OCCIPITAL. 453 



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 cases of hemorrhage from the 

 lips, the result either of an accidental wound, or from an operation ; but its application 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 involving 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 a tenaculum. In order to prevent hemorrhage in cases of excision, or in the removal of 

 diseased growths from the part, the lip should be compressed on each side between the finger 

 and thumb, whilst the surgeon excises the diseased part. In order to stop hemorrhage 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 

 hemorrhage 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, hemorrhage 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 lachrymalis, the sac should always 

 be opened on its outer side, in order that this vessel may be avoided. 



The Occipital Artery (Fig. 276) arises from the posterior part of the external 

 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 part of the parotid gland, the hypoglossal nerve winding around 

 it from behind forwards ; higher up, it passes across the internal carotid artery, 

 the internal jugular vein, and the pneumogastric 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 backwards, 

 grooving the surface of the latter bone, being covered by the Sterno-mastoid, 

 Splenius, Digastric, and Trachelo-mastoid muscles, and resting upon the Corn- 

 plexus, Superior Oblique, and Rectus Posticus Major muscles ; it then ascends 

 vertically upwards, piercing the cranial attachment of the Trapezius, and passes 

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

 into numerous branches. 



The branches given off from this vessel are, 



Muscular. Inferior Meningeal. 



Auricular. Arteria Princeps Cervicis. 



The muscular branches supply the Digastric, Stylo-hyoid, Sterno-mastoid, 

 Splenius, and Trachelo-mastoid muscles. The branch distributed to the Sterno- 

 mastoid is of large size. 



The auricular branch supplies the back part of the concha. 



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 

 posterior fossa. 



The arteria princeps cervicis (Fig. 279) is a large branch which descends along 

 the back part of the neck, and divides into a superficial and deep branch. The 

 former runs beneath the Splenius, giving off branches which perforate that 

 muscle to supply the Trapezius, anastomosing with the superficial cervical 

 artery : the latter passes beneath the Complexus, between it and the Semispi- 

 nalis Colli, and anastomoses with the vertebral, and deep cervical branch of the 

 superior intercostal. The anastomosis between these vessels serves mainly to 

 establish the collateral circulation after ligature of the carotid or subclavian 

 artery. 



The cranial branches of the occipital artery are distributed upon the occiput; 

 they are very tortuous, and lie between the integument and Occipito-frontalis, 

 anastomosing with the artery of the opposite side, the posterior auricular, and 

 temporal arteries. They supply the back part of the Occipito-frontalis muscle, 

 the integument and pericranium, and one or two branches occasionally pass 

 through the parietal or mastoid foramina, to supply the dura mater. 



