The first metatarsophalangeal angle is used for evaluating the presence of a true hallux valgus deformity. It can only be measured on a radiograph performed whilst weightbearing.

It is the angle between the axis of the 1st metatarsal and the axis of the proximal phalanx of the 1st toe.

A normal angle is ≤15°. A greater value indicates hallux valgus.