Muscles of the Hand

Muscles of the hand • • Extrinsic muscles of the hand arise in the foreman (described above) * Intrinsic muscles of the hand are organised into five compartments. Interosseous compartment • Located between the metacarpals. Name Origin Insertion Dorsal Adjacent sides of • 1 & 2: Radial bases of interossei metacarpal proximal bones 1-5 phalanges/extensor expansions of digits 2 & 3 • 3 & 4: Ulnar bases of proximal phalanges/extensor expansions of digits 3 and 4 Palmar Ulnar side of • 1: Ulnar base of proximal interossei metacarpal bone phalanx/extensor 2, Radial side of expansion of digit 2 metacarpal • 2 & 3: Radial base of bones 4 and 5 proximal phalanges/extensor expansions of digits 4 and 5 Innervation Function Deep branch of • Metacarpophalangeal ulnar nerve (C8 joints 2-4: Finger – T1) abduction, finger flexion. • Interphalangeal joints 2-4: Finger extension Deep branch of ulnar nerve (C8-T1) • • Metacarpophalangeal joints 2,4 & 5: Finger adduction, Finger flexion. Interphalangeal joints 2,4 & 5: Finger extension Central compartment • With long flexor tendons Name Origin Lumbricals Tendons of flexor digitorum profundus muscle Insertion Extensor expansion hand Innervation Function • Lumbricals 1-2: • Metacarpophalangeal of Median nerve (C8joints 2-5: Finger T1) flexion • Lumbricals 3-4: • Interphalangeal joints Ulnar nerve (C82-5: Finger extension T1) • Mnemonic: '1 2 me, 3 4 u' (One to me, three for you) Thenar Compartment • Located at the base of the thumb for the thumb movement Name Origin Insertion Innervation Opponens Tubercle of trapezium Radial border of Recurrent branch pollicis bone, flexor metacarpal bone median nerve (C8, T1) retinaculum 1 Function of Carpometacarpal joint 1: Thumb opposition Abductor pollicis brevis Tubercles of scaphoid Lateral aspect of Recurrent branch of and trapezium bones, base of proximal median nerve (C8, T1) Flexor retinaculum phalanx 1 (via radial sesamoid bone) Lateral aspect of • Superficial • Superficial head: base of proximal head: Flexor Recurrent branch phalanx 1 (via retinaculum, of median nerve tubercle of radial sesamoid • Deep head: Deep bone) trapezium branch of ulnar bone nerve (C8, T1) • Deep head: Trapezoid and capitate bones Flexor pollicis brevis Carpometacarpal joint 1: Thumb abduction Carpometacarpal and metacarpophalangeal joint 1: Thumb flexion Hypothenar Compartment • Name Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis Located at the base of the cute little fingers. Origin Insertion Innervation Hook of hamate bone, Ulnar aspect of Deep branch of ulnar nerve flexor retinaculum metacarpal bone (C8, T1) 5 Pisiform bone Ulnar side of base • Metacarpophalangeal (Pisohamate of proximal joint 5: Finger ligament, Tendon of phalanx of digit 5, abduction and flexor carpi ulnaris) Extensor flexion. expansion of digit • Interphalangeal 5 joints: Finger extension Hook of hamate, Base of proximal Deep branch of ulnar nerve flexor retinaculum phalanx of digit 5 (C8, T1) Function Carpometacarpal joint 5: Finger flexion, finger lateral rotation/opposition Deep branch of ulnar nerve (C8, T1) Metacarpophalangeal joint 5: Finger flexion (+ finger lateral rotation/opposition) Adductor Compartment Name Adductor pollicis Origin • Transverse head: Palmar base of metacarpal bone 3 • Oblique head: Capitate bone, palmar bases of metacarpal bones 2 & 3 Insertion Innervation Function Medial base of Deep branch of ulnar nerve Carpometacarpal joint 1: proximal phalanx (C8, T1) Thumb adduction 1 (via ulnar sesamoid bone) Not Compartmentalised Muscles Name Origin Insertion Innervation Function Palmaris brevis Palmar aponeurosis, Dermis of skin of Superficial branch of ulnar Tightens palmar flexor retinaculum hypothenar region nerve (C8, T1) aponeurosis, tightens grip Blood Vessels For the following blood vessels and nerves, identify the origin, course, and major branches Arteries • • Radial - Deep palmer arch - Princeps pollicis Ulnar - Superficial palmer arch - Common palmer digital Veins • • Cephalic - Dorsal venous arch Basilic - Dorsal venous arch Nerves • • • Median - Recurrent - Palmer digital Ulnar - Superficial - Deep Radial - Superficial