THE ANKLE-JOINT 



299 



tubercle to the medial side of the flexor hallucis longus groove. The fibres next 

 in front are numerous and form a thick and strong mass, filling up the rough 

 depression on the medial surface of the talus, whilst some pass over the talo- 

 calcaneal joint to the upper and medial border of the sustentaculum tali. The 

 fibres which are connected above with the anterior surface of the malleolus pass 

 downward and somewhat forward to be attached to the navicular and to the 

 margin of the calcaneo-navicular ligament. 



The lateral ligament (figs. 329 and 334) consists of three distinct slips (fas- 

 ciculi). The anterior talo-fibular ligament (anterior fasciculus), is ribbon-like 

 and passes from the anterior border of the lateral malleolus near the tip to the 

 rough surface of the talus in front of the lateral facet, and overhanging the sinus 

 pedis. The calcaneo -fibular ligament (middle fasciculus), is a strong roundish 

 l3undle, which extends downward and somewhat backward from the anterior 

 border of the lateral malleolus close to the attachment of the anterior fasciculus, 

 .and from the lateral surface of the malleolus, just in front of the apex, to a tuber- 

 cle on the middle of the lateral surface of the calcaneum. The posterior talo- 



FiG. 331. — Ligaments seen from the Back of the Ankle-joint. 



Posterior ligament of ankle-joint 



Posterior part of the deltoid 

 ligament 



The lower part of the interosseous 

 membrane 



_Transverse ligament of inferior 

 ^V ^f '^ tibio-fibular joint 



Posterior talo-fibular ligament 

 Calcaneo-fibular ligament 



fibular ligament (posterior fasciculus), is almost horizontal; it is a strong, thick 

 band attached at one end to the posterior border of the malleolus, and slightly to the 

 fossa on the medial surface; and at the other end to the talus, behind the articular 

 facet for the fibula, as well as to a tubercle on the lateral side of the groove for 

 the flexor hallucis longus. 



The middle fasciculus is covered by the tendons of the peronei longus and brevis; and in 

 extension, the posterior fasciculus is received into the pit on the medial surface of the lateral 

 malleolus. 



The synovial membrane is very extensive. Besides lining the ligaments of 

 the ankle, it extends upward between the tibia and fibula, forming a short cul- 

 de-sac as far as the interosseous ligament. Upon the anterior and posterior liga- 

 ments it is very loose, and extends beyond the limits of the articulation. It is 

 said to contain more synovia than any other joint. 



The nerve -supply is from the saphenous, posterior tibial, and the lateral di\'ision of the 

 anterior tibial. 



