284 SKELETON. 



ligament is placed on the superior end of the sternum, and ex- 

 tends from the internal end of one clavicle to that of the other. 

 It is flat before and behind, thin and narrow, is blended with 

 the contiguous ligamentous structure of the sternum, and might, 

 with propriety, be considered only an appendage to the capsu- 

 lar ligaments, or a process sent between them. In front it 

 corresponds with the integuments, and behind with the sterno- 

 hyoid muscles. 



Of the Inter-Articular Cartilage. -~- When the capsule of the 

 joint is cut open, this is brought into view. It separates the 

 bones completely from each other by its extent, and supplies by 

 its shape the want of correspondence in their articular faces. 

 It is thicker above than below; its centre is thin, and sometimes 

 perforated. Its margins adhere closely to the capsular ligament; 

 it is also fixed by adhesion to the upper posterior margin of the 

 surface of the clavicle, and below to the union of the sternum 

 with the first rib; in consequence of which it has but little mo- 

 tion, and in luxations must be lacerated. Its structure is fibro- 

 cartilaginous. 



Of the Synovia! Membranes. There are two of these, one on 

 each side of the inter-articular cartilage; in consequence of 

 which, a double cavity exists in this articulation, excepting the 

 cases where the cartilage is perforated. These membranes^ 

 contain but little synovia: they adhere closely to the adjoining 

 surfaces, and cannot be made very distinct, except in points 

 where there are small interstices in the' capsule, when, by press- 

 ing the bones strongly together, they protrude in little vesicles. 



Of the Costo-Clavicular Articulation. It consists in a short 

 fasciculus of ligamentous fibres, frequently called the Rhomboid 

 Ligament, which, arising from the upper surface of the cartilage 

 of the first rib, ascends obliquely outwards, and is implanted into 

 the roughness on the inferior face of the clavicle, near its sternal 

 end. Its fibres are parallel, all oblique, and longer at its external 

 than at its internal margin. It corresponds in front with the 

 origin of the subclavius muscle, and behind with the subclavian 

 vein. It has for its object the strengthening of the junction of 

 the clavicle with the sternum. 



