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Palmaris Longus Muscle
Muscular System

Palmaris Longus Muscle

Musculus palmaris longus

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Quick Facts

Origin: Medial epicondyle of humerus, via common flexor tendon.

Insertion: Palmar aponeurosis and flexor retinaculum of hand.

Action: Flexes hand at radiocarpal (wrist) joint; stabilizes palmar aponeurosis.

Innervation: Median nerve (C7-C8).

Arterial Supply: Median artery and anterior branch of ulnar recurrent artery.

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The palmaris longus muscle originates from the:

- medial epicondyle of humerus, via the common flexor tendon;

- adjacent antebrachial fascia.

The common flexor tendon is the combined tendon for all five superficial muscles in the anterior compartment of the forearm, which are the:

- pronator teres muscle;

- flexor carpi radialis muscle;

- palmaris longus muscle;

- flexor carpi ulnaris muscle;

- flexor digitorum superficialis muscle.


The fibers of the palmaris longus muscle travel inferiorly to the hand and insert, via a long tendon, onto the:

- palmar aponeurosis;

- flexor retinaculum of hand.

Key Features & Anatomical Relations

The palmaris longus muscle is one of the muscles of the superficial part of anterior compartment of the forearm. It is a thin, fusiform type of skeletal muscle. In the middle of the forearm, the muscle belly gives rise to a long tendon, which travels inferomedially. At the wrist, the tendon travels superficial to the flexor retinaculum of hand.

The palmaris muscle is located:

- anterior (superficial) to the flexor digitorum superficialis muscle (at its muscle belly) and the median nerve (at its distal tendon);

- medial to the flexor carpi radialis longus muscle;

- lateral to the flexor carpi ulnaris muscle.

Actions & Testing

The palmaris longus muscle is involved in multiple actions:

- flexes the hand at the radiocarpal (wrist) joint;

- stabilizes the palmar aponeurosis and surrounding skin during shearing forces.

The palmaris longus muscle can be tested by flexing the hand at the radiocarpal joint against resistance, during which its tendon can be seen and palpated (Standring, 2016).

List of Clinical Correlates

- The palmaris longus muscle is absent in some individuals

- It is used for some tendon transplant procedures


Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

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Palmaris Longus Muscle

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It lies deep to and between the tendons of the palmaris longus muscle and the flexor carpi radialis muscle at the wrist.

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Complete Anatomy

The world's most advanced 3D anatomy platform

Complete Anatomy