298 



THE ARTICULATIONS, OR JOINTS 



The articular disk (discus articularis) is frequently absent in this articulation. 

 When the meniscus exists it is generally incomplete and only partially separates 

 the articular surfaces, and occupies the upper part of the articulation. More 

 rarely it completely separates the joint into two cavities. 



The Synovial Membrane. There is usually only one synovial membrane in this articu- 

 lation, but when a complete articular disk exists there are two synovial membranes. 



The coracoclavicular ligament (ligamentum coracoclaviculare) (Figs. 244 and 

 245) serves to connect the qlavicle with the coracoid process of the scapula. It 

 does not properly belong to this articulation, but as it forms a most efficient means 

 in retaining the clavicle in contact with the acromial process, it is usually described 

 with it. It consists of two fasciculi, called the trapezoid and conoid ligaments. 



FIG. 244. The left shoulder-joint, scapuloclavicular articulations, and proper ligaments of the scapula. 



The trapezoid ligament (ligamentum irapezoidcum'), the anterior and external 

 fasciculus, is broad, thin, and quadrilateral; it is placed obliquely between the 

 coracoid process and the clavicle. It is attached, below, to the upper surface 

 of the coracoid process; above, to the oblique line on the under surface of the 

 clavicle. Its anterior border is free; its posterior border is joined with the conoid 

 ligament, the two forming by their junction a projecting angle. 



The conoid ligament (ligamentum conoideum), the posterior and internal fas- 

 ciculus, is a dense band of fibres, conical in form, the base being directed upward, 

 the summit downward. It is attached, below, by its apex to a rough impression at 

 the base of the coracoid process, internal to the trapezoid ligament; above, by its 

 expanded base, to the conoid tubercle on the under surface of the clavicle, and 

 to a line proceeding internally from it for half an inch. These ligaments are 



