1 70 TOPOGRAPHIC AND APPLIED ANATOMY. 



astragalus ; the trochlea and the lateral surfaces of the astragalus are surrounded by the articular 

 surface of the lower end of the tibia and by the two malleoli. The capsular ligament is 

 attached anteriorly and posteriorly to the astragalus at a slight distance from its articular surface 

 and runs to the margins of the malleoli and of the articular surface of the tibia. The articular 

 cavity communicates with that of the inferior tibiofibular articulation. The movements of the 

 joint are those of dorsal and plantar flexion. 



2. The talotarsal articulation (Figs. 88 and 89) consists of two separate portions: (a) The 

 posterior calcaneo-astragaloid articulation (Artie, talocalcanea), between the posterior articular 

 surfaces of the astragalus and of the os calcis. The capsular ligament is attached close to the 

 margins of the articular surfaces, (b) The anterior calcaneo-astragaloid articulation (Artie. 

 talonavicularis), between the middle and anterior articular surfaces of the astragalus and of the 

 os calcis, and also between the head of the astragalus and the scaphoid bone. The capsular 

 ligament is attached to the margins of the cartilaginous surfaces and is strengthened by the 

 superior astragalonavicular ligament (ligamentum talonaviculare). The movement is chiefly 

 that of pronation and supination. 



The remaining joints are: 



3. The calcaneocuboid (Fig. 89), between the corresponding articular surfaces of the os 

 calcis and of the cuboid bone. This joint, together with the astragaloscaphoid, although sepa- 

 rate anatomically, forms the so-called Choparfs joint (Artie, tarsi transversa). 



4. The intertarsal articulations, between the remaining tarsal bones. 



5. The tarsometatarsal articulations, Lisjranc's joint (the second metatarsal bone extends 

 further posteriorly than the others). This articulation usually consists of three separate cavities 

 (as shown in Fig. 89), of which the middle one communicates with the intertarsal articulations 

 and with the joint between the scaphoid and the cuneiform bones. 



6. The metatarsophalangeal and the inter phalangeal articulations. 



These articulations are strengthened by a number of ligaments. The external lateral liga- 

 ment is composed of three fasciculi: The anterior astragalofibular ligament, from the external 

 malleolus to the outer surface of the astragalus; the posterior astragalofibular ligament, from 

 the external malleolus to a tubercle on the posterior surface of the os calcis ; the calcaneofibular 

 ligament, from the tip of the external malleolus to the outer surface of the os calcis. 



The internal lateral ligament (ligamentum deltoideum) radiates from the internal malleolus 

 to the scaphoid, astragalus, and calcaneum. 



The astragalus and the calcaneum are united by the calcaneoastragaloid ligaments. Special 

 mention should be made of the interosseous ligament which unites the anterior end of the cal- 

 caneum with the inferior surface of the neck of the astragalus. The ligamentum bifurcatum* 

 is situated upon the dorsal surface and unites the anterior end of the dorsal surface of the cal- 

 caneum with the cuboid and scaphoid bones. 



Upon the plantar aspect the foot is strengthened by the ligaments proceeding from the 

 os calcis and running to the scaphoid, to the cuboid, and to the bases of the metatarsal bones. 

 The chief of these is the long plantar ligament passing from the inferior surface of the os calcis 

 to the cuboid and to the metatarsal bones. The inferior calcaneonavicular ligament is also found 

 in this situation. 



* Superior calcaneonavicular + internal calcaneocuboid. 



