The intermetatarsophalangeal bursa--its significance in Morton's metatarsalgia.

The intermetatarsophalangeal bursa was investigated by dissection, radiography and injection. In the web spaces between the second and third and the third and fourth digits the bursa lies superior to the transverse metatarsal ligament but projects distally to it, closely applied to the neurovascular bundle. Tissue from the web spaces of patients with classical Morton's metatarsalgia often shows lymphocytic infiltration, with additional fibrinoid necrosis of the bursal wall. It is suggested that inflammatory changes in this bursa could account for the pathological and histological findings in this condition. The bursa in the most lateral web space does not extend beyond the ligament and is not in contact with the neurovascular bundle, which may explain the rarity of symptoms in this space.