Hand Anatomy

Aka: Hand Anatomy, Radial Nerve, Median Nerve, Ulnar Nerve, Superficial Palmar Arch, Deep Palmar Arch, Hand Muscle

1. See Also
   1. Wrist Anatomy
   2. Hand Injury
2. Muscles
   1. Intrinsic (Originate in hand)
      1. General
         1. Delicate finger movements
      2. Thenar and Hypothenar muscles
         1. Position thumb and small finger for pinching
      3. Interossei and Lumbricals
         1. Insert into proximal phalanges and extensor hoods
         2. Metacarpal phalangeal joint flexion
         3. Interphalangeal joint extension
   2. Extrinsic (Originate in forearm)
      1. Wrist flexors and extensors
         1. Stabilize wrist in slight dorsiflexion
      2. Finger Flexors
         1. Deep Flexors (5)
            1. Flex distal phalanges of fingers and thumb
         2. Superficial Flexors (4)
            1. Flex middle phalanges of fingers
         3. Course
            1. Under Annular ligaments (Pulleys)
            2. Between distal palmar crease and IP joint
         4. Conditions
            1. DIP Flexor Tendon Avulsion
            2. Flexor Tendon Laceration
      3. Finger Extensors
         1. Course dorsally over fingers and thumb
         2. Extend proximal phalanges
         3. Conditions
            1. Extensor Tendon Laceration
            2. DIP Extensor Tendon Avulsion
3. Blood Supply
   1. Neurovascular bundles
      1. Contain digital artery, vein, and nerve
      2. Two bundles: one radial and the other ulnar
   2. Radial and Ulnar arteries join in 2 arches
      1. Superficial Palmar Arch: superficial to flexor tendon
         1. Located at base of first web space
      2. Deep Palmar Arch (deep to flexor tendons)
         1. Proximal to superficial arch by 1 cm
4. Nerve
   1. Ulnar Nerve
      1. Motor
         1. Allows for power grip
         2. Innervates all hand intrinsic muscles except:
            1. Does not innervate two radial lumbricals
            2. Does not innervate thenar muscles
      2. Sensation
         1. Ulnar 1.5 fingers (palmar)
      3. Course
         1. Passes with ulnar artery via Guyon's Canal in wrist
      4. Test function
         1. Finger abduction against resistance
         2. Palpate belly of first dorsal interosseus muscle
      5. Conditions
         1. Cubital Tunnel
         2. Ulnar Tunnel
   2. Median Nerve
      1. Motor
         1. Allows for fine control of pincer grasp
         2. Innervates thenar muscles and two radial lumbricals
      2. Sensation
         1. Radial 3.5 fingers, and their dorsal tips
         2. Cutaneous innervation Image
            1. 
      3. Course
         1. Passes via Carpal Tunnel through volar wrist
      4. Test function
         1. Opposition of thumb to each finger
         2. Observe thenar muscles for contractions
   3. Radial Nerve
      1. Motor
         1. Innervates extrinsic wrist and finger extensors
         2. Does not innervate any intrinsic muscles
      2. Sensation
         1. Dorsally for 3.5 fingers
         2. Cutaneous innervation image
            1. 
      3. Test function
         1. Wrist and hand extension against resistance