USMLE Step 2: MSK Flashcards
What nerve is at risk wtih anterior shoulder dislocation?
Axillary nerve
How does someone hold their arm with an anterior dislocation?
Slight abduction and external rotation
What nerve can be injured in anterior hip dislocation?
obturator nerve
What is the most common type of shoulder dislocation?
Anterior (posterior is rare and from seizure)
What is the most common hip dislocation
Posterior (“dashboard injury)
Colles Fracture
Distal radius- fall onto an outstretched hand
Scaphoid Fracture
Takes 2 weeks to show up on x-ray. Assume there is a fracture if there is tenderness in the anatomical snuff box
What nerve is at risk with humerus fracture
radial nerve (wrist drop and loss of thumb extension)
Monteggia’s Fracture
diaphyseal fracture of the proximal ulna with subluxation of the radial head
Galeazzi’s fracture
Diaphyseal fracture of the radius with dislocation of the distal radioulnar join
What causes Galeazzi’s fracture?
Direct blow to the radius
Achilles Tendon Rupture
Presents with a sudden “pop” like a rifle shot
What is the mechanism of ACL injury
Noncontact twisting (+ anterior drawer sign)
What is the mechanism of PCL tear
Posteriorly directed forced on a flexed knee (+ posterior drawer sign)
Radial Nerve Injury
Wrist extension, loss of dorsal forearm and hand (1st 3 fingers). wrist drop
Median Nerve
Loss of pronation/thumb opposition, sensory on palmar surface **weak wrist flexion and flat thenar eminence)
Ulnar nerve injury
Loss of finger abduction, palmar and dorsal sensory claw hand
Axillary nerve
Loss of abduction, sensory over lateral shoulder
Peroneal nerve injury
Loss of dorsiflexion/eversion, sensory over dorsal foot and lateral leg foot drop
Herniated Disk & Passive Straight leg pain
Pain increases (high sensitivity but not specific)
Herniated disk and straight-leg raise
Increased pain (highly specific but not sensitive)
Cauda Equina Syndrome
Bowel or bladder dysfunction, impotence, and saddle area anesthesia surgical emergency
S/sx of herniated disk
Presents with sudden onset of severe, electricity-like LBP, usually preceded by several months of aching “discogenic” pain
L4 nerve root
Foot dorsiflexion (tibialis anterior), patellar reflex, sensory for medial aspect of lower leg
L5 nerve root
Big toe dorsiflexion (EHL), foot eversion (peroneus muscles), sensory to dorsum of the foot and lateral aspect of lower leg
S1
Plantar flexion (gastrocs/soleus), hip extension (glut max), achilles reflex, sensory to plantar and lateral aspect of the foot
Presentation of spinal stenosis
Neck pain, back pain that radiates to the arms or but/legs, leg numbness/weakness
Presentation of lumbar stensosi
Leg cramping is worse with standing and walking, but symptoms improve with flexion at the hips and bending forward (relieves pressure on the nerves)
Where does osteosarcoma occur?
Metaphyseal regions of the distal femur, prox tibia, and prox humerus
Presentation of osteosarcoma
Progressive and eventually intractable pain that worsens at night, constitutional symptoms
Radiographs for osteosarcoma
Codman’s triangle or sunburst pattern
Classic finding of Ewing Sarcoma
child 10-20 yo with a multilayered “onion-skinning” finding on xray is the diaphyseal regions of femur
Classic findings of a giant cell tumor of bone
female 20-40 yo presenting with knee pain and a mass, a “soap bubble” appearance
Diagnosis of septic arthritis (WBC count)
WBC count > 80,000
Most common organisms of septic arthritis
Staph (#1), strep, gram negative rods
Treatment of septic arthritis
Empirically with ceftriaxone and vancomycin until cultures come back
Heberden’s nodes
DIP enlargement
Bouchard’s Nodes
PIP enlargement
How long does stiffness last in the morning with osteoarthritis?
