THE LYMPHATICS OF THE HEAD. 



953 



The first or apical group (Fig. 805) consists of from two to four stems which 

 arise from the net-work at the tip of the tongue and pass downward and backward, 

 half of them lying on one side of the frenum and half on the other side. They follow 

 at first the anterior border of the genio-hyo-glossus muscle and then pass upon the 

 outer surface of that muscle and are continued downward and backward, either 

 external or internal to the hyo-glossus, until they reach the greater cornu of the 

 hyoid bone, just below the attachment of the stylo-hyoid. They then cross obliquely 

 over the outer surface of the greater cornu, and are continued down the neck along 

 the outer border of the omo-hyoid muscle to open into one of the inferior deep 

 cervical nodes situated upon the jugular vein just above the point where it is crossed 

 by the omo-hyoid muscle. Sometimes an additional apical stem passes down the 

 frenum in company with those just described, but continues on downward to 

 perforate the mylo-hyoid muscle and terminate in one of the submental nodes. 



A second or lateral group consists of a number of vessels which -emerge from the 

 net-work along the borders of the tongue (Fig. 804 J 

 stems in this group on 



There are from eight to twelve 



Fig. S04. 



Median 



basal 



lymphatics 



Lateral 



basal 



lymphatics 



Lateral net- 

 work of 

 lymphatics 



in 

 either side, and all are at 

 first directed almost verti- 

 cally downwards, a few, 

 three or four, passing later- 

 ally to the sublingual gland 

 and the rest medial to it. 

 The former continue their 

 downward course, perforate 

 the mylo-hyoid muscle, and 

 terminate in the submaxil- 

 lary nodes, while the others 

 take a course obliquely 

 downward and backward, 

 and, passing some upon 

 the median and others 

 upon the lateral surface 

 of the hyo-glossus muscle, 

 terminate in the superior 

 deep cervical nodes and 

 especially in one situated a 

 little above the level of the 

 bifurcation of the common 

 carotid artery. This node, 

 on account of its relations to 

 these lingual stems, has been 

 termed the principal node 

 of the toyigiie (Fig. 805). 



A third or basal group takes its origin from the dense portion of the submucous 

 net-work which surrounds the circumvallate papillae and the foramen caecum. Four 

 stems issue from the net-work in the neighborhood of the median line, and two on each 

 side more laterally. The median stems pass at first directly backward and then bend 

 outward in the glosso-epiglottidean folds, two on either side, and join the lateral stems 

 beneath the tonsils. The lateral stems, which drain the regions of the lateral circum- 

 vallate papillae, the foliate papillae, and the glandular region of the tongue, are directed 

 backward towards the lower border of the tonsil, and, after being joined in that situation 

 by the median stems, they pass deeply to terminate in the superior deep cervical nodes. 



Finally, a fourth or 7nedian group arises from the net-work of the median 

 portion of the tongue, anterior to the circumvallate papillae. These stems are five 

 or six in number, and pass at first directly downward through the substance of the 

 tongue and through the interval which separates the two genio-hyo-glossal muscles. 

 One or two of them then continue in their downward course and pass, in some cases 





Apical 

 net-work of 

 lymphatics 



Lymphatics of dorsum and margins of tongue. {Kilttner.*) 



* Beitrage f. klin. Chiriirgie, Rd. xxi., 1895. 



