Interossei of the hand

Musculi interossei dorsales et palmares manus

MuscularDeep musclesArmLeft and right

View left in 3D View right in 3D

What it is

Seven small muscles filling the spaces between the metacarpals: four two-headed dorsal interossei and three palmar interossei, inserting on the proximal phalanges and extensor expansions.

Function

Dorsal interossei spread the fingers (DAB), palmar interossei draw them together (PAD); together they flex the knuckles and straighten the finger joints.

Size

Each about 5–6 cm long.

Clinical note

Supplied by the ulnar nerve; wasting of the first dorsal interosseous hollows the thumb web in ulnar palsy.