<30 min
X-ray findings in osteoarthritis
Joint space narrowing, osteophytes, subchondral sclerosis, and subchondral bone cysts
What diagnosis do you consider in a child with gout and inexplicable injuries?
Lesch-Nyhan syndrome
What do gout crystals look like?
YeLLow when paraLLel to the condensor; needle-shaped, negatively birefringent crystals
Treatment of acute gout
High dose NSAIDs (indomethacin) + colchicine
Maintenance of gout
Allopurinol for overproducers; probenecid for undersecreters
Crystals in pseudogout
Rhomboid + crystal birefringence
Reactive Arthritis
Arthritis, uveitis, conjunctivits, urethritis;
Bugs in reactive arthritis
usually following campylobacter, shigella, salmonella, chlamydia, or ureaplasma infection
Pencil in cup deformity
Psoriatic arthritis
Polymyositis
symmetric, progressive, proximal muscle weakness, pain, and difficulty breathing or swallowing
Dermatomyositis
Heliotrope rash, shawl sign, gottron’s papules
HLA associated with RA
HLA-DR4
How long does morning stiffness last for RA?
> 1 hour
Best initial DMARD
methotrexate
Other DMARD
hydroxychloroquine and sulfasalazine
Second line agents for RA
TNF inhibitors, rituximab, leflunomide
CREST Syndrome
Calcinosis, Raynaud’s, Esophageal Dysmotility, Sclerodactyly, Telangiectasias
What can diffuse scleroderma lead to?
Pulmonary fibrosis, cor pulmonale, acute renal fialure, and malignant hypertension
What is mortality due to in scleroderma?
pulmonary hypertension and complications of pulmonary hypertensions
Libman-Sacks endocarditis
Noninfectious vegetations often seen on the mitral valve in association wtih SLE and antiphospholipid syndrome
Polymyalgia Rheumatica
Pain and stiffness of the shoulder and pelvic girdle (difficulty getting out of a chair or lifting the arms above the head). Increased ESR. Females >50yo
Inheritance of Duchenne Muscular Dystrophy
X-linked recessive
Greenstick Fracture
Incomplete fracture involving the cortex of only 1 side (tension side) of the bone
Nursemaid’s Elbow
Radial head subluxation that typically occurs as a result of being pulled or lifted by the hand presents with pain and refusal to bend the elbow
Torus Fracture
Buckling of the compression side of the cortex of a long bone secondary to trauma. Usually occurs in the distal radius or ulna
Osgood-Schlatter Disease
Overuse apophysitis of the tibial tubercle. Causes localized pain, especially with quds contraction
Salter-Harris Fracture
Fractures of the growth plate in children
Salter-Harris I
Physis (growth plate)
Salter-Harris II
Metaphysis and physis
Salter-Harris III
Epiphysis & physis
Salter-Harris IV
Epiphysis, metaphysis, and physis
Salter-Harris V
Crush injury of the physis
Congenital Dislocation of the hip- who is it most common in?
First-born females born in the breech position
Barlow’s Maneuver
Posterior pressure is places on the inner aspect of the abducted thigh and the hip is then adducted, leading to an audible “clunk” as the femoral head dislocates posteriorly [in congenital hip dislocation)
Ortolani’s Maneuver
The thighs are gently abducted from the midline with anterior pressure on the greater trochanter. A soft click signifies reduction of the femoral head into the acetabulum [congenital hip dislocation]
Allis’ (Galeazzi’s sign)
The knees are at unequal heights when the hips and knees are flexed (dislocated side is lower) [in congenital hip dislocation]
How is congenital dislocation of the hip diagnosed?
ultrasound
Legg-Calve-Perthes Disease
Idiopathic AVN of femoral head
Slipped capital femoral epihpysis
separation of the proximal femoral epiphysis through the growth plate (leading to inferior and posterior displacement of the femoral head relative to the femoral neck) epiphysis remains within the acetabulum while the metaphysis moves anteriorly and superiorly
