Palmaris Longus

Joe Muscolino

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The palmaris longus of the wrist flexor group is seen. The other two muscles of the group: flexor carpi radialis and flexor carpi ulnaris have been ghosted in.

The Palmaris Longus is in the Superficial Layer of the Anterior Compartment of the forearm. It is also a member of the Wrist Flexor Group; the muscles of the wrist flexor group are:

  • Flexor carpi radialis
  • Palmaris longus
  • Flexor carpi ulnaris

 

ATTACHMENTS:

  • Medial epicondyle of the humerus via the common flexor belly/tendon to the palmar fascia.
    • The distal attachment is into the palmar aponeurosis and the transverse carpal ligament (aka flexor retinaculum).

 

ACTIONS:

  • Flexes the hand at the wrist joint.
  • Wrinkles the skin of the palm.
  • Flexes the forearm at the elbow joint.
  • Pronates the forearm at the radioulnar joints.

 

NOTES:

  1. The palmaris longus is one of five muscles of the common flexor belly/tendon that is involved with medial elbow tendinopathy (aka golfer’s elbow).
  2. Wrinkling the skin of the palm helps to increase strength and security when an object is grasped.
  3. The palmaris longus is absent either unilaterally or bilaterally in approximately 10-20% of people.