OCCIPITAL ARTERY. 351 



ment of the nasal branches of the ophthalmic at the inner side of the orbit ; occa- 

 sionally by branches from the transverse facial or internal maxillary arteries. 



Branches. The ascending palatine artery is in some instances transferred to the 

 external carotid. This branch varies in size and the extent to which it reaches. Not 

 unfrequently it is expended without furnishing any branch to the soft palate. When 

 it is thus reduced in size, the pharyngeal artery takes its place on the soft palate. 



The tonsillar branch is not unfrequently altogether wanting. 



The submental branch has been observed to take its rise from the lingual artery. 

 On the other hand, the facial artery, instead of the lingual, has been found to furnish 

 the branch which supplies the sublingual gland. 



IV. OCCIPITAL ARTERY. 



The occipital artery, arising from the posterior part of the external carotid, 

 usually opposite the facial or a little higher up, is directed upwards and 

 backwards, beneath the posterior belly of the digastric muscle, to the 

 interval between the transverse process of the atlas and the mastoid process 

 of the temporal bone. From that point it turns horizontally backwards 

 along the skull in the occipital groove of the temporal bone, internal to the 

 mastoid process and the sterno-mastoid, splenius, digastric, and trachelo- 

 mastoid muscles, and resting on the superior oblique and complexus muscles. 

 Lastly, changing its direction a second time, and piercing the cranial attach- 

 ment of the trapezius, it ascends beneath the integument on the back of the 

 head accompanied by the great occipital nerve, and divides into numerous 

 branches upon the upper and back part of the cranium. While in the neck, 

 the occipital artery crosses over the internal carotid artery, the vagus and 

 spinal accessory nerves, and the internal jugular vein ; and the hypoglossal 

 nerve turns from behind over it at its origin. 



BRANCHES. The following branches are given from the occipital artery : 



(a) Small muscular offsets to the digastric and stylo-hyoid muscles, and one of 

 larger size to the sterno-mastoid. This last is so regular a branch that it is known as 

 the sterno-mastoid branch. 



(b) An auricular branch to the back part of the concha of the ear, and two or three 

 other muscular branches to the splenius and trachelo-mastoid. 



(c) The meninneal branch. This runs up with the internal jugular vein, enters the 

 skull through the foramen jugulare, and ramifies in the dura mater of the posterior 

 fossa of the base of the skull. 



(d) The cervical branch (rainus cervicalis princeps}. To the upper and back part of 

 the neck the occipital artery furnishes a branch thus designated. Descending a 

 short way, this vessel divides into a superficial and a deep branch. The former 

 ramifies beneath the splenius, sending offsets through that muscle to the trapezius ; 

 while the deep branch passes beneath the complexus, and anastomoses with branches 

 of the vertebral artery, and with the deep cervical artery. The size of this branch 

 varies very much. 



(e) The superficial or cranial branches. These pursue a tortuous course between 

 the integument and the occipito-frontalis muscle ; and in proceeding upwards on the 

 skull they separate into diverging branches, which communicate with the branches 

 of the opposite artery, as well as with those of the posterior auricular artery, and of 

 the temporal artery at the vertex and side of the skull. 



A small twig, the mastoid branch, enters the skull through the mastoid foramen, 

 and ramifies in the dura mater. 



PECULIARITIES. Origin. The occipital artery is occasionally derived from the 

 internal carotid, and from the ascending cervical branch of the inferior thyroid an 

 offset of the subclavian artery. 



Course. The occipital artery sometimes passes outside the trachelo-mastoid muscle, 

 instead of internally to it. The chief portion of the vessel was found, in one instance, to 

 pass over the sterno-mastoid muscle, only a small artery being placed in the usual 



