172 SURGICAL APPLIED ANATOMY. [Chap. xi. 



si low that important structures may be wounded in 

 severe fractures associated with much displacement 

 and with sharp fragments. Several cases are reported 

 of paralysis of the upper limb (as a rule incomplete) 

 following upon fracture of this bone. In some cases 

 this symptom was due to actual compression, or 

 tearing of some of the great nerve-cords by the 

 displaced fragments. In other cases the nerve in- 

 jury, while due to "the original accident, was yet 

 independent of the broken clavicle. Cases are reported 

 of wound of the subclavian artery, of the subclavian 

 vein, of the internal jugular vein, and of the acromio- 

 thoracic artery. In several instances the fracture has 

 been associated with wound of the lung, with or with- 

 out a fracture of the upper ribs. 



The clavicle begins to ossify before any bone in 

 the body. At birth the entire shaft is bony, the two 

 ends being still cartilaginous. The bone has one 

 epiphysis for its sternal end that appears between the 

 eighteenth and twentieth year, and joins the shaft 

 about twenty-five. It is a mere shell, is closely 

 surrounded by the ligaments of the sternal joint, and 

 cannot, therefore, be well separated by accident.* 



Sterno-clavicular joint. Although this is 

 the only articulation that directly connects the upper 

 limb with the trunk, yet it is possessed of such 

 considerable strength that luxation at the joint is 

 comparatively rare. The amount of movement in the 

 joint depends to a great extent upon the lack of 

 adaptability between the facet on the sternum and 

 the sternal end of the clavicle. The disproportion 

 between these parts is maintained by the inter- 

 articular cartilage, which reproduces only the outline 



* Mr. Heath (Lancet, Nov. 18, 1882) reports a case which 

 is probably unique. It concerns a lad, aged 14, who, when in the 

 act of bowling at cricket, tore the clavicle away from its epiphyseal 

 cartilage, which remained in situ. The muscle producing the 

 accident was apparently tfye pectoralis major. 



