muscles of the thenar eminence
abductor pollicis brevis
flexor pollicis brevis
opponens pollicis
adductor pollicis
abductor pollicis brevis
-origin
flexor retinaculum
tubercles of scaphoid and trepezium
abductor pollicis brevis
-insertion
lateral side of base of proximal phalanx of thumb
abductor pollicis brevis
-action
thumb abduction
helps with thumb opposition
abductor pollicis brevis
-innervation
recurrent branch of median nerve (C8, T1)
flexor pollicis brevis
-origin
superficial head -flexor retinaculum -tubercle of trapezium deep head -floor of carpal tunnel
flexor pollicis brevis
-insertion
lateral side of base of proximal phalanx of thumb
flexor pollicis brevis
-action
flexes thumb
flexor pollicis brevis
-innervation
superficial head
-recurrent branch of median nerve (C8, T1)
deep head
-deep branch of ulnar nerve (C8, T1)
opponens pollicis
-origin
flexor retinaculum
tubercle of trapezium
opponens pollicis
-insertion
lateral side of base of proximal phalanx of thumb
opponens pollicis
-actions
opposes thumb toward center of palm
rotates it medially
opponens pollicis
-innervation
recurrent branch of median nerve (C8, T1)
also possibly deep branch of ulnar nerve
adductor pollicis
-origin
oblique head -bases of metacarpal 2, 3 -capitate -adjacent carpal bones transverse head -anterior surface of 3rd metacarpal
adductor pollicis
-insertion
medial side of base of proximal phalanx of thumb
adductor pollicis
-actions
adducts thumb toward middle digit
adductor pollicis
-innervation
deep branch of ulnar nerve (C8, T1)
abductor digiti minimi
-origin
pisiform bone
abductor digiti minimi
-insertion
medial side of base of proximal phalanx of digit 5
abductor digiti minimi
-action
abducts digit 5
abductor digiti minimi
-innervation
deep branch of ulnar nerve (C8, T1)
flexor digiti minimi brevis
-origin
hook of hamate
flexor retinaculum
flexor digiti minimi brevis
-insertion
medial side of base of proximal phalanx of digit 5
flexor digiti minimi brevis
-action
flexes proximal phalanx of digit 5
flexor digiti minimi brevis
-innervation
deep branch of ulnar nerve (C8, T1)
opponens digiti minimi
-origin
hook of hamate
flexor retinaculum
opponens digiti minimi
-insertion
medial border of 5th metacarpal
opponens digiti minimi
-action
draws 5th metacarpal bone anteriorly and rotates it to bring digit 5 into opposition to thumb
opponens digiti minimi
-innervation
deep branch of ulnar nerve (C8, T1)
muscles of hypothenar eminence
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi
lumbricals 1 and 2
-origin
lateral two tendons of flexor digitorum profundus (index and middle finger)
lumbricals 1 and 2
-insertion
lateral sides of extensor expansions of digits 2 and 3
lumbricals 1 and 2
-action
flex digits at MCP joint
extend IP joints
lumbricals 1 and 2
-innervation
median nerve (C8, T1)
lumbricals 3 and 4
-origin
medial two tendons of flexor digitorum profundus (ring and little finger)
lumbricals 3 and 4
-insertion
lateral sides of extensor expansions of digits 4 and 5
lumbricals 3 and 4
-action
flex digits at MCP joint
extend IP joints
lumbricals 3 and 4
-innervation
deep branch of ulnar nerve (C8, T1)
dorsal interossei 1-4
-origin
adjacent sides of two metacarpal bones
dorsal interossei 1-4
-insertion
extensor expansions and bases of proximal phalanges of digits 2-4
middle finger has 2 insertions
dorsal interossei 1-4
-action
abduct digits
assist lumbricals in extension at the IP joints
dorsal interossei 1-4
-innervation
deep branch of ulnar nerve (C8, T1)
palmar interossei 1-3
-origin
palmar surfaces of 2nd, 4th, and 5th metacarpals
palmar interossei 1-3
-insertion
extensor expansions and bases of proximal phalanges of digits 2, 4, 5
palmar interossei 1-3
-action
adduct digits
assist lumbricals in flexion at the MCP joint
palmar interossei 1-3
-innervation
deep branch of ulnar nerve (C8, T1)
short muscles of the hand
lumbricals 1-4
dorsal interossei 1-4
palmar interossei 1-3
