Palmaris Longus Beneath the Skin, Palmar View

Description

Running centrally along the volar forearm, the palmaris longus muscle belly tapers into a long, slender tendon that becomes superficial as it approaches the distal wrist crease. The tendon passes anterior to the flexor retinaculum and fans into the palmar aponeurosis, lying superficial to the flexor digitorum superficialis and profundus tendons that traverse the carpal tunnel. On either side, flexor carpi radialis sits more lateral (radial) and flexor carpi ulnaris more medial (ulnar), while the carpal bones form the deep osseous contour at the wrist and the metacarpals and phalanges align distally in the palm. Skin is retained as a semi-transparent layer, reinforcing the superficial topography you palpate in anatomical position. Palmaris longus matters because it is both a surface landmark and a frequent anatomical variant, absent unilaterally or bilaterally in a substantial minority of patients. Its tendon is commonly harvested for grafting in hand and wrist reconstruction (for example, tendon transfers, ligament reconstruction, or pulley augmentation) because removal usually produces minimal functional deficit. The relationship to the flexor retinaculum and palmar aponeurosis also helps teach why palmaris longus does not traverse the carpal tunnel, and why median nerve symptoms in carpal tunnel syndrome arise deep to this superficial tendon. Use this artwork in upper-limb anatomy modules to contrast superficial palmar landmarks with the deeper flexor tendon compartments, or in surgical and rehabilitation texts to illustrate tendon-graft donor anatomy and safe harvest planes at the distal forearm. It also fits patient-education material for explaining palpable wrist tendons during physical examination and preoperative planning. Anatomical accuracy verified by SciePro's Medical Advisory Board.