396 THE ARTERIES OF THE HEAD AND NECK. 



eating around the foramen caecum with the corresponding branch of the opposite 

 side. It is often replaced by several smaller offsets. 



(c) The sublingual branch takes origin at the anterior margin of the hyo-glossus, 

 and runs forwards between the genio-glossus muscle and the sublingual gland. It 

 supplies the substance of the gland, and gives branches to the mylo-hyoid and other 

 muscles connected with the lower jaw. Small branches are also distributed to the 

 mucous membrane of the mouth and the inside of the gum, and a considerable 

 offset anastomoses across the middle line with the artery of the other side. 



(d) The ranine artery passes forwards with a tortuous course, giving numerous 

 branches as it proceeds, and being for the most part embedded in the substance of 

 the tongue between the genio-glossus and inferior lingualis muscles. Near the tip 

 of the tongue it communicates with the opposite ranine artery in a small loop 

 (Krause), but with this exception the right and left arteries do not form other than 

 capillary anastomoses. In the last part of its course the ranine artery lies quite 

 superficially, at the side of the fhenum. 



Varieties. The lingual artery is often united at its origin with the facial; less fre- 

 quently with the superior thyroid ; and the three vessels occasionally arise by a common trunk. 

 Instead of passing beneath the hinder border of the hyo-glossus, the artery sometimes pierces 

 the origin of the muscle. The lingual artery has been seen replaced entirely or in large part 

 by a branch of the internal maxillary, or of the submental branch of the facial. The hyoid 

 branch is often absent ; and it appears that this branch varies in size inversely with the hyoid 

 branch of the superior thyroid artery. The sublingual branch is sometimes derived from the 

 facial artery, and then perforates the mylo-hyoid muscle. The lingual artery has been 

 observed to give off, as unusual branches, the superior laryngeal, the submental, and the 

 ascending palatine. 



Surgical anatomy. The lingual artery may be tied either in the carotid triangle, before 

 it passes under the digastric muscle, or farther forwards, while it is beneath the hyo-glossus ; 

 preferably in the latter situation, since its place of origin is subject to variation and its rela- 

 lation to the tip of the great cornu of the hyoid bone is therefore not constant. To reach the 

 artery in the submaxillary triangle, a curved incision, reaching from a point a little outside 

 the symphysis nearly to the angle of the lower jaw and descending in the middle to the hyoid 

 bone, is made through the integuments, the platysma and the deep fascia, and the sub- 

 maxillary gland is drawn upwards, when the intermediate tendon of the digastric is brought 

 into view, together with portions of its two bellies, and the lower end of the stylo-hyoid 

 muscle. Crossing the angle formed by the two bellies of the digastric the hypoglossal nerve 

 is seen, accompanied by the ranine vein and passing forwards beneath the hinder border of 

 the mylo-hyoid ; and some fibres of the last muscle may be cut if necessary. By then dividing 

 carefully the hyo-glossus muscle in the interval bstween the hypoglossal nerve and the tendon 

 of the digastric the lingual artery is exposed and maybe secured. The facial vein is 'fre- 

 quently seen in the posterior angle of the wound, and may be injured if ths primary incision 

 is made too freely. ' 



3. Facial artery (iv). The facial artery (external maxillary), taking origin a 

 little above the lingual, is at first directed upwards, beneath the digastric and stylo- 

 hyoid muscles, and enters the hinder part of the submaxillary triangle ; it then runs 

 horizontally forwards under cover of the base of the lower jaw, resting on the 

 mylo-hyoid muscle, and being lodged in a groove on the deep surface of the sub- 

 maxillary gland. Emerging from beneath the gland, it turns sharply upwards and 

 crosses the base of the jaw immediately in front of the masseter, being covered 

 only by the platysma and the integuments : here the pulsation of the artery is 

 easily felt, and the circulation through it may be controlled by pressure against the 

 bone ; at this point also th3 vessel may be readily ligatured. 



On the side of the face the artery ascends obliquely, passing near the angle of 

 the mouth and by the side of the nose, to the inner canthus of the eye, where it 

 ends by inosculating with the nasal branch of the ophthilmic artery. In this part 

 of its course the artery is exceedingly tortuous, a circumstance connected with the 

 great mobility of the parts on which it rests. It is crossed by the risorius and the 

 zygomaticus major muscles ; it lies upon the buccinator, the levator anguli oris 



