Intertarsal Articulations

7e. Intertarsal Articulations

FIG. 357– Coronal section through right talocrural and talocalcaneal joints.

(Articulationes Intertarseæ; Articulations of the Tarsus)

Talocalcaneal Articulation (articulatio talocalcanea; articulation of the calcaneus and astragalus; calcaneo-astragaloid articulation).—The articulations between the calcaneus and talus are two in number—anterior and posterior. Of these, the anterior forms part of the talocalcaneonavicular joint, and will be described with that articulation. The posterior or talocalcaneal articulation is formed between the posterior calcaneal facet on the inferior surface of the talus, and the posterior facet on the superior surface of the calcaneus. It is an arthrodial joint, and the two bones are connected by an articular capsule and by anterior, posterior, lateral, medial, and interosseous talocalcaneal ligaments.

The Articular Capsule (capsula articularis).—The articular capsule envelops the joint, and consists for the most part of the short fibers, which are split up into distinct slips; between these there is only a weak fibrous investment.

The Anterior Talocalcaneal Ligament (ligamentum talocalcaneum anterius; anterior calcaneo-astragaloid ligament) (Figs. 356, 359).—The anterior talocalcaneal ligament extends from the front and lateral surface of the neck of the talus to the superior surface of the calcaneus. It forms the posterior boundary of the talocalcaneonavicular joint, and is sometimes described as the anterior interosseous ligament.

The Posterior Talocalcaneal Ligament (ligamentum talocalcaneum posterius; posterior calcaneo-astragaloid ligament) (Fig. 354).—The posterior talocalcaneal ligament connects the lateral tubercle of the talus with the upper and medial part of the calcaneus; it is a short band, and its fibers radiate from their narrow attachment to the talus.

The Lateral Talocalcaneal Ligament (ligamentum talocalcaneum laterale; external calcaneo-astragaloid ligament) (Figs. 356, 359).—The lateral talocalcaneal ligament is a short, strong fasciculus, passing from the lateral surface of the talus, immediately beneath its fibular facet to the lateral surface of the calcaneus. It is placed in front of, but on a deeper plane than, the calcaneofibular ligament, with the fibers of which it is parallel.

The Medial Talocalcaneal Ligament (ligamentum talocalcaneum mediale; internal calcaneo-astragaloid ligament).—The medial talocalcaneal ligament connects the medial tubercle of the back of the talus with the back of the sustentaculum tali. Its fibers blend with those of the plantar calcaneonavicular ligament (Fig. 354).

The Interosseous Talocalcaneal Ligament (ligamentum talocalcaneum interosseum) (Figs. 357, 359).—The interosseous talocalcaneal ligament forms the chief bond of union between the bones. It is, in fact, a portion of the united capsules of the talocalcaneonavicular and the talocalcaneal joints, and consists of two partially united layers of fibers, one belonging to the former and the other to the latter joint. It is attached, above, to the groove between the articular facets of the under surface of the talus; below, to a corresponding depression on the upper surface of the calcaneus. It is very thick and strong, being at least 2.5 cm. in breadth from side to side, and serves to bind the calcaneus and talus firmly together.

Synovial Membrane (Fig. 360).—The synovial membrane lines the capsule of the joint, and is distinct from the other synovial membranes of the tarsus.

Movements.—The movements permitted between the talus and calcaneus are limited to gliding of the one bone on the other backward and forward and from side to side.

Talocalcaneonavicular Articulation (articulatio talocalcaneonavicularis).—This articulation is an arthrodial joint: the rounded head of the talus being received into the concavity formed by the posterior surface of the navicular, the anterior articular surface of the calcaneus, and the upper surface of the planter calcaneonavicular ligament. There are two ligaments in this joint: the articular capsule and the dorsal talonavicular.

The Articular Capsule (capsula articularis).—The articular capsule is imperfectly developed except posteriorly, where it is considerably thickened and forms, with a part of the capsule of the talocalcaneal joint, the strong interosseous ligament which fills in the canal formed by the opposing grooves on the calcaneus and talus, as above mentioned.

