AUKICULAR AND TEMPORAL ARTERIES. 367 



Varieties. — Origin. — The occipital artery is occasionally derived from the 

 internal carotid, and from the ascending cervical branch of the inferior thyi-oid 

 — an offset of the subclavian artery. 



Courgc. — The occipital artery sometimes passes outside the trachelo-mastoid 

 instead of internal to it. The chief portion of. the vessel was found, in one in- 

 stance, to pass over the stemo-mastoid muscle, only a small artery being placed 

 in the usual position. The artery has, in a few instances, been seen to turn 

 backwards below the transverse process of the atlas. 



Branclu:\\ — The posterior amicular and the pharyngeal eateries sometimes take 

 origin from the occipital. 



5. Posterior Auricular Artery. — The ]50sterior auricular artery, 

 a small vessel, arises from the external carotid a little higher up than 

 the occipital. It ascends under cover of the parotid gland, and resting 

 on the styloid process of the temporal bone, readies the angle formed 

 by the cartilage of the ear with the mastoid process. It is crossed by 

 the portio dura of the seventh nerve. Somewhat above the mastoid 

 portion of the temporal bone it divides into two sets of branches, of 

 which one set inclines forwards to anastomose with the posterior branch 

 of the temporal artery, and the other backwards towards the occiput, 

 on which it communicates with the occipital artery. 



Brandies. — The following are the branches of this artery : — 



(a) Small branches to the parotid gland and the digastric muscle. 



(J)) The xtijip-majiio'ul branch. This twig enters the foramen of the same name 

 in the temporal bone ; on reaching the tympanum, it di\'ides into delicate vessels, 

 which pass, some to the mastoid cells, others to the labj-rinth. One branch is 

 constantly found in j'oung bodies to form, with the tjonpanic branch of the 

 internal maxillary artery which enters the fissure of Glaser. a vascular cii-cle 

 around the auditory meatus, from which delicate oifsets ramify upon the mem- 

 brana tympani. This small tympanic branch sometimes arises from the occipital 

 artery. 



(c) Am'lcular branches. — As it passes the back of the ear, the auricular artery 

 gives one or two branches which supply the posterior surface of the concha, and 

 turn over the margin, or perforp - the substance of the auricle to gain the ante- 

 rior surface. 



Varieties. — The posterior auricular artery is frequently very smaU, and has 

 been seen to end in the stylo-mastoid branch. It is often a branch of the 

 occipital. 



6. Temporal Artery. — The temporal artery, one of the two 



branches into which the external carotid artery finally divides a little 

 below the condyle of the lower jaw, continues upwards in the direction 

 of the main trunk, whilst the other branch (the internal maxillary) 

 curves forwards under cover of the jaw. The temporal artery is at 

 first imbedded in the substance of the parotid gland, in the interval 

 between the meatus of the ear and the condyle of the lower jaw. 

 Thence it ascends over the root of the zygoma, against which it may 

 readily be compressed. From this point onwards, it lies close beneath 

 the skin, upon the temporal fascia ; and, about two inches above the 

 zygoma, divides into two branches, which again subdivide and ramify 

 beneath the integument on tlie side and upper part of the head. 



Branches. — Besides several small offsets to the parotid gland, some branches 

 to the articulation of the lower jaw, and one or two to the masseter muscle, the 

 temporal artery gives off the following branches : 



(rt) The transvcnr artery of the face. This branch arises whilst the temporal 



