ABNORMAL CONDITION OF THE ANKLE-JOINT. 



163 



synovitis, with purulent deposition in the joint, 

 and in a young man aged twenty, but have not 

 observed it ever to occur in older subjects ; and 

 conclude that it is one of the consequences 

 synovitis of the ankle-joint, which is only to be 

 noticed at an age when the epiphyses are not 

 yet consolidated with the shaft of the tibia. 



In these very acute attacks of inflamma- 

 tion, its ravages are seldom confined to the 

 structure which seemed to be the 'point du 

 depart' of the disease ; the cartilages are in 

 some cases removed from the tibia, fibula, and 

 upper surface of the astragalus with astonishing 

 rapidity ; the porous surface of the bones has 

 also been found exposed, and their substance 

 to afford evidence of its having been in a state 

 of inflammation. Surgeons should ever bear 

 in mind, that the synovial membrane of the 

 ankle-joint passes very far forwards on the 

 upper surface of the astragalus, even as far as 

 within a few lines of the junction of this bone 

 with the os naviculare, so that an accidental 

 wound high upon the instep might very readily 

 give rise to a fatal synovitis of the ankle-joint. 

 Moreover, by an experiment on the dead sub- 

 ject, it may be shown that a very slight direc- 

 tion too much upwards of the edge of the knife 

 when the operation of partial amputation, ac- 

 cording to Chopart, is performed, may wound 

 the most anterior part of the synovial sac of the 

 ankle-joint, and the consequences of such a 

 mishap might prove fatal, or at all events 

 greatly aggravate the ills which even without 

 such cause too frequently follow Chopart's 

 operation. 



Again, the synovial membrane extends very 

 low down, even to the lowest point of the inner 

 side of the peroneal malleolus, along the outer 

 or fibular surface of the astragalus (Jig. 61, ). 

 It has very frequently happened to the wri- 

 ter's knowledge, that inflammation commencing 

 in the body of the os calcis, or in the fibrous or 

 synovial tissue of the articulation between the 

 os calcis and under surface of the astragalus, has 

 crept up to the ankle-joint by this route between 

 the fibula and astragalus; when, therefore, opera- 

 tions and cauterizations are performed by surgeons 

 to cure the carious state of the os calcis, the close 

 contiguity of such an important articulation as 

 that of the ankle should be recollected. The 

 great proximity of the ankle-joint to that be- 

 tween the under surface of the astragalus and 

 os calcis can only be estimated by making a 

 vertical section of the tibia, fibula, astragalus, 

 and os calcis, passing transversely across these 

 bones and through the malleoli, as may be seen 

 in Jig. 61 ; and if a subject be selected in which 

 the epiphysis has not been consolidated with 

 the rest of the bone, a useful view may be had 

 illustrating many of the preceding practical 

 observations, and explaining clearly how in- 

 flammation, traumatic or idiopathic, once esta- 

 blished in the ankle-joint, can pass through the 

 epiphysis to the periosteum of the tibia ; and ori- 

 ginating either in the body of the os calcis, or in 

 some of the structures composing the articulation 

 between this bone and the under surface of the 

 astragalus, can be propagated to the ankle-joint : 

 such a viewas this will shew the necessity of con- 



Ftg.61. 



sidering, in connexion, the normal and abnor- 

 mal state of these important articulations. 



b. Chronic disease. The effects of chronic 

 diseases on the tissues composing the ankle- 

 joint are next to be considered ; these are vari- 

 ous, and may be referred to the influence of 

 specific diseases, such as gout, syphilis, struma, 

 rheumatism, &c. ; but the effects of most of these 

 on this particular articulation need not here be 

 discussed, as they will be sufficiently dwelt on 

 elsewhere in this work (see JOINT) : we deem it, 

 however, right to enter somewhat into detail in 

 the description of those morbid appearances of 

 the ankle-joint which are supposed to be of a 

 scrophulous origin, and which are denominated 

 white swelling of the ankle-joint. The external 

 characters of the affection are pretty much those 

 in common with the same melancholy disease, 

 in whatever articulation of the extremity it is 

 situated ; the swelling, at first soft, and appear- 

 ing in front of each malleolus, seems divided 

 into two by the extensor tendons ; after a time 

 it becomes more solid, and assumes somewhat of 

 a globular form ; here as elsewhere, however, it 

 does not completely surround the joint. The 

 limb above is wasted and the heel is retracted ; 

 the foot is oedematous, and the toes are pointed 

 downwards, no motion of flexion or extension 

 can be communicated to the foot ; but when the 

 bones are moved laterally, an unnatural motion 

 is communicated to the foot, and a grating of 

 rough and carious surfaces in advanced cases 

 can be felt: the sides of the swelling are 

 studded over with numerous fistulous orifices, 

 from which even now a thin sanious matter can 

 be pressed ; a probe introduced passes either 

 directly through one or other of the malleoli, 

 or by a circuitous route into the interior of 

 the joint through the sinuses, which are, as 



M 2 



