Medial plantar nerve

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The medial plantar nerve is the larger of the two terminal branches of the tibial nerve. It originates deep to the flexor retinaculum and lies lateral to the medial plantar artery. As it enters the foot, it passes deep to the abductor hallucis muscle, running between it and the flexor digitorum brevis. It gives rise to a medial proper digital nerve to the great toe and eventually divides into three common plantar digital nerves near the bases of the metatarsals.  

The motor distribution of the medial plantar nerve is to the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis and the first lumbrical. The cutaneous distribution is to the anterior two-thirds of the medial sole and medial three and one-half digits, including the nail beds.

A useful mnemonic for remembering the muscles supplied by the medial plantar nerve is “LAFF muscles” (First Lumbrical, Abductor Hallucis, Flexor digitorum brevis, Flexor hallucis brevis).