ABTERIES. :." 



parotionofthfatierietofHu luml. After carefully removing the skin, direct the 



lii-ial artei ii> t' one side thut is. tin- external inaxill;iry, iiuixilln-iiiiihcular, the 



temptnil trunk, and the posterior auricular arteries, excising the pu-ntM to ex]K>.se the 



cit' tin- three last-named vi >-ds. On tin- dpi tin- ili.p arieries are 



cl. an. t .i;-]....- ing of the hranch of tin- maxilla, as in tl.o preparation of the 



mii.-cles of the tongue; the orbitul and /ygonmtic pnxvssos being removed in three 



:s \vitli tin; saw, ad iu ligure '_'So. \\hich will serve aj> a guide in the dissection of 



all the.e an 



OCCIPITAL ARTERY. (Fig. 286, 6.) 



The occipital artery is a slightly flexuous vessel, lying beside the upper 

 third of the internal carotid. It ascends beneath the transverse process 

 of the atlas in passing behind the guttural pouch, between the maxillary 

 gland and the straight anterior muscles of the head. It then insinuates 

 itself between the small lateral straight muscle and the inferior arch of the 

 above vertebra, to pass through its anterior foramen, and terminate by two 

 branches, after coursing along the short fissure which unites this foramen 

 with the superior. In its track, this artery is crossed, outwardly, by the 

 pncumogastric and spinal nerves, and the occipital nerve of the great sym- 

 pathetic, and is accompanied by the divisions of the inferior branch of the 

 first pair of cervical nerves. 



The two terminal branches of the vessel are the occipito-muscular and 

 cerebro-spiii"! art* ries. 



The collateral branches are three in number, and in the order of their 

 emission are named: 1, The prevertebral artery; 2, The mastoid artery; 3, 

 The atloido muscular artery. 



COLLATERAL BRANCHES. 1. PREVERTEBRAL ARTERY (Fig. 286, 9). The 

 smallest of all the branches emanating from the occipital, this artery is 

 detached at a very acute angle, and. immediately divides into several 

 lilaments, some muscular, the others meningeal. The majority of the first 

 pass between the occipito-atloid articulation and the small anterior reetns 

 muscle of the head, and expend themselves either in that muscle, or the 

 great rectus ; the second, generally two in number, are always very slender, 

 and reach the dura mater by entering, one through the posterior foramen 

 lae. rum, the other by the coudyloid foramen. 



_'. MASTOID ARTERY (Fig. 286, "6). This vessel arises at an acut<- 

 angle above the preceding, and goes towards the mastoid foramen by 

 creeping on the external surface of the styloid process of the occipital bone, 

 beneath the small oblique muscle of the head. It enters the parieto- 

 tcmporal canal by this foramen, to anastomose by inosculation with tin; 

 spin iu)-spinous artery. 



In its course it describes a curve downwards, and throws off a large 

 nunilHjr of collateral branches. Among tlie.-e. are some which originate 

 re the artery enters its bony canal, and which are destined for tho 

 muscles of the nape of the neck. Others arise in the interior of this canal, 

 aiil escape from it by the orifices that cribble the temporal fossa, to expend 

 tin msclves in the temporal muscle. Some rannmculea reach the dura mater. 



We have seen tho mastoid artery ariso directly from tho common 

 eamtid, and furnish a parotideal branch. 



3. ATLOIDO-MUSCULAR OB RETROGRADE AUTERT (Fig. 286, 7^. Thin 

 liraneh is n>rt cMiistant.aiid when i; it presents a variable volume. It 



is iletai-ln-il t'n.ni tho occipital, 111 Ynieath the transverse process of the | 



rming with tho parent branch a right, or even an obtuse angle : it is 

 directed backward**, traverses the inferior foramen of the process of the 



2 i 



