The flexor digitorum brevis is the muscle in the middle of the sole of the foot. It lies firmly attached to and immediately above the central part of the plantar aponeurosis.
Its deep surface is separated from the lateral plantar vessels and nerves by a thin layer of fascia.
It arises by a narrow tendon, from the medial process of the tuberosity of the calcaneus, from the central part of the plantar aponeurosis, and from the intermuscular septa between it and the adjacent muscles.
It passes forward, and divides into four tendons, one for each of the four lesser toes.
Opposite the bases of the first phalanges, each tendon divides into two slips, to allow of the passage of the corresponding tendon of the flexor digitorum longus; the two portions of the tendon then unite and form a grooved channel for the reception of the accompanying long Flexor tendon.
The muscle is supplied by the medial plantar nerve