Palmaris longus

A muscle located in the forearm that plays a role in wrist flexion.

The palmaris longus is a slender muscle situated in the anterior compartment of the forearm. It originates from the medial epicondyle of the humerus and inserts into the fascia of the palm. Notably, this muscle is absent in about 10-15% of the population, indicating its non-essential role in everyday function.

Terminologia Anatomica

musculus-palmaris-longus

System

Muscular system

Function

The primary function of the palmaris longus is to assist in wrist flexion, contributing to the movement of the hand towards the forearm. While it is considered an auxiliary muscle, its presence can enhance grip strength and stability during various hand movements. Despite being a relatively weak flexor compared to other muscles, it serves an important role in the coordination of the wrist, particularly during activities that require finesse, such as writing or playing musical instruments. Additionally, the palmaris longus aids in tensing the palmar fascia, which provides support to the palm during gripping actions.

Location

The palmaris longus is located in the anterior compartment of the forearm, lying medial to the flexor carpi radialis and lateral to the flexor carpi ulnaris. It runs alongside other flexor muscles, spanning from the elbow down to the wrist. Specifically, it can be palpated between the other muscle tendons when a person flexes their wrist. The muscle's distinct location makes it an important landmark for various medical procedures, such as tendon grafting.

Did You Know?

The palmaris longus can be absent in some individuals without affecting hand function significantly.
In some cultures, the presence of the palmaris longus is considered an indicator of a person's physical versatility or manual skill.
It is often harvested for surgical procedures, such as tendon repair, due to its relative redundancy in the anatomy of the forearm.