736 HUMAN ANATOMY. 



common to it and one or other of these arteries, especially the facial. In the first part 

 of its course it passes forward and slightly upward and inward towards the tip of the 

 lesser cornu of the hyoid bone, and is crossed by the posterior belly of the digastric 

 and the stylo-hyoid muscles and by the hypoglossal nerve. On reaching the pos- 

 terior border of the hyo-glossus, it passes beneath that muscle and is continued 

 almost directly forward beneath the mucous membrane covering the under surface of 

 the tongue and between the genio-hyo-glossus and the inferior lingualis muscles. In 

 this terminal portion it has a sinuous course, and is frequently termed the ranine 

 artery (a. profunda linguae) ; it gives branches to the adjacent muscular substance 

 and mucous membrane of the tongue, and near its termination anastomoses with its 

 fellow of the opposite side. 



Branches, — {a) The suprahyoid branch (ramus hyoideus), given off from the first portion, 

 passes horizontally forward over the hyoid bone, sending branches to the muscles which are 

 inserted into that Sone from below. 



(d) The dorsal lingual branch (rami dorsales linguae), from the second portion, arises 

 under cover of the posterior border of the hyo-glossus and, passing upward medial to the stylo- 

 glossus, breaks up into branches which are distributed to the mucous membrane of the dorsum 

 of the tongue, as far back as the epiglottis, and also to the tonsil. Occasionally a branch unites 

 with a corresponding one from the artery of the opposite side, immediately in front of the fora- 

 men caecum, and is continued forward in the median line, immediately beneath the mucous 

 membrane of the dorsum of the tongue, as far as the tip. 



{c) The sublingual branch (a. sublingualis) is given off near the anterior border of the hyo- 

 glossus muscle and runs forward in the same plane as the ranine artery, but on a lower level, 

 resting upon the mylo-hyoid muscle and lying between the genio-hyoid laterally and the genio- 

 hyo-glossus medially. It is accompanied by the submaxillary (Wharton's) duct, which lies upon 

 its medial side, and it terminates in the sublingual gland, also sending branches to the neighbor- 

 ing muscles and to the alveolar border of the mandible. 



Anastomoses. — The various branches of the lingual artery anastomose exten- 

 sively with their fellows of the opposite side. The anastomoses of the two aa. dor- 

 sales linguae take place, however, only through exceedingly fine twigs, so that the 

 tongue may be divided longitudinally in the median line without any great loss of 

 blood, except towards the tip, where a larger anastomosis of the ranine arteries occurs. 

 In addition to these contra-lateral anastomoses, the lingual also anastomoses through 

 its suprahyoid branch with the infrahyoid of the superior thyroid artery, through 

 its sublingual branch with the submental branch of the facial, and through the a. 

 dorsalis linguae with the various tonsillar arteries. 



Variations. — The lingual artery sometimes arises from a common trunk with the facial, 

 and it has been observed to terminate at the root of the tongue, being replaced in the rest of its 

 course by branches from the internal maxillar>- or by the submental branch of the facial. The 

 sublingual branches are not infrequently lacking, being replaced by branches of the submental, 

 and, in addition to its normal branches, the main arterj' may give rise to a superior laryngeal and 

 an accessory superior thyroid branch. 



Practical Considerations. — The lingual artery is tied most frequently as a 

 preliminary to excision of the whole or part of the tongue, but one or both arteries 

 may be ligated to stop bleeding following wound or malignant ulceration of that 

 organ, or in an effort to arrest growth by cutting off blood-supply, as in cases of 

 cancer of the tongue or of macroglossia. 



Ligation. — The artery is for convenience divided into three portions, the _/?r.y/ 

 between its origin — about opposite the greater cornu of the hyoid — and the posterior 

 edge of the hyo-glossus muscle, lying upon the middle constrictor of the pharynx ; 

 the second beneath the hyo-glossus muscle, lying upon the genio-glossus ; the third, 

 ( ranine^ from the anterior border of the hyo-glossus along the under surface of the 

 tongue to its termination. 



The place of election is in the second part. The skin incision, two inches in 

 length, curved, with the concavity upward, begins a half- inch below and external to 

 the mandibular symphysis and ends a little below and internal to the point where 

 the facial artery crosses the lower edge of the inferior maxilla ; its centre is just 

 above the grea«^er cornu of the hyoid. If the incision is carried too far backward, 



