280 SURGICAL ANATOMY OF 



that they may still fulfil their functions as far as possible, 

 and an accurate knowledge of the parts in contact with 

 the articulation is necessary. The integument only 

 being divided by an incision which commences just 

 above and behind the outer malleolus and extending 

 across the joint to a corresponding point above the 

 inner, the flap being dissected back, the peronei tendons 

 are to be dislodged and the external lateral ligament 

 divided. In order to obtain access to the joint on the 

 outside, the lower end of the fibula is to be snipped off, 

 and its connection with the tibia severed. Next, to get 

 at the inner aspect of the articulation, the flexor com- 

 mtinis digitorum and tibialis posticus tendons are to be 

 dissected from behind the inner malleolus, and care 

 taken to avoid the posterior tibial vessels and nerve. 

 The lower end of the tibia can now by a wrench be dis- 

 located through the wound ; the diseased surfaces are 

 then to be removed (Hancock). The diseased surfaces 

 can be reached and removed by two lateral incisions 

 (Barwell). 



The articulation of the astragalus with the os calcis 

 is one of great strength, owing to the interosseous liga- 

 ments which lie in the grooves of these bones ; it is rup- 

 tured in cases of dislocation of the astragalus from the 

 os calcis. This is by far the most important of the lux- 

 ations of the tarsal bones, and may occur either forwards 

 and inwards, or forwards and outwards, or backwards. 



Amputation at the Ankle-joint. The landmarks for the 

 guidance of the knife are, in the first place, for the an- 

 terior flap, the two malleoli, which are to be united by 

 a semilunar incision ; and for the posterior, one cutting 

 the sole transversely and a little obliquely forwards, and 

 extending between the limits of the preceding incision ; 



