INTEETAESAL JOINTS. 357 



A distinct synovial stratum lines all parts of the capsule of the joint. 



Articulatio Calcaneocuboidea. This is situated between the anterior con- 

 cavo-convex surface of the calcaneus and the posterior similar surface of the 

 cuboid. 



The ligaments which invest this joint constitute a calcaneo- cuboid capsule, whose 

 parts are arranged in relation to the four non-articular sides of the cuboid bone, 

 and are especially strong upon the plantar aspect, in relation to their great import- 

 ance in resisting strains. 



The medial calcaneo - cuboid ligament occupies part of the interval between 

 the talus and calcaneus the sinus tarsi. It is the calcaneo -cuboid part of the lig. 

 bifurcatum, and is a V-shaped structure, of which the single end is attached to 

 the calcaneus, and the double ends separate to reach contiguous areas on the 

 navicular and cuboid respectively. 



The dorsal calcaneo-cuboid ligament (Fig. 324) is a broad portion of the fibrous 

 stratum of the capsule extending from the dorsal and lateral surfaces of the 

 calcaneus to the dorsal surface of cuboid. 



The lateral calcaneo-cuboid ligament is another but narrower part of the 

 capsule which extends from the lateral aspect of the calcaneus to the lateral side 

 of the cuboid, immediately behind the facet on the tuberosity. 



The inferior calcaneo-cuboid ligament consists of two parts a superficial and 

 a deep. The superficial series of fibres, the long plantar ligament (Fig. 326), is 

 attached to the plantar surface of the calcaneus in front of the processes of the tuber 

 calcanei. It forms a long powerful structure which runs forwards to be fixed to 

 the plantar surface of the cuboid ridge, but many of its fibres pass superficial to the 

 tendon of the peronseus longus, and extend to the bases of the third, fourth, and 

 fifth metatarsal bones. 



The deep series of fibres, the plantar calcaneo-cuboid ligament (O.T. short plantar 

 ligament) (Fig. 326), is distinctly separated from the long plantar ligament by a layer 

 of areolar tissue. It forms a broad but short band of great strength, which is 

 attached to the plantar surface of the distal end of the calcaneus, and extends 

 to the plantar surface of the cuboid just behind the ridge. Both of these ligaments 

 are of great importance in maintaining the longitudinal arch of the foot, and in this 

 respect are only second to the plantar calcaneo-navicular ligament. 



A synovial stratum lines the capsule. 



Articulatio Tarsi Transversa (Choparti). This is a term sometimes applied 

 to the talo-navicular and calcaneo-cuboid joints. These articulations do not 

 communicate with each other ; and although there is an occasional direct articula- 

 tion between the navicular and cuboid, it does not constitute an extension of 

 the transverse tarsal joint, but is a prolongation from the series of cuneo-navicular 

 and cuneo-cuboid articulations. 



Nevertheless there is always a set of ligaments which bind the navicular and 

 cuboid bones together, and these may be regarded as accessory to the various 

 transverse tarsal joints. 



The dorsal cuboideo - navicular ligament (Fig. 324) consists of short oblique 

 fibres which attach the contiguous dorsal surfaces of the cuboid and navicular 

 bones. 



The plantar cuboideo -navicular ligament is transverse in direction, and extends 

 between adjacent plantar areas of the cuboid and navicular bones. 



The interosseous cuboideo - navicular ligament intervenes between contiguous 

 surfaces of the same bones. When there is an extension of the cuneo-navicular joint 

 backwards between the navicular and cuboid, it is situated in front of the last- 

 mentioned ligament, and is called the articulatio cuboideonavicularis. Around 

 this joint the preceding ligaments are grouped. Since, however, the joint is 

 inconstant while the ligaments are always present, it is preferable to consider them 

 as above indicated. 



Articulatio Cuneonavicularis. The cuneo - navicular articulation joint is 

 situated between the navicular and the three cuneiform bones. The anterior surface 

 of the navicular presents a facet for each of the cuneiform bones, but its articular 

 surface is not interrupted. These facets form a somewhat convex anterior surface 



