hand Flashcards
what is the central slip
terminal EDC tendon, inserts on base of middle phalanx, PIP extension
what is the terminal extensor tendon
convergence of lateral bands (contributions from common extensor and intrinsics), inserts on base of distal phalanx
whats the most radial structure in the carpal tunnel
FPL tendon
action of intrinsics
flex MCP and extend PIP
where do lumbricals originate
radial aspect of FDP tendon
where do lumrbicals insert
radial lateral bands
lumbrical innervation
radial two innervated by median nerve, ulnar two by ulnar nerve
which muscles are innervated by the median nerve
pronator teres, FDS, FCR, PL, radial two lumbricals.
what does AIN innervate
FPL, index and long FDP (long 50% of the time), PQ
what does the recurrent motor branch of the median nerve innervate
APB, opponens pollicis, superficial head of FPB
what does the ulnar nerve innervate
FCU, ring/small/long (50% of the time) FDP, ulnar two lumbricals
what does the deep motor branch of the ulnar nerve innervate
interossei, ADM, flexor digiti minimi, palmaris brevis, deep head of FPB
what does the radial nerve innervate
lateral brachialis, triceps, anconeus, BR, ECRL, ECRB
what does the PIN innervate
APL, EPB, EPL, EIP, EDC, EDM, ECU, supinator
scaphoid view xray
30 degrees wrist extension, 20 degrees ulnar deviation
most common vascularized bone graft for proximal pole scaphoid AVN
1,2 ICSRA (dorsal distal radius) - but not if humpback deformity
what approach do you use for a scaphoid humpback deformity
volar
SNAC stage 1
radioscaphoid arthritis
SNAC stage 2
involvement of scaphocapitate joint
SNAC stage 3
involvement of lunocapitate joint
treatment for SNAC stage 1
distal pole excision or radial styloidectomy
treatment for SNAC stage 2 or 3
PRC (lose some motion and strength), 4 corner fusion, wrist fusion
ligament disrupted in DISI
scapholunate (dorsal fibers stronger)
ligament disrupted in VISI
lunotriquetral interosseous ligament (volar fibers stronger)
what ligament must be preserved in PRC and why
radioscaphocapitate ligament to prevent ulnar subuxation
acceptable angulation for metacarpal neck fractures
index and long fingers <15-20, ring <30-40, small <70
acceptable angulation for metacarpal shaft fracture
index and long <10, ring and small <30
deforming forces in bennett fracture
APL and thumb extensors displace shaft proximal, dorsal, radial. adductor pollicis supinates and adducts shaft
extensor tendon zones
1 - at/distal to DIP, 2 - middle phalanx, 3 - PIP, 4 - proximal phalanx, 5 - MCP, 6 - metacarpal, 7 -wrist, 8 - distal forearm
mallet finger
zone 1 extensor tendon injury
treatment for acute mallet finger
in first 12 weeks - full-time DIP joint extension splinting x 6 weeks, part time x 4-6 weeks. ORIF if large bony fragment (>50%)
what percentage of extensor tendon laceration requires operative repair
> 50%
boutonierre deformity
zone 3 extensor tendon injury (central slip at PIP). volar subluxation of lateral bands causes DIP hyperextension
what percentage of flexor tendon laceration requires operative fixation?
> 60%
when is the risk of flexor tendon rupture greatest after repair?
3 weeks, failure occurs at suture knots
flexor tendon zones
1 - distal to FDS insertion, 2 - FDS to A1, 3 - palm, 4 - carpal tunnel, 5 - forearm
what is the most likely block to reduction for galeazzi
ECU
what position do you splint in for galeazzi with reducible DRUJ
supination