MSS-Week 2

Question 1

Limb Development

Answer 1

Mesenchyme: Somatic mesoderm, somitic mesoderm
surface ectoderm
Upper limb ahead of lower by 1-2days
Week 4: limb fields of somatic mesoderm
Budding: apical ectodermal ridge (AER), mesoderm thickening
Week 5-9: lengthening, epithelial-mesenchymal interactions at AER interface
Differentiation: proximal->distal
somatic mesoderm->cartilage
somite derived myoblasts-> skeletal muscle

Question 2

Limb development Axes

Answer 2

Proximal-distal: elongation, segment formation
Anterior-Posterior: digit devo (zone of polarizing activity- posterior border of limb)
Dorsal-ventral: compartments, muscles and neurovascular

Question 3

Scaphoid fracture

Answer 3

FOOSH (fall onto outstretched hand)
snuffbox tenderness
immobilize w splint
can have problem with necrosis bc retrograde blood supply through bone

Question 4

Femoral head fracture

Answer 4

Like scaphoid, can have blood supply probs bc medial circumflex may be disrupted

Question 5

Recurrent shoulder dislocations

Answer 5

pain from all motion
crepitus, strength wnl
positive apprehension sign
Arthritis bc of recurrent trauma

Question 6

Arthritis

Answer 6

stiffness (esp after rest)
worse again after prolonged use
joint line tenderness, mild swelling, deformity
NSAIDs, cortisone, surgery, PT, hyaluronic acid injection

Question 7

Capsulitis

Answer 7

Joint capsule thickening, inflammation, scarring
risk factors: injury, diabetes, thyroid dx
Limited ROM, painful early (freeze), then non-painful (frozen), then non-painful with increasing ROM (thaw)
Gradually tightening endpoint w/ decreased ROM
Takes 2 yrs, maintain ROM, pain control

Question 8

Bicep tendon rupture

Answer 8

pop in shoulder while pulling
FROM, normal strength
muscle bulge

Question 9

Enthesopathy

Answer 9

Disorder of muscular or tendinous bony attachment

Question 10

Tendititis

Answer 10

Acute inflammation of tendon

traumatic blow or pull

Question 11

Tendinosis

Answer 11

Chronic degenerative condition of tendon

submaximal repititive irritation

Question 12

Strain

Answer 12

Muscle fiber damage from overstretching
usually from eccentric loading
stiffness, bruising, swelling, soreness

Question 13

Acromioclavicular sprain

Answer 13

most common fall directly onto shoulder
pain with overhead motion, deformity of shoulder
pain with cross-body adduction
Grade I: AC ligament injury
Grade II: AC tear and CC stretch
Grade III: AC+CC tear

Question 14

Sprain

Answer 14

Ligamentous damage from overloading
instability or laxity, swelling
Grade I: micro damage
Grade II: partial tear
Grade III: complete tear

Question 15

Shoulder dislocation

Answer 15

Most common: anterior (subcoracoid) (90%), open-arm tackle
Should check sensation of axiallary and musculocutaneous nerves
apprehension test
Vacuum (capsule pressure) is most effective passive stabilizer

Question 16

Carpal tunnel syndrome

Answer 16

median nerve compression in wrist
flexor retinaculum
after long time, thenar wasting, parasthesias

Question 17

Pathologic fractures

Answer 17

e.g. from bone cancers

when something that shouldnt have broken a bone breaks a bone

Question 18

Myotomes

Answer 18

C5- elbow flex (bicep)
C6- wrist extend (brachioradialis)
C7- elbow extend (triceps)
C8- distal finger flex
T1- little finger abduction
L2- hip flexor
L3- knee extend
L4- ankle dorsiflex (quadracep)
L5- big toe extend (medial hamstring)
S1- ankle plantarflex (gastroc)

Question 19

Dermatomes

Answer 19

C3- supraclavicular fossar
C4- AC joint
C5- lateral antecubital fossa
C6- thumb
C7- long finger
C8- little finger
T1- medial antecubital fossa
T4- nipples
T10- umbilicus
T12/L1- inguinal/groin
L3- medial femoral condyle
L4- medial malleolus
L5- foot dorsum
S1- lateral heel
S2- popliteal fossa

Question 20

Muscle strength scale

Answer 20

5/5= normal
4/5= against gravity and mod resistance
3/5= against gravity
2/5= movement but not against gravity
1/5= trace movements
0/5= no contraction

Question 21

Reflex test scale

Answer 21

0= absent
1= less than normal
2= low end of normal
3= high end of normal
4= more than normal/clonus

Question 22

Lhermitte’s sign

Answer 22

passive anterior cervical flexion-> electric-like sensation down spine/extremities
implies cervical spinal cord pathology

Question 23

Spurling’s Neck Compression test

Answer 23

Cervical spine extension, rotation, lateral flexion-> radicular sx
nerve root pathology

Question 24

Hoffman’s sign

Answer 24

Flick middle finger distal phalanx-> flexion-adduction of ipsilateral thumb and index finger
upper motor neuron problem

Question 25

Straight-leg raising test

Answer 25

lie supine, raise leg with knee extended-> pain at 30-70deg-> lumbar nerve root path (L5 or S1)

