hallux

The hallux is the medical term for the big toe, the first digit of the foot. It lies on the medial side of the foot and, in humans, is typically composed of two phalanges with a metatarsophalangeal joint at its base, making it the primary weight-bearing toe during gait.

Anatomy and function: The hallux plays a major role in standing and locomotion, providing stability and push-off. It is moved by several muscles and tendon systems, including intrinsic muscles such as the abductor hallucis and flexor hallucis brevis, as well as tendons of the extensor and flexor muscles that cross the ankle. The joint surfaces and surrounding ligaments help stabilize the toe during movement.

Common conditions: The most frequent toe-related deformity is hallux valgus, or bunion, in which the big toe drifts toward the second toe and the first metatarsophalangeal joint becomes prominent. Hallux rigidus refers to degenerative arthritis of this joint, causing pain and stiffness. Less commonly, hallux varus (inward deviation) can occur, sometimes alongside other toe deformities or conditions such as gout or trauma.

Clinical basics: Evaluation typically involves physical examination and radiographs to assess alignment and joint health, including measurements such as the hallux valgus angle. Treatment ranges from conservative approaches—footwear modification, orthotics, and anti-inflammatory medications—to surgical correction in cases with persistent pain or functional limitation.

Etymology and scope: The term hallux derives from Latin for “great toe.” In clinical practice, it denotes the big toe of the human foot, though the concept applies to similar digits in other primates. Overall, the hallux is a key component of foot function in standing and locomotion.