The Dorsal Talonavicular Ligament (ligamentum talonaviculare dorsale; superior astragalonavicular ligament) (Fig. 354).—This ligament is a broad, thin band, which connects the neck of the talus to the dorsal surface of the navicular bone; it is covered by the Extensor tendons. The plantar calcaneonavicular supplies the place of a plantar ligament for this joint.

Synovial Membrane.—The synovial membrane lines all parts of the capsule of the joint.

Movements.—This articulation permits of a considerable range of gliding movements, and some rotation; its feeble construction allows occasionally of dislocation of the other bones of the tarsus from the talus.

Calcaneocuboid Articulation (articulatio calcaneocuboidea; articulation of the calcaneus with the cuboid).—The ligaments connecting the calcaneus with the cuboid are five in number, viz., the articular capsule, the dorsal calcaneocuboid, part of the bifurcated, the long plantar, and the plantar calcaneocuboid.

The Articular Capsule (capsula articularis).—The articular capsule is an imperfectly developed investment, containing certain strengthened bands, which form the other ligaments of the joint.

The Dorsal Calcaneocuboid Ligament (ligamentum calcaneocuboideum dorsale; superior calcaneocuboid ligament) (Fig. 355).—The dorsal calcaneocuboid ligament is a thin but broad fasciculus, which passes between the contiguous surfaces of the calcaneus and cuboid, on the dorsal surface of the joint.

The Bifurcated Ligament (ligamentum bifurcatum; internal calcaneocuboid; interosseous ligament) (Fig. 355, 359).—The bifurcated ligament is a strong band, attached behind to the deep hollow on the upper surface of the calcaneus and dividing in front in a Y-shaped manner into a calcaneocuboid and a calcaneonavicular part. The calcaneocuboid part is fixed to the medial side of the cuboid and forms one of the principal bonds between the first and second rows of the tarsal bones. The calcaneonavicular part is attached to the lateral side of the navicular.

The Long Plantar Ligament (ligamentum plantare longum; long calcaneocuboid ligament; superficial long plantar ligament) (Fig. 358).—The long plantar ligament is the longest of all the ligaments of the tarsus: it is attached behind to the plantar surface of the calcaneus in front of the tuberosity, and in front to the tuberosity on the plantar surface of the cuboid bone, the more superficial fibers being continued forward to the bases of the second, third, and fourth metatarsal bones. This ligament converts the groove on the plantar surface of the cuboid into a canal for the tendon of the Peronæus longus.

The Plantar Calcaneocuboid Ligament (ligamentum calcaneocuboideum plantare; short calcaneocuboid ligament; short plantar ligament) (Fig. 358).—The plantar calcaneocuboid ligament lies nearer to the bones than the preceding, from which it is separated by a little areolar tissue. It is a short but wide band of great strength, and extends from the tubercle and the depression in front of it, on the forepart of the plantar surface of the calcaneus, to the plantar surface of the cuboid behind the peroneal groove.

Synovial Membrane.—The synovial membrane lines the inner surface of the capsule and is distinct from that of the other tarsal articulations (Fig. 360).

Movements.—The movements permitted between the calcaneus and cuboid are limited to slight gliding movements of the bones upon each other.

The transverse tarsal joint is formed by the articulation of the calcaneus with the cuboid, and the articulation of the talus with the navicular. The movement which takes place in this joint is more extensive than that in the other tarsal joints, and consists of a sort of rotation by means of which the foot may be slightly flexed or extended, the sole being at the same time carried medially (inverted) or laterally (everted).

The Ligaments Connecting the Calcaneus and Navicular.—Though the calcaneus and navicular do not directly articulate, they are connected by two ligaments: the calcaneonavicular part of the bifurcated, and the plantar calcaneonavicular.

The calcaneonavicular part of the bifurcated ligament is described on page 354.

FIG. 358– Ligaments of the sole of the foot, with the tendons of the Peronæus longus, Tibialis posterior and Tibialis anterior muscles. (Quain.)

