Hand Flashcards
8 carpal bones of the hand
see attached image
Sensory distribution of nerves on hand
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Which intrinsic muscles of hand does radial nerve innervate?
Trick question- none. All intrinsic muscles of hand innervated by either median or ulnar nerve
Which intrinsic muscles of hand does ulnar nerve innervate?
Opponens pollicis, 3rd and 4th lumbricals, hypothenar group (opponens digiti minimi, flexor digiti minimi, abductor digiti minimi), palmaris brevis
Which intrinsic muscles of hand does the median nerve innervate?
All others. Includes rest of thenar group (abductor and adductor pollicis brevis, flexor pollicis brevis), palmar/dorsal interossei, 1st and 2nd lumbricals
Which hand tendon repairs can usu fixed in ER?
Extensor tendon lacs. Flexor tendons are more difficult to repair.
Extrinsic muscles of the hand innervation
Extensor muscles: radian nerve. All the rest are median, with exception of flexor carpi ulnaris (ulnar), and medial flexor digitorum profundis (ulnar)
Flexor tendon zones of the hand
Zones I and II: 1-3 weeks for repair. Zones III-V: immediate repair warranted. see attached image
Extensor tendon zones of the hand
see attached image
What is the “safe” position for hand splinting prior to hand surgery?
see attached image
Felon
Infection of pulp space of any of the distal phalanges, caused by minor trauma over finger pad. Complications: cellulitis, flexor tendon sheath infection, osteomyelitis. Tx: I&D (NOT over flexor crease of DIP). Abx: 1st gen cephalosprin for staph
Paronychia
Infection of the lateral nail fold, caused by nail biting, manicures. Tx: if non-fluctuant, 7 days abx, warm soaking. If fluctuant, I&D, usu don’t need abx unless cellulitis present.
Tenosynovitis
Surgical emergency! Infection of flexor tendon and sheath due to penetrating trauma/dirty wound (e.g. dog bite). Infection can spread along sheath and involve other digits. Organisms: polymicrobial, Staph, Gonorrhea. Tx: Immobilize and elevate hand, IV abx, consult hand surgery stat.
Gamekeeper’s thumb (aka skier’s thumb)
Avulsion of ulnar collateral ligament of first MCP joint due to forced abduction of thumb -> inability to pinch. Tx: thumb spica cast 3-6 wks for partial, surgery for complete tear.
Carpal tunnel syndrome causes
Tumor (lipoma, fibroma), ganglion cyst, tenosynovitis (2/2 RA, trauma), edema (pregnancy, thyroid dz, amyloid), gout, trauma to carpal bones
Ganglion cyst
Synovial cyst caused by leakage of synovial fluid from joint into surrounding tissue. Most commonly on radial wrist. Dx: xray should show no changes since it is soft tissue deal. Tx: reassurance, aspiration if severe pain, surgery if median nerve compression or really ugly.
Mallet finger
Rupture of extensor tendon at insertion into distal phalanx -> inability to extend DIP. Splint for 6-8 weeks, surgery may be needed for those injuries not splinted early.
Trigger finger
Stenosis of tendon sheath flexor digitorum leading to nodule formation within the sheath -> snapping or clicking when flexing and extending the digit. Tx: splint MP joint in extension, steroid injection, surgical release if these fail.
High pressure injection injuries
For example from grease gun, spray gun. Can appear harmless puncture at first but progresses to more severe pain, swelling, tissue necrosis in 24 hrs. Tx: IV abx, I&D by surgery team, amputation may be necessary.
Scaphoid fracture
Snuffbox tenderness. May not show up on radiographs for 2 weeks so if xray negative, immobilize in thumb spica cast and reimage in a few weeks
Colles’ fracture
Distal radius fracture, fall on outstretched hand. Tx: short arm cast 4-6 weeks unless complexity requires surgery
What is a thumb spica cast anyway?
see attached image
