Long plantar ligament

At a glance

English

Long plantar ligament

Latin (TA2)

Ligamentum plantare longum

System

Ligament

Region

Foot

Side

Paired, left and right

Arises from

The first metatarsal bone, fourth metatarsal bone, second metatarsal bone and third metatarsal bone

About the long plantar ligament

The long plantar ligament is a thick fibrous band in the sole of the foot, lying along its lateral part. Its posterior end is anchored to the underside of the heel bone, ahead of the calcaneal tuberosity and behind the anterior tubercle. From there it runs forwards to the ridge under the cuboid. Its deeper fibres stop at the cuboid, but the more superficial ones carry on past it and spread out to the bases of the middle metatarsals, usually the second, third and fourth.

As it passes forwards over the cuboid, the ligament bridges the groove on the bone's plantar surface. The groove is thereby turned into a fibro-osseous tunnel, through which the tendon of fibularis longus crosses the sole on its way to the medial cuneiform and first metatarsal. Directly above the long ligament, nearer the bones and separated by a little loose tissue, lies the shorter and wider plantar calcaneocuboid ligament. Below it, the two heads of quadratus plantae lie on either side, the ligament separating them at their origin from the calcaneus.

The long plantar ligament is one of the main passive supports of the lateral longitudinal arch. Acting like the tie-beam of a truss, it resists the spreading of the calcaneus and cuboid under body weight, working with the short plantar ligament, the plantar aponeurosis and the tendons that cross the sole. Its length gives it a long lever on the arch.

Because muscles become tired while ligaments do not, prolonged standing loads ligaments such as this one more heavily. Strain of the plantar ligaments contributes to pain along the lateral sole, and their failure, together with that of the spring ligament on the medial side, is part of the collapse seen in acquired flatfoot.

Attachments and function

Attaches from

The underside of the calcaneus, ahead of the calcaneal tuberosity.

Attaches to

The ridge under the cuboid; its superficial fibres go on to metatarsal bases two to four.

Function

Ties the calcaneus to the cuboid and forefoot to support the lateral longitudinal arch, and roofs the tunnel for the tendon of fibularis longus.

Nerve supply

Articular branches of the lateral plantar nerve.

Blood supply

Branches of the lateral plantar artery.