Question 26

Femoral nerve stretch test

Answer 26

pt prone, flex knee, extend hip-> pain on anterior thigh | upper lumbar nerve root path (L2-L4)

Question 27

Lumbar strain

Answer 27

axial low back pain after acute injury, better with rest, muscle problem localized muscle tenderness, reduced ROM, normal neuro tx: rest, NSAIDs, PT

Question 28

Radiculopathy

Answer 28

usually posterolateral disc herniation affects nerve root of the higher number (e.g. L3-L4 disc hernia pinches L4 nerve root) Most common: C6,7 and L5,S1 Both physical/mechanical and biochemical irritation of nerve root sx: myotomal weakness, dermatomal pain/numbness, decreased reflex, spurling or SLR positive tx: lass activity (no bedrest), pain meds, PT, epidural steroids for pain, sometimes surgery if refractory or bowel/bladder issues

Question 29

Ankylosing Spondylitis

Answer 29

Sx: chronic back stiffness, worse in morning/after rest, gradually progressive, decreased ROM, normal neuro Early: widening of sacroiliac joints, adjacent sclerosis, sacroiliitis Late: fusion of both sacroiliac joints Chronic inflammatory disease of sacroiliac and axial skeletal joints (3:1 male) Labs: elevated CRP, Sed Tx: NSAIDs, PT, sometimes anti-TNFa agents

Question 30

Facet joint arthropathy

Answer 30

axial low back pain, gradual onset,, cervical worse with extension, lumbar worse walking degenerative changes/osteoarthritis of facet joints pain on active extension, relieved with flexion Tx: NSAIDs, PT, joint steroid injections

Question 31

Lumbar stenosis

Answer 31

Slowly progressive pain in back and legs, worse walking, relieved with flexion narrowing of spinal canal (disc, osseous thickening, ligament flavum thickening) Tx: PT, gait aid (walker), NSAIDs, epidural steroids, sometimes surgery

Question 32

Compression fracture (spine)

Answer 32

usually in weaker anterior triangle part of lumbar vertebre usually with osteoporosis, many asymptomatic sudden onset, worse with flexion/movement usually no leg pain local tenderness, painful ROM, normal neuro Tx: NSAIDs, acetaminophen, calctonin, mild opiods, bracing, workup osteoporosis or malignancy suspect

Question 33

Cauda Equina Syndrome

Answer 33

Leg pain, numbness, weakness, saddle anesthesia, bowel/bladder dysfunction usually herniated disc compressing cauda equina absent reflexes, weakness, decreased rectal tone Tx: surgical emergency

Question 34

Cervical myopathy

Answer 34

loss of fine motor skills, gait disturbance, BB dysfunction, motor weakness, LE numbness, >50yo upper and lower motor neuron findings, hyperreflexia Lhermitte, Romberg + wide base, ataxic spinal cord compression, uaually osteophyte Tx: surgery, laminectomy

Question 35

Scoliosis

Answer 35

lateral and rotational curve of spine

Question 36

Kyphosis

Answer 36

hunchback, flexion of thoracic spine

Question 37

Lordosis

Answer 37

Swayback, accentuated extension of lumbar spine

Question 38

Spondylolysis

Answer 38

congenital defect or acquired stress fracture of the lamina, usually L5-S1 site Scottie dog with a collar

Question 39

Spondylolisthesis

Answer 39

Bilateral (dislocation) and anterior displacement of L5 body body and transverse process Scottie dog with broken neck

Question 40

Slipped Capital Femoral Epiphysis (SCFE)

Answer 40

overweight early adolescent with groin and knee pain, often bilateral repititive overload, vague sx, worse with activity limited hip internal rotation, visible on XRay Tx: surgery

Question 41

Transient Synovitis of the hip

Answer 41

ages 3-10, usually viral, post-vaccine, or drug induced holds hip flexed and external rotated, motion causes pain test: sed rate increased, leukocytosis Tx: NSAIDs

Question 42

Septic Joint

Answer 42

``` from gonorrhea or skin flora swollen, painful joint ROM extreme pain red, hot joint, usually systemic signs Tx: surgical drainage+ IV antibiotics ```

Question 43

Osgood-Schlatter Condition

Answer 43

Muscle pulls off a small piece of bone due to weak immature skeleton Tibial tubercle

Question 44

Apophysitis

Answer 44

Pain and inflammation of ossification centers from repetitive tension (can lead to bony knob on anterior knee) Tx: activity, stretching, NSAIDs

Question 45

Effusions vs Bursitis vs Ganglions

Answer 45

Effusion: fluid in joint, uniform and diffuse, non-mobile Bursitis: usually squishy, localized and mobile Ganglion: fluid filled soft tissue mass, usually hard, common on wrist, relatively small

Question 46

Unhappy Triad

Answer 46

Rupture of ACL, MCL, and lateral meniscus

Question 47

Lachman test

Answer 47

Knee slighlty bent, pull forward on tibia-> ACL tear

Question 48

Compartment syndrome

Answer 48

When pressure builds inside a compartment enough to cut off blood supply can be due to edema or exertional Exertional: anterior tibia most common