MSK Flashcards
4 Types of Bone Cells
- Osteoprogenitor: proliferate to form osteoblasts
- Osteoblasts: mineralization, bone remodelling, can become osteocytes
- Osteocytes: centrepiece of boney matrix
- Osteoclasts: bone breakdown
Muscle Hierarchy
- Myofilaments (myosin + actin)
- Sarcomere
- Myofibres
- Muscle fibres (covered by endomyseium)
- Muscle fasciculus (covered by perimyseium)
- Muscle (covered by epimyseium)
Tendon vs Ligament
- Tendon: muscle-bone, more collagen, limited perfusion, best for large uni-directional loads
- Ligament: bone-bone (“like”), less collagen, limited perfusion, better for multi-directional loads
3 Types of Joints
- Fibrous: little/ no mvmnt, skull
- Cartilaginous: some mvmnt, femur, bw vertebrae
- Synovial: ball + socket (hip), condyloid (MCP), saddle (CMC), hinge (elbow), pivot (atlanto-axial), plane (acromioclavicular)
3 Types of Cartilage
- Fibro: transitional cartilage, labrum, menisci
- Elastic: outer ear, epiglottis
- Hyaline/ Articular: thin, dense, translucent, no BVs/ lymphatic channels/ innervation
MSK Embryology
- Somites: condensed cuboidal mesoderm tissue, form majority of MSK system, axial specification (same fncn even in a new spot).
- Ossification (bone formation):
- Intramembranous: bone directly from mesoderm. (mesoderm → mesenchymal cell → osteoblasts → secrete collagen matrix → Ca pulled into the matrix → Ca lays down spicules of bone → connect to each other over time → bone)
- Endochondral: bone from hyaline cartilage model. (mesoderm → chondrocytes (committed cartilage cells) → compact nodules → proliferating chondrocytes → hypertrophic chondrocytes → atrophy → angiogenesis here → brings Ca → bone) (then secondary ossification of the epiphyseal plate after growth)
Congenital Defect - Achondroplasia
- FGF 3 - auto dom defect
- Affects cartilage production → affects endochondral formation (no cartilage model for elongation) → ↓ limb bone length BUT normal head size/ skull/ calvarium bc intramembranous formation unaffected.
Acute Injury - “SHARP”
- SHARP: swelling, heat, altered fncn, red, pain
- From 1 single event
- Quick onset of sx
- Usually worst during 48-72 hrs post-injury
- Tx: RICE: rest, ice, compression, elevation
3 Degrees of a Sprain (Ligament)
- Minor: can weight bear, little swelling, no laxity/ solid end feel.
- Tx: RICE + max 7-10 days non-wt bearing - Moderate: muscle spasms, partial laxity, some swelling and dec ROM, point tenderness, usually can’t wt bear
- Tx: RICE + 2-4 wks non-wt bearing. Expect full healing with immobilization with full healing expected. - Severe: laxity/ empty end feel, big dec ROM, can not wt bear
- Tx: RICE, 4-6 wks non-wt bearing, possibly surgical repair.
3 Degrees of a Strain (Muscle)
- Minor: DOMS, small dec ROM, can generate force + maintain contraction
- Moderate: muscle spasms, sub-optimal muscle contraction, big dec ROM, lots of pain + swelling
- Severe: visible deformity, can’t contract, no ROM.
3 Types of Fracture
- Sudden impact #: normal bone + abnormal force
- Stress #: normal bone + repetitive force
- Pathologic #: abnormal bone + normal force (underlying disease)
Tendonitis/ Tendinopathy
- Itis = acute inflammation
- Opathy = chronic, less of an inflammatory component
- From chronic eccentric loading of musculotendinous region
Ectopic Calcification/ Myositis Ossificans
- Bone formation in or around muscle
- From severe or repetitive contusions, or continuous use of injured muscle
Osteoarthritis
- Progressive degeneration of a joints articular cartilage
- Location:
Rheumatoid Arthritis
- Location:
Compartment Syndrome
- Inc interstitial pressure in an enclosed myofascial compartment
- Hallmark = pain with passive stretch
- Can compromise muscle, nerve, and vascular function
- S+S: pain out of proportion with injury, ↓ muscle fncn, ↓ neuro + vascular response distal to injury (ie diminished pulse or sensation).
