THE ANKLE-JOINT 



267 



tibial vessels and nerve, the extensor tendons of the toes, and the peroneus tertlus ; 

 and behind with a mass of fat and synovial membrane. 



The posterior ligament (fig. 254) is a very thin and disconnected membranous 

 structure, connected above with the external malleolus, internal to the peroneal 

 groove; to the posterior margin of the lower end of the tibia external to the groove 

 for the tibialis posticus; and to the posterior inferior tibio-fibular ligament. Below, 

 it is attached to the posterior surface of the astragalus from the internal to the 

 external lateral ligaments. The passage of the flexor longus hallucis tendon over 

 the back of the joint serves the purpose of a much stronger posterior ligament. 



The internal lateral or deltoid ligament (fig. 253) is attached superiorly to 

 the internal malleolus along its lower border, and to its anterior surface superficial 

 to the anterior ligament; some very strong fibres are fixed to the notch in the lower 

 border of the .malleolus, and, getting attachment below to the rough depression on 

 the inner side of the astragalus, form a deep portion to the ligament. The ligament 

 radiates; the posterior fibres are short, and incline a little backwards to be fixed 



Fig. 



253. — Inner View of the Ankle and the Tarsus, showing the Groove for the 

 Tendon of the Tibialis Posticus. 



Internal lateral 

 ligament 



Inferior cal- 



eaneo-seaphoid 



ligament 



Short plantar ligament 



Long plantar ligament 



to the rough inner surface of the astragalus, close to the superior articular facet, 

 and into the tubercle to the inner side of the flexor longus hallucis groove. The 

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

 rough depression on the inner surface of the astragalus, whilst some pass over the 

 calcaneo-astrngaloid joint to the upper and inner border of the sustentaculum tali. 

 The fibres, wliich are connected above with the anterior surface of the malleolus, 

 pass downwards and somewhat forwards to be attached to the scaphoid and to the 

 margin of tlie calcaneo-sca])li()id ligament. 



The external lateral ligament (figs. 254 and 255) consists of three distinct sHps. 

 The anterior fasciculus is ribbon-like and passes from the anterior l)order of the 

 external malleolus near the tip to the rough surface of the astragalus in front of the 

 external lateral facet, and overhanging the sinus pedis. The middle fasciculus is 

 a strong roundish bundle, which extends downwards and somewhat backwards from 

 the anterior border of the external malleolus close to the attachment of the anterior 

 fasciculus, and from the outer surface of the malleolus, just in front of the apex, 



