ANKLE-JOINT. 



229 



The anterior fasciculus, the shortest of the three, passes from the anterior margin 

 of the summit of the external malleolus, downwards and forwards, to the astra- 

 galus, in front of its external articular facet. 



The posterior fasciculus, the most deeply seated, passes from the depression at the 

 inner and back part of the external malleolus to the astragalus, behind its external 

 malleolar facet. Its fibres are almost horizontal in direction. 



The middle fasciculus, the longest of the three, is a narrow rounded cord, pass- 

 ing from the apex of the external malleolus downwards and slightly backwards 

 to the middle of the outer side of the os calcis. It is covered by the tendons of 

 the Peroneus longus and brevis. There is no posterior ligament, its place being 

 supplied by the transverse ligament of the tibia and fibula. 



The Synovial Membrane invests the inner surface of the ligaments, and sends 

 a duplicature upwards between the lower extremities of the tibia and fibula for a 

 short distance. 



Fig. 144. Ankle-joint : Tarsal and Tarso-metatarsal Articulations. External View. Right Side. 



NFERIOR TIBIO-FIBUUAI* 

 ARTIC" 



ANKLE-JOINT 



TARSAL ARTICF 



TARSO-METATARSAL ARTICI! 



Relations. The tendons, vessels, and nerves in connection with the joint are, 

 in front, from within outwards, the Tibialis anticus, Extensor proprius pollicis, 

 anterior tibial vessels, anterior tibial nerve, Extensor communis digitorum, and 

 Peroneus tertius ; behind, from within outwards, Tibialis posticus, Flexor longus 

 digitorum, posterior tibial vessels, posterior tibial nerve, Flexor longus pollicis, 

 and, in the groove behind the external malleolus, the tendons of the Peroneus 

 longus and Peroneus brevis. 



The Arteries supplying the joint are derived from the malleolar branches of 

 the anterior tibial and peroneal. 



The Nerves are derived from the anterior tibial. 



Actions. The movements of the joint are limited to flexion and extension. 

 There is no lateral motion. 



5. ARTICULATIONS OF THE TARSUS. 



These articulations may be subdivided into three sets : 1. The articulation of 

 the first row of tarsal bones. 2. The articulation of the second row of tarsal 

 bones. 3. The articulations of the two rows with each other. 



