Deep transverse metatarsal ligament

At a glance

English

Deep transverse metatarsal ligament

Latin (TA2)

Ligamentum metatarseum transversum profundum

System

Ligament

Region

Foot

Side

Paired, left and right

About the deep transverse metatarsal ligament

The deep transverse metatarsal ligament is a series of short bands that run across the ball of the foot, joining each metatarsal head to its neighbour. Unlike its counterpart in the hand, the deep transverse metacarpal ligament, it includes the first metatarsal, so the big toe is tied into the row with the others. This is one reason the big toe cannot be opposed like the thumb.

The ligament does not attach directly to the bone along its length. Instead it blends with the front edges of the plantar ligaments, the thick plates on the underside of each metatarsophalangeal joint, and joins one plate to the next. The result is a continuous strap across the sole at the level of the joints.

Its relations sort the structures of the forefoot into layers. On its plantar surface it is shallowly grooved where the long and short flexor tendons, in their fibrous sheaths, run forwards to the toes. The lumbrical tendons, and the plantar digital nerves and vessels, pass below it, between the toes. Above it, on its upper side, the tendons of the interosseous muscles run to their insertions. This arrangement is why the interossei act from above and the lumbricals from below the ligament.

By holding the metatarsal heads together the ligament keeps the forefoot from splaying under load and helps the heads share weight during push-off. Its edge can compress a common plantar digital nerve against the ground, usually between the third and fourth heads. Repeated irritation thickens the nerve into a Morton's neuroma, which causes burning pain and tingling into the toes. One treatment divides the ligament to release the nerve.

Attachments and function

Attaches from

The plantar ligament of each metatarsophalangeal joint, at the side next to the adjacent metatarsal head.

Attaches to

The plantar ligament of the neighbouring metatarsophalangeal joint, so that all the metatarsal heads are linked in a row.

Function

Binds the metatarsal heads together, stops the forefoot splaying and separates the interosseous tendons above from the lumbricals and digital nerves below.

Nerve supply

Twigs of the common plantar digital nerves.

Blood supply

Branches of the plantar metatarsal arteries.