Hand Surgery Basics

Hand Anatomy - Bones, Nerves, & Grips

• Bones (27):
  • Carpals (8): Proximal row (Scaphoid, Lunate, Triquetrum, Pisiform), Distal row (Trapezium, Trapezoid, Capitate, Hamate). 📌 Some Lovers Try Positions That They Can't Handle.
  • Metacarpals (5)
  • Phalanges (14: Proximal, Middle, Distal)
• Nerves:
  • Median: Thenar eminence (APB, FPB, OP), Lumbricals 1&2. Sensory: Palmar radial 3.5 digits.
  • Ulnar: Hypothenar, Interossei, Adductor Pollicis, Lumbricals 3&4. Sensory: Ulnar 1.5 digits.
  • Radial: Wrist/finger/thumb extensors. Sensory: Dorsal radial hand.
• Vascular: Superficial & Deep Palmar Arches. Allen's Test (checks patency of radial/ulnar arteries before procedures).
• Grips:
  • Power: Cylindrical, Spherical, Hook.
  • Precision: Pincer (tip-to-tip), Tripod (3-jaw chuck).

⭐ Scaphoid is the most commonly fractured carpal bone, often presenting with tenderness in the anatomical snuffbox. It has a tenuous retrograde blood supply, predisposing to avascular necrosis and non-union if fractured, especially at the waist or proximal pole.

Hand Examination - Sleuth Skills

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Common Hand Conditions - Daily Woes

• Fractures:
  • Scaphoid Fx: FOOSH, anatomical snuffbox tenderness. High AVN risk.
  • Boxer's Fx: 5th metacarpal neck fracture, punch injury.
• Tendon Injuries & Deformities:
  • Mallet Finger: Forced DIP flexion; extensor tendon avulsion at DIP.
  • Boutonniere Deformity: PIP flexion, DIP hyperextension (central slip rupture).
  • Swan Neck Deformity: PIP hyperextension, DIP flexion (volar plate injury).
• Nerve Compressions:
  • Carpal Tunnel Syndrome (CTS): Median nerve compression; Phalen's, Tinel's.
  • Cubital Tunnel Syndrome: Ulnar nerve at elbow; Froment's sign.
• Other Conditions:
  • Dupuytren's Contracture: Palmar fascia thickening & contracture (ring/little).
  • Trigger Finger: Stenosing tenosynovitis at A1 pulley; locking.
  • De Quervain's Tenosynovitis: 1st dorsal (APL, EPB); Finkelstein's test +.
  • Flexor Sheath Infection: 📌 Kanavel's signs (surgical emergency):
    • Fusiform swelling (Sausage digit)
    • Finger held in slight Flexion
    • Pain on passive Extension
    • Tenderness along tendon Sheath

⭐ Scaphoid fracture: Most common carpal bone fracture; proximal pole high AVN risk due to retrograde blood supply.

Hand Surgery Essentials - Fix-It Tricks

• Incisions:
  • Brunner (zig-zag volar) prevents contractures.
  • Mid-lateral for digits; avoid crossing flexion creases at 90°.
• Anaesthesia:
  • Digital Block: Webspace or volar approach.
  • Bier's Block (IVRA): Prilocaine preferred; double tourniquet.
• Tendon Repair:
  • Core sutures (e.g., Kessler, Bunnell) + epitendinous suture.
  • Goal: Strong, smooth repair for early protected motion.
• Nerve Repair:
  • Epineural (common) or fascicular (group). Tension-free coaptation.
• Reimplantation:
  • Sequence: Bone → Extensors → Flexors → Arteries → Nerves → Veins (📌 Boys Eat Fish And Nice Veg).
  • Warm ischemia: Digit <6 hrs; Proximal <4 hrs.
• Splinting (Post-op):
  • Position of safety (Intrinsic Plus): Wrist ext 20-30°, MCP flex 70-90°, IP ext.

⭐ Flexor tendon Zone II ("No Man's Land") injuries carry the poorest prognosis due to high adhesion risk.

High‑Yield Points - ⚡ Biggest Takeaways

• Allen's test confirms dual blood supply (radial/ulnar arteries) before hand procedures.
• Kanavel's signs (flexion, fusiform swelling, pain on extension, tenderness) indicate flexor tenosynovitis.
• Mallet finger: extensor tendon avulsion at DIP, causing extension lag.
• Boutonniere deformity: PIP flexion and DIP hyperextension from central slip rupture.
• Scaphoid fractures: most common carpal fractures, risk avascular necrosis; check anatomical snuffbox.
• Carpal Tunnel Syndrome: median nerve compression diagnosed by Phalen's and Tinel's signs.