Palmaris brevis muscle

What is Palmaris brevis muscle?

The palmaris brevis is a small quadrangular muscle in the hand’s hypothenar area. Even though it is in this area, the palmaris brevis is not part of the hypothenar muscle group; rather, it is considered an exceptional superficial muscle of this area on its own.

This muscle tightens the palmar aponeurosis, which is located between the hand’s fibrous structures and the hypothenar skin. Doing so helps create and keep a strong grip.

Origin of Palmaris brevis muscle

It comes from the palmar aponeurosis and the flexor retinaculum.

Insertion

It inserts into the skin of the hand’s medial border.

Relations

The palmaris brevis muscle on the ulnar side of the hand is the most superficial because it lies directly beneath the skin. The ulnar artery, superficial palmar arch, and superficial branch of the ulnar nerve are deep into the muscle, as are the hypothenar eminence muscles (opponens digiti minimi, abductor digiti minimi, and flexor digiti minimi brevis).

Guyon’s canal, the fibro-osseous canal on the ulnar side of the palm through which the ulnar artery and nerve enter the palmar hand, is formed by the palmaris brevis.

Innervation

The shallow portion of the ulnar nerve innervates the palmaris brevis (C8, T1). This nerve rises out of the medial cord of the brachial plexus.

Blood supply

The shallow palmar curve, which is a blood vessel network that is primarily framed by the ulnar artery, provides the palmaris brevis muscle with blood supply. The superficial palmar branch of the radial artery or the princeps pollicis artery may also contribute to some people.

Function of Palmaris brevis muscle

While contracting, the palmaris brevis muscle tightens the palmar aponeurosis, which deepens the palmar fossa and wrinkles the hypothenar skin. During a spherical power grip, where the hand must be positioned in a cup formation, or during repetitive grip movements, this action helps to position and stabilize the palm.

Clinical relevance

The innervation of the Palmaris Brevis is the main engine part of the shallow part of the ulnar nerve. Because of this, the palmaris brevis function can be used to determine the location of ulnar nerve lesions at the wrist. It may also protect the ulnar nerve and artery from being compressed in the ulnar canal when grasping repeatedly.

Palmaris brevis muscle stretching

To increase the stretch (Palmaris Longus), stand or sit and extend the arm in front of you. Then, with the elbow fully extended or locked out, bring the wrist into extension and pull it toward you with the other hand. Pull on the fingers with the other hand to stretch the Flexor Digitorum Superficialis and Profundus.

Palmaris brevis muscle strengthening exercise

Making a fist

Spread your fingers as wide as you can while holding your hand out in front of you. Make a fist by closing your fingers toward your palm and placing your thumb on the outside of the fingers. After 30 to 60 seconds in this position, release your fingers and return to the starting position with your fingers spread as wide as possible. On both hands, perform this exercise at least four times for three sets.

Grip strengthener

Place a firm but soft hand exercise ball in the palm of your hand and wrap all of your fingers around it to make it comfortable. Hold the position for a few seconds while you squeeze the ball as hard as you can, and then relax. Two to three times per week, perform this motion with each hand 10 to 15 times. However, to avoid overworking the muscles, make sure to rest your hand for 48 hours between sessions.

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