“Osteo-“ Diseases
- Osteoarthritis: separate card
- Osteoporosis: primary (age, post-menopause, ↓ estrogen/ Ca/ exercise) & secondary (Vit D def, corticosteroids)
- Osteopenia: bone mineral density (BMD) < peak BMD, but not yet osteoporosis
- Osteomalacia: ↓ Vit D, Ca, or PO4 - soft, weak bones. S+S: bowing of long bones, frontal bossing, etc. (Rickets in children)
- Osteomyelitis: inflamm/ infection, esp in metaphysis, mostly in kids, severe pain, tenderness with mvmnt, spread via hematogenous seeding
- Osteosarcoma: bone cancer, usually <20 yrs, S+S: painful enlarging mass, usually from mets (PB-KTL)
- Osteogenesis Imperfecta: aka brittle bone disease, • auto dom, ↓ collagen synthesis, S+S: blue sclera, hearing loss, many #s
Carpal Tunnel Syndrome
- (Carpal tunnel contains: flexor digitorum superficialis + profundus tendons, flexor pollicis longus tendon, and median nerve. Roof = flexor retinaculum)
- Feel pain/ numbness/ tingling from the median nerve being compressed
- Test: tap for 60 secs bw scaphoid tubercle + pisiform → numbness in median distribution
Wrist # - Colles & Scaphoid
1) Colles #
- Distal radial #
- 60% will have associated ulnar styloid # → “dinner fork/ bayonet deformity” (wrist shifted dorsally like the curve of a fork)
- Tx: hematoma block (local anesthetic into the # site) → traction → closed reduction + appropriate pressure (volar + ulnar in this case) → splint → repeat
2) Scaphoid #:
- FOOSH → Xray can be normal at first, but TREAT anyways if radial snuffbox pain/ tenderness + limited ROM
- Immobilize with thumb spica splint & re-assess in 2 wks bc ↑↑ risk of non-union and of AVN (↓ blood supply)
- If # present → immobilize for 6-12wks (we care less about stiffness in this case)
Epicondylopathy (tennis + golfer’s elbow)
1) Tennis elbow/ lateral epicondylitis
- Lateral epicondyle, extensor muscle tendons are overworked (think backhand in tennis) → micro tears → new unorganized collagen + vessels and nerves
- Test: resisted wrist extension
2) Golfers elbow/ medial epicondylitis
- Medial epicondyle, flexor muscle tendons are overworked.
- Less common but worse than tennis elbow, associated with ulnar n. issues
- Test: resisted wrist flexion
Tx:
- 3 mos = steroid injections (controversial)
- 6 mos-1 yr = surgery (~30%, debride the tendon)
- Anti-inflammatories DON’T work bc not “itis”
GH Dislocation
- Glenoid + humerus separate (subluxation if partial), humeral head moves anteriorly 95% of the time
- Usually when in external rotation + abduction.
Associated injuries:
- Hill-Sachs: depression # on posterior humeral head from the head being compressed against the bony glenoid rim
- Bankart lesion: labrum damage, in 95% of ppl from their first dislocation
- SLAP injury: labrum damage.
Tx:
- Closed reduction, sling, early ROM
- Deciding on surgery:
- -> AMBRI: atraumatic, multidirectional, bilateral, rehab focus, inferior capsular release. (These pts don’t do as well with surgery, so strengthen + correct mechanics)
- -> TUBS: traumatic, unidirectional, bankart lesion, surgery.
Salter-Harris # (pic in folder)
- A # that involves the growth plate/ epiphyseal plate in the metaphysis (so, common in kids)
- Type 1: S-straight, transverse #, don’t see on x-ray, heals rapidly, growth usually unaffected
- Type 2: A-above, across plate + metaphysis (most common)
- Type 3: L-low, across plate + epiphysis, chronic disability from the articular cartilage healing with fibrous cartilage (ie early OA), but no deformity, so ok prognosis, often surgical tx or reduction
- Type 4: T-through all, across plate + epiphysis + metaphysis, chronic disability + deformity, more likely to produce growth arrest
- Type 5: ER-cRush, crush/ compression # of growth plate (poor fncnal prognosis)
MSK - Finger Abnormalities (pic in folder)
1) Mallet finger: hyperflexion of the extensor digitorum tendon to DIP
- Tx: dorsal splint the DIP joint in full extension – don’t ever let it come into flexion or you’re starting all over again, 4-6 wks for bone injury, 6-8 wks for tendon injury
2) PIP injury/ Boutonniere (“Button-hole” deformity):
- Sprained PIP –> PIP flexion + DIP hyperextension
- Tx: need to tx fast, splint finger in extension
3) Boxer’s #: 5th metacarpal neck #, with the metacarpal head displaced in the volar (palm) direction
- Assess rotatinal deformity, allow up to 30° of volar angulation (normal = 15°)
- Tx: >30° needs to have a closed reduction with hematoma block + 90/90 position (90° flexion at MCP + 90° flexion at PCP)
- Tx: “buddy tape” 5th digit to 4th digit via ulnar gutter splint or cast for 4-6 wks (in MCP flexion to keep the ligaments long)
Ligaments of the Knee
1) MCL (medial collateral ligament): fan-shaped, not easily palpable.
- Fncn: resists valgus force
- Attached to medial meniscus so often injured together
- Test with valgus stress test, look for laxity
2) LCL (lateral collateral ligament): cord-like, easily palpated.
- Fncn: resists varus force.
3) ACL (ant cruciate ligament): ant portion of intercondylar eminence on tibia → runs posteriorly → attaches on medial aspect of lateral femoral condyle.
