AXILLARY SPACE 



27 



cephalic vein. Its other tributaries correspond, more or 

 less closely, to the branches of the axillary artery. 



M. Subclavius. The subclavius is a small muscle which 

 lies immediately below the clavicle enclosed between the 

 two layers of the costo-coracoid membrane. It takes origin 

 by a short rounded tendon from the superior surface of 

 the first costal arch, at the junction of the bone with the 

 cartilage, and the fleshy belly is inserted into the shallow 

 groove on the inferior surface of the clavicle. The nerve of 



Joint capsule 

 Joint cavity 



Interarticular 

 ligament 



Joint cavity 



Anterior chondro- 

 sternal ligament 



FIG. 12. Sterno-clavicular and Costo-sternal Joints. 



supply is derived from the fifth cervical nerve and enters 

 the posterior surface of the muscle. When the muscle 

 contracts it depresses the clavicle and draws it slightly 

 forwards. 



Dissection. When the subclavius has been examined it must be 

 divided horizontally, and when this has been done the costo-clavicular 

 ligament will be found behind the medial end of the muscle. 



The clavicle must now be detached from the sternum and the cartilage 

 of the first rib, and turned laterally so that the brachial plexus may be 

 properly examined, but before this is done the sterno-clavicular joint 

 should be studied. With the assistance of the dissector of the head 

 and neck the clavicular part of the sterno-cleidomastoideus muscle must be 



