Intrinsic Muscles of Hand

Question 1

Opponens Pollicis (thenar eminence)

Answer 1

Proximal: flexor retinaculum, scaphoid, & trapezium
Distal: lateral 1st metacarpal
Innervation: recurrent branch of median nerve (C8-T1)
Blood supply: radial artery
Functions: thumb opposition

Question 2

Abductor Pollicis Brevis (thenar eminence)

Answer 2

Proximal: flexor retinaculum, scaphoid, & trapezium
Distal: radial base of PIP of thumb
Innervation: recurrent branch of median nerve (C8-T1)
Blood supply: radial artery
Functions: ABD of thumb

Question 3

Flexor Pollicis Brevis (thenar eminence)

Answer 3

Proximal: flexor retinaculum & trapezium (superficial head); trapezoid & capitate (deep head)
Distal: base of PIP of thumb
Innervation: recurrent branch of median nerve (C8-T1) (superficial head); ulnar nerve (C8-T1) (deep head)
Blood supply: radial artery
Functions: 1st MCP FLX & thumb opposition

Question 4

Adductor Pollicis

Answer 4

Proximal: capitate & MCP 2-3
Distal: medial surface of thumb proximal phalanx (1 sesamoid bone)
Innervation: deep branch of ulnar nerve (C8-T1)
Blood supply: deep palmar arch branches
Functions: ADD of thumb

Question 5

Abductor Digiti Minimi (hypothenar eminence)

Answer 5

Proximal: pisiform
Distal: medial proximal phalanx of 5th digit
Innervation: deep branch of ulnar nerve (C8-T1)
Blood supply: ulnar artery
Functions: ABD of 5th digit

Question 6

Flexor Digiti Minimi Brevis (hypothenar eminence)

Answer 6

Proximal: flexor retinaculum & hook of hamate
Distal: base of 5th digit proximal phalanx
Innervation: deep branch of ulnar (C8-T1)
Blood supply: ulnar artery
Functions: fllexion of 5th digit MCP

Question 7

Opponens Digiti (hypothenar eminence)

Answer 7

Proximal: flexor retinaculum & hook of hamate
Distal: medial border of 5th MCP
Innervation: deep branch of ulnar nerve (C8-T1)
Blood supply: ulnar artery
Functions: opposition of 5th MCP

Question 8

Lumbricals (worm-like)

Answer 8

Proximal: tendons of flexor digitorum profundus
Distal: extensor hood/extension expansion system of same digit
Innervation: median nerve (the 1st & 2nd); deep branch of ulnar nerve (C8-T1) (the 3rd & 4th)
Blood supply: palmar arches & branches
Functions: MCP FLX & PIP/DIP EXT

Question 9

Dorsal Interossei (1st-4th)

Answer 9

Proximal: adjacent metacarpals
Distal: base of digits 1-4 proximal phalanges & extensor hood
Innervation: deep branch of ulnar nerve (C8-T1)
Blood supply: metacarpal arteries
Functions: digits 2 & 4 ABD with 3rd digit as axis

Question 10

Palmar Interossei (1st-3rd)

Answer 10

Proximal: metacarpal 2 (medial surface) 4 & 5 (radial surface)
Distal: extensor hood of 2, 4, & 5
Innervation: deep branch of ulnar nerve (C8-T1)
Blood supply: palmar metacarpal arteries
Functions: with ADD pollicis for finger ADD (3rd digit as axis)