The Plantar Calcaneonavicular Ligament (ligamentum calcaneonaviculare plantare; inferior or internal calcaneonavicular ligament; calcaneonavicular ligament) (Figs. 354, 358).—The plantar calcaneonavicular ligament is a broad and thick band of fibers, which connects the anterior margin of the sustentaculum tali of the calcaneus to the plantar surface of the navicular. This ligament not only serves to connect the calcaneus and navicular, but supports the head of the talus, forming part of the articular cavity in which it is received. The dorsal surface of the ligament presents a fibrocartilaginous facet, lined by the synovial membrane, and upon this a portion of the head of the talus rests. Its plantar surface is supported by the tendon of the Tibialis posterior; its medial border is blended with the forepart of the deltoid ligament of the ankle-joint.

FIG. 359– Talocalcaneal and talocalcaneonavicular articulations exposed from above by removing the talus.

The plantar calcaneonavicular ligament, by supporting the head of the talus, is principally concerned in maintaining the arch of the foot. When it yields, the head of the talus is pressed downward, medialward, and forward by the weight of the body, and the foot becomes flattened, expanded, and turned lateralward, and exhibits the condition known as flat-foot. This ligament contains a considerable amount of elastic fibers, so as to give elasticity to the arch and spring to the foot; hence it is sometimes called the “spring” ligament. It is supported, on its plantar surface, by the tendon of the Tibialis posterior, which spreads out at its insertion into a number of fasciculi, to be attached to most of the tarsal and metatarsal bones. This prevents undue stretching of the ligament, and is a protection against the occurrence of flat-foot; hence muscular weakness is, in most cases, the primary cause of the deformity.

Cuneonavicular Articulation (articulatio cuneonavicularis; articulation of the navicular with the cuneiform bones).—The navicular is connected to the three cuneiform bones by dorsal and plantar ligaments.

The Dorsal Ligaments (ligamenta navicularicuneiformia dorsalia).—The dorsal ligaments are three small bundles, one attached to each of the cuneiform bones. The bundle connecting the navicular with the first cuneiform is continuous around the medial side of the articulation with the plantar ligament which unites these two bones (Figs. 354, 355).

The Plantar Ligaments (ligamenta navicularicuneiformia plantaria).—The plantar ligaments have a similar arrangement to the dorsal, and are strengthened by slips from the tendon of the Tibialis posterior (Fig. 358).

Synovial Membrane.—The synovial membrane of these joints is part of the great tarsal synovial membrane (Fig. 360).

Movements.—Mere gliding movements are permitted between the navicular and cuneiform bones.

Cuboideonavicular Articulation.—The navicular bone is connected with the cuboid by dorsal, plantar, and interosseous ligaments.

The Dorsal Ligament (ligamentum cuboideonaviculare dorsale).—The dorsal ligament extends obliquely forward and lateralward from the navicular to the cuboid bone (Fig. 355).

The Plantar Ligament (ligamentum cuboideonaviculare plantare).—The plantar ligament passes nearly transversely between these two bones (Fig. 358).

The Interosseous Ligament.—The interosseous ligament consists of strong transverse fibers, and connects the rough non-articular portions of the adjacent surfaces of the two bones Fig. 360).

Synovial Membrane.—The synovial membrane of this joint is part of the great tarsal synovial membrane (Fig. 360).

Movements.—The movements permitted between the navicular and cuboid bones are limited to a slight gliding upon each other.

FIG. 360– Oblique section of left intertarsal and tarsometatarsal articulations, showing the synovial cavities.

Intercuneiform and Cuneocuboid Articulations.—The three cuneiform bones and the cuboid are connected together by dorsal, plantar, and interosseous ligaments.

The Dorsal Ligaments (ligamenta intercuneiformia dorsalia).—The dorsal ligaments consist of three transverse bands: one connects the first with the second cuneiform, another the second with the third cuneiform, and another the third cuneiform with the cuboid.

The Plantar Ligaments (ligamenta intercuneiformia plantaria).—The plantar ligaments have a similar arrangement to the dorsal, and are strengthened by slips from the tendon of the Tibialis posterior.

The Interosseous Ligaments (ligamenta intercuneiformia interossea).—The interosseous ligaments consist of strong transverse fibers which pass between the rough non-articular portions of the adjacent surfaces of the bones (Fig. 360).

Synovial Membrane.—The synovial membrane of these joints is part of the great tarsal synovial membrane (Fig. 360).

Movements.—The movements permitted between these bones are limited to a slight gliding upon each other.