Morton’s neuroma -Quick revision card

compression neuropathy of the interdigital nerve also known by several other names as intermetatarsal neuroma , intermetatarsal neuritis , plantar interdigital neuroma , interdigital neuritis , plantar interdigital neuroma how it happens / pathomechanisms are controversial but the histologic end point is perineural fibrosis not true neuromas ( no histological evidence of neuroma with axonal degeneration and collagen proliferation ) but masses composed of perineural fibrosis & nerve degeneration ( they become symptomatic once they reach 5 mm size ) it is not sure what happens and several theories have been proposed○ the interdigital nerve is compressed against the deep transverse intermetatarsal ligament ○ an enlarged intermetatarsal bursa may cause ischaemia or compression of the nerve ○ repeated trauma to the interdigital nerve at the edge of the intermetatarsal ligament○ vascular injury the common digital nerve to the 3rd space receives branches from medial & lateral plantar nerve -ie it has increased thickness and is prone to compression & trauma typically this happens between the 3rd and 4th metatarsal space ( about 80 % occur in the 3rd webspace )

Presentation -pain in forefoot , worse on weight bearing 2nd or 3rd web space or metatarsal interspace location of pain...