236 The Upper Extremity 



For compressing the brachial artery the assistant should stand 

 upon the outer side of the limb, and, passing the fingers round the 

 biceps and just beyond the surface-groove, should drag and hook the 

 artery with the tips of his fingers, and gently fix it against the bone. 

 Very little force is needed, only it must be properly directed outwards. 

 At the back of the arm the triceps may be seen narrowing into its 

 insertion into the olecranon process. The course of the musculo-spiral 

 nerve may be shown by drawing the chalk from below the posterior 

 fold of the axilla downwards, backwards, outwards, and then forwards 

 to the front of the external condyle. 



The condyiar ridges descend from the middle of the shaft to the 

 internal and external condyles ; the ulnar nerve may be felt as it 

 passes along the back of the inner ridge to the space between the 

 condyle and the olecranon. The inner ridge separates the biceps 

 and brachialis at the front from the triceps behind. The outer ridge 

 extends between the supinator longus and the long radial extensor, in 

 front, and the triceps posteriorly. 



In a thin subject the internal intermuscular septum may be clearly 

 made out. 



The external condyle is best examined on the forearm being fully 

 extended, when it is found in a depression which is bounded on the 

 inner side by the olecranon and the insertions of the triceps and 

 anconeus, and on the outer side by the mass of the supinator longus 

 and the extensors. In this depression, just below the condyle, is the 

 prominent margin of the bead of the radius, between which and the 

 condyle is a transverse groove corresponding to the elbow-joint. 



In suspected fractitre of the radius^ if there be no impaction of the 

 fragments, the head of the bone does not rotate when the wrist is 

 being pronated and supinated. The student should practise this 

 method of examining the radius, the thumb or index-finger being 

 pressed firmly against the radial head. 



A little above the internal condyle a small spur of bone is occasion- 

 ally met with ; it projects downwards, and beneath it the brachial 

 artery and median nerve may take an irregular course as in the car- 

 nivora. It may be felt beneath the skin, and should not be taken for 

 an exostosis or any other morbid growth. 



To measure the length of the arm, dot with ink the tip of each 

 acromion process, and each external condyle of humerus, and then 

 compare the two sides. To compare the forearms, dot the external 

 condyles as before, and the tip of each radial styloid process, and then 

 measure. 



Between the chest and the arm is the depression corresponding to 

 the floor of the armpit ; when the arm is raised the axillary fascia is 

 tightened and the borders of the pectoralis major in front and the teres 

 major and latissimus dorsi behind become prominent. When the arm 

 is raised to the utmost, and the fingers are forcibly thrust towards 



