118 STERNO-CLAVICULAR LIGAMENTS. 



1. Sterno-clavicular articulation. 



2. Scapulo-clavicular articulation. 



3. Ligaments of the scapula. 



4. Shoulder joint. 



5. Elbow joint. 



6. Radio-ulnar articulation. 



7. Wrist joint. 



8. Articulation between the carpal bones. 



9. Carpo-metacarpal articulation. 



10. Metacarpo-phalangeal articulation. 



11. Articulation of the phalanges. 



1. Sterno-clavicular Articulation. The sterno-clavicular is an 

 arthrodial articulation ; its ligaments are, 



Anterior sterno-clavicular, 

 Posterior sterno-clavicular, 

 Inter-clavicular, 

 Costo-clavicular (rhomboid), 



Interarticular fibro-cartilage, 



Two synovial membranes. 



The anterior sterno-clavicular ligament is a broad ligamentous 

 layer, extending obliquely downwards and forwards, and covering 

 the anterior aspect of the articulation. This ligament is in illation 

 by its anterior surface with the integument and with the sternal 

 origin of the sterno-mastoid muscle ; and behind with the interarti- 

 cular fibro-cartilage and synovial membranes. 



The posterior sterno-clavicular ligament is a broad fasciculus, 

 covering the posterior surface of the articulation. It is in relation 

 by its anterior surface with the interarticular fibro-cartilage and 

 synovial membranes, and behind with the sterno-hyoid muscle. 



The two ligaments are continuous at the upper and lower part 

 of the articulation, so as to form a complete capsule around the 

 joint. 



The inter-clavicular ligament is a cord-like band which crosses 

 from the extremity of one clavicle to the other, and is closely con- 

 nected with the upper border of the sternum. It is separated by 

 cellular tissue from the sterno-thyroid muscles. 



The costo-clavicular ligament (rhomboid) is a thick fasciculus of 

 fibres, connecting the sternal extremity of the clavicle with the 

 cartilage of the first rib. It is situated obliquely between the rib 

 and the under surface of the clavicle. It is in relation in front 

 with the tendon of origin of the subclavius muscle, and behind 

 with the subclavian vein. 



Actions. The movements of the sterno-clavicular articulation, 

 are a gliding movement of the fibro-cartilage with the clavicle, upon 

 the articular surface of the sternum in the directions forwards, 

 backwards, upwards, and downwards; and circumduction. This 

 articulation is the centre of the movements of the shoulder. 



