INTERNAL CAROTID ARTERY. 



291 



tributes a branch to the anterior palatine canal, which reaches the naies, 

 and inosculates with the branches of the spheno-palatine artery. 



The Vidian branch passes backwards along the pterygoid canal, and is 

 distributed to the sheath of the Vidian nerve, and to the Eustachian tube. 



INTERNAL CAROTID ARTERY. 



The internal carotid artery curves slightly outwards from the bifurcation 

 of the common carotid, and then ascends nearly perpendicularly through 

 the maxillo-pharyngeal space* to the carotid foramen in the petrous bone. 

 It next passes inwards* along the carotid canal, forwards by the side of 

 the sella turcica, and upwards by the anterior clinoid process, where it 

 pierces the dura mater, and divides into three terminal branches. The 

 course of this artery is remarkable for the number of angular curves which 

 it forms ; one or two of these flexures are sometimes seen in the cervical 

 portion of the vessel, near the base of the skull ; and by the side of the 

 sella turcica it resembles the italic letter s, placed horizontally. 



Relations. In consideration of its connexions, the artery is divisible 

 into a cervical, petrous, cavernous, and cerebral portion. The Cervical 

 portion is in relation posteriorly with the rectus anticus major, sympathetic 

 nerve, pharyngeal and laryngeal nerves, which cross behind it, and near 

 the carotid foramen with the glosso-pharyngeal, pneumogastric, and hypo- 

 glossal nerves, and partially with the internal jugular vein. Internally it 

 is in relation with the side of the pharynx, the tonsil, and the ascending 

 pharyngeal artery. Externally with the internal jugular vein, glosso- 

 pharyngeal, pneumogastric, and hypo-glossal nerves; and in front with 

 the stylo-glossus, and stylo-pharyngeus muscle, glosso-pharyngeal nerve, 

 and parotid gland. 



Plan of the Relations of the Cervical Portion of the Internal Carotid 



Jlrtery. 



In Front. 

 Parotid gland, 

 Stylo-glossus muscle, 

 Stylo-pharyngeus muscle, 

 Glosso-pharyngeal nerve. 



Behind. 



Superior cervical ganglion, 

 Pneumogastric nerve, 

 Glosso-pharyngeal nerve, 

 Pharyngeal nerve, 

 Superior laryngeal nerve, 

 Sympathetic nerve, 

 Rectus anticus major. 



The Petrous portion is separated from the bony wall of the carotin 

 canal by a lining of dura mater ; it is in relation with the carotid plexus, 

 and is covered in by the Casserian ganglion. 



* For the boundaries of this space see page 188. 



