STERNO-CLAVICULAR. 



285 



I. STERNO-CLAVICULAR ARTICULATION. (Fio. 197.) 



The Sterno-clavicular is an arthrodial joint. The parts entering into its 

 formation are the sternal end of the clavicle, the upper and lateral part of the 



Fig. 197. Sterno-clavicular Articulation. Anterior Yiew. 



first piece of the sternum, and the cartilage of the first rib. The articular 

 surface of the clavicle is much longer than that of the sternum, and invested 

 with a layer of the cartilage, 1 which is considerably thicker than that on the 

 latter bone. The ligaments of this joint are the 



Anterior Sterno-clavicular. Interclavicular. 



Posterior Sterno-clavicular. Costo-clavicular (rhomboid). 



Interarticular Fibro-cartilage. 



The Anterior Sterno-clavicular Ligament is a broad band of fibres, which 

 covers the anterior surface of the articulation, being attached, above, to the 

 upper and front part of the inner extremity of the clavicle; and, passing 

 obliquely downwards and inwards, is attached, below, to the front and upper 

 part of the first piece of the sternum. This ligament is covered in front by 

 the sternal portion of the Sterno-cleido-mastoid and the integument ; behind, 

 it is in relation with the interarticular fibro-cartilage and the two synovial 

 membranes. 



The Posterior Sterno-clavicular Ligament is a similar band of fibres, which 

 covers the posterior surface of the articulation, being attached, above, to the 

 posterior part of the inner extremity of the clavicle; and which, passing 

 obliquely downwards and inwards, is connected, below, to the posterior and 

 upper part of the sternum. It is in relation, in front, with the interarticular 

 fibro-cartilage and synovial membranes; behind, with the Sterno-hyoid and 

 Sterno-thyroid muscles. 



The Interclavicular Ligament is a flattened band, which varies considerably 

 in form and size in different individuals; it passes from the upper part of the 

 inner extremity of one clavicle to the other, and is closely attached to the upper 

 margin of the sternum. It is in relation, in front, with the integument ; behind, 

 with the Sterno-thyroid muscles. 



The Costo-clavicular Ligament (rhomboid) is short, flat, and strong : it is of a 

 rhomboid form, attached, below, to the upper and inner part of the cartilage 

 of the first rib: it ascends obliquely backwards and outwards, and is attached, 



1 According to Bruch, the sternal end of the clavicle is covered by a tissue, which is rather 

 fibrous than cartilaginous in structure. 



