348 LYMPHATICS OF THE HEAD AND NECK. 



clavian with the internal jugular vein on the right side of the root 

 of the neck. 



The lacteah are the lymphatics of the small intestines ; they 

 have received their distinctive appellation from conveying the milk- 

 like product of digestion the chyle to the great centre of the lym- 

 phatic system the thoracic duct. They are situated in the mesen- 

 tery, and pass through the numerous mesenteric glands in their 

 course. 



The communications between lymphatic vessels are less frequent 

 than those of arteries or veins; their anastomoses take place by means 

 of branches of equal calibre that unite at acute angles, and con- 

 stitute a combined trunk which is scarcely larger than either of the 

 single branches by which it is formed. 



Lymphatic vessels are composed of two coats ; an external or 

 cellular, and an internal or serous. 



The External coat resembles the external tunic of veins and arte- 

 ries, but is extremely thin arid dense. The Internal coat is continuous 

 with the internal lining of the veins; and, like that membrane, is 

 most probably provided with an epithelium. At short intervals this 

 coat forms semilunar folds which are disposed in pairs in the 

 cylinder of the vessel and constitute the valves. It is to these valves, 

 which are extremely numerous in lymphatics, that their peculiar 

 knotted appearance is due, when filled with injection. 



The lymphatic glands are small oval and somewhat flattened or 

 rounded bodies, composed of a plexus of minute lymphatic vessels, 

 associated with a plexus of blood-vessels, and enclosed in a thin 

 cellular capsule. The larger glands have a lobed or cellular 

 appearance. The lymphatic vessels and glands are supplied with 

 arteries, veins, and nerves, like other structures. 



I shall describe the lymphatic vessels and glands according to the 

 arrangement adopted for the vein,s, commencing with those of the 

 head and neck, and proceeding next to those of the upper extremity, 

 lower extremity, and trunk. 



LYMPHATICS OF THE HEAD AND NECK. 



The Superficial lymphatic glands of the head and face are small 

 and few in number ; they are the occipital, which are situated near 

 the origin of the occipito-frontalis muscle; posterior auricular, 

 behind the ear; parotid, in the parotid gland; zygomatic, in the 

 zygomatic fossa; buccal, upon the buccinator muscle; and sub- 

 maxillary, beneath the margin of the lower jaw. There are no 

 deep lymphatic glands within the cranium. 



The Superficial cervical lymphatic glands are few in number ; 

 they are situated in the course of the external jugular vein, between 

 the sterno-mastoid and trapezius muscles, at the root of the neck 

 and about the larynx. 



The Deep cervical glands are very numerous and of large size ; 

 they are situated around the internal jugular vein and sheath of the 



