282 A MANUAL OF ANATOMY. 



The lateral cutaneous branches of the third, fourth, 

 fifth, and sixth intercostal nerves may be found as they 

 appear along the side of the chest after coming through the 

 intercostal muscles. The first one or two usually help to 

 form a loose plexus with the intercostohumeral nerve. 

 These nerves decrease in size from above downward. The 

 third is usually distributed to a small part of the integu- 

 ment of the inner side of the arm and axilla, the others to 

 the integument of the side of the chest. 



(The description of the brachial plexus will be delayed 

 until the dissection of the neck has proceeded far enough 

 to permit removal of the clavicle, when the entire extent of 

 the plexus will be uncovered.) 



DISSECTION. 



Incisions. (l) Continue the median incision to the wrist. 

 (2) Make two short transverse cuts at the lower end of (l). 

 Reflect the skin from the arm and forearm, saving the superficial nerves 

 and veins. 



The Superficial Fascia. 



This is usually a thin layer, but may be thickened by the 

 presence of adipose tissue over the lower part of the fore- 

 arm and hand. In the hand the superficial fascia consists 

 of fatty granules between the palmar fascia and the skin. 

 In the superficial fascia ramify the subcutaneous vessels 

 and nerves. 



The Superficial Veins of the Arm and Forearm. Fig. 



6 5 . 



On the outer side of the forearm is the radial vein ; in 

 front, the median ; at the inner side, two, the anterior and 

 posterior ulnar, which unite to form the common ulnar 

 at the elbow. These pass up to the elbow, where the an- 

 terior and posterior ulnar unite to form the common ulnar, 



