mm; anatomy in a nutshell. 



parietal layer of the pelvic fascia. This layer passes from the white line on the 

 pelvis tn cover the Obturator interims muscle, and above Alcock's canal gives 

 off the anal fascia (ischio-rectal) over the lower surface of the Levator ani mus- 

 cle. This fascia with the corresponding fascia of the opposite side forms the 

 deep superior layer of the triangular ligament. 



LESSON CLXIII. 

 Lymphatic System. (Plates CCLXXXIX-CCXC.) 

 "niphatic system consists of lymphatic vessels, and lymphatic nodes. 

 The lymphatic vessels of the small intestine are called lacteals or chyliferous 

 vessels because during the process of digestion they contain chyle which they 

 carry into the blood through the thoracic duct. The lymphatic vessels are 

 present in all the pari of the body except the hair, nails, cuticle, and cartilage. 

 The lymphatic system is in the form of the human body. It commences in 

 microscopic space- which join one another to make larger spaces until they 

 finally form the two lymphatic ducts, the righl and the left. The left one is 

 called the thoracic duct because it passes through the thorax. It collects lymph 

 from all the body except the right half of the head, the right half of the thorax. 

 and the upper surface of the liver, and the right arm. The lymph in these 

 structures just named pass into the right lymphatic duct. This right lympha- 

 tic duct is about half an inch long and empties into the tight subclavian vein. 

 The lefi lymphatic or thoracic duct is about eighteen inches long and passes 

 upon the vertebral column behindthe archof the aorta, ii finallyends in the left 

 subclavian vein. This duct may be double for part of its way or throughits en- 

 ure course, and it may empty into the vena azygos major. It has constric- 

 tions through its entire course and a double valve at its termination. 



Every cell in the body is surrounded by lymph and is therefore an aquatic 

 animal. These cells receive their food from the lymph into which they also 

 throw their waste products. 



The lymphatic vessels in the body are in two sets, superficial and deep. 

 The superficial lymphatics pass just under the skin with the superficial veins 

 and they pierce the deep fascia to join the deep lymphatic vessels. The deep 

 lymphatics although not so numerous as the superficial ones are larger and 

 accompany the deep blood vessels. The lymphatic, absorbent, or conglobate 

 nodes are small bodies of adenoid tissue which the lymphatic vessels pass 

 through on their way to the thoracic and lymphatic duct-. These nodes vary 

 in size from very small ones which are microscopic, to large one- which are 

 aboui the si/.e of a small bean. Their color is pinkish-gray, but those in the 

 bronchial region are a darker color. 



The lymphatics, like veins, have three coats, but the smallest lymphatic 

 vessels have one coat which is composed of epithelial cells. Those vessels 

 which have three coat.- have the following arrangement, (1) an inner coat of 

 epithelium and a -mull amount of yellow fibrous tissue: (2) \ MIDDLE COAT 

 composed of muscular tissue and yellow fibrous tissue: (3) AX OUTER COAT 

 which consists of white fibrous tissue and a little of the yellow fibrous tissue. 

 All three of these coat- pu1 together are transparent. Valves are present in 



