PELVIC LIMBS. 91 



Distad the two malleoli forming the ends of the fibula and 

 tibia are closely and immovably united. The capsule of the 

 joint is here an extension proximad of the capsule of the articu- 

 lation with the astragalus. On the dorsal side a short broad 

 band of strong fibres passes from the surface of the tibia 

 obliquely laterodistad to the border of the fibula; this forms the 

 anterior ligament of the lateral malleolus. On the ventral 

 side a very much weaker set of fibres forms the ventral wall of 

 the articular capsule; it is called the posterior ligament of the 

 lateral malleolus. Tibia and fibula are also connected on the 

 dorsal side by the ligamentum transversum cruris, or trans- 

 verse ligament of the lower leg (Fig. 91, 5), which spans the 

 tendons of Mm. extensor longus digitorum and tibialis anterior. 

 From the middle of the distal margin of this a slender sup- 

 porting ligament passes distad and is inserted on the dorsal 

 surface of the tarsus. The grooves in the two malleoli for the 

 passage of the tendons are spanned by ligamentous fibres 

 (rctinacula) for holding the tendons in place. 



Articulation betv^een the Leg and the Foot. — At the 

 distal end there is formed between the two malleoli a deep 

 irregular fossa, into which is received the trochlea of the 

 astragalus. The joint is covered by a large articular capsule, 

 which passes also, as above noted, between the tibia and fibula. 

 In addition to the capsule the following ligaments may be dis- 

 tinguished: (<^) On the lateral side, (i) a short ligament from 

 the fibula to the astragalus, directed toward the proximal end 

 of the foot; (2) a ligament from the fibula to the calcaneus, 

 attached to the latter proximad of the peroneal tubercle ; 

 (3) a stronger ligament from the fibula to the calcaneus, lying 

 beneath the last-mentioned and directed toward the proximal 

 end of the bone, {b) On the medial side may be distinguished 

 (i) a strong ligament from the tibia (medial malleolus) to the 

 sustentaculum tali, and passing thence onto the scaphoid; (2) 

 a short ligament from the medial malleolus to the astragalus. 



The Tarsus. — The articulations between the separate bones 

 of the tarsus and between the tarsus and metatarsus have a 

 considerable number of variously communicating articular cap- 

 sules. The separate bones are connected by many ligaments. 



