Fourth metatarsal web-space

The metatarsal web space refers to the anatomical region between adjacent metatarsal heads in the forefoot, bounded dorsally and plantarly by soft tissue structures. Each intermetatarsal space is divided into two levels by the deep transverse metatarsal ligament:

• The superior (dorsal) level contains the interosseous muscles and tendons, the synovial intermetatarsal bursa, and the collateral ligament complexes of the metatarsophalangeal joints.

• The inferior (plantar) level contains the lumbrical muscles and the neurovascular bundles, including the common plantar digital nerves and vessels, which are clinically relevant in conditions such as Morton’s neuroma.

The deep transverse metatarsal ligament is a key structure, running transversely and connecting the metatarsal heads, preventing splaying of the forefoot and anchoring the plantar plates.

The plantar aspect of the web space is further reinforced by the plantar aponeurosis and the plantar interdigital ligament, which anchor the skin and provide mechanical stability.

The intermetatarsal bursa is present above and below the deep transverse metatarsal ligament, with its distal extension varying by web space; in the second and third spaces, it extends close to the neurovascular bundles, while in the first and fourth spaces, it does not extend beyond the DTML.