THE ARTICULATIONS. 



6] 



long head of the biceps, 7 and attached around the mar- FIG. 34 



gin of the glenoid cavity in order to deepen the articu- 

 lar surface. 



Describe the Elbow-joint. It is a ginglymus articulation, 

 formed by the lower end of the humerus with the greater 

 sigmoid cavity of the ulna and the head of the radius. Its 

 Synovial Membrane is reflected over the ligaments, and dips 

 down between the surfaces of the superior radio-ulnar articu- 

 lation. Its Arteries are derived from the anastomotica magna, 

 radial, ulnar, and interosseous recurrent, superior and inferior 

 profunda arteries. Its Nerves are branches of the ulnar and 

 the musculo-cutaneous. It has 4 ligaments, 



Anterior, from the inner condyle and anterior surface of 

 the humerus to the orbicular ligament of the radius and 

 the coronoid process of the ulna. 

 Posterior, from the posterior surface of the humerus to the 



olecranon process of the ulna. 



External Lateral,* from the external condyle of the hu- 

 merus to the orbicular ligament of the radius. 

 Internal Lateral, from the internal condyle of the humerus 



to the coronoid and olecranon processes of the ulna. 

 Describe the Radio-ulnar Articulations. They are 3 in number, as follows, 

 viz. 



SUPERIOR RADIO-ULNAR ARTICULATION is a lateral ginglymoid joint, formed 

 by the head of the radius and the lesser sigmoid cavity of the ulna. It* 

 synovial membrane is a continuation of that in the elbow-joint. It has I 

 ligament, the 



Orbicular Ligament ?> forms four- fifths of a circle and surrounds the neck ot 

 the radius. It is attached to the margins of the lesser sigmoid cavity of 

 the ulna, and to the external lateral ligament of the elbow-joint. 

 MIDDLE RADIO-ULNAR ARTICULATION is formed by the shafts of the radius 

 and ulna, which do not touch each other, but are connected by 2 ligaments, a? 

 follows, viz. 



Oblique Ligament, from the tubercle at the base of the coronoid process of 



the ulna to the shaft of the radius. 



Interosseous Membrane? obliquely downwards from the interosseous ridge on 

 the radius to that on the ulna. Through the interval between its upper 

 border and the oblique ligament, the posterior interosseous vessels pass. 

 INFERIOR RADIO-ULNAR ARTICULATION is a lateral ginglymoid joint, formed 

 by the head of the ulna and the sigmoid cavity of the radius. Its Synovia* 

 Membrane (membrana sacciformis) is very loose, and sometimes communicates 

 6 



