Plantar interphalangeal ligaments

At a glance

English

Plantar interphalangeal ligaments

Latin (TA2)

Ligamenta interphalangea plantaria

System

Ligament

Region

Foot

Side

Paired, left and right

About the plantar interphalangeal ligaments

The plantar interphalangeal ligaments, often called the plantar plates of the toe joints, lie on the sole side of each interphalangeal joint of the foot. The great toe has one such joint and each of the lesser toes has two, the proximal and the distal. Each plate is a dense pad that forms the floor of the joint capsule, filling the space between the head of one phalanx and the base of the next. Its distal end is thick and anchored firmly to the base of the more distal phalanx, while its proximal end is thinner and looser, attached to the neck of the bone above.

The plate is made of tough but pliable fibrocartilage, rich in type I collagen and similar in make-up to the menisci of the knee. Its deep face is smooth and becomes part of the articular surface, taking pressure from the phalangeal head. Most of its fibres run along the length of the toe, so it resists stretching in that direction well. On each side the plate is joined by a collateral ligament and an accessory collateral ligament, and together these form a box that encloses the joint. Its superficial face is grooved for the long and short flexor tendons, whose fibrous sheath is fixed to its edges.

The plates carry weight through the toes and stop the joints being forced into extension, while the collateral ligaments resist sideways and twisting movements. In contrast to the plates of the metatarsophalangeal joints, those of the toe joints do not join the deep transverse metatarsal ligament, which is absent in the toes.

Imbalance between the long flexors and extensors, often with narrow footwear, can leave the joints fixed in flexion, as in hammer toe or claw toe. Over time the plates and capsule become contracted on the plantar side.

Attachments and function

Attaches from

The neck of the more proximal phalanx at each interphalangeal joint of the toes (thin, loose attachment).

Attaches to

The plantar margin of the base of the more distal phalanx (thick, firm attachment).

Function

Form the floor of the interphalangeal joints of the toes, bear load through the digits and prevent hyperextension; the collateral ligaments on each side resist sideways movement.

Nerve supply

Articular branches of the plantar digital nerves.

Blood supply

Branches of the plantar digital arteries.