380 



THE ARTICULATIONS 



Peroneus tertius and the external lateral ligament on the outer side. In addition to this, bulging 

 frequently occurs posteriorly, and a fluctuating swelling may be detected on either side of the 

 tendo Achillis. 



Chronic synovitis may result from frequent sprains, and when once this joint has been 

 sprained it is more liable to a recurrence of the injury than it was before ; or it may be tuber- 



FIG. 265. Section of the right foot near its inner border, dividing the tibia, astragalus, navicular, internal 

 cuneiform, and first metatarsal bone, and the first phalanx of the great toe. (After Braune.) 



cular in its origin, the disease usually commencing in the astragalus and extending to the joint, 

 though it may commence as a tubercular synovitis the result probably of some slight strain in a 

 tubercular subject. 



Excision of the ankle-joint is not often performed for two reasons. In the first place, 

 disease of the articulation for which this operation is indicated is frequently associated with 

 disease of the tarsal bones, which prevents its performance; and, secondly, the foot after 

 excision is frequently of very little use ; far less, in fact, than after a Symes's amputation, which 

 is often, therefore, a preferable operation in these cases. P]xcision may, however, be attempted 

 in cases of tubercular arthritis, in a young and otherwise healthy subject, where the disease is 

 limited to the bones forming the joint. It may also be required after injury where the vessels 

 and nerves have not been damaged and the patient is young and free from visceral disease. 

 The excision is best performed by two lateral incisions. One commencing two and a half inches 

 above the external malleolus, carried down the posterior border of the fibula, round the end of 

 the bone, and then forward and downward as far as the calcaneo-cuboid joint, midway between 

 the tip of the external malleolus and the tuberosity on the fifth metatarsal bone. Through this 

 incision the fibula is cleared, the external lateral ligament is divided, and the bone sawn through 

 at the upper end of the incision and removed. A similar curved incision is now made on the 

 inner side of the foot, commencing two and a half inches above the lower end of the tibia, 

 carried down the posterior border of the bone, round the internal malleolus, and forward and 

 downward to the tuberosity of the navicular bone. Through this incision the tibia is cleared in 

 front and behind, the internal lateral, the anterior and posterior ligaments divided, and the end 

 of the tibia protruded through the wound by displacing the foot outward, and sawn off sufficiently 

 high to secure a healthy section of bone. The articular surface of the astragalus is now to be 

 sawn off or the whole bone removed. In cases where the operation is performed for tubercular 

 arthritis the latter course is probably preferable, as the injury done by the saw is frequently the 

 starting point of fresh caries; and after removal of the whole bone the shortening is not appreci- 

 ably increased, and the result as regards union appears to be as good as when two sawn surfaces 

 of bone are brought into apposition. 



V. Articulations of the Tarsus. 



1. ARTICULATIONS OF THE Os CALCIS AND ASTRAGALUS. 



The articulations between the os calcis and astragalus are two in number 

 anterior and posterior. They are arthrodial joints. The bones are connected 

 together by four ligaments : 



External Calcaneo-astragaloid. 

 Internal Calcaneo-astragaloid. 



Posterior Calcaneo-astragaloid. 

 Interosseous. 



