Lower Extremity Articulations

THE TARSOMETATARSAL JOINTS

These are plane joints. The first metatarsal bone articulates with the medial cuneiform bone; the second is dovetailed in between the medial and lateral cuneiform bones, articulating by its base with the intermediate cuneiform bone; the third articulates with the lateral cuneiform bone; the fourth, with the cuboid and lateral cuneiform bones; and the fifth with the cuboid bone. The bones are connected by dorsal, plantar, and interosseous ligaments.

The dorsal ligaments are strong, flat bands. The first metatarsal is joined to the medial cuneiform bone by a capsular ligament; the second metatarsal receives three bands, one from each cuneiform bone; the third, one from the lateral cuneiform bone; the fourth, one from the lateral cuneiform bone, and another from the cuboid bone; and the fifth, one from the cuboid bone.

The plantar ligaments consist of longitudinal and oblique bands, disposed with less regularityAban the dorsal ligaments. Those for the first and second metatarsal bones are the strongest; the second and third metatarsal bones are joined by oblique bands to the medial cuneiform bone; the fourth and fifth metatarsal bones are connected by a few fibers to the cuboid bone.

The interosseous ligaments are three in number. The first is the strongest and passes from the lateral surface of the medial cuneiform bone to the adjacent angle of the second metatarsal bone (fig, 576). The second connects the lateral cuneiform bone with the adjacent angle of the second metatarsal bone. The third connects the lateral angle of the lateral cuneiform bone with the adjacent side of the base of the third metatarsal bone.

Movements.—The movements permitted between the tarsal and metatarsal bonzes are limited to slight gliding of the bones upon each other.

THE INTERMETATARSAL JOINTS

The base of the first metatarsal bone is not connected with that of the second by any ligaments; in this respect the great toe resembles the thumb. A small bursa is often interposed between the lateral aide of the base of the first metatarsal bone and the medial side of the shaft of the second (fig. 576).

The bases of the second, third, fourth, and fifth metatarsal bones are connected by dorsal, plantar, and interosseous ligaments.

The heads of all the metatarsal bones are connected indirectly by the deep transverse ligaments of the sole.

The dorsal and plantar ligaments pass transversely between the bases of the adjacent bones.

Figure 576
Foot synovial cavities of intertarsal and tarsometatarsal joints, oblique section, superior view - Figure 576
The interosseous ligaments consist, of strong transverse fibers which connect the rough nou-artieular portions of the adjacent surfaces (fig. 576).

Movements-The movements permitted between the tarsal ends of the metatarsal bones are limited to a slight gliding of the articular surfaces one upon another.

SYNOVIAL CAVITIES OF THE TARSUS AND METATARSUS

The synovial cavities (fig. 576) present in the joints of the tarsus and metatarsus are six in number : one for the talocaleanean; a second for the talocalcaneonavicular; a third for the calcaneocuboid; a fourth for the euneonavicular, intercuneiform, and cuneocuboid articulations, the articulations of the intermediate and lateral cuneiform bones with the bases of the second and third metatarsal bones, and the adjacent surfaces of the bases of the second, third, and fourth metatarsal bones; a fifth for the medial cuneiform bone with the metatarsal bone of the great toe; and a sixth, for the articulation of the cuboid bone with the fourth and fifth metatarsal bones. A small synovial cavity is sometimes found between the contiguous surfaces of the navicular and cuboid bones; it usually communicates with that between the cuboid and third cuneiform bones.

 


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