332 



LYMPHATIC SYSTEM. 



layer of endothelium, a subendothelial layer, and an elastic fibrous 

 layer; a middle, consisting of connective, elastic, and muscular 

 tissues ; and an external, also containing connective, elastic, and 

 muscular tissues. 



I/ymphatic Glands (Fig. 178). The lymphatic glands are 

 bodies of a pale reddish color, and are oval in shape. Their 

 diameter is from 2 mm. to 20 mm. Lymphatic vessels run into 

 the glands the afferent; and out of them the efferent; and 

 through them pass the lymph and the chyle. They consist of a 

 capsule of connective tissue, from which are given off trabevulce 



Longus colli muscle. 



Thyroid 

 gland. 



Vertebra] 

 artery. 



Esophagus. 



Trachea. 



Thyrocervi- 

 cal artery. 



Costocervi- 

 cal artery. 



Axillary 

 lymphatic 

 trunk. 



Internal jugular vein. 

 FIG. 177. Topography of the thoracic duct (Zuckerkandl). 



made up of connective tissue with some muscular fiber-cells ; 

 these pass into the gland toward the center or medullary portion 

 (M) for about one-fourth of the distance, dividing this outer or 

 cortical portion into alveoli (C). The trabeculse then divide and 

 subdivide, forming a network in the medullary portion, the spaces 

 between these smaller trabecul^ being also alveoli. The alveoli 

 contain gland-pulp or lymphoid tissue, which consists of retiform 

 tissue with lymph-corpuscles, with numerous capillary blood- 

 vessels. Between the gland-pulp and the trabeculse in the cortical 

 portion there is a space (l.s), which is termed a lymph-path or lymph- 



