THE TARSAL JOINTS 



303 



the whole weight of the body when the heel is first placed on the ground; (ii) by the upward 

 pressure of this facet against the talus it transfers the weight to the ball of the toes as the heel 

 is raised, the posterior edge of the sustentaculum tali and the anterior and lateral part of the 

 upper surface of the calcaneus preventing the talus from being displaced too far forward by 

 the superincumbent weight; and (iii) the calcaneus serves to suspend the talus when, with the 

 heel raised by muscular action, the other foot is being swung forward. 



Fig. 334. — ^Lateral View of the Ligaments of the Foot and Ankle. 



Anterior lateral malleolar ligament 



Anterior ligament of ankle-joint 



Anterior (interosseous) talo 

 calcaneal ligament 

 Latrral calcaneo-navic 

 ular ligament 



Posterior lateral malleolar 

 ligament 



Fasciculus of posterior 

 ligament of ankle 



Posterior talo-fibular ligament 



1 bold eo -navicular I 

 igament 



Medial calcaneo-cuboid Dorsal Lateral Calcaneo-fibular ligament 

 calcaneo- talo- 

 cuboid calcaneal 

 ligament 



(6) The Articulations of the Anterior Part of the Tarsus 



These include (i) the cuboideo-navicular; (ii) cuneo-navicular; (iii) inter- 

 cuneiform; and (iv) cuneo-cuboid joints. 



(i) The Cuboideo-navicular Union 



Class. — Diarthrosis. Subdivision. — Arlhrodia. 



The joint cavity is only occasionally present and this joint is often included 

 in the transverse tarsal. 



The ligaments which unite the cuboid and navicular are: — 



Interosseous. 



Dorsal. 



Plantar. 



The dorsal cuboideo-navicular ligament (fig. 334) runs forward and laterally from the 

 lateral end of the dorsal surface of the navicular to the middle third of the medial border of the 

 cuboid on its dorsal aspect, passing over the posterior lateral angle of the third cuneiform bone. 

 It is wider laterally. 



The plantar cuboideo-navicular ligament is a well-marked strong band, which runs forward 

 and laterally, from the plantar surface of the navicular to the depression on the medial surface 

 of the cuboid, and slightly into the plantar surface just below it. 



The interosseous cuboideo-navicular ligament is a strong band which passes between the 

 apposed surfaces of these bones from the dorsal to the plantar ligaments. Some of its posterior 

 fibres reach the plantar surface of the foot behind the cuboideo-navicular ligament, and radiate 

 laterally and backward over the medial border of the cuboid to blend with the anterior ex- 

 tremity of the plantar calcaneo-cuboid ligament. 



