PART FOUKTH. 



SUPERIOR EXTREMITY. 



THE SUPERIOR EXTREMITY COMPRISES BONES, LIGAMENTS, MUSCLES, 



FASCIJE, BLOOD-VESSELS, AND NERVES, AND WILL BE EXAMINED 



UNDER THESE SEVERAL HEADS RESPECTIVELY. 



CHAPTER I. 



THE BONES. 



THE Bones are arranged into those of the .Shoulder, 

 Arm, Forearm, and Hand. 



SECTION I. 

 BONES OF THE SHOULDER. 



The bones of the shoulder are two in number : 1. The 

 Scapula ; 2. The Clavicle. 



THE SCAPULA OR SHOULDER BLADE, (Fig. 215.) 



The Scapula is situated upon the posterior and superior 

 part of the chest. Its form is triangular, and it presents 

 two surfaces, three edges, and three angles. The anterior 

 surface looks toward the ribs, and is also the internal sur- 

 face or subscapular fossa. It is concave, divided by several 

 irregular lines, and occupied by the subscapular muscle. 

 The posterior or external surface is the dorsum, and is cut 

 transversely into two unequal parts by a very prominent 

 process called the spine of the scapula. 



This spine proceeds forward, and terminates in the aero- 

 mlon process, which is flattened superiorly and inferiorly, 

 and overhangs the shoulder joint. This spine also divides 

 the dorsum into the sityra and infra spinal fossce^ which 

 contain the supra and infra spinal muscles. The upper 

 edge of the spine has the trapezius attached to it, the 

 lower edge the deltoid muscle. 

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