Morton's Neuroma, also known as interdigital, intermetatarsal or forefoot neuroma, is a common foot injury characterized by Neuritic type pain (stabbing, burning or shooting) that radiates from the ball of the foot distally into the digits. Commonly the pain is caused by entrapment and thickening of the interdigital nerve lying between the 3rd and 4th metatarsal bones (sometimes the 2nd and 3rd metatarsal).
Assessment
 The major cause of Morton's Neuroma is compression of the digital nerves by the metatarsal heads and the transverse intermetatarsal ligament. Problems often develop between the 3rd & 4th metatarsals, because part of the lateral plantar nerve combines with part of the medial plantar nerve here. When the two nerves combine, they are typically larger in diameter than those going to the other toes. As the nerves travel distally, they pass plantar to the transverse inter metatarsal ligament. This ligament is very strong, holds the metatarsal bones together, and creates the ceiling of the nerve compartment. The ground pushes up on the enlarged nerve with each step and the deep transverse metatarsal ligament pushes down. This causes compression of the nerve in a confined space. Excessive Pronation and narrow-fitting footwear further reduce the space between the metatarsal heads, thereby increasing the likelihood of neuroma formation.
Diagnosis
 The patient presents with an acute or burning pain in the ball of the foot. Often patients feel the need to remove their shoe and massage the foot and toes. Pain may or may not be associated with numbness, tingling and discoloration of the third and fourth (lesser) toes. There are two simple tests for Morton's Neuroma: the Lateral Squeeze test and Axial Pressure test. Both will be painful when a neuroma is present. Axial Pressure test: Palpate the area to elicit pain, squeezing the toes from the side. Lateral Squeeze test: Hold the patient's first, second, and third metatarsal heads with one hand and the fourth and fifth metatarsal heads in the other and pushing half the foot up and half the foot down slightly. In many cases of Morton's neuroma, this causes an audible click, known as Mulder's sign.
Thirdly, check for Excess Pronation at the Subtalar Joint
Treatment
 Treatment for a Morton's Neuroma involves removing the pressure that is causing the nerve irritation and reducing the inflammation around the nerve.
1) application of a Metatarsal Raise (or 'Met Dome') placed under the heads of the 3 central metatarsals increases the intermetatarsal space, thereby reducing the entrapment.
2) if Excess Pronation is present, orthotic prescription is recommended. A Met Dome can be used together with orthotic treatment (see picture).
3) Ice can be applied - in particular to provide relieve after athletic activity.
4) The patient should be advised to wear shoes with wide toe boxes and avoid high heeled footwear.
5) Surgery: a) Dorsal approach: this involves cutting the deep transverse metatarsal ligament, which typically causes most of the nerve compression. This procedure can lead to instability in the forefoot that may require attention in the future. b) Plantar approach: in which the incision is made on the sole of the foot. The patient must use crutches for about 3 weeks and the scar that forms can make walking uncomfortable. The advantage of the plantar approach is that the neuroma can be reached easily and resected without cutting any structures.
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