Fig. 3

A schematic representation of the mechanism of tip of toe ulcer formation and treatment. a The normal toe. Note how the interosseii (and lumbricals, not delineated) pass below the center of the head of the metatarsal (marked with a cross) inserting into the extensor hood. They act as flexors of the metatarso-phalangeal joint and extensors of the proximal and distal inter-phalangeal joints [45].. b In absence of the flexing moment of the interosseii, the extensor digitorum longus forces the metatarso-phalangeal joint into extension. In absence of the extending moment of the interosseii and lumbricals through the extensor sheath, the flexor digitorum longus forces the proximal and distal inter-phalangeal joints into flexion. c The flexor tenotomy with the Beaver knife straightens the toe, relieving pressure from the ulcer sites. Reproduced with permission from Foot & Ankle International [15]