12 SURGICAL APPLIED ANATOMY. [Chap. i. 



frontal artery and supratrochlear nerve ascend. This 

 artery gives life to the flap that in rhinoplasty is 

 taken from the forehead to form a new nose. The tem- 

 poral artery, with the auriculo-temporal nerve behind 

 it, crosses the base of the zygoma just in front of 

 the ear. The vessel divides into its two terminal 

 branches (the anterior and posterior) two inches 

 above the zygoma. The branches of this artery, 

 especially the anterior branch, are often veiy 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 

 and the mastoid process. 



Certain of the emissary veins are of great 

 importance in surgery. These veins pass through 

 apertures in the cranial wall, and establish communi- 

 cations 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 

 connecting the lateral sinus with the posterior auri- 

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

 and most constant of the series. The existence of 

 this mastoid vein serves to answer the question, 

 Why is it a common practice to apply leeches and 

 blisters behind the ear in certain cerebral affections ? 



2. A vein connecting the superior longitudinal sinus 

 with the veins of the scalp through the parietal 



