Palmaris brevis muscle


Palmaris brevis is a thin, quadrilateral muscle, placed beneath the integument of the ulnar side of the hand. It acts to fold the skin of the hypothenar eminence transversally.

Origin and insertion

It arises by tendinous from the transverse carpal ligament and palmar aponeurosis; the fleshy fibers are inserted into the skin on the ulnar border of the palm of the hand, and occasionally on the pisiform.

Action

It tenses the skin of the palm on the ulnar side during a grip action, and deepens the hollow of the palm.
The palmaris brevis may protect the ulnar nerve and ulnar artery from compressive forces during repetitive grasping actions. The muscle has a fatigue resistant fiber type profile, which supports the idea of a protective function to the ulnar neurovasculature during repetitive intermittent grasping tasks.

Innervation

It is the only muscle innervated by the superficial branch of the ulnar nerve.

Blood supply

It is supplied by the palmar metacarpal artery of the deep palmar arch.

Additional images