Flexor Hallucis Brevis: Flexor hallucis brevis is one of the third layers of plantar muscle lies within the sole of the foot. The muscle connects to the bottom of the cuboid bone and extends across the sole to the base of the hallux bone. The muscle plays a dual role in both movements of the big toe and the arching of the foot.
Lateral part of the muscle is originated medically to the cuboid bone. The medial part of the muscle is originated from the tendon of tibialis posterior muscle.
Both parts of the muscle are inserted on the hallux.
Medial plantar nerve (S1-S2)
Posterior tibial artery
Flexion of the great toe at the metatarsophalangeal joint.