BRANCHES OF THE EXTERNAL CAROTID. 493 



foramen, with the transverse facial, a branch of the temporal ; with the infra-orbital, 

 a branch of the internal maxillary, and with the nasal branch of the ophthalmic. 



Peculiarities. The facial artery not unfrequently arises by a common trunk with the 

 lingual. This vessel is also subject to some variations in its size and in the extent to which it 

 supplies the face. It occasionally terminates as the submental, and not unfrequently supplies 

 the face only as high as the angle of the mouth or nose. The deficiency is then supplied by 

 enlargement of one of the neighboring arteries. 



Surgical Anatomy. The passage of the facial artery over the body of the jaw would 

 appear to afford a favorable position for the application of pressure in case of haemorrhage 

 from the lips, the result either of an accidental wound or during an operation ; but its applica- 

 tion is useless, except for a very short time, on account of the free communication of this 

 vessel with its fellow and with numerous branches from different sources. In a wound involv- 

 ing the lip it is better to seize the part between the fingers, and evert it, when the bleeding 

 vessel may be at once secured with pressure -forceps. In order to prevent haemorrhage in cases 

 of removal of diseased growths from the part, the lip should be compressed on each side 

 between the fingers and thumb or by a pair of specially devised clamp-forceps, whilst the surgeon 

 excises the diseased part. In order to stop haemorrhage where the lip has been divided in an 

 operation, it is necessary, in uniting the edges of the wound, to pass the sutures through the 

 cut edges, almost as deep as its mucous surface ; by these means not only are the cut surfaces 

 more neatly and securely adapted to each other, but the possibility of haemorrhage is prevented 

 by including in the suture the divided artery. If the suture is, on the contrary, passed through 

 merely the cutaneous portion of the wound, haemorrhage occurs into the cavity of the mouth. 

 The student should, lastly, observe the relation of the angular artery to the lachrymal sac, and 

 it will be seen that* as the vessel passes up along the inner margin of the orbit, it ascends on 

 its nasal side. In operating for fistula laehrymalis the sac should always be opened on its outer 

 side, in order that this vessel may be avoided. 



The Occipital Artery (Figs. 285, 286) arises from the posterior part of the ex- 

 ternal carotid, opposite the facial, near the lower margin of the Digastric muscle. At 

 its origin it is covered by the posterior belly of the Digastric and Stylo-hyoid muscles, 

 and the hypoglossal nerve winds around it from behind forward ; higher up, it 

 passes across the internal carotid artery, the internal jugular vein, and the pneumo- 

 gastric and spinal accessory nerves ; it then ascends to the interval between the 

 transverse process of the atlas and the mastoid process of the temporal bone, and 

 passes horizontally backward, grooving the surface of the latter bone, being covered 

 by the Sterno-mastoid, Spleriius, Trachelo-mastoid, and Digastric muscles, and 

 resting upon the Rectus lateralis, the Superior oblique, and Complexus muscles ; 

 it then changes its course and passes vertically upward, pierces the fascia which 

 connects the cranial attachment of the Trapezius with the Sterno-mastoid, and 

 ascends in a tortuous course over the occiput, as high as the vertex, where it 

 divides into numerous branches. It is accompanied in the latter part of its course 

 by the great occipital, and occasionally by a cutaneous filament from the suboccip- 

 ital nerve. 



The branches given off from this vessel are 



Muscular. Auricular. 



Sterno-mastoid. Meningeal. 



Arteria Princeps Cervicis. 



The muscular branches supply the Digastric, Stylo-hyoid, Splenius, and 

 Trachelo-mastoid muscles. 



The sterno-mastoid is a large and constant branch, generally arising from the 

 artery close to its commencement, but sometimes springing directly from the 

 external carotid. It first passes downward and backward over the hypoglossal 

 nerve, and enters the substance of the muscle in company with the spinal acces- 

 sory nerve. 



The auricular branch supplies the back part of the concha. It frequently 

 gives off a branch, which enters the skull through the mastoid foramen and sup- 

 plies the dura mater, the diploe, and the mastoid cells. 



The meningeal branch ascends with the internal jugular vein, and enters the 

 skull through the foramen lacerum posterius, to supply the dura mater in the pos- 

 terior fossa. 



The arteria princeps cervicis (Fig. 289), the largest branch of the occipital, 

 descends along the back part of the neck and divides into a superficial and a deep 



