PECTORAL REGION 19 



space. In a well- injected subject a small artery, from the 

 distal part of the axillary trunk, may be seen ramifying on 

 the surface of the fascia. 



Dissection. Cut through the deep fascia along the sulcus 

 between the pectoralis major and the deltoid, and display the 

 cephalic vein (Figs. 31, 33) and the deltoid branch of the thoraco- 

 acromial artery which accompanies it. " Clean " them by 

 removing the loose fascia in which they are embedded. Follow 

 both vessels upwards to the delto-pectoral triangle where they 

 disappear under cover of the upper border of the pectoralis 

 major. 



In the delto-pectoral triangle look for the delto-pectoral 

 lymph glands which are sometimes present. Lymph glands 

 are rounded or ovoid masses of fairly dense tissue, which vary 

 in colour; they may be yellowish-pink, rose-pink, reddish- 

 brown, purple-brown, or in some regions quite black. Their 

 surfaces are usually glistening, and attached to the borders 

 and surfaces are many fine white vessels, the lymph vessels, 

 which convey a fluid called lymph to and from the glands. 

 Lymph glands vary very much in size, and the delto-pectoral 

 glands may be as small as a pin-head or as large as a good-sized 

 pea. After the contents of the delto-pectoral triangle have been 

 studied, clean the anterior part of the deltoid and the whole of 

 the pectoralis major muscle, and note the natural separation of 

 the latter muscle into sternal and clavicular parts. 



The " cleaning " of a muscle means the removal of the 

 whole of the deep fascia from its surface. To do this success- 

 fully the dissector must follow three rules, (i) He must cut 

 boldly down through the deep fascia till he exposes the red 

 fibres of the muscle. (2) As he removes the fascia he must 

 keep the knife edge playing against the fibres of the muscle. 

 (3) As he makes his cuts he must carry the knife blade in the 

 direction of the fibres of the muscle. If he follows rules i and 

 2 he will not leave a thin film of fascia on the muscle, and as 

 he follows rule 3 he will find that the direction of his incisions 

 changes as the course of the fibres of the muscle changes. If 

 the work is well done the deep fascia should be removed from 

 the muscle as a continuous unperforated layer of fibrous tissue, 

 and the surface of the muscle will be clean. 



To clean the anterior part of the deltoid, cut through the 

 deep fascia along the anterior border of the muscle, and reflect 

 the fascia until the base of the skin flap is reached. As the 

 fascia is reflected some cutaneous twigs of the axillary nerve 

 may be noted piercing the surface of the muscle, and filaments 

 of the lateral cutaneous nerve of the arm will also be found 

 (see Figs. 31, 32, 33). 



To clean the pectoralis major commence at the upper border 

 of the muscle on the right side, and at the lower border on the 

 left side, reflecting the fascia in the first case downwards, and 

 in the second upwards. Before the removal of the fascia is 

 begun make the muscle tense by abducting the arm. 



The delto-pectoral glands, sometimes represented by a 

 single gland, receive lymph from the lateral side of the arm 



