Joints and ligaments of the foot

Ligaments

Medial collateral ligament

The medial collateral ligament, also known as the deltoid ligament, is a triangular band that attaches to the medial malleolus proximally and to the calcaneus, talus and navicular bones distally. The ligament consists of four main groups of fibres:

• The tibionavicular fibres (anterior segment)
• The tibiocalcaneal fibres (intermediate segment)
• The anterior tibiotalar fibres (deep segment)
• The posterior tibiotalar fibres (posterior segment)

The tendons of the tibialis posterior and flexor digitorum longus cross this ligament.

Lateral collateral ligament

The lateral collateral ligament consists of three separate ligaments:

• The anterior talofibular ligament
• The posterior talofibular ligament and;
• The calcaneofibular ligament

As the name suggests, the anterior talofibular ligament connects the talus with the lateral malleolus of the fibula. It extends from the anterior aspect of the malleolus to the lateral surface of the talar neck. The posterior talofibular ligament runs horizontally from the distal aspect of the fibular malleolus to the lateral tubercle of the posterior process of the talus. The calcaneofibular ligament is a long cord that runs from a depression anterior to the fibular malleolus to a tubercle on the lateral aspect of the calcaneus.

Innervation

The ankle joint is innervated by the branches of the sural, tibial, saphenous and deep fibular nerves.

Occasionally, it is also supplied by the superficial fibular nerve.

Muscles

The tibialis anterior allows dorsiflexion at the ankle joint and is assisted by the tendons of the fibularis tertius, hallucis longus and extensor digitorum longus.

The soleus and gastrocnemius muscles allow plantar flexion with assistance from the tibialis posterior, flexor hallucis longus, plantaris and flexor digitorum longus muscles.

Ligaments

It consists of three separate ligaments:

• The anterior tibiofibular ligament
• The posterior tibiofibular ligament
• The interosseus tibiofibular ligament

The anterior tibiofibular ligament is a flat band that descends between the tibia and fibula anterior to the syndesmosis. The posterior tibiofibular ligament descends posteriorly to the syndesmosis between the tibia and fibula. The distal part of this ligament, the inferior transverse ligament, is a yellow band that connects the medial and lateral malleoli. The interosseus tibiofibular ligament is a continuation of the interosseus membrane and is the strongest of the three ligaments.

Innervation

The inferior tibiofibular joint is innervated by branches of the deep fibular and sural nerves.

No muscles act on this joint.

Ligaments

This joint is stabilized by a fibrous capsule and four ligaments:

• The medial talocalcaneal ligament
• The lateral talocalcaneal ligament
• The interosseus talocalcaneal ligament
• The cervical ligament

The medial talocalcaneal ligament connects the medial tubercle of the talus with the substentaculum tali, a horizontal eminence on the calcaneus. The lateral process of the talus is connected to the lateral aspect of the calcaneus by the lateral talocalcaneal ligament. The interosseus talocalcaneal ligament runs between the sulcus tali, a groove on the inferior aspect of the talus, and the calcaneus sulcus. The cervical ligament ascends from the superior calcaneal surface to the inferolateral tubercle on the talar neck.

Innervation

The talocalcaneal joint is innervated by branches of the sural, medial plantar and posterior tibial nerves.

Muscles

The tibialis anterior, tibialis posterior, gastrocnemius and soleus muscles contribute together to perform heel inversion (movement of the sole of the foot towards the midline).

Eversion (movement away from the midline) results from the action of the fibularis longus, fibularis tertius and fibularis brevis muscles.

Mnemonic

In order to remember the muscles that participate in inversion and eversion of the foot you can use the mnemonic called "Second letter rule":

Eversion muscles

• pEroneus longus
• pEroneus brevis
• pEroneus terius

Inversion muscles

• tIbialis anterior
• tIbialis posterior

Ligaments

These two articulations are stabilized by a fibrous capsule and by the talonavicular and plantar calcaneonavicular ligaments. The calcaneonavicular part of the bifurcate ligament also helps to stabilize this joint.

The talonavicular ligament is a thin band connecting the dorsal aspect of the talar neck with the navicular bone and is covered by extensor tendons. The plantar calcaneonavicular ligament, also known as the spring ligament, runs from the anterior aspect of the sustentaculum tali to the plantar surface of the navicular bone.

Innervation

The innervation of the talocalcaneonavicular joint is provided by the medial plantar and deep fibular nerves.

Muscles

The muscles producing the movement of this joint are the same as the talocalcaneal joint.

Ligaments

The three ligaments that stabilize this joint are:

• The bifurcate ligament
• The long plantar ligament 
• The plantar calcaneocuboid ligament

The bifurcate ligament is a Y-shaped band, which attaches proximally to the anterior aspect of the calcaneus. Distally, it divides into two parts: the calacaneocuboid and the calcaneonavicular parts. The calcaneocuboid part attaches to the dorsomedial surface of the cuboid bone whilst the calcaneonavicular part attaches to the dorsolateral aspect of the navicular bone.

