948 



HUMAN ANATOMY. 



Longus colli muscle, stump 



Retro- 

 pharyngeal 

 node 



vical node 



Superior 

 cervical 

 sympathetic 

 node 



surfaces of the hyo-glossus muscle and in the interval between the two genio-hyo- 

 glossi. F^roni the surgical standpoint they are of comparatively little importance, 

 and have been termed "intercalated nodes," to distinguish them from the true 

 terminal nodes of the lingual lymphatics (page 954), in which enlargement occurs in 



cases of cancerous or 

 Fig. 799. other infection of the 



tongue. 



The retro-phar- 

 yngeal nodes are for 

 the most part small, 

 appearing as slight en- 

 largements of the lym- 

 phatics which drain the 

 posterior surface of the 

 pharynx. In addition 

 to these ' ' intercalated 

 nodes," however, one 

 or two much larger 

 nodes occur at the junc- 

 tion of the lateral and 

 posterior surfaces of 

 the pharynx, about on 

 a level with the anterior 

 arch of the atlas. They 

 are imbedded in the 



buCCO-pharyngeal fas- 

 Ret ropharyngeal lymph-nodes. {Most.*) cia and rest upou the 



lateral portions of the 

 rectus capitis anticus major. Afferents come to them from the upper part of the 

 pharynx and from the mucous membrane of the nose, and their efferents pass to the 

 upper deep cervical nodes (Fig. 799). • 



The Lymphatic Vessels. 



The Scalp. — The lymphatics of the scalp form a rich net-work, which is espe- 

 cially dense in the neighborhood of the vertex, the meshes becoming more elongated 

 as the vessels pass away from the median line. From the frontal region some ten to 

 twelve vessels pass downward and backward to terminate in the parotid nodes ; from 

 the parietal and temporal regions from six to ten vessels pass downward, some in 

 front of the external auditory meatus to terminate in the anterior auricular and paro- 

 tid nodes, and some behind the meatus to reach the posterior auricular nodes ; and 

 from the occipital region the more posterior vessels pass downward, partly to the 

 occipital and partly to the superior deep cervical nodes, while the more anterior five or 

 six converge to form a single large trunk which descends along the posterior border 

 of the sterno-cleido-mastoid muscle and terminates in the inferior deep cervical nodes. 



The Brain and the Meninges. — No lymphatic vessels have as yet been cer- 

 tainly demonstrated either in the central nervous system or in the meninges, although 

 they have been described as accompanying the middle meningeal artery in the dura 

 mater and the middle cerebral artery in the pia (Poirier). Lymph-spaces, how- 

 ever, some of them of considerable size, are abundantly present. Of these there may 

 be mentioned, first, the: pericelhilar spaces which surround the individual cells of the 

 brain and spinal cord, both the actual nerve-cells and the neuroglia-cells, those 

 accompanying the latter extending along their processes to communicate with an 

 epicerebral space believed to exist between the surface of the brain and the pia (His), 

 and also with spaces which occur along the course of the cerebral blood-vessels. Of 

 this second group of spaces, the perivascular spaces, two sets have been described, 

 one occurring in the adventitia surrounding the vessels and the other between the 

 adventitia and the brain substance, and, accompanying the blood-vessels into the pia, 



* Archiv f. klin. Chirurgie, Bd. 41, 1900. 



