THE FACIAL ARTERY. 737 



the facial vein may be cut. The remainder of the operation may be described as if 

 it were done in four stages. i. That portion of the deep fascia constituting the 

 anterior layer of the capsule of the submaxillary gland is divided in the line of the 

 incision, the lower edge of the gland exposed, and the gland itself cleared and ele- 

 vated over the lower jaw, with due care to avoid injury to the facial artery which 

 passes through its substance and the facial vein which runs upon its surface. 2. 

 The thin posterior leaf of the capsule of the gland being divided, the white, shining 

 aponeurotic loop attaching the digastric tendon to the greater cornu of the hyoid 

 will be seen. The tendon near the bone or the digastric aponeurosis should be fixed 

 by a blunt hook or tenaculum and drawn downward and towards the surface. 3. 

 After the division of the posterior layer of the capsule of the submaxillary gland, the 

 posterior edge of the mylo-hyoid muscle, the fibres running upward and slightly 

 backward, can be recognized at the anterior angle of the wound and should be 

 clearly defined. 4. The hypoglossal nerve separates from the artery at the poste- 

 rior border of the hyo-glossus muscle, where the vessel disappears to run between 

 that muscle and the middle constrictor. The nerve, accompanied by the ranine 

 vein, runs almost horizontally across the surface of the hyo-glossus, and in its turn 

 disappears under the edge, of the mylo-hyoid muscle. It will have been brought 

 into view when the submaxillary gland has been raised, the posterior layer of its 

 capsule divided, and a little fatty connective tissue picked away. In the irregular 

 triangle formed by the nerve above, the mylo-hyoid anteriorly, and the posterior 

 belly and tendon of the digastric posteriorly, the lingual artery runs beneath the 

 hyo-glossus muscle and near the apex of the triangle — /. e. , near the hyoid bone. 

 The nerve and vein, which are on a slightly higher level — a few millimetres — 

 having been raised and the fibres of the hyo-glossus divided parallel with the hyoid 

 and just above it, the artery will be brought into view. 



In ligation of the lingual for carcinoma of the tongue, the state of the salivary 

 gland, which varies in size, in density, and in the closeness of its attachments, is the 

 main element of uncertainty (Treves). 



3. The Facial Artery. — The facial artery (a. raaxillaris externa) (Fig. 691) 

 arises usually a short distance above the lingual, from the anterior surface of the 

 external carotid. It passes at first forward and slightly upward, lying beneath the 

 posterior belly of the digastric and the stylo-hyoid muscles and the hypoglossal nerve, 

 and is then continued almost horizontally forward in a groove in the submaxillary 

 gland. When it reaches the level of the anterior border of the masseter muscle, it 

 assumes a vertical direction and passes over the ramus of the mandible, and is then 

 continued in a sinuous course obliquely across the face towards the naso-labial angle, 

 resting upon the buccinator and levator anguli oris muscles, and being crossed by the 

 risorius and zygomatic muscles and by some branches of the facial nerve. Arrived at 

 the naso-labial angle, it again takes an almost vertical course, passing upward beneath 

 (or sometimes over) the levator labii superioris and the levator labii superioris alaeque 

 nasi towards the inner angle of the orbit, where it terminates by anastomosing with 

 the nasal branch of the ophthalmic artery. This terminal vertical portion of the 

 vessel is usually termed the angular artery (a. angularis). 



Branches.— The branches of the facial artery ( Fi,a:s. 691, 693) may be arranged in two 

 groups according to their origin from the cervical or facial portions of the artery. 



From the cervical portion arise : (a) The ascending palatine branch (a. palatina ascen- 

 dens), a small artery which passes upward between the stylo-giossus and stylo-pharyngeus mus- 

 cles, to which it sends branches, and then comes to lie upon the outer surface of the superior 

 constrictor of the pharynx. It terminates by sending branches to the soft palate, the tonsil, 

 and the Eustachian tube. 



{b) The tonsillar branch (ramus tonsillaris) is another small branch which passes verti- 

 cally upward. It arises close to the ascending palatine and, passing over the stylo-glossus 

 muscle, pierces the superior constrictor of the pharynx to be distributed to the tonsil. 



((t) The glandular branches (rami glandulares), two or three in number, are distributed to 

 the submaxillary gland. 



frf) The submental branch (a. submentalis) arises just before the artery bends upward 

 over the mandible, and continues onward in the horizontal course followed by the facial, 



47 



