THE CLAVICLE 



109 



ascondintr from tlic last rib to the lower border of the gladiolus (mesosternuiu). 

 These two borders form the subcostal angle, and the xiphoid (metasternum) 



Fkj. 117.— The Thorax. (Frout view.) 



projects into the middle of it. The intervals between the ribs are the intercostal 

 spares, and are eleven in number on each side. 



THE CLA VICLE 



The clavicle is a rod of bone passing from the top of the sternum to the acro- 

 mion process of the scapula. It presents two curves: an inner, with the convexity 

 ihrected forwards; and an outer, the smaller, with the convexity directed back- 

 wards. The clavicle consists, for descriptive purposes, of an outer tiattenefl, and 

 an inner prismatic portion. 



The outer third has two surfaces and two borders. The superior surface 

 looks directly upwards, and affords attachment to the trapezius muscle posteriorly, 

 and the dcltirid anteriorly; a small tract intervening between the muscles is subcu- 

 taneous. The inferior "surface is rough, and at its most j)osterior part presents 

 tlie tuberosity (or conoid tubercle) of tlie clavicle; it overhangs the coracoid 

 ])n)(ess and gives attachment to the conoid ligament. From the tuberosity a ridge, 

 the oblique line, runs outwards and forwards; to it, the trapezoid ligament is 

 attached. The anterior border is thin; presents often a small jirominence, the 



