1. THE TALOCALCANEANL JOINT
There are two articulations between the calcaneum and talus, an anterior and a posterior; the anterior forms part of the talocalcaneonavicular joint, and is described with that articulation. The posterior or talocalcanean articulation is formed between the posterior calcanean facet on the inferior surface of the talus, and the posterior facet on the superior surface of the calcaneum. It is a plane joint, and the two bones are connected by a capsular ligament and by anterior, posterior, lateral, medial and interosseous talocalcaneal ligaments.
The capsular ligament envelops the joint, and consists for the most part of short fibers; it is split into slips, and between these there is only a weak fibrous investment. It is lined with synovial membrane; and the joint-cavity does not communicate with any of the other tarsal joints.
The anterior talocalcaneal ligament (fig. 575) extends from the inferior and lateral surfaces of the neck of the talus to the superior surface of the calcaneum. It is identical with the posterior part of the interosseous talocalcanean ligament.
The posterior talocalcaneal ligament (fig. 570) connects the posterior tubercle of the talus with the upper surface of the calcaneum close to the posterior facet; it is a short band; and its fibers radiate from their narrow attachment on the talus.
The lateral talocalcaneal ligament (fig. 572) is a short, flattened fasciculus, which passes downwards and backwards from the lateral tubercle of the talus to be attached to the lateral surface of the calcaneum, above and in front of the calcaneofibular ligament.
The interosseous talocalcaneal ligament (figs. 573, 575) forms the chief bond of union between the bones and is attached, above, to the sulcus tali; below, to the sulcus caleanei. It comprises the posterior ligament of the talocalcaneonavicular joint and the anterior ligament of the talocalcaneal joint. Medially, these two ligaments are fused, but laterally they are separated by a band of fibers derived from the fibrous loop which encloses the tendons of the peroneus tertius and the extensor digitorum longus in front of the ankle-joint. The lateral part of the anterior portion of the talocalcaneal interosseous ligament is especially strengthened and extends between the inferolateral aspect of the neck of the talus and the upper surface of the calcaneum (fig. 575). It is rendered taut when the foot is inverted and. prevents the occurrence of too great a degree of this movement.
Movements.–The movements permitted between the talus and calcaneum are closely associated with the movements at the talocalcaneonavicular joint and will be described with them.
2. TALOCALCANEONAVICULAR JOINT
This articulation is a restricted form of ball-and-socket joint: the rounded head of the talus being received into the concavity formed by the posterior surface of the navicular, the anterior upper articular surface of the calcaneum, and the upper surface of the plantar calcaneonavicular ligament. The bones forming the joint are connected by a capsular ligament, and by the talonavicular, the plantar calcaneonavicular and the lateral calcaneonavicular ligaments.
The capsular ligament is imperfectly developed except posteriorly, where it is considerably thickened and forms the anterior part of the interosseous ligament, which fills the sinus tarsi formed by the opposing grooves on the calcaneum and talus, as mentioned above.
The talonavicular ligament (fig. 570) is a broad, thin band, connecting the neck of the talus to the dorsal surface of the navioular bone; it is covered with the extensor tendons. The plantar calcaneonavicular ligament is the plantar and the lateral calcaneonavicular (vide infra) the lateral ligament for this joint.
Movements-A considerable range of gliding and rotatory movement is permitted at both the talocalcanean and the talocaleaneonavieular joints. The calcaneum and the navicular, carrying the foot with them; can be moved medially on the talus in a combination of gliding movement and rotation. This movement results in the elevation of the medial border and a corresponding depression of the lateral border of the foot, so that the plantar aspect of the foot is directed medially-the position of inversion. The opposite movement, which does little more than restore the foot to its usual position, is termed eversion. During both inversion and eversion a slight degree of gliding movement occurs at the other tarsal joints but it has little actual value. The chief factor in the limitation of inversion is the strong lateral part of the interosseous talocalcanean ligament. The other tarsal interosseous ligaments and the calcaneofibular ligament are less important factors. Eversion is arrested by the deltoid ligament.
Muscles producing the movements:
- Inversion – Tibialis anterior and posterior.
- Eversion – Peroneus longus and brevis.
3. THE CALCANEOCUBOID JOINT
The articular surfaces of the calcaneocuboid joint are somewhat saddleshaped. The ligaments of the joint are : the capsular, the dorsal calcaneocuboid, the calcaneocuboid portion of the bifurcated ligament, the long plantar and the short plantar (plantar calcaneocuboid).
The capsular ligament contains certain bands which form the other ligaments of the joint. Its synovial membrane is distinct from that of the other tarsal articulations (fig. 571).
