The flexor hallucis brevis muscle lies within the sole of the foot. The muscle connects to the bottom of the cuboid bone (located in the middle of the foot) and extends across the sole to the base of the hallux bone, better known as the big toe. The muscle plays a dual role in both movement of the big toe and the arching of the foot.

The hallucis brevis is one of several muscles located along the sole of the foot that are responsible for the flexing or curling of the toes. It works opposite of the extensor hallucis longus muscle located on the top of the foot, with the two muscles pulling on the hallux bone to create the motions of the big toe.

As with the other muscles of the sole of the foot, the flexor hallucis brevis receives impulses from the medial plantar nerve, a branch of the tibial nerve that travels behind the knee and down the leg.

The medial plantar artery supplies blood flow to the hallucis brevis.