554 



THE ARTERIES. 



the tongue. The operation is a difficult one, on account of the depth of the artery, the number 

 of important parts by which it is surrounded, the loose and yielding nature of the parts upon 

 which it is supported, and its occasional irregularity of origin. An incision is to be made in 

 a curved direction from a finger's breadth external to the symphysis of the jaw downward to the 

 cornu of the hyoid bone, and then upward to near the angle of the jaw. Care must be taken 

 not to carry this incision too far backward, for fear of endangering the facial vein. In the first 

 incision the skin, superficial fascia, and Platysma will be divided, and the deep fascia exposed. 

 This is then to be incised and the submaxillary gland exposed and pulled upward by retractors. 

 A triangular space is now exposed, bounded internally by the posterior border of the Mylo- 

 hyoid muscle : below and externally, by the tendon of the Digastric ; and above, by the hypo- 

 glossal nerve. The floor of the space is formed by the Hyo-glossus muscle, beneath which the 

 artery lies. The fibres of this muscle are now to be cut through horizontally and the vessel 

 exposed, care being taken, while near the vessel, not to open the pharynx. 



Troublesome haemorrhage may occur in the division of the fraenum in children if the ranine 

 artery, which lies on each side of it, is wounded. The student should remember that the opera- 

 tion is always to be performed with a pair of blunt-pointed scissors, and the mucous membrane 

 only is to be divided by a very superficial cut, which cannot endanger any vessel. The scissors, 

 also, should be directed away from the tongue. Any further liberation of the tongue which may 

 be necessary can be effected by tearing. 



The Facial Artery (Fig. 349) arises a little above the lingual, and passes 

 obliquely upward, beneath the Digastric and Stylo-hyoid muscles ; it then runs 



Arteria septi nasi. 

 Superior coronary. 



Inferior coronary. 

 Inferior labial. 



I 

 FIG. 349. The arteries of the face and scalp. 1 



forward under cover of the body of the lower jaw, lodged in a groove on the 

 posterior surface of the submaxillary gland ; this may be called the cervical part 

 of the artery. It then curves upward over the body of the jaw at the anterior 

 inferior angle of the Masseter muscle ; passes forward and upward across the 



1 The muscular tissue of the lips must be supposed to have been cut away, in order to show the 

 course of the coronary arteries. 



