162 PRACTICAL ANATOMY. 



POSTERIOR. 



Origin Above olecranon fossa. 

 Insertion Upper surface of olecranon. 

 EXTERNAL. 



Origin External epicondyle. 



Insertion Orbicular ligament and outer surface of 



radius. 

 INTERNAL. 



Origin Internal epicondyle. 

 Insertion Coronoid and olecranon processes. 

 Passing from the edges of these ligaments is a mem- 

 branous expansion, converting them practically into a 

 capsular ligament. 



RADIO-ULNAR ARTICULATIONS. 

 LIGAMENTS : 



ORBICULAR. 



Origin and Insertion An incomplete fibrous ring ; 

 arises from the anterior border of lesser sigmoid 

 cavity of ulna, passes around the head of the 

 radius, and is inserted into the posterior edge of 

 the lesser sigmoid cavity. 

 OBLIQUE. 



Origin Base of coronoid process. 

 Insertion Below the tuberosity of the radius. 

 INTEROSSEOUS. 



Origin and Insertion Membrane stretched between 

 the radius and ulna ; attached to the outer border 

 of the ulna and inner border of radius. 

 ANTERIOR INFERIOR. 



Origin and Insertion Anterior margin of sigmoid 



cavity of radius to the head of the ulna. 

 POSTERIOR INFERIOR. 



Origin and Insertion Posterior margin of sigmoid 

 cavity of radius to the head of the ulna. 



