The musculus palmaris longus, also commonly referred to as the palmaris longus muscle, is a slender, relatively weak, and superficial flexor muscle of the forearm. Located in the inner side of the forearm, it originates from the medial epicondyle (a bony projection) of the humerus bone and attaches to the palmar aponeurosis (a tough, fibrous band of tissue) of the hand.
The main function of the musculus palmaris longus is to flex the hand at the wrist, causing it to move towards the palm side of the forearm. This action helps in generating a grasping motion, allowing for activities such as gripping objects firmly or making a fist.
Although present in most individuals, the musculus palmaris longus displays a high degree of anatomical variation in the human population. Approximately 10-20% of people either have a partially developed or completely absent musculus palmaris longus. This natural variation has no significant impact on hand function or strength.
Due to its relatively minor role in hand movement, the musculus palmaris longus is often used as a source of graft tissue for surgical procedures. Its tendon is frequently harvested for reconstructive surgeries such as ligament repairs, tendon transfers, or to supplement other tendons in cases of injury or congenital absence.
In summary, the musculus palmaris longus is a slender forearm muscle responsible for flexing the hand at the wrist, aiding in grasping and gripping actions. Its anatomical variability allows for its tendon to be used as a graft in reconstructive surgeries when needed.
