Palmaris Longus

The palmaris longusFlexor Front and inner side; bends wrist and moves hand toward pinky side. is a slender muscle located in the anteriorThe front of the body or toward the front when standing in the anatomical position. forearm. It is superficialNear the surface of the body. and just medialToward the midline of the body to the flexor carpi radialisFlexor / Abductor Front of forearm; bends wrist and moves hand toward thumb side.. It originates from the medial epicondyleProminent bump on distal medial side; attachment for forearm muscles (“funny bone”). of the humerusLong bone of the upper arm; articulates with scapula at shoulder and radius/ulna at elbow. and inserts into the palmar aponeurosis and flexor retinaculum. On some models—and in real anatomy—it may be absent, as this muscle is congenitally missing in about 10–15% of people. When present, its long, thin tendon is often visible just under the skinThe body’s largest organ, providing protection and regulation.. You can see it when you touch your thumb to your pinky and flex the wrist slightly.

This muscle is used during actions that tense the palm. Examples include gripping a ball, wringing out a cloth, or doing a push-up. While it’s not a major contributor to wrist strength, overuse can still occur in repetitive gripping tasks. Exercises like plank holds can also lead to overuse because the wrist is flexed under load. In surgical procedures, the palmaris longus tendon is often harvested for grafts. Its absence does not significantly impair hand function.

Origin

Palmar aponeurosis

Flexor retinaculum of the hand

Insertion

Palmar aponeurosis

Flexor retinaculum of the hand

Actions

Tenses the palmar aponeurosis

Assists in wrist flexion