310 THE ARTICULATIONS, OR JOINTS 



posterior ligament. Occasionally, a well-marked, triangular projection may be seen on the outer 

 side of the olecranon, from bulging of the synovial membrane beneath the Anconeus muscle. 

 Again, there is often some swelling just above the head of the radius, in the line of the radio- 

 humeral joint. There is generally not much swelling at the front of the joint, though sometimes 

 deep-seated fulness beneath the Brachialis anticus may be noted. When suppuration occurs the 

 abscess usually points at one or other border of the Triceps muscle; occasionally the pus dis- 

 charges itself in front, near the insertion of the Brachialis anticus muscle. Chronic synovitis, 

 usually of tuberculous origin, is of common occurrence in the elbow -joint; under these circum- 

 stances the forearm tends to assume the position of semiflexion, which is that of greatest ease 

 and relaxation of ligaments. It should be borne in mind that should ankylosis occur in this or 

 the extended position, the limb will not be nearly so useful as if it becomes ankylosed in a position 

 of rather less than a right angle. Loose cartilages are sometimes met with in the elbow-joint, 

 not so commonly, however, as in the knee; nor do they, as a rule, give rise to such urgent .symp- 

 toms. They rarely require operative interference. The elbow-joint is also sometimes affected 

 with osteoarthritis, but this affection is less common in this articulation than in some other 

 of the larger joints. Bursitis about the elbow, generally known as miners' elbow, is not 

 uncommon. 



Excision of the elbow is principally required for one of three conditions viz., tuberculous 

 arthritis, injury and its results, and ankylosis in a position which greatly impairs the useful- 

 ness of the limb; but may be necessary for some other rarer conditions, such as disorganizing 

 arthritis after pyemia, unreduced dislocation, and osteoarthritis. The results of the operation 

 are, as a rule, more favorable than those of excision of any other joint, and it is one, therefore, 

 that the surgeon should never hesitate to perform, especially in the first three of the conditions 

 mentioned above. The operation is best performed by a single vertical incision down the back 

 of the joint, a transverse incision, over the outer condyle, being added if the parts are much 

 thickened and fixed. A straight incision is made about four inches long, the mid-point of which 

 is on a level with and a little to the inner side of the tip of the olecranon. This incision is made 

 down to the bone, through the substance of the Triceps muscle. The operator with the point 

 of his knife, and guarding the soft parts with his thumb-nail, separates them from the bone. 

 In doing this there are two structures which he should carefully avoid the ulnar nerve, which 

 lies parallel to his incision, but a little internal, as it courses down between the internal condyle 

 and the olecranon process, and the prolongation of the Triceps into the deep fascia of the fore- 

 arm over the Anconeus muscle. Having cleared the bones and divided the lateral and posterior 

 ligaments, the forearm is strongly flexed and the ends of the bone turned out and sawed off. The 

 section of the humerus should be through the base of the condyles, that of the ulna and radius 

 should be just below the level of the lesser sigmoid cavity of the ulna and the neck of the radius. 

 In this operation the object is to obtain such fibrous union as shall allow free motion of the 

 bones of the forearm; and, therefore, passive motion must be commenced early, that is to say, 

 about the tenth day. 



VI. Radioulnar Articulation (Articulatio Radioulnaris) . 



The articulation of the radius with the ulna is effected by ligaments which 

 connect both extremities as well as the shafts of these bones. It may, conse- 

 quently, be subdivided into three articulations: (1) The superior radioulnar, 

 which is a portion of the elbow-joint; (2) the middle radioulnar; and (3) the 

 inferior radioulnar articulations. 



1. SUPERIOR ARTICULATION (ARTICULATIO RADIOULNARIS PROXIMALIS). 



This articulation is a trochoid or pivot-joint. The bones entering into its forma- 

 tion are the inner side of the circumference of the head of the radius rotating 

 within the lesser sigmoid cavity of the ulna. Its only ligament is the annular 

 or orbicular. 



The orbicular or annular ligament (lie/amentum annulare radii) (Figs. 248, 249, 

 and 252) is a strong, flat band of ligamentous fibres which surrounds the head of 

 the radius and retains it in firm connection with the lesser sigmoid cavity of the 

 ulna. It forms about four-fifths of an osseofibrous ring, attached by each end to 

 the extremities of the lesser sigmoid cavity, and is smaller at the lower part of its 



