72 



ABNORMAL CONDITION OF THE ELBOW-JOINT. 



prominence formed by the inner condyle of the 

 humerus, and its lower extremity. The fore-arm 

 is flexed, and the patient feels it impossible to 

 move the joint. The deviation and curved direc- 

 tion outwards given to the biceps and triceps, 

 and approximation of the olecranon to the 

 outer condyle of the humerus, all taken toge- 

 ther sufficiently characterize this rare accident. 



In the incomplete luxation inwards, the 

 cavity of the superior extremity of the radius, 

 in abandoning the small head of the humerus, 

 may be carried more or less inwards, and be 

 placed under the internal border of the articu- 

 lar pulley or trochlea of this bone, while the 

 inner edge of the great sigmoid cavity of the 

 ulna and olecranon process must project in- 

 wards beneath the inner condyle of the humerus. 

 The ligaments must be all torn as well as some 

 of the muscles arising from the internal con- 

 dyle of the humerus, the biceps and triceps 

 are turned from their usual direction and are 

 curved inwards, and the ulnar nerve must be 

 more or less stretched. The external signs of 

 incomplete luxation inwards are what the 

 anatomy of the parts above described would 

 lead us to expect; there is a remarkable increase 

 of breadth across the line of the joint, perma- 

 nent flexion of the fore-arm, and a powerless 

 condition of the limb, all which were noticed 

 in the former case. We must add to these a 

 remarkable projection below and internal to 

 the inner condyle of the humerus, formed by 

 the internal edge of the great sigmoid cavity 

 of the ulna. Our attention is also attracted by 

 the approximation of the olecranon process 

 and inner condyle of the humerus to each other, 

 and the distance of the olecranon from the 

 outer condyle of the humerus, which forms a 

 remarkable projection externally. 



3. Under the head of lateral luxations of 

 the elbow-joint, Sir A. Cooper has described 

 accidents which might perhaps be more cor- 

 rectly designated a, complete luxation of the 

 bones of the fore-arm at the elbow backwards 

 and outwards; 6, complete luxation of the 

 bones of the fore-arm at the elbow backwards 

 and inwards. 



a. Luxation of the bones of the fore-arm 

 backwards and outivards. In this case the 

 ulna, instead of being thrown into the posterior 

 fossa of the os humeri, has its coronoid process 

 situated on the back part of the external con- 

 dyle of the humerus. The projection of the 

 ulna backwards is greater in this than in the 

 former luxation, and the radius forms a pro- 

 tuberance behind and on the outer side of the 

 os humeri, so as to produce a depression above 

 it. The rotation of the head of the radius can 

 be distinctly felt by rolling the hand. 



b. Luxation of the bones of the fore-arm 

 backwards and inwards. Sometimes the ulna 

 is thrown on the internal condyle of the os 

 humeri, but it still projects posteriorly, as in 

 the external dislocation, and then the head of 

 the radius is placed in the posterior fossa of 

 the humerus. The external condyle of the 

 humerus in this case projects very much out- 

 wards, and the usual prominence of the inter- 



nal condyle is lost. The olecranon process 

 approaches nearer than natural to the middle 

 line of the body, and is pointed inwards, being 

 thrown more posteriorly than in any other lux- 

 ation. 



4. Luxation of the ulna alone directly back- 

 wards. The ulna is sometimes thrown back 

 upon the os humeri, without being followed 

 by the radius. The appearance of the limb is 

 much deformed by the contortion inwards of 

 the fore-arm and hand ; the olecranon projects, 

 and can be felt behind the os humeri. Exten- 

 sion of the arm is impracticable but by force, 

 which will reduce the luxation, and it cannot 

 be bent to more than a right angle. It is an 

 accident somewhat difficult to detect, but its 

 distinguishing marks are the projection of the 

 ulna, and the twist of the fore-arm inwards. 

 A specimen of this accident is preserved in the 

 Museum of St. Thomas's Hospital ; the luxa- 

 tion had existed for a length of time. The 

 coronoid process of the ulna was thrown into 

 the posterior fossa of the humerus, and the 

 olecranon was found projecting behind the 

 humerus much beyond its usual situation. 

 The radius rested upon the external condyle, 

 and had formed a small socket for its head, in 

 which it was able to roll.* The coronary and 

 oblique ligaments had been torn through, and 

 also a small part of the interosseous ligament. 

 The brachialis anticus was stretched round the 

 trochlea of the humerus, and the triceps had 

 been carried backwards with the olecranon. 



5. Luxations of the upper extremity of the 

 radius from the humerus and ulna. When we 

 look into the best books we possess for infor- 

 mation on this subject, we must be struck with 

 the remarkable discrepancy of the opinions we 

 find expressed by the authors. Thus, upon 

 the subject of luxation forwards of the radius, 

 we find the celebrated Boyer stating that he 

 doubts such a luxation can occur without being 

 complicated with a fracture. Sanson states that 

 this luxation forwards has never been observed, 

 and moreover advances what he considers as 

 anatomical and physiological explanations, to 

 show the impossibility of such an occurrence- 

 Sir A. Cooper, on the contrary, gives six 

 examples of the luxation of the upper extre- 

 mity of the radius forwards. The French 

 writers state of the luxation of this extremity 

 of the radius backwards, that although it is 

 rare it has been many times witnessed, while 

 Sir A. Cooper, alluding to this luxation back- 

 wards, says, " this is an accident which I have 

 never seen in the living," but he gives an 

 anatomical account of the appearances found 

 in a subject, the history of which was unknown, 

 brought into St. Thomas's Hospital for dissec- 

 tion. Having thus stated the different opinions 

 of authors upon this subject, we shall proceed 

 to give an account of a, the luxation of the 

 upper extremity of the radius forwards ; 6, of 

 its luxation laterally and upwards ; c, of its 

 luxation backwards ; d, of its sub-luxation ; 

 e, of its congenital luxation backwards. 



* Sec plate xxiv.yZj/. 2, in Sir A. Cooper's work. 



