Flexor digiti minimi brevis
Flexor digiti minimi brevis is located on the lateral border of the foot. It runs from the medial plantar surface of the base of the 5th metatarsal to the lateral side of the base of the proximal phalanx of the 5th toe. It is worth noting that flexor digiti minimi brevis demonstrates attachment points to tendinous sheath of peroneus longus and to the plantar fascia at its origin.
The function of flexor digiti minimi brevis is to flex and help abduct the 5th toe. To test its function, ask your subject to flex their 5th digit against resistance while you apply two fingers to the plantar aspect of the shaft of the 5th metatarsal. As the lateral surface of flexor digiti minimi is covered by the belly of abductor digiti minimi, you will need to place your fingers slightly toward the medial aspect of the 5th metatarsal shaft.