28 Arteries of Head and Neck 



begin his incision in front of the tragus, and keep away from the 

 parotid gland, and avoid the branches of the facial nerve. 



Collateral circttlation is established by the empty branches bring- 

 ing in arterial blood as follows : the superior thyroid, lingual, facial, 

 superficial temporal, and occipital from their fellows of the opposite 

 side ; the superior thyroid from the inferior thyroid of its own side ; 

 the facial by its anastomosis with the ophthalmic at the inner 

 corner of the orbit ; the superficial temporal by its anastomosis 

 with the supra-orbital of the ophthalmic ; and the occipital with the 

 profimda cervicis of the superior intercostal, and also with the 

 vertebral. 



Branches. The superior thyroid is given off in the superior 

 carotid triangle (p. 10), being covered by skin, superficial fascia, 

 platysma, and deep fascia. It runs upwards for a little, and then 

 downwards and forwards, under the omo-hyoid, sterno-hyoid, and 

 sterno-thyroid, to enter the thyroid body, where it anastomoses with 

 its fellow and with the inferior thyroid. It sends a twig across the 

 middle line below the hyoid bone, which anastomoses with its fellow, 

 and a branch, which descends obliquely over the sheath of the com- 

 mon carotid, to supply the sterno-mastoid, which is probably severed 

 in ligation of that artery. The superior laryngeal branch runs with 

 the nerve of that name, through the thyro-hyoid membrane, for the 

 interior of the larynx. The crico-thyroi d branch runs across the 

 crico-thyroid membrane to join its fellow. It is wounded in laryngo- 

 tomy. 



The lingual artery is given off opposite the great cornu of the 

 hyoid bone, sometimes coming off in a common branch with the facial ; 

 it reaches the tip of the tongue as the ramne. In its course it not 

 only ascends, but passes deeply, running out of the superior carotid 

 triangle beneath the stylo-hyoid and digastric, and then under cover 

 of the hyo-glossus, where it rests on the middle constrictor of the 

 pharynx. It soon rests upon the genio-hyo-glossus, and ultimately 

 upon the lingualis, being then beneath the mucous membrane of the 

 tongue, by the side of the fraenum. Its position there must be re- 

 membered in dividing the fraenum, for if the scissors be clumsily 

 directed upwards it may very easily be cut. The ranine vein may 

 be seen through the mucous membrane on raising the tongue, but the 

 artery, which is more deeply placed, cannot be made out. 



The lingual sends inwards a hyoid twig which anastomoses with 

 its fellow above the hyoid bone, and then a larger branch the 

 dorsalis lingua which ascends under the hinder part of the hyo- 

 glossus to the tongue, soft palate, and tonsil. It anastomoses with its 

 fellow in front of the epiglottis. The sublingual branch comes oft 

 just after the lingual has passed beyond the hyo-glossus. It supplies 

 the sublingual gland and the floor of the mouth. 



legation of the lingual artery may be performed in the superior 



