Origin: Fifth metatarsal bone
Insertion: Phalanx of the fifth toe
Nerve: Plantar nerve
Action: Flex and adduct the fifth toe
Antagonist: Abductor digiti minimi muscle
The Flexor digiti minimi brevis (Flexor digiti quinti brevis) lies under the metatarsal bone of the little toe, and resembles one of the Interossei. It arises from the base of the fifth metatarsal bone, and from the sheath of the Peronaeus longus; its tendon is inserted into the lateral side of the base of the first phalanx of the fifth toe. Occasionally a few of the deeper fibers are inserted into the lateral part of the distal half of the fifth metatarsal bone; these are described by some as a distinct muscle, the Opponens digiti minimi of foot (Opponens digiti quinti.).