Wrist + Hand Muscles

Flexor Digitorum Superficialis

A- flexes MCPs and PIPs 2-5, wrist flexion

O- (humeroulnar head) common flexor tendon and coronoid process of ulna, (radial head) arises from the anterior surface of the radius

I- shafts of the middle phalanges of digits 2-5

Inn- median nerve

Blood supply- radial and ulnar arteries

Flexor Digitorum Profundus

A- flexes MCPs, DIPS, and PIPs 2-5

O- anteromedian surface of the ulna, the interosseous membrane

I- base of the distal phalanx of digits 2-5, after passing though the split in FDS tendons

Inn- 1/2 median (radial side), 1/2 ulnar (ulnar side)

Blood supply- radial and ulnar arteries

Extensor Indicis

A- extends MCP, PIP, DIP of index finger

O- posterior distal ulna and interosseous membrane

I- extensor hood of 2nd digit

Inn- radial nerve (posterior intersseous)

Blood supply- radial artery and posterior interosseus artery off ulnar artery

Extensor Digiti Minimi

A- extends MCP, DIP, PIP of 5

O- common extensor tendon

I- extensor expansion of digit 5

Inn- radial nerve (posterior interosseous nerve)

Blood supply- radial artery and posterior interosseus artery off ulnar artery

Extensor Digitorum

A- extends MCPs, DIPS, PIPS of 2-5, wrist extension

O- common extensor tendon

I- through the "extensor "extensor expansion/hood" inserts on dorsal center of middle phalanx both sides of distal phalanx of digits 2-5

Inn- radial nerve (posterior interosseous n.)

Blood supply- radial artery and posterior interosseus artery off ulnar artery

Extensor Policis Longus

A- flexes 1st GNC, MCP, IP joints

O- posterior distal ulna and interosseous membrane

I- base of distal phalanx of thumb

Inn- radial nerve

Blood supply- radial and ulnar arteries

Extensor Pollicis Brevis

A- 1st CMC, MCP, and IP extension

O- posterior distal ulna and interosseous membrane

I- base of distal phalanx of thumb

Inn- radial nerve (posterior interosseous nerve)

Blood supply- radial artery and posterior interosseus artery off ulnar artery

Abductor Pollicis Longus

A- 1st CMC abduction

O- posterior radius, ulna, interosseuos membrane

I- base of 1st metacarpal

Inn- radial nerve (posterior interosseous n.)

Blood supply- radial artery and posterior interosseus artery off ulnar artery

Flexor Pollicis Longus

A- flexes 1st CMC, MCP, IP joints

O- anterior surface of radius and interosseous membrane

I- base of distal phalanx of thumb

Inn- median nerve

Blood supply- radial and ulnar arteries

Abductor Pollicis Brevis

A- abducts thumb at carpometacarpal joint

O- scaphoid and trapezium

I- base of 1st proximal phalanx

Inn- recurrent branch of median n.

Flexor Pollicis Brevis

A- flexes carpometacarpal joint, proximal interphalangeal joint

O- trapezium

I- base of 1st proximal phalanx

Inn- recurrent branch of median n. + deep head innervated by ulnar n.

Opponens Pollicis

A- opposes thumb at carpometacarpal joint

O- trapezium

I- shaft of 1st metacarpal

Inn- recurrent branch of median n.

Adductor Pollicis

A- adducts thumb

O- (oblique head) base of 2nd + 3rd metacarpals, (transverse head) shaft of 3rd metacarpal

I- base of proximal phalanx

Inn- ulnar n. (deep branch)

Abductor Digiti Minimi

A- abducts 5th digit

O- pisiform

I- base of 5th proximal phalanx

Inn- ulnar n.

Flexor Digiti Minimi Brevis

A- flexes 5th carpometacarpal joint + metacarpophalngeal (knuckle)

O- hamate

I- base 5th proximal phalanx

Inn- ulnar n.

Opponens Digiti Minimi

A- opposes 5th digit

O- hamate

I- shaft of 5th metacarpal

Inn- ulnar n.

Lumbricals

A- flexes metacarpophalangeals, extends proximal interphalangeal joints and distal phalangeal joints of digits 2-5

O- flexor digitorum profundus tendons, radial side of 1 + 2, radial and ulnar side of 3+4

I- radial side of proximal phalanges 2-5, on extensor hood

Inn- median n. (1-2), ulnar n. (3-4)

Palmar Interossei (3 muslces)

A- when metacarpophalangeal joints extended = ab/add, when MCP joints flexed = flexors

O- shafts of metacarpals 2, 4, 5

I- base of proximal phalanx and extensor expansion ulnar side of digit 2, radial side digits 4 +5

Inn- ulnar n.

Dorsal Interossei

A- when metacarpophalanges extented = ab/adduction, when MCPs flexed = flexion

O- adjacent metacarpal shafts 1-5

I- base of proximal phalanx and extensor expansion on radial side of 2nd digit, radial and ulnar sides 3rd, ulnar side 4th

Inn- ulnar n.