- Fncn: prevents tibia from sliding anteriorly on femur.
- Most commonly injured. MUCH more likely to get OA, and earlier.
- Test with ant drawer + Lachman’s maneuver
- Tx: surgery helps return to original fncn but doesn’t improve overall prognosis.
4) PCL (post cruciate ligament): post portion of intercondylar eminence on tibia → runs anteriorly → attaches on lateral aspect of medial femoral condyle.
- Fncn: prevents tibia from sliding posteriorly on femur.
5) Meniscus: medial (C-shape, attached to MCL) + lateral (O-shape, attached to popliteus muscle)
- Location of tear determines healing, only outer 1/3 has a blood supply
- Test with McMurray’s test
- Tx: arthroscopy surgery is the gold std
Unhappy triad: torn ACL + MCL + medial meniscus
Hip Dislocation (DRRIFT) vs # (BREAKS)
DRRIFT
- aDduction, Reduction, Rotate Internally, Flexion, Trauma
- 90% posterior dislocations
- ER, reduce ASAP, check neurovascular before + after
- Osteonecrosis in 10%
BREAKS
- aBduction, Rotate Externally, Avascular necrosis, Kills 10-30% in 1 yr, Surgery w/i 48 hrs.
- Usually from lower energy impact
Avascular Necrosis (AVN)
- Most common places: hip, scaphoid, talus, femoral head
- Hip causes: “ASEPTIC” - alcoholism, steroids, environ (temp injury), pancreatitis/ pregnancy, trauma, infection/ idiopathic, congenital
- Best is MRI. Will see lucency (black) on x-ray
Osgood Schlatter’s Disease
- Avulsion injury of the patellar tendon from the apophysis of the tibial tuberosity from repeated eccentric quad activity
- Esp seen in 12-15 yro M
- Sx: swelling, tenderness, ↑ tibial tubercle prominence, unilateral or bilateral lower extremity pain, worse with exercise, esp running and jumping
- NO restrictions of ROM, and knee + PFJ joints should be stable (more of a strength issue)
- Imaging: bilateral = don’t image, unilateral = image (r/o more dangerous causes)
- Tx: self-limiting, but may take mo-yrs to resolve (when the epiphyses closes during late adolescence the pain goes away), relative rest, RICE, brace
Patellofemoral Joint Pain Syndrome
- Most common knee complaint in active young people (25%)
- Sx: diffuse aching pain in retro-patellar region of the knee, grinding + swelling in patellar region
- Dx: Theatre sign (pain from sitting a long time without extending knee), Clarke’s sign (pt contracts quads, push down on patella)
Achilles Tendon Rupture
- Tendon rupture of soleus, plantaris, + gastrox, 5-7 cm proximal to the insertion onto calcaneus
- Esp in middle aged men
- Sx: sudden, severe pain, maybe a “pop”, v hard to walk after (plantar flexion affected).
- Dx: a divot seen on posterior calf, swelling, Thompson test (squeeze calf from either side → should see slight plantar flexion of the foot, otherwise + test).
- Tx: immobilize in plantar flexion, no wt bearing, may need surgery
Ankle Sprain
- 85% inversion (medial malleolus is shorter so doesn’t restrict inversion as much, and fewer/ weaker lateral ligaments)
Ligament sprained often dictated by position during injury:
- *Plantarflexion + inversion → ATF Damage
- Mid-stance + inversion → CF damage
- Dorsi flexion + inversion → PTF damage
- Plantar flexion → ATF + ant tib-fib + ant TT ligament damage
- Eversion sprains usually from dorsiflexion + eversion → damage to deltoid ligament complex.
Degrees
- 1st: more of a stretch (usually ATF), can wt bear, full ROM. Full recovery, back to activity in 2-3 days.
- 2nd: some stretch + tear (usually ATF + CF), can’t wt bear, dec ROM. Recovery in 2-4 wks, rest, brace.
- 3rd: tear several (ATF + CF + PTF +/- talo-crural joint dislocation)
- 2nd & 3rd: + ant drawer or talar tilt test, always IMAGE to check for #s
Ankle #
- Stable #: only 1 side of the joint, determined by evaluating the medial clear space (>5mm suggests unstable)
- Unstable #: both sides of the joint:
- -> Bimalleolar #: both malleoli, usually from forced eversion + torsion of the foot
- -> Trimalleolar #: both malleoli + talus forced posteriorly → breaks posterior lateral margin of tibia for the 3rd #
- Potts #: fibular # above lateral malleolus + medial malleolus #
- Avulsion #: ligament/ tendon pulls piece of bone away at attachment to foot or ankle, often seen with 3rd degree
Shin Splints/ Tibial Stress Syndrome
- Stress in lower leg isn’t absorbed properly/ legs can’t remodel fast enough → stress reaction in the fascia, bone or periosteum → overuse injury
a) Anterior
b) Posterior/ medial + distal 1/3 of the tibia - No night pain
