palmaris brevis

A thin, quadrilateral muscle, placed beneath the integument (skin) of the ulnar side of the hand.
It acts to fold the skin of the hypothenar eminence transversally.

(Functions)
• tenses the skin of the palm on the ulnar side during a grip action
• deepens the hollow of the palm
• protects the ulnar nerve and ulnar artery from compressive forces during repetitive grasping actions witha a fatigue-resistant fiber

(Origin)
• flexor retinaculum
• palmar aponeurosis

(Insertion)
• dermis of the skin on the medial margin of the hand

(Blood supply)
• superficial palmar arch

(Innervation)
• superficial branch of ulnar nerve (C8, T1)

(Comparison: palmaris)
• palmaris brevis: Tenses the skin of the palm on the ulnar side during a grip action, and so on. The origins are flexor retinaculum and palmar aponeurosis.
• palmaris longus: Tenses palmar aponeurosis besides wrist flexion. The insertions are flexor retinaculum and palmar aponeurosis.