The abductor hallucis muscle runs along the medial, or interior, border of each foot, covering the origins for most of the plantar (sole of foot) nerves and vessels.
This muscle originates from the medial processes of the calcaneus tuberosity (part of the heel bone), the laciniate ligament, the intermuscular septum, and flexor digitorum brevis muscle. The abductor hallucis fibers end with a tendon (strong, fibrous tissue that connects muscle to bone) that inserts into the first phalanx of the big toe along with the flexor hallucis brevis medial tendon. This muscle is part of the third layer of plantar muscles.
The abductor hallucis abducts the big toe (spreads it outward), whereas the adductor hallucis muscle adducts the big toe (moving it in toward to other toes). Both muscles insert into the first phalanx of the big toe.
This muscle also plays a vital role in posture and gait by supporting the foot's medial arch. The abductor hallucis muscle can become strained, resulting in pain along the foot's longitudinal arch and over-pronation, a positioning of the foot where it rolls too far inward. Sports massage, electrotherapy, ibuprofen, sports taping, cold therapy, and rest can all aid in resolving the injury.