560 THE LYMPHATICS OF THE HEAD AND NECK. 



tricles. At the base of the brain they are collected into larger vessels which descend 

 along the internal carotid and vertebral arteries and the internal jugular vein to the 

 deep cervical glands. The lymphatics springing from the choroid plexuses of the 

 lateral and third ventricles run backwards and unite into a considerable trunk 

 which accompanies the veins of Galen between the layers of the velum interpositum. 



The lymphatics of the tongue are mainly directed backwards in company with 

 the ranine vein, and traverse two or three small lingual glands, lying on the outer 

 surface of the hyo-glossus muscle, on their way to join the deep cervical glands in 

 the neighbourhood of the bifurcation of the common carotid artery. From the fore 

 part of the tongue also, one or two vessels pass downwards together with the 

 lymphatics of the floor of the mouth and, after perforating the mylo-hyoid muscle, 

 enter the submaxillary glands. 



The lymphatics of the larynx form two groups, superior and inferior. The 

 superior are from four to six trunks which pierce the thyro-hyoid membrane and pass 

 to the glands about the bifurcation of the common carotid artery. The inferior 

 vessels, from three to five, arise from the infraglottic portion of the larynx, and 

 emerge through the crico-thyroid membrane ; they either enter a small prelaryngeal 

 gland lying on the surface of that membrane, or pass directly to some inferior 

 laryngeal glands at the lower and lateral part of the larynx. 1 



The lymphatics of the pharynx are abundant. Those from the upper part 

 of the cavity are joined by lymphatic vessels from the nose and superior surface of 

 the soft palate, and pass backwards to a gland near the skull, between the pharynx 

 and the prevertebral muscles. The lymphatics from the lower part of the pharynx 

 pass out with the superior laryngeal lymphatic vessels and enter the same glands. 



1 P. Poirier, " Vaisseaux lymphatiques du larynx," &c. Bull. Soc. Anat.. Paris, 1887. 



