Hand (4A) Flashcards
Attachments of abductor pollicis brevis (ABP)
- most radial (lateral) of the three thenar muscles
- proximal = flexor retinaculum, trapezium, and scaphoid
- distal = base of 1st proximal phalanx
Innervation of abductor pollicis brevis (ABP)
Median nerve
Actions of abductor pollicis brevis (ABP)
- abduct the thumb (CMC and MCP)
- opposition of the thumb (assist)
Attachments of flexor pollicis brevis (FPB)
- medial to abductor pollicis brevis (ABP)
- proximal = flexor retinaculum, trapezium, trapezoid, and capitate
- distal = base of 1st proximal phalanx - more of a medial line pull that makes it flex instead of abduct
Innervation of flexor pollicis brevis (FPB)
- median nerve
- ulnar nerve
no need to separate
Actions of flexor pollicis brevis (FPB)
- flex the thumb (CMC and MCP)
- opposition of the thumb (assist)
Attachments of opponens pollicis
- deep to abductor pollicis brevis (APB) and flexor pollicis brevis (FPB)
- proximal = flexor retinaculum and trapezium
- distal = entire length of 1st metacarpal - allows for the opposition motion
Innervation of opponens pollicis
Median nerve
Actions of opponens pollicis
- opposition of the thumb (CMC)
Attachments of palmar interossei
- proximal = 2nd, 4th, 5th metacarpals facing the middle finger
- distal = base of 2nd, 4th, 5th proximal phalanx as part of extensor mechanism
Innervation of palmar interossei
Ulnar nerve
Actions of palmar interossei
- adduction 2nd, 4th, 5th fingers toward the 3rd finger
- flex 2nd, 4th, 5th fingers (MCP) (assist)
- extend 2nd, 4th, 5th fingers (IP) (assist)
Attachments of dorsal interossei
- middle finger has 2, one on each side (2nd and 3rd interosseus muscles)
- proximal = 1-5 metacarpals facing the middle finger
- distal = proximal phalanx facing the middle finger as part of extensor mechanism
Innervation of dorsal interossei
Ulnar nerve (if you lose the ulnar nerve, you can’t do the key pinch)
- first dorsal interosseus = large (palpate)
- along with adductor pollicis, important with key (lateral) pinch
Actions of dorsal interossei
- abduct 2nd, 3rd, 4th fingers (MCP)
- flex 2nd, 3rd, 4th fingers (MCP) (assist)
- extend 2nd, 3rd, 4th fingers (IP) (assist)
Attachments of lumbricals
- proximal = flexor digitorum profundus (FDP) tendon - FDP also has 2 innervation
- distal = extensor hood (extensor mechanism)
Innervation of lumbricals
- median nerve = index and middle fingers
- ulnar nerve = ring and small fingers
Actions of lumbricals
- extend 2nd-5th fingers (IP)
- flex 2nd-5th fingers (MCP)
Attachments of opponens digiti minimi
- deep to abductor and flexor (like thenar)
- proximal = hook of hamate and flexor retinaculum
- distal = shaft of 5th metacarpal
Innervation of opponens digiti minimi
Ulnar nerve
Actions of opponens digiti minimi
- opposition of 5th finger at CMC joint
Thenars
- abductor pollicis brevis (APB)
- flexor pollicis brevis (FPB)
- opponens pollicis (OP)
- identified as the fat pad of the thumb
Hypothenars
- abductor digiti minimi
- flexor digiti minimi
- opponens digiti minimi
- identidad as the fat pad of the small finger
