Hibb angle
Hibb angle has been used to identify the apex of deformity in patients with pes cavus on lateral weight bearing radiograph. Hibb angle is formed by the lines running along the axes of the calcaneus and the first metatarsal. The intersection of the lines represents apex of the deformity.
Normally Hibb angle is greater than 150 degrees. Hibb angle less than 150 degrees indicates pes cavus.