Origin: Flexor retinaculum (medial), palmar aponeurosis
Nerve: Superficial branch of ulnar nerve
Action: Wrinkle skin of palm
The Palmaris brevis is a thin, quadrilateral muscle, placed beneath the integument of the ulnar side of the hand. It arises by tendinous fasciculi 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.