284 



APPLIED ANATOMY. 



ligament and so luxate it. The supinator (drems) arises partly from the orbicular 

 ligament and strengthens the joint somewhat. 



The external lateral ligament is a strong band which is attached above to 

 the lower portion of the lateral (external) condyle, blends with the orbicular liga- 

 ment and is attached below to the ulna along the anterior and posterior edges of the 

 lesser sigmoid cavity (Fig. 295). 



The internal lateral ligament is a strong band attached above to the lower 

 and anterior portion of the medial (internal) condyle, the groove beneath, and 

 descends in the shape of a fan to insert into the inner edge of the coronoid process 

 and olecranon (Fig. 296). 



The anterior ligament is capsular in its nature and function, and is a broad, 

 comparatively thin membrane which stretches between the lateral ligaments on the 



FIG. 296. The internal lateral ligament of the elbow- joint, showing its fan-like shape. 



sides and is attached above to the upper edge of the coronoid fossa and below to the 

 coronoid process and orbicular ligament. It sometimes possesses a few coarse fibres 

 passing downward and outward, but it is mostly very thin, in places barely covering 

 the lining membrane. 



The posterior ligament resembles the anterior. It blends on each side with 

 the lateral ligaments and is attached above across the upper portion of the olecranon 

 fossa and below to the olecranon and posterior portion of the orbicular ligament. It 

 also has some cross fibres; but, especially at its upper attachment, it is very weak. 



MUSCLES OF THE ELBOW. 



The elbow-joint is interposed between the long bones of the forearm below and 

 the long humerus above. The arm muscles come down and pass over the joint to 

 insert close to it in the bones of the forearm. The muscles of the forearm in a similar 

 manner cross the joint and are attached comparatively near it to the humerus above. 

 Thus we see the joint strengthened by the crossing of the various muscular insertions. 

 The elbow having only an anteroposterior motion, the muscles must of necessity be in 

 two main groups, one in front and the other behind the joint. 



Lateral Muscles. It is true that there are lateral muscles but they have little 

 or no influence on the movements of the elbow-joint. The medial (internal) condyle 

 gives origin to the flexor muscles of the forearm and the pronator radii feres, and 

 the lateral (external) condyle gives origin to the extensor muscles; but the bony 



