50 THE SUPERIOR EXTREMITY 



scapula is very mobile, and moves to a greater or less 

 degree with every movement of the limb. The spine and 

 acromion of the scapula are subcutaneous throughout. 

 Below the scapula the lower five ribs can be distinguished, 

 and the tip of the last rib can be felt at a point about two 

 inches or less above the iliac crest. 



As the back is dissected the following are the parts which 

 must be examined : 



1. The cutaneous vessels and nerves of the back. ] 



2. The trapezius muscle. I ist day. 



3. The latissimus dorsi muscle. 



4. The rhomboid muscles and their nerve. 



5. The levator scapulae muscle. 



6. The accessory nerve and the nerves from the cervical plexus 



which supply the trapezius. J>2nd day. 



7. The transverse cervical artery and its two terminal branches. 



8. The posterior belly of the omo-hyoid muscle. 



9. The transverse scapular artery and the suprascapular nerve, j 



This dissection must be completed in two days, in order that 

 the dissector of the head and neck may be enabled to con- 

 tinue the deeper dissection of the back. The first day's work 

 should comprise (i) the reflection of the skin ; (2) the 

 dissection of the cutaneous nerves and vessels ; and (3) the 

 cleaning of the latissimus dorsi and trapezius muscles. The 

 remainder of the dissection can be undertaken on the second 

 day. 



Dissection. Reflection of the Skin. The following incisions 

 are necessary : i. From the tip of the coccyx, at the lower end 

 of the vertebral column, upwards, along the median line of the 

 body, to the spine of the seventh cervical vertebra. 2. From 

 the upper end of i transversely, to the tip of the acromion of the 

 scapula. 3. From the lower extremity of the median incision 

 in a curved direction laterally and forwards, along the crest of 

 the ilium, to within two inches of the anterior superior iliac spine. 

 4. An oblique incision from the spine of the first lumbar vertebra, 

 upwards and laterally, to the posterior fold of the axilla, and along 

 the latter to the arm. The two large flaps (17 and 18, Fig. 25) 

 which are now mapped out upon the back must be carefully 

 raised from the subjacent fatty tissue. Reflect the upper 

 triangular flap first, and then the lower flap. 



Panniculus Adiposus (Superficial Fascia). In subjects 

 which have been allowed to lie for some time on the back 

 the superficial fascia is usually more or less infiltrated with 

 fluid which has gravitated into its meshes ; otherwise it has 

 the ordinary characters of superficial fascia (p. 1 1 ). 



