Plantar tarsometatarsal ligaments

At a glance

English

Plantar tarsometatarsal ligaments

Latin (TA2)

Ligamenta tarsometatarsea plantaria

System

Ligament

Region

Foot

Side

Paired, left and right

About the plantar tarsometatarsal ligaments

The plantar tarsometatarsal ligaments strengthen the sole side of the tarsometatarsal joints, the row of plane joints where the distal tarsal bones meet the five metatarsal bases. Unlike the neat dorsal set on the upper side of the foot, the plantar bands are less regular in their arrangement. Some run straight forwards along the length of the foot and others cross obliquely from one bone to a neighbouring one.

The strongest bands are those to the first and second metatarsals. The first metatarsal is held to the medial cuneiform on its underside. From the medial cuneiform, oblique bands also cross laterally to the bases of the second and third metatarsals; the one to the second is closely related to the Lisfranc ligament, the strong interosseous band that runs from the medial cuneiform to the second metatarsal base. On the lateral side, the fourth and fifth metatarsals receive only a few fibres from the cuboid. Throughout, the bands are reinforced by tendon slips: tibialis posterior fans out to the cuneiforms and middle metatarsal bases, and fibularis longus crosses the sole to reach the first metatarsal and medial cuneiform.

Because the plantar ligaments are thicker and stronger than the dorsal ones, the midfoot is better able to resist forces that would push the metatarsal bases upwards, which happens with every step as weight passes forwards to the forefoot. The ligaments act as ties on the underside of the transverse arch formed by the wedge-shaped bases, and allow only small gliding movements.

In a tarsometatarsal (Lisfranc) injury these bands can be torn together with the dorsal and interosseous ligaments. The pattern of the plantar bands partly explains why displacement of the metatarsal bases is usually towards the upper side of the foot.

Attachments and function

Attaches from

The plantar parts of the medial cuneiform, the other cuneiforms and the cuboid.

Attaches to

The plantar parts of the bases of the first to fifth metatarsals.

Function

Bind the metatarsal bases to the distal tarsal row from below, resist upward displacement of the bases and support the transverse arch.

Nerve supply

Articular branches of the medial and lateral plantar nerves.

Blood supply

Branches of the deep plantar arch and the medial and lateral plantar arteries.