ABNORMAL CONDITION OF THE ANKLE-JOINT. 



155 



the ligaments are merely stretched ; but that a 

 greater effort produces a separation of the 

 lateral ligament from one or other of the mal- 

 leoli by laceration of its compact tissue, or of 

 the periosteum which covers it, while the liga- 

 ments themselves remain unbroken. Oppor- 

 tunities do not often occur of discovering 

 the effects of sprains on the joints by anato- 

 mical examination made at various periods 

 after the accident ; but although Dupuytren's 

 opinion may be correct as to the majority of 

 cases, still others have found the lateral liga- 

 ments ruptured across, instead of having been 

 torn from the bone. Mr. Wilson found, in 

 a case where the patient died five days after 

 a severe sprain of the ankle-joint, that the del- 

 toid ligament binding the tibia to the foot was 

 lacerated, and that the synovial membrane of 

 the ankle-joint was also much torn. In older 

 cases he found evidences of chronic inflamma- 

 tion in the ligamentous structures around the 

 joint ; that these structures were thickened 

 and vascular, and had lost much of their plia- 

 bility. 



The pain and inability to walk, the sudden 

 effusion around the injured ankle, the ecchy- 

 mosis, tenderness of the skin and tension, 

 the sins of this injury expressed by the living 

 structures, are all accounted for by the lesions 

 which an anatomical examination of these in- 

 juries of the ankle-joint discovers. This also 

 explains what practical writers have noted of 

 sprains, viz. that sometimes the ankle-joint 

 which has been affected by this accident, 

 rapidly and perfectly recovers, that, on the 

 other hand, it is not unfrequently so weakened 

 by the injury, as to become peculiarly suscep- 

 tible of a renewal of the sprain from slight 

 causes ; sometimes the articulation contracts a 

 rigidity, by which for a time, or even for life 

 itself, its proper functions are interfered with, 

 and a permanent oedema of the soft parts 

 around the joint is too often in these cases 

 established. 



Bones. The bones which contribute to 

 form the ankle-joint are liable to fracture and 

 to luxation. These bones, we know, are the 

 tibia, fibula, and astragalus ; for an account of 

 the accidents which affect the latter particularly, 

 we refer to the article FOOT, and shall here, 

 as succinctly as we can, notice the various dis- 

 placements of the bones of the leg at the 

 ankle-joint, which have been observed to be 

 the result of a fracture through one or both 

 of the malleoli, or of an accidental rupture of 

 the ligaments which tie these eminences to the 

 foot. 



When we reflect on the great strength of the 

 ligaments which connect the astragalus to the 

 tibia and fibula, and the support which the ar- 

 ticulation derives from the prolongation down- 

 wards of the malleoli, we can easily perceive 

 that a luxation of the foot must be the effect 

 only of some very violent cause, and that this 

 accident can very rarely (in a true sense) be a 

 simple one. Effusions of blood, rupture of all 

 the surrounding ligaments, fracture of the 

 external or even of both the malleoli, wounds 

 of the soft parts, and even protrusion of the 



bones, are contingences which frequently render 

 the dislocation of the tibia at the ankle-joint 

 a very complex accident. 



The most superficial view of the structure 

 of the ankle-joint will convince any one that 

 no lateral displacement of the bones of the 

 leg can occur, without its having been im- 

 mediately preceded by a fracture of either the 

 tibial or peronaeal malleolus ; but such a view 

 would warrant the conjecture, that a luxation 

 in the direction forwards or backwards may 

 possibly take place, simply from the rupture 

 of the ligaments of the joint alone, and the 

 action of muscles. Such a luxation as this 

 last, when no fracture exists, should be best 

 entitled to the name of simple ; yet those 

 luxations of this articulation (such is the 

 vagueness of surgical language), whether ac- 

 companied with fracture or not, are all called 

 simple, provided there be no wound through 

 the integuments communicating with the cavity 

 of the joint. In this latter case alone the 

 luxation is denominated compound, of which 

 it is not our intention here to treat. 



We shall arrange the luxations of the bones 

 of the leg at the ankle-joint in the above sense 

 called simple luxations, into those which occur 

 in the direction inwards, outwards, forwards, 

 and backwards, and each of these, it is be- 

 lieved, may be a partial or a complete lux- 

 ation. 



Luxation of the Tibia inwards. This luxa- 

 tion may be complete or incomplete : we 

 shall first treat of the most common form of it 

 or that termed partial Dislocation of the Tibia 

 inwards from the Astragalus, or Pott's luxation. 

 Mr. Pott, in describing this accident, observes, 

 " that the support of the body, and the due 

 and proper use and execution of the office of 

 the joint of the ankle, depend almost entirely 

 on the perpendicular bearing of the tibia upon 

 the astragalus, and on its firm connexion with 

 the fibula. If the former bone is forced from 

 its just and perpendicular position on the 

 astragalus ; or, if it be separated by violence 

 from its connexion with the latter, the joint of 

 the ankle will suffer a partial luxation inter- 

 nally : this is the case when, by leaping or 

 jumping, the fibula breaks in its weak part, 

 within two or three inches of its lower ex- 

 tremity. When this happens, the inferior frac- 

 tured end of the fibula falls inwards towards 

 the tibia, that extremity of the bone which 

 forms the outer ankle is turned somewhat out- 

 wards and upwards, and the tibia, having lost its 

 proper support, and not being of itself capable 

 of steadily preserving its true perpendicular 

 bearing, is forced off from the astragalus, in- 

 wards, by which the ligaments are torn, thus 

 producing a perfect fracture and a partial dis- 

 location."* 



If we are called to examine a patient who 

 has recently suffered this accident, we find that 

 the ankle-joint now possesses some degree 

 of lateral mobility. In the normal state of the 

 ankle-joint we know that the quadrilateral 

 cavity formed by the tibia and fibula for the 



* Pott's Works by Earle, vol. i. p. 327. 



