Tendon of extensor hallucis brevis

The tendon of the extensor hallucis brevis is the distal tendinous portion of the extensor hallucis brevis (EHB) muscle, which is an intrinsic muscle of the dorsal foot. The extensor hallucis brevis muscle originates from the superolateral surface of the calcaneus and the adjacent inferior extensor retinaculum. Its tendon courses anteriorly and medially over the dorsum of the foot, lying lateral to the tendon of the extensor hallucis longus (EHL).

The EHB tendon inserts into the dorsal aspect of the base of the proximal phalanx of the hallux, just lateral to the extensor hallucis longus (EHL) tendon insertion. This anatomical relationship is consistent across cadaveric studies, and the insertion is distinct from the EHL, which continues distally to the base of the distal phalanx. The EHB tendon is relatively short and broad compared to the EHL tendon, and its insertion is important to preserve during surgical procedures involving the hallux, as excessive resection can compromise toe extension and lead to deformity.

Anatomic variations exist, including occasional fusion or merging with accessory tendons or slips from the EHL, but the classic anatomy is a single tendon inserting at the base of the proximal phalanx.