Morton neuroma is a common podiatric condition affecting the forefoot. It affects 10 times as many women as men and is usually diagnosed between 40 and 60 years of age. It mainly affects the third interspace but can also occur in other interspaces.
Anatomically, a Morton neuroma is an enlargement of the third common digital branch of the medial plantar nerve. The third common digital nerve receives a communicating branch from the lateral plantar nerve that passes deep to the deep transverse metatarsal ligament in the third interspace. It is a benign growth from the fibrous coverings of the nerve.
Many etiologies have been proposed, including trauma, ischemia, overpronation, equinus, intermetatarsal bursitis, and nerve entrapment due to mechanical impingement by the deep transverse metatarsal ligament.