Hand

Hand

1. Thenar Muscles

   • Opponens pollicis
     • to oppose the thumb, it draws 1st metacarpal medially to center of palm and rotates it medially
       • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
         • Distal: Lateral side of 1st metacarpal
   • Abductor pollicis brevis
     • abducts thumb; helps oppose it
       • Distal: lateral side of base of proximal phalanx of thumb
         • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
   • Flexor Pollicis brevis (superficial and deep head)
     • Supeficial head: Recurrent brach of median nerve (C8,T1)
       • Distal: lateral side of base of proximal phalanx of thumb
         • Origin: Flexor retinaculum and tubercles of scaphoid and trapezium
     • Deep head: deep branch of ulnar nerve
   • Recurrent branch to the medial nerve (C8,T1)

2. Hypothenar Muscles

   • Abductor digiti minimi
     • Abducts 5th digit; assist in flexion of its proximal phalanx
       • Origin: pisiform
         • medial side of base of proximal phalanx of 5th digitDistal: Medial
   • Opponens digiti
     • draws 5th metacarpal anterior and rotates it, bringing 5th digit into opposition with thumb
       • Origin: Hook of hamate and flexor retinaculum
         • Distal: Medial border of 5th mertacarpal
   • Flexor digiti minimi brevis
     • Flexes proximal phalanx of 5th digit
       • Origin: Hook of hamate and flexor retinaculum
         • Distal: medial side of base of proximal phalanx of 5th digit
   • Deep branch of ulnar nerve (C8,T1)

3. Short Muscles

   • Lumbricals 1&2
     • Flexes metacarpophalangeal joints; extend interphalangeal joints
       • Origin: lateral two tendons of flexor digitorum profundus
         • Distal: Lateral sides of extensor expansions of 2nd - 5h digits
     • Exception: Innervated by Median nerve (C8,T1)
   • Lumbricals 3&4
     • Flexes metacarpophalangeal joints; extend interphalangeal joints
       • Distal: Distal: Lateral sides of extensor expansions of 2nd - 5h digits
         • Origin: Medial three tendons of flexor digitorum profundus
   • Dorsal Interossei 1-4th
     • Abduct 2nd- 4th digits from axial line; act with lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
       • Origin: Adjacent sides of two metacarpals
         • Distal: bases of proximal phalanges, extensors expansions of 2nd - 4th digits
   • Palmar interossei 1-3rd
     • Adducts 2nd, 4th, and 5th digits toward axial line; assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints; extensor expansions of 2nd - 4th digits
       • Origin: palmar surface of 2nd, 4th, and 5th metacarpals
         • Distal: bases of proximal phalanges, extensor expansions of 2nd, 4th, and 5th digits
   • Deep branch of ulnar nerve (C8,T1)

4. Adductor

   • Adductor pollicis oblique head and transverse head
     • adducts thumb toward lateral border of palm
     • Oblique head origin: bases of 2nd and 3rd metacarpals, capitate, and adjacent carpals
       • transverse head origin: anterior surface of shaft of 3rd metacarpal
         • Distal: medial base of proximal phalanx of thumb
   • Deep branch of ulnar nerve (C8, T1)