Intermetatarsal (Morton’s) Neuroma

An inflammatory fibrosing process of the interdigital nerve characterized by pain on the plantar surface of the foot

Most commonly occurs between the heads of the 3rd and 4th metatarsals, although may also involve the 2nd and 3rd intermetatarsal space

Occurs just before the nerve bifurcates at the metatarsal area to innervate sides of 2 adjacent toes

Usually unilateral symptoms

Occurs more often in women than men

Found in kickboxers, ballet dancers, and runners

Caused by nerve thickening from repetitive dorsiflexion of the toes, causing microtrauma to the nerve as it is compressed either under the transverse metatarsal ligament or by an inflamed intermetatarsal bursa (1)

The repetitive trauma causes swelling of the plantar digital nerve that pathologically resembles other nerve entrapment syndromes

Intermittent, episodic pain, usually on the plantar surface of the foot between the 3rd and 4th metatarsals

Forefoot pain radiating to the affected interspace, toes, and ankle (1)[C]

Paresthesias in the toes and interdigital space are common (1)[C].

Pain exacerbated with exercise and relieved with rest

Tenderness to palpation on the plantar surface of the foot, usually between the 3rd and 4th metatarsals

Mulder's click: Audible, painful click after compressing the metatarsal heads and releasing the forefoot (1)[C]

No weakness noted on strength testing of the foot

Primarily a clinical diagnosis

Imaging usually not needed

Metatarsalgia

Metatarsal stress fracture

Ganglion cyst

Neuropathies (diabetic, alcoholic, toxic, nutritional)

Freiberg's disease (osteochondrosis of the head of the metatarsal in teenagers)