Plantar metatarsophalangeal ligaments

At a glance

English

Plantar metatarsophalangeal ligaments

Latin (TA2)

Ligamenta metatarsophalangea plantaria

System

Ligament

Region

Foot

Side

Paired, left and right

About the plantar metatarsophalangeal ligaments

The plantar metatarsophalangeal ligaments, generally called plantar plates, form the floor of the five joints at the ball of the foot. Each is a thick rectangular pad lying beneath a metatarsal head. Its distal edge is anchored strongly to the base of the proximal phalanx, and its proximal edge is thinner and more loosely joined to the metatarsal neck, so the plate travels with the toe as it bends and straightens and slides under the head of the metatarsal.

The plate is firm yet flexible fibrocartilage, built mainly of type I collagen in a way that resembles the knee menisci. Its deep surface acts as part of the joint socket and takes compressive load from the metatarsal head, while its fibres run chiefly lengthwise, in line with the plantar aponeurosis, letting it resist strong tension. On each side it is joined by the main and accessory collateral ligaments, forming a fibrous box fixed on either side of the metatarsal head. The longitudinal bands of the plantar aponeurosis insert into it, and the deep transverse metatarsal ligaments link neighbouring plates into a continuous band across the forefoot. Its plantar face is grooved for the flexor tendons. In the great toe the plate encloses the two sesamoid bones.

This linked arrangement acts as both a longitudinal and a transverse tie. The longitudinal system, through the aponeurosis, controls the arches; the transverse one, through the plates and transverse ligaments, limits splaying of the forefoot. Both come under load when weight presses on the metatarsal heads, especially as the toes extend during push-off, which tightens the aponeurosis and raises the arch.

Repeated hyperextension, as in high-heeled shoes, strains the plate. A tear of the second toe plate is a common cause of pain under the forefoot and can let the toe drift upwards or across the great toe. Turf toe is the corresponding injury of the first joint.

Attachments and function

Attaches from

The neck of each metatarsal, by a thin and loose proximal attachment.

Attaches to

The plantar margin of the base of the proximal phalanx, by a thick and firm distal attachment.

Function

Floor the metatarsophalangeal joints, bear load from the metatarsal heads, prevent hyperextension of the toes and, linked by the deep transverse metatarsal ligaments, limit splaying of the forefoot.

Nerve supply

Articular branches of the plantar digital nerves from the medial and lateral plantar nerves.

Blood supply

Branches of the plantar metatarsal and plantar digital arteries.