Hand OIA Flashcards
Palmaris brevis
Origin: Flexor reticulum
Insertion: Dermis on the ulnar border
Innervation: Ulnar nerve
Main action: Wrinkles the skin of the palm
Adductor pollicis
Origin:
Oblique head: 2nd and 3rd metacarpals and capitates
Transverse head: 3rd metacarpal
Insertion: Proximal 1st phalange
Innervation: Ulnar nerve
Main action: Adduction of the thumb
Lumbricals (4 muscles)
Origin: 1st and 2nd: lateral tendons of flexor digitorum profundus
3rd and 4th: medial tendons of flexor digitorum profundus
Insertion: Lateral side of the dorsal expansion of 2-5
Innervation: Median nerve (1st and 2nd lumbricals)
Ulnar nerve (3rd and 4th lumbricals)
Main action: Flexion of the MCP, extension of DIP and PIP
Dorsal interossei (4 muscles)
Origin: Adjacent side of metacarpals
Insertion: Dorsal expansion and base of 2-4 proximal phalanges
Innervation: Ulnar nerve
Main action: Abduction of the digits, flexion of MCP and extension of IP joint
Palmar interossei (3 muscles)
Origin: Palmer surface of 2nd, 4th, and 5th metacarpal
Insertion: Doral expansion and base of 2nd, 4th, and 5th proximal phalange
Innervation: Ulnar nerve
Main action: Adduction of the digit towards the center of the hand, flexion of the MCP and extension of the IP joints
*Note that the 3rd finger does note contain a palmar interosseous muscle
Flexor pollicis brevis
Origin: Deep head: Trapezium and flexor retinaculum
Superficial head: trapezoid and capitate
Insertion: Proximal phalange of the 1st digit
Innervation: Median nerve
Main action: Flexion of the 1st digit
Opponens pollicis
Origin: Trapezium and flexor retinaculum
Insertion: Lateral side of 1st metacarpal
Innervation: Median nerve
Main action: Brings 1st digit medial to the center of the palm
Abductor pollicis brevis
Origin: Flexor retinaculum, scaphoid, and trapezium
Insertion: Proximal 1st phalange
Innervation: Median nerve
Main action: Abduction of thumb
Opponens digiti minimi
Origin: Hook of hamate and flexor retinaculum
Insertion: 5th metacarpal
Innervation: Ulnar nerve
Main action: Lateral rotation of the 5th metacarpal towards the center of the palm
Abductor digiti minimi
Origin: pisiform, tendon of the flexor carpi ulnaris
Insertion: Proximal 5th phalange
Innervation: Ulnar nerve
Main action: Abduction of the 5th digit
Flexor digiti minimi brevis
Origin: Hook of hamate and flexor retinaculum
Insertion: Proximal 5th phalange
Innervation: Ulnar nerve
Main action: Flexion of the 5th MCP joint
