The palmaris brevis muscle lies just underneath the skin. It is a short muscle on the flat of the hand. The muscle begins at the flexor retinaculum in the wrist and is attached to the dermis at the ulnar side of the palm. The superficial branch of the ulnar nerve provides motor functions. The palmaris brevis muscle strengthens the grip of the hand on an object and helps form the hand into a cup shape. Because it is attached to the skin, it also wrinkles the skin during the cupping motion. It protects the ulnar nerve and artery. The palmaris brevis muscle is not present in some people. The anatomist and physician Giovanni Battista first described the muscle in the 16th century. The next mention of the muscle did not occur until 1713 when William Cheselden included it in an anatomy textbook. To find the palmaris brevis muscle, cup the hand. The muscle dimples the skin of the palm along the edge of the palm below the little finger. The muscle is under the dimple.