The dorsal calcaneocuboid ligament (fig. 572) is a thin but broad fasciculus, which passes between the contiguous surfaces of the calcaneum and the cuboid bone on the dorsal surface of the joint.
The bifurcated ligament (figs. 572, 575) is a strong band attached behind to the anterior part of the upper surface of the calcaneum and dividing in front in a Y-shaped manner into a medial calcaneocuboid and a lateral calcaneo navicular ligament. The medial calcaneocuboid ligament is fixed to the dorsal part of the medial side of the cuboid bone and forms one of the principal bonds between the first and second rows of the tarsal bones. The lateral calcaneonavicular ligament is attached to the dorsilateral aspect of the navicular bone.
The long plantar ligament (fig. 574), the longest of the tarsal ligaments, is attached posteriorly to the plantar surface of the calcaneum in front of the medial and lateral tubercles, and anteriorly to the ridge and tuberosity on the plantar surface of the cuboid bone, the more superficial fibers being continued forwards to the bases of the second; third, and fourth metatarsal bones. This ligament converts the groove on the plantar surface of the cuboid bone into a tunnel for the tendon of the pero.neus longus. It possesses great strength and is an important factor in the maintenance of the lateral longitudinal arch of the foot.
The short plantar (plantar caleaneocuboid) ligament (fig. 574) lies nearer to the bones than the preceding ligament, from which it is separated by a little areolar tissue. It is a short but wide band of great strength; and stretches from the anterior tubercle of the calcaneum and the depression in front of it, to the adjoining part of the plantar surface of the cuboid bone. Like the preceding ligament; it contributes support to the lateral longitudinal arch of the foot.
The calcaneocuboid and talonavicular articulations together form what is known as the transverse tarsal joint.
4. THE LIGAMENTS CONNECTING THE CALCANEUM AND NAVICULAR
Though the calcaneum and the navicular bone do not articulate directly, they are connected by two ligaments : the lateral calcaneonavicular and the plantar calcaneonavicular.
The lateral calcaneonavicular ligament has been described above; it forms the medial band of the bifurcated ligament.
The plantar calcaneonavicular or ‘spring’ ligament (fig. 574) is a broad; thick band connecting the anterior margin of the sustentaculum tali of the caleancum to the plantar surface of the navicular bone. This ligament not only unites the calcaneum with the navicular bone; but supports the head of the talus, forming part of the articular cavity in which the head is received. It therefore plays an important part in maintaining the medial longitudinal arch of the foot (p.506). The dorsal surface of the ligament presents a fibrocartilaginous facet upon which a portion of the head of the talus rests (fig. 575). Its plantar surface is supported by the tendon of the tibialis posterior, medially; and by the tendons of the flexor hallucis longus and the flexor digitorum longus, laterally; its medial border is blended with the anterior fibers of the superficial part of the deltoid ligament of the ankle-joint.
5. CUNEONAVICULAR JOINT
The navicular bone is connected to the three cuneiform bones by dorsal and plantar ligaments.
The dorsal ligaments are three small fasciculi, one attached to each of the cuneiform bones. The fasciculus connecting the navicular bone with the medial cuneiform bone is continuous round the medial side of the joint with the plantar ligament which mites these two bones.
The plantar ligaments have a similar arrangement to the dorsal, and are strengthened by slips from the tendon of the tibialis posterior.
Movements.-Gliding movements are permitted between the navicular and cuneiform bones.
6. CUBONAVICULAR JOINT
The cuboid bone is connected with the navicular bone by dorsal, plantar and interosseous ligaments.
The dorsal ligament extends obliquely forwards and laterally while the plantar passes nearly transversely from the cuboid bone to the navicular bone. The interosseous ligament consists of strong transverse fibers, and connects the rough non-articular portions of the adjacent surfaces of the two bones.
Movements.—The movements permitted between the navicular and cuboid bones are limited to a slight gliding upon each other.
7. INTERCUNEIFORM AND CUNEOCUBOID JOINTS
The three cuneiform bones and the cuboid bone are connected together by dorsal, plantar, and interosseous ligaments.
The dorsal and plantar ligaments each consist of three transverse bands one connects the medial and intermediate, cuneiform hones, another the intermediate and lateral cuneiform bones, and another the lateral cuneiform and cuboid bones. The plantar ligaments are strengthened by slips from the tendon of the tibialis posterior.
The interosseous ligaments connect the rough non-articular portions of the adjacent surfaces of the bones and possess considerable strength; they assist in the support of the transverse arch of the foot.
Movements.-The movements permitted between these bones are limited to a slight gliding upon each other.
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