Tendon of extensor hallucis longus

The tendon of the extensor hallucis longus (Extensor hallucis longus tendon; EHL) emerges distally from the extensor hallucis longus muscle, passing deep to the superior and inferior extensor retinacula, and traverses the dorsum of the foot to the great toe.

The main tendon of the EHL typically inserts on the dorsal aspect of the base of the distal phalanx of the hallux. However, anatomical studies consistently demonstrate frequent accessory tendons or slips. The most common configuration is a single tendon inserting into the distal phalanx (Type I), but up to two or three distal tendons may be present, with accessory slips inserting into the proximal phalanx or the capsule of the first metatarsophalangeal (MTP) joint. In some populations, accessory tendons are present in the vast majority of individuals, most often inserting into the MTP joint capsule or proximal phalanx, and may play a role in joint stabilization during extension.

The EHL tendon runs dorsal to the bone but plantar (deep) to the nail matrix as it approaches its insertion, with the extensor tendon interposed between the nail matrix and the dorsal aspect of the distal phalanx.