660 THE LYMPHATICS 



o. The cervical portion of the thoracic duct as^eends as higli as the level of 

 the seventh cervical vertebra, and then curves, downwards and forwards, over the 

 apex of the pleura in front of the sul)clavian artery, scalenus anticus muscle, and 

 vertebral vein, behind the left internal jugular vein, and behind and suljsequently 

 external to the left common carotid artery, and, having received the left jugular 

 lymphatic trunk, opens into the left innominate vein at the confluence of the inter- 

 nal jugular and subclavian veins. The cervical portion receives the lymphatics 

 from the left upper extremity and left side of the head and neck. 



The chief variations in the thoracic duct. — (1) The thoracic duct luaj' be double ; when 

 tliis is the case, the left duct may eud normally in the left inuomiuate vein, and the right in the 

 corresponding situation on the right side ; or the two ducts maj' unite at the root of the neck, 

 and open into the left innominate vein. (2) The reduplication may be incomplete. Thus: {a) 

 The duct may at first be single, but divide into two separate vessels at a variable distance from 

 its termination, and then (i) one branch of the duct may enter the left confluence of veins at the 

 root of the neck ; the other the right confluence, a normal condition in some animals ; or one 

 may enter the confluence of veins in the normal manner, the other either the subclavian or inter- 

 nal jugular vein ; or (ii) the two branches may reunite — this is a frequent variety, and is regarded 

 as a normal condition by some anatomists, {h) It maj' break up into several branches in its 

 course throuafh the thorax, forming a plexus of vessels, which subsequently reunite into a single 

 duct. (3) The thoracic duct may lie altogether to the left side of the aorta, and terminate as 

 normal. (4) The duct may open into the confluence of the subclavian and internal jugular veins 

 on the right side, an abnormal arrangement which may occur under the following conditions : — 

 (fl) when the viscera are transposed ; (6) when there is a right aortic arch without transposition 

 of vi-scera ; and (c) when the vessels and viscera are normal. (5) The duct may end in the 

 vena azygos major. 



THE LYMPHATICS OF THE ABDOMEN AND PELVIS 



The lymphatics of the abdomen and pelvis may be divided into the parietal, 

 which ramify in the abdominal and pelvic w^alls; and the visceral, which receive 

 the lymph from the pelvic viscera, and the lymph and chjde from the abdominal 

 viscera. 



I. THE PARIETAL LYMPHATIC VESSELS AXD GLANDS 

 OF THE ABDOMEN AND PELVIS 



1. The parietal lymphatic vessels may be subdivided into the superficial, 

 which ramify beneath the skin in the subcutaneous tissue, and include the 

 lymphatics of the skin of the penis and scrotum and of the external genital 

 organs in the female; and into the deep, which accompany the deep arteries of the 

 abdominal and pelvic walls. The former for the most part end in the superficial 

 inguinal glands; the latter in the lumbar glands. 



(1) The superficial parietal lymphatics. — The sui)erficial parietal lymphatics 

 of the abdominal walls are situated betwec^n tlie skin and the abdominal muscles. 

 Those from the front of the abdomen, below the level of the umbilicus, ])ass down- 

 wards along the course of the superficial epigastric artery and veins, and end in the 

 superficial inguinal glands. The lymphatics from the upper part of the front of 

 the abdomen, above the level of the umbilicus, pass upwards and outwards with 

 the lymphatics from the front and side of the chest to the axillary glands. The 

 lymi)hatics from the lateral abdominal walls run, in part over the crest of the 

 ilium, in the course of the superficial circumflex iliac artery and veins, into the 

 outer superficial inguinal glands, and in part follow the course of the lumbar and 

 ilio-lumbar arteries, and, after perforating the al)dominal muscles, end in the lateral 

 lumbar glands. The suj)erficial lymphatics from the lower part of the back and 

 from the gluteal region for the most part pass outwards over the gluteal muscles 

 to end in the outermost superficial inguinal glands; but those from the region of 



