io SURGICAL APPLIED ANATOMY. [Chap, i 



anterior branch, are often very tortuous in the aged, 

 and afford early evidence of arterial degeneration. 

 Arteriotomy is sometimes practised on the anterior 

 branch of this vessel. The superficial temporal vessels 

 are very liable to be the seat of cirsoid aneurism, as, 

 to a less extent, are the other scalp arteries. Cirsoid 

 aneurism is more often met with in the superficial 

 temporal arteries than in any other artery in the 

 body. The posterior auricular artery and nerve 

 run in the groove between the mastoid process and 

 the ear, and the occipital artery and great occipital 

 nerve reach the scalp just internal to a point midway 

 between the occipital protuberance arid the mastoid 

 process. 



Certain of the emissary veins are of great im- 

 portance in surgery. These veins pass through aper- 

 tures in the cranial wall, and establish communications 

 between the venous circulation (the sinuses) within 

 the skull and the superficial veins external to it. 

 The principal emissary veins are the following : 1. 

 A vein passing through the mastoid foramen and con- 

 necting the lateral sinus with the posterior auricular 

 vein or with an occipital vein. This is the largest and 

 most constant of the series. The existence of this 

 mastoid vein serves to give an answer to the question, 

 Why is it a common practice to apply leeches and 

 blisters behind the ear in certain cerebral affections 1 

 2. A vein connecting the superior longitudinal sinus 

 with the veins of the scalp through the parietal 

 foramen. 3. A vein connecting the lateral sinus with 

 the deep veins at the back of the neck through the 

 posterior coiidylar foramen (inconstant). 4. Minute 

 veins following the ninth nerve through its foramen, 

 and connecting the occipital sinus with the deep veins 

 of the neck. 5. Minute veins passing through the 

 foramen ovale, foramen lacerum and carotid canal to 

 connect the cavernous sinus with (respectively) the 



