What are the primary actions of the palmaris longus muscle?

The palmaris longus muscle primarily functions to facilitate wrist flexion, but its notable role is in tensing the palmar aponeurosis. This ligamentous structure helps provide stability to the palm and facilitates grip by increasing the strength of the hand’s grasp. When the palmaris longus contracts, it not only aids in bending the wrist but also pulls on the palmar aponeurosis, making it tight. This tightening enhances the functional mechanics of the hand during activities involving grasping.

The palmaris longus is often considered a vestigial muscle and is not present in everyone, but for those who have it, its contribution to both wrist flexion and the stabilization of the palm is significant. Therefore, understanding the dual role of this muscle—both in motion and in providing structural support—highlights its importance in hand function.