The longest ligament associated with the tarsus is known as the long plantar ligament. It runs from the plantar surface of the calcaneus bone to the tuberosity located on the plantar aspect of the cuboid bone. More superficial fibres continue on to attach to the bases of the second to fourth metatarsals.

The plantar calcaneocuboid ligament is located deep to the long plantar ligament and is separated from it by areolar tissue. It extends from the anterior tubercle of the calcaneus to the plantar aspect of the cuboid.

Innervation

Innervation of the calcaneocuboid joint is provided by the lateral plantar nerve (plantar aspect), sural and deep fibular nerves (dorsally).

Muscles

The muscles producing movement of this joint are the same ones that act on the talocalcaneal and talocalcaneonavicular joints, aiding in the gliding and rotational movements between the calcaneus and cuboid bones.

Ligaments

Two ligaments help form connections between these bones: the dorsal ligaments and the plantar ligaments.

The dorsal and plantar ligaments connect the navicular bone with each cuneiform. The medial dorsal ligament continues as a capsule around the medial aspect of the joint.

Innervation

Innervation of the cuneonavicular joint is provided by the deep fibular (dorsally), medial and lateral plantar nerves (plantar surface).

Muscles

Slight gliding and rotation occurs at this joint. These movements are produced by the action of the fibularis longus and brevis, tibialis anterior and tibialis posterior muscles. The long extensors and flexors of the toes also contribute to the production of these movements.

Ligaments

The bones are connected together by dorsal, plantar and interosseus ligaments.

Both the dorsal and plantar ligaments consist of three transverse bands, which run between the cuneiform bones and between the lateral cuneiform and the cuboid bone. The interosseus ligaments connect non-articular surfaces of the bones.

Innervation

The innervation of these two joints is from the deep fibular nerve (dorsally), medial and lateral plantar nerves (plantar surface).

Muscles

The muscles that produce movement of these joints are the same as those for the the naviculocuneiform joint.

Ligaments

There are three bands of ligaments involved in stabilising these joints:

• The dorsal tarsometatarsal ligaments
• The plantar tarsometatarsal ligaments and;
• The interosseus cuneometatarsal ligaments

Eight dorsal tarsometatarsal ligaments connect the metatarsal bones to the cuboid and cuneiform bones. These ligaments form the following connections:

• First metatarsal to the medial cuneiform
• Second metatarsal to each cuneiform
• Third metatarsal to the lateral cuneiform
• Fourth metatarsal to the lateral cuneiform and cuboid
• Fifth metatarsal to the cuboid

The plantar tarsometatarsal ligaments consist of both longitudinal and oblique bands.

The strongest of the three interosseus cuneometatarsal ligaments is the Lisfranc’s ligament. It runs from the second metatarsal to the lateral aspect of the medial cuneiform. The other two ligaments connect the lateral cuneiform with the second metatarsal and the lateral cuneiform with the base of the fourth metatarsal.

Innervation

The innervation of the tarsometatarsal joints is from the deep fibular nerve (dorsally), medial and lateral plantar nerves (plantar surface).

Muscles

Flexion and extension at the level of tarsometatarsal joints are produced by the short and long extensors and flexors of the toe.

Abduction and rotation can also occur at the first tarsometatarsal joint and are carried out by the tibialis anterior and fibularis longus muscles.

Ligaments

The sesamoid bones are connected together by the intersesamoid ligament. Other ligaments that stabilize the metatarsophalangeal joints include the:

• Plantar ligaments
• Deep transverse metatarsal ligaments
• Collateral ligaments

The thick plantar ligaments lie between the collateral ligaments, are attached firmly to the phalangeal bases and loosely to the metatarsal heads. They blend with both the deep transverse metatarsal and collateral ligaments.

Four flat bands, the deep transverse metatarsal ligaments, unite the plantar ligaments and lie between the interossei and the lumbricals.

The collateral ligaments run from the dorsal tubercles of the metatarsal heads before widening and attaching to the bases of the proximal phalanges.

Innervation

The innervation of the metatarsophalangeal joints is provided by the plantar interdigital nerve, digital branches of the lateral plantar nerve, medial dorsal cutaneous branch of the superficial fibular nerve and the deep fibular nerve.

Muscles

The flexor digitorum brevis, lumbricals and interossei produce flexion at the lateral four metatarsophalangeal joints. Flexion of the hallux is produced by the action of flexor hallucis longus and brevis.

Extensor digitorum longus and brevis, as well as extensor hallucis longus are all involved in extension at the metatarsophalangeal joints.

Abduction is produced by the adductor hallucis and the plantar interossei, whilst adduction is carried out by the actions of abductor hallucis, the dorsal interossei and abductor digiti minimi.

Innervation

The innervation of the interphalangeal joints is from the plantar interdigital nerves and the medial dorsal cutaneous branch of the superficial fibular nerve. Occasionally, branches of the sural, deep fibular and intermediate dorsal cutaneous nerves innervate these joints.

Muscles

Flexion is produced by flexor digitorum longus and brevis as well as by flexor hallucis longus in the hallux. Extensor digitorum longus and brevis, as well as extensor hallucis longus are involved in extension of the interphalangeal joints.

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