Intrinsic muscles of the hand Flashcards
Palmaris brevis
Origin:
- Palmar aponeruosis and flexor retinaculum
Insertion:
- Dermis of skin on the medial margin of the hand
Innervation:
- Superficial branch of the ulnar nerve (C8, T1)
Function:
- Improves grip
Dorsal interossei (four muscles)
Origin:
- Adjacent sides of the metacarpals
Insertion:
- Extensor hood and base of proximal phalanges of index, middle and ring fingers
Innervation:
- Deep branch of ulnar nerves (C8, T1)
Function:
- Abduction of index, middle and ring fingers at the metacarpophalangeal joints
Palmar interossei
Origin:
- Sides of metacarpals
Insertion:
- Extensor hoods of the thumb, index, ring and little fingers and the proximal phalanx of thumb
Innervation:
- Deep branch of ulnar nerve (C8, T1)
Function:
- Adduction of the thumb, index, ring, and little fingers at the metacarpophalangeal joints
Adductor pollicis
Origin:
- Transverse head - metacarpal III;
- Oblique head - capitate and bases of metacarpals II and III
Insertion:
- Base of proximal phalanx and extensor hood of thumb
Innervation:
- Deep branch of ulnar nerves (C8, T1)
Function:
- Adducts thumb
Lumbricals
Origin:
- Tendons of flexor digitorum profundus
Insertion:
- Extensor hoods of index, ring, middle and little fingers
Innervation:
- Medial two by the deep branch of the ulnar nerve;
- lateral two by digital branches of the median nerve
Function:
- Flex metacarpophalangeal joints while extending interphalangeal joints
Opponens pollicis (thenar muscle)
Origin:
- Tubercles of trapezium and flexor retinaculum
Insertion:
- Lateral margin and adjacent palmar surface of metacarpal I
Innervation:
- Recurrent branch of median nerve (C8, T1)
Function:
- Medially rotates thumb
Abductor pollicis brevis
Origin:
- Tubercles of scaphoid and trapezium and adjacent flexor retinaculum
Insertion:
- Proximal phalanx and extensor hood of thumb
Innervation:
- Recurrent branch of median nerve (C8, T1)
Function:
- Abducts thumb at metacarpophalangeal joint
Flexor pollicis brevis
Origin:
- Tubercle of the trapezium and flexor retinaculum
Insertion:
- Proximal phalanx of the thumb
Innervation:
- Recurrent branch of median nerve (C8, T1)
Function:
- Flexes thumb at metacarpophalangeal joint
Opponens digiti minimi
Origin:
- Hook of hamate and flexor retinaculum
Insertion:
- Medial aspect of metacarpal V
Innervation:
- Deep branch of ulnar nerve (C8, T1)
Function:
- Laterally rotates metacarpal V
Abductor digiti minimi
Origin:
- Pisiform, the pisohamate ligament, and tendon fo flexor carpi ulnaris
Insertion:
- Proximal phalanx of little finger
Innervation:
- Deep branch of ulnar nerve (C8, T1)
Function:
- Abducts little finger at metacarpophalangeal joint
Flexor digiti minimi brevis
Origin:
- Hook of hamate and flexor retinaculum
Insertion:
- Proximal phalanx of little finger
Innervation:
- Deep branch of ulnar nerve (C8, T1)
Function:
- Flexes little finger at metacarpophalangeal joint
Origin:
- Palmar aponeruosis and flexor retinaculum
Insertion:
- Dermis of skin on the medial margin of the hand
Innervation:
- Superficial branch of the ulnar nerve (C8, T1)
Function:
- Improves grip
Palmaris brevis
Origin:
- Adjacent sides of the metacarpals
Insertion:
- Extensor hood and base of proximal phalanges of index, middle and ring fingers
Innervation:
- Deep branch of ulnar nerves (C8, T1)
Function:
- Abduction of index, middle and ring fingers at the metacarpophalangeal joints
Dorsal interossei (four muscles)
Origin:
- Sides of metacarpals
Insertion:
- Extensor hoods of the thumb, index, ring and little fingers and the proximal phalanx of thumb
Innervation:
- Deep branch of ulnar nerve (C8, T1)
Function:
- Adduction of the thumb, index, ring, and little fingers at the metacarpophalangeal joints
Palmar interossei
Origin:
- Transverse head - metacarpal III;
- Oblique head - capitate and bases of metacarpals II and III
Insertion:
- Base of proximal phalanx and extensor hood of thumb
Innervation:
- Deep branch of ulnar nerves (C8, T1)
Function:
- Adducts thumb
Adductor pollicis