Surgical exploration of the ankle and foot demonstrates a muscle arising from the medial and lateral processes of the tuberosity of the calcaneus and inseing into the lateral side of the base of the proximal phalanx of the 5th toe. How does this muscle act on the 5th toe?
The muscle is the abductor digiti minimi, the function of which is to abduct (separate) the toe away from the 4th toe. The abductor digiti minimi is supplied by the lateral plantar nerve. This muscle also helps act as a "spring" on the sole of the foot during walking.Adduction (opposition of the toes) is supplied by the plantar interossei.Extension is supplied by the extensor digitorum longus.The flexor digitorum brevis flexes both the middle phalanx on the proximal phalanx and the proximal phalanx on the metatarsal. Ref: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 34. Overview of the Lower Limb. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.
Abduction
Adduction
Extension
Flexion of the middle phalanx on the proximal phalanx