488 THE INFERIOR EXTREMITY 



surface (p. 481). The removal of the talus opens both the 

 talo-calcanean and the talo-calcaneo-navicular joint-cavities, 

 and if the synovial membrane which lines them is infected, it 

 must be removed. 



After excision of the talus, the sustentaculum tali may be 

 removed^ and the calcaneus may be further trimmed till it can 

 be fitted in between the malleoli. When this is carried out, the 

 lateral malleolus projects too far, and therefore requires to be 

 shortened. 



Before the wound is finally closed, the peroneal tendons are 

 sutured, and the retinacula are stitched over them again. 



Arthrodesis of the Ankle - Joint is rarely followed by 

 completely satisfactory results, because the necessary removal 

 of the articular cartilage decreases the size of the talus while 

 increasing the size of the cavity into which it is to be received. 

 This disadvantage may be minimised by inserting a large nail 

 in an upward direction through the calcaneus and talus into 

 the tibia, the foot meanwhile being maintained at right angles ; 

 when the nail is removed at the end of three weeks, the limb is 

 put up in a plaster case. 



The Calcaneus (Os Calcis). Tuberculous disease may not 

 infrequently originate in the body of the calcaneus close to the 

 epiphyseal line, and may spread (i) upwards and forwards, to 

 penetrate the articular cartilage and infect the talo-calcanean 

 joint ; (2) medially, through the periosteum to infect the 

 synovial sheaths of the tendons of the tibialis posterior, etc. 

 (p. 475) ; (3) laterally, through the periosteum, to infect the 

 peroneal tendon sheaths (p. 473). Early recognition by 

 radiograms is important in order that these complications may 

 be prevented. 



The surgical approach to the calcaneus is obtained by means, 

 of a lateral or a medial flap operation. The incisionjies below 

 the level of the tendons and the flap includes all the soft parts 

 and the periosteum. In the child, since the body of the bone 

 is not completely ossified, a thin layer of its cartilaginous surface 

 is elevated with the periosteum. The focus may then be gouged 

 out and the flap replaced. 



In more advanced cases, where freer access is desired, the 

 incision begins behind the tuberosity of the fifth meiatarsal 

 and, passing backwards round the heel below the tendo calcaneus, 

 ends on the medial aspect slightly in front of the medial malleolus. 

 A large flap, consisting of soft parts, periosteum, and cartilage, 



