170 



SPECIAL ANATOMY OF THE SKELETON 



from the inferior surface, and extends from the conoid tubercle to the rhomboid 

 impression. It forms the posterior boundary of the groove for the Subclavius 

 muscle, and gives attachment to a layer of cervical fascia covering the Omohyoid 

 muscle. 



Surfaces. The anterior surface is included between the superior and anterior 

 borders. It is directed forward and a little upward at the sternal end, outward 

 and still more upward at the acromial extremity, where it becomes continuous 

 with the upper surface of the flat portion. Externally, it is smooth, convex, 

 nearly subcutaneous, being covered only by the Platysma; but, corresponding 

 to the inner half of the bone, it is divided by a more or less prominent line into 

 two parts a lower portion, elliptical in form, rough, and slightly convex, for the 

 attachment of the Pectoralis major; and an upper part, which is rough, for 

 the attachment of the Sternomastoid. Between the two muscular impressions 



Acromial ertremity. 



Sternal extremity. 



FIG. 136. Left clavicle. Superior surface. 



Capfndar 

 Ligament 



Capsidar 

 ligament 



FIG. 137. Left clavicle. Inferior surface. 



is a small subcutaneous interval. The posterior or cervical surface is smooth, 

 flat, and looks backward toward the root of the neck. It is limited, above, by the 

 superior border; below, by the posterior border; internally, by the margin of the 

 sternal extremity; externally, it is continuous with the posterior border of the flat 

 portion. It is concave from within outward, and is in relation, by its lower part, 

 with the suprascapular vessels. This surface, at about the junction of the inner 

 and outer curves, is also in close relation with the brachial plexus and subclavian 

 vessels. It gives attachment, near the sternal extremity, to part of the Sternohyoid 

 muscle; and presents, at or near the middle, a foramen, nutrient foramen. It 

 opens into a canal, nutrient canal, which is directed obliquely outward and trans- 

 mits the chief nutrient artery of the bone. Sometimes there are two foramina 

 on the posterior surface, or one on the posterior and one on the inferior surface. 

 The inferior or subclavian surface is bounded, in front, by the anterior border; 



