BRANCHES OF THE EXTERNAL CAROTID. 553 



however, the collateral circulation between this vessel and the artery of the opposite side, and 

 the inferior thyroid, is completely re-established, the tumor usually regains its former size. 



The position of the superficial descending branch is of importance in connection with the 

 operation of ligature of the common carotid artery. It crosses and lies on the sheath of this 

 vessel, and may chance to be wounded in opening the sheath. The position of the crico-thyrpid 

 branch should be remembered, as it may prove the source of troublesome haemorrhage during 

 the operation of laryngotomy. 



The Lingual Artery (Fig. 352) arises from the external carotid between the 

 superior thyroid and facial ; it runs obliquely upward and inward to the great 

 cornu of the hyoid bone, then passes horizontally forward parallel with the great 

 cornu, and. ascending perpendicularly to the under surface of the tongue, turns 

 forward on its under surface as far as the tip of that organ, under the name of 

 the ranine artery. 



Relations. Its first, or oblique, portion is superficial, being contained in the 

 triangular space already described, resting upon the middle constrictor of the 

 pharynx, and covered by the Platysina and fascia of the neck. Its second, or 

 horizontal, portion also lies upon the middle constrictor, being covered at first by 

 the tendon of the Digastric and the Stylo-hyoid muscle, and afterward by the 

 Hyo-glossus. the latter muscle separating it from the hypoglossal nerve. Its 

 third, or ascending, portion lies between the Hyo-glossus and Genio-hyo-glossus 

 muscles. The fourth, or terminal, part, under the name of the ranine, runs along 

 the under surface of the tongue to its tip : it is very superficial, being covered 

 only by the mucous membrane, and rests on the Lingualis on the outer side of 

 the Genio-hyo-glossus. The hypoglossal nerve crosses the lingual artery, and then 

 becomes separated from it, in the second part of its course, by the Hyo-glossus 

 muscle. 



The branches of the lingual artery are the 



Hyoid. Sublingual. 



Dorsalis Linguae. Ranine. 



The hyoid branch rims along the upper border of the hyoid bone, supplying 

 the muscles attached to it and anastomosing with its fellow of the opposite side. 



The dorsalis linguae (Fig. 352) arises from the lingual artery beneath the Hyo- 

 glossus muscle (which, in the figure, has been partly cut away to show the vessel) ; 

 ascending to the dorsum of the tongue, it supplies the mucous membrane, the 

 tonsil, soft palate, and epiglottis, anastomosing with its fellow from the opposite 

 side. 



The sublingual, which may be described as a branch of bifurcation of the 

 lingual artery, arises at the anterior margin of the Hyo-glossus muscle, and 

 runs forward between the Genio-hyo-glossus and the sublingual gland. It 

 supplies the substance of the gland, giving branches to the Mylo-hyoid and 

 neighboring muscles, the mucous membrane of the mouth and gums. One 

 branch runs behind the alveolar process of the lower jaw in the substance of the 

 gum to anastomose with a similar artery from the other side. 



The ranine may be regarded as the other branch of bifurcation, or, as is more 

 usual, as the continuation of the lingual artery ; it runs along the under surface 

 of the tongue, resting on the Inferior lingualis. and covered by the mucous 

 membrane of the mouth ; it lies on the outer side of the Genio-hyo-glossus, 

 accompanied by the lingual nerve. On arriving at the tip of the tongue it has 

 been said to anastomose with the artery of the gpposite side, but this is denied 

 by Hyrtl. These vessels in the mouth are placed one on each side of the fraenum. 



Surgical Anatomy. The lingual artery may be divided near its origin in cases of cut 

 throat, a complication that not unf'requently happens in this class of wounds ; or severe 

 haemorrhage which cannot be restrained by ordinary means may ensue from a wound or deep 

 ulcer of the tongue. In the former case the primary wound may be enlarged if necessary, and 

 the bleeding vessels secured. In the latter ease it has been suggested that the lingual artery 

 should be tied near its origin. Ligature of the lingual artery is also occasionally practised, as a 

 palliative measure, in cases of cancer of the tongue, in order to check the progress of the 

 disease by starving the growth, and it is sometimes tied as a preliminary measure to removal of 



