Tendon of adductor hallucis

The distal tendon of the adductor hallucis is defined as the conjoined tendon formed by the terminal fibers of both the oblique and transverse heads of the adductor hallucis muscle. This tendon courses distally and inserts primarily onto the lateral aspect of the lateral sesamoid bone of the first metatarsophalangeal joint, and then continues to the lateral base of the proximal phalanx of the hallux.

The insertion is not a discrete, isolated tendon; rather, it is a conjoined structure with fibers from the lateral flexor hallucis brevis tendon, forming a unified attachment at the lateral base of the proximal phalanx and the lateral sesamoid. No separate slip of the adductor hallucis tendon inserts independently into the base of the proximal phalanx in typical anatomy.