360 A MANUAL OF ANATOMY. 



The left : In front, phrenic nerve and anterior pulmonary 

 plexus ; above, the arch of the aorta ; below, same as right ; 

 behind, descending aorta, pneumogastric nerve, and poste- 

 rior pulmonary plexus. 



UPPER EXTREMITY AND THORAX, Posterior. 



DISSECTION. 



Incisions. (l) From the base of the skull (made by the one on the head 

 and neck) in the median line along the back of the thorax (made by the one 

 on the upper extremity), to terminate at the tip of the coccyx (extended by 

 the one dissecting the lower extremity) . 



(2) From the median incision out along the spine of the scapula (same for 

 head and neck, page 128) to meet the similar incision in front over the point 

 of the shoulder. 



(3) Carry a transverse cut from twelfth dorsal spine around the body to 

 meet the similar one from the front. 



This incision answers for both upper and lower extremities. Reflect 

 the integument from the back of the neck, thorax, and trunk ; from 

 the arm to below the elbow. To expose the last no farther incisions in the 

 skin are necessary ; simply reflect it, beginning at the point where its anterior 

 dissection stopped, and working from the outer to the inner side of the limb. 



This method will also hold for the removal of the integument from the 

 back of the forearm, hand, and fingers. 



The Superficial Fascia. 



The superficial fascia covering the back of the body from 

 the base of the skull to the end of the spine is a dense, 

 brawny layer composed of connective and granular fatty 

 tissue. In the subject it is often found infiltrated by gravi- 

 tated fluid. 



The superficial fascia is continuous with the similar layer 

 of other adjacent parts of the body. It should be removed 

 in the same manner as the integument In its removal an 

 outlook should be kept for the superficial nerves and 

 vessels. The cutaneous nerves are the posterior divisions 



