve

posterior circumflex artery

65
Q

midshaft of the humerus has what nerve / artery?

A

radial nerve

deep brachial artery

66
Q

distal humerus = what nerve/artery?

A

median nerve

brachial artery

67
Q

popliteal fossa has what nerve/artery?

A

tibial nerve

popliteal artery

68
Q

posterior to medial malleolus is what nerve / artery

A

tibial nerve

posterior tibial artery

69
Q

muscle contraction steps (6)

A

1) AP depolarization –> voltage-gated Ca2+ channels open –> NT release
2) post-snayptic binding –> depolarization at motor end plate
3) depolarization down T-tubule
4) depolarization of voltage-sensitive dihydropyridine receptor, mechanically coupled to the ryanodine receptor of the sarcoplasmic reticulum triggers Ca2+ release from SR
5) Ca2+ released binds to troponin C –> conformational change moving tropomyosin out of the myosin-binding groove on actin filaments
6) myosin releases bound ADP + Po4 displacement

70
Q

what bands are shortened during muscle contraction?

A

H& I bands b/w Z lines

71
Q

what bands remain the same length during muscle contraction?

A

A band

72
Q

what are the regulators of smooth muscle contraction?

A

Ca2+ –> MLCK –> contraction

nitric oxide –> MLCP –> relaxation

73
Q

where does endochondral ossification occur?

A

axial / appendicular skeleton, base of skull

74
Q

what is mechanism of endochondral ossification?

A

cartilaginous bone made first by chondrocytes.

osteoclasts / osteoblasts replace w/ woven bone –> remodelled to lamellar bone

75
Q

what is the mechanism of membranous ossification:

A

woven bone formed directly w/o cartilage –> remodelled to lamellar bone

76
Q

what is the different in origin of osteoblasts and osteoclasts?

A

1) osteoblasts originate from mesenchymal cells in the periosteum
2) osteoclasts are derived from macrophages / monocytes

77
Q

what is the genetic inheritance of achondroplasia?

A

constitutively activated FGFR3 –> inhibition of chondrocyte proliferation
autosomal dominant inheritance

78
Q

histology of osteoporosis

A

trabecular spongy bone loses masses / interconnections

79
Q

what are the lab values for calcium / phos in osteoporosis?

A

normal Ca / PO4 values

80
Q

what is denosumab?

A

monoclonal antibody against RANKL

used for osteoporosis

81
Q

pathogenesis of osteopetrosis

A

mutations in carbonic anhydrase II impair osteoclast ability to create acidic environment necessary for bone resorption

82
Q

lab findings of osteomalacia

A

hyperactive osteoclasts –> incr. ALP (osteoblasts require alkaline environment)

83
Q

paget disease of bone histology findings

A

mosaic pattern of woven / lamellar bone

84
Q

associated risks of paget’s disease?

A

1) incr. blood flow from arteriovenous shunts –> high-output heart failure
2) incr. risk of osteogenic sarcoma

85
Q

what is artery involved in AVN of femoral head?

A

medial circumflex femoral artery

86
Q

what is osteitis fibrosa cystica?

A

brown tumors due to fibrous replacement of bone, subperiosteal thinning

87
Q

causes of 1* hyper PTH

A

1) idiopathic parthyroid hyperplasia
2) adenoma
3) carcinoma

88
Q

2* hyper PTH causes

A

1) ESRD (dec. Po4 excretion + production of activated vit D)

89
Q

giant cell tumor

A

1) locally aggressive benign tumor aroud knee.
2) soap bubble appearance on X-ray w/ multinucleated cells
3) 20-40 yo at epiphyseal end of long bones

90
Q

osteochondroma

A

1) most common benign tumor, affecting males < 25 yo

2) mature bone w/ cartilaginous cap, rarely transforms to chondrosarcoma

91
Q

osteosarcoma risks

A

1) paget disease of bone
2) bone infarcts
3) radiation
4) familial retinoblastoma
5) Li-Fraumeni syndrome (germline P53 mutation)

92
Q

x-ray findings of osteosarcoma

A

1) codman triangle (due to elevation of periosteum

2) sunburst pattern on x-ray

93
Q

ewing sarcoma genetic mutation

A

11,22
onion skin appearance on bone
anaplastic small blue cell malignant tumor
-extremely aggressive w/ early metastases, but responsive to chemo

94
Q

chondrosarcoma

A

rare, malignant, cartilaginous tumor –> seen as expansile glistening mass w/in medullary cavity

95
Q

pathophysiology of RA:

A

cytokines + type III/IV hypersensitivity

96
Q

what is composition of rheumatoid nodules?

A

fibrinoid necrosis

97
Q

pseudogout findings

A

basophilic, rhomboid crystals weakly positively birefringent

98
Q

presentation of pseudogout

A

pain / effusion in a joint, due to deposition of calcium pyrophosphate w/in the joint space (chondrocalcinosis seen on x-ray)

99
Q

what are libman-sacks endocarditis?

A

wart-like vegetations on both sides of the valve, often seen in SLE

100
Q

what type of hypersensitivity is lupus nephritis?

A

type III

101
Q

findings for sarcoidosis

A
  • immune mediated, widespread noncaseating granulomas
  • elevated ACE
  • CXR Bilateral hilar adenopathy / reticular opacities
102
Q

polymyalgia rheumatica symptoms

A

pain / stiffness in shoulders, hips, associated w/ fever malaise, weight loss

103
Q

what is PMR associated w?

A

temporal arteritis

104
Q

fibromyalgia

A

chronic, widespread musculoskeletal pain, associated w/ stiffness, paresthesia, poor sleep, fatigue

105
Q

treatment for fibromyalgia

A
  • exercise
  • antidepressants (TCAs, SNRIs)
  • anticonvulsant
106
Q

polymyositis

A

progressive, symmetric proximal muscle weakness, with endomysial inflammation w/ CD8_ T cells

107
Q

dermatomyositis:

A

polymyositis + malar rash, Gottron papules, heliotrope rash, with increased risk of occult malignancy

108
Q

what’s the difference, mechanistically, b/w polymyositis vs. dermatomyositis?

A

1) polymyositis = endomysial inflammation, CD8+ associated

2) dermatomyositis = perimysial inflammation, CD4+ associations

109
Q

comparison of pathophys of myasthenia gravis vs. lambert-eaton?

A

1) myasthenia gravis = autoantibodies to postsynaptic Ach receptor
2) lambert-eaton = autoantibodies to pres-synaptic Ca2+ channel –> dec. ACh release

110
Q

acantholysis vs. acanthosis?

A

1) acantholysis = separation of epidermal cells –> i.e.: pemphigus vulgaris
2) acanthosis = epidermal hyperplasia –> i.e.: acanthosis nigricans

111
Q

characteristic of urticaria

A

superficial dermal edema + lymphatic channel dilation