82 THE SURGICAL ANATOMY OF THE HORSE 



movement in man and the dog — a fact which renders it necessary that the 

 ligaments should be more loosely attached, and the bones are in conse- 

 quence more liable to displacement. 



TRAUMATIC ARTHRITIS 



Attention has already been directed to the lack of protection to this 

 joint on its external lateral aspect. Inflammation of the joint as a result 

 of external injury is in consequence very common. Any wound in the 

 neighbourhood of the joint should be promptly treated, and closed as 

 quickly as possible to prevent an extension into the joint. Deep wounds 

 are frequently found in the muscular mass formed by the bellies of the 

 extensor metacarpi magnus and extensor pedis. When the animal falls 

 and skids along the ground this mass is one of the prominent points of 

 contact, and wounds to a depth of over two inches, with an external 

 opening not more than an inch in length, have been found in these 

 muscles, caused by a sharp, small, loose piece of stone when the animal 

 is forced along the ground in the manner indicated. The direction 

 which such wounds take should be carefully ascertained, and it will 

 usually be found that they run in an oblique manner downwards and 

 backwards, i.e.^ in the direction of the articular surfaces of the joint. 

 Although at first sight the position and extent of the external opening 

 and the depth of muscular tissue in the region might lead one to attach 

 slight importance to such wounds, their treatment is a matter of great 

 urgency, since the distal extremity, even when it does not actually extend 

 into the joint, is in close proximity to it. It is not usual to close wounds 

 of this nature immediately, since absolute cleanliness of the depth of the 

 wound is a matter of uncertainty. Healing from the bottom is therefore 

 encouraged. The direction of the wound, however, hinders free drainage, 

 and to secure this and prevent the condition extending into the joint a 

 good method of treatment is to pass in a curved probe or seton needle, 



