Intrinsic Muscles of Hand Flashcards
What is the insertion of opponens pollicis?
Lateral side of 1st metacarpal
What is the origin of opponens pollicis?
Flexor retinaculum and tubercles of scaphoid and trapezium
What innervates opponens pollicis?
Recurrent branch of median nerve (C8, T1)
What is the action of opponens pollicis?
To oppose thumb, it draws 1st metacarpal medially to center of palm and rotates it medially
What is the origin of abductor pollicis brevis?
Flexor retinaculum and tubercles of scaphoid and trapezium
What is the insertion of abductor pollicis brevis?
Lateral side of base of proximal phalanx of thumb
What is the action of abductor pollicis brevis?
Abducts thumb; helps oppose it
What is the origin of flexor pollicis brevis?
Flexor retinaculum and tubercles of scaphoid and trapezium
What is the insertion of flexor pollicis brevis?
Lateral side of base of proximal phalanx of thumb
What innervates flexor pollicis brevis?
Superficial head: Recurrent branch of median (C8, T1)
Deep head: Deep branch of ulnar nerve (C8, T1)
What is the action of flexor pollicis brevis?
Flexes thumb
What is the origin of adductor pollicis?
Oblique head: Bases of 2nd & 3rd metacarpals, capitate, adjacent carpals
Transverse head: Anterior surface of shaft of 3rd metacarpal
What is the insertion of adductor pollicis?
Medial side of base of proximal phalanx of thumb
What innervates adductor pollicis?
Deep branch of ulnar nerve (C8, T1)
What is the action of adductor pollicis?
Adducts thumb toward lateral border of palm
What is the origin of abductor digiti minimi?
Pisiform
What is the insertion of abductor digiti minimi?
Medial side of base of proximal phalanx of 5th finger
What innervates abductor digiti minimi?
Deep branch of ulnar nerve (C8, T1)
What is the action of abductor digiti minimi?
Abducts 5th finger; assists in flexion of its proximal phalanx
What is the origin of flexor digiti minimi brevis?
Hook of hamate and flexor retinaculum
What is the insertion of flexor digiti minimi brevis?
Medial side of base of proximal phalanx of 5th finger
What innervates flexor digiti minimi brevis?
Deep branch of ulnar nerve (C8, T1)
What is the action of flexor digiti minimi brevis?
Flexes proximal phalanx of 5th finger
What is the origin of opponens digiti minimi?
Hook of hamate and flexor retinaculum
What is the insertion of opponens digiti minimi?
Medial border of 5th metacarpal
What innervates opponens digiti minimi?
Deep branch of ulnar nerve (C8, T1)
What is the action of opponens digiti minimi?
Draws 5th metacarpal anterior and rotates it, bringing 5th finger into opposition with thumb
What is the origin of lumbricals 1 & 2?
Lateral 2 tendons of flexor digitorum profundus (as unipennate muscles)
What is the insertion of lumbricals 1 & 2?
Lateral sides of extensor expansions of 2nd-5th fingers
What innervates lumbricals 1 & 2?
Median nerve (C8, T1)
What is the action of lumbricals 1 & 2?
Flex metacarpophalangeal joints; extend interphalangeal joints of 2nd-5th fingers
What is the origin of lumbricals 3 & 4?
Medial 3 tendons of flexor digitorum profundus (as bipennate muscles)
What is the insertion of lumbricals 3 & 4?
Lateral sides of extensor expansions of 2nd-5th fingers
What innervates lumbricals 3 & 4?
Deep branch of ulnar nerve (C8, T1)
What is the action of lumbricals 3 & 4?
Flex metacarpophalangeal joints; extend interphalangeal joints of 2nd-5th fingers
What is the origin of dorsal interossei (1-4)?
Adjacent sides of two metacarpals (as bipennate muscles)
What is the insertion of dorsal interossei (1-4)?
Bases of proximal phalanges; extensor expansions of 2nd-4th fingers
What innervates dorsal interossei (1-4)?
Deep branch of ulnar nerve (C8, T1)
What is the action of dorsal interossei (1-4)?
Abduct 2nd-4th fingers from axial line; act with lumbricals in flexing metacarpophalangeal joints & extending interphalangeal joints
What is the origin of palmar interossei (1-3)?
Palmar surfaces of 2nd, 4th, & 5th metacarpals (as unipennate muscles)
What is the insertion of palmar interossei (1-3)?
Bases of proximal phalanges; extensor expansions of 2nd, 4th, & 5th fingers
What innervates palmar interossei (1-3)?
Deep branch of ulnar nerve (C8, T1)
What is the action of palmar interossei (1-3)?
Adduct 2nd, 4th, & 5th fingers toward axial line; assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints
What is the innervation of abductor pollicis brevis?
Recurrent branch of median nerve (C8, T1)
