Abductor hallucis muscle

The abductor hallucis muscle is located in the medial border of the foot and contributes to form the prominence that is observed on the region.

It is inserted behind on the tuberosity of the calcaneus, the flexor retinaculum, and the plantar aponeurosis.

It ends in a common tendon with the medial head of the flexor hallucis brevis that inserts on the medial surface of the base of the first proximal phalanx and its related sesamoid bone.

Its medial surface is superficial and covered with the muscle's fascia and the skin.

This article incorporates text in the public domain from page 491 of the 20th edition of Gray's Anatomy (1918)

The abductor hallucis as seen from an inferior projection of the foot. This diagram shows the bottom-most layer of muscles, just under the plantar skin of the foot.