THE INTERNAL JUGULAR VEIN. 629 



Nerves. The pneumo-gastric is contained in the sheath at the of nerves, 

 back between the artery and vein, being parallel to them ; and the 

 .sympathetic, also running longitudinally, lies behind the sheath of 

 the vessels. Crossing the artery superficially, from below upwards, 

 are the hypoglossal, which sends its descending branch downwards 

 along the vessel ; next the pharyngeal branch of the vagus ; and lastly 

 the glosso-pharyngeal. Directed inwards beneath the carotid are the 

 pharyngeal offsets of the upper ganglion of the sympathetic and the 

 aiperior laryngeal nerve, the latter furnishing the external laryngeal 

 branch. Close to the skull, the cranial nerves of the neck are inter- 

 posed between the artery and the vein. Around the carotid entwine 

 branches of the sympathetic and offsets of the glosso-pharyngeal nerve. 



The cervical portion of the artery remains much the same in size 

 to the end, though it is sometimes very tortuous ; and it usually 

 does not furnish any branch. 



The PART IN THE TEMPORAL BONE is described on page 682. 



The INTERNAL JUGULAR VEIN is continuous with the lateral sinus internal 

 >f the skull, and extends from the jugular foramen nearly to the first {"fn 

 rib. Behind the inner end of the clavicle it joins the subclavian to joins sub- 

 form the innominate vein. 



As far as the thyroid cartilage the vein accompanies the internal is outside 

 carotid, but below that point it is the companion to the common ca 

 -.arotid artery ; and it lies on the outer side of each. Its contiguity 

 to the artery is not equally close throughout, for near the skull there 

 is a small interval between them, containing the cranial nerves ; 

 and at the lower part of the neck there is a larger intervening space, 

 in which the pneumo-gastric nerve, with its cardiac branch, is found. 



The size of the vein remains much the same from the skull to the enlarged 

 hyoid bone, where it is suddenly increased owing to the junction of 

 a number of tributaries corresponding to branches of the external 

 carotid artery. Its lower dilatation and its valve have been before 

 referred to (p. 601). 



The following tribwtafies open into the internal jugular, viz., the branches 

 inferior petrosal sinus close below the skull, the pharyngeal, lingual, 

 facial and superior thyroid veins near the hyoid bone, and the 

 middle thyroid vein opposite the lower part of the larynx. 



The ASCENDING PHARYNGEAL ARTERY (fig. 225, (/) is a long slender Ascending 



branch of the external carotid, which arises near the beginning of ar 

 that vessel. It runs upwards between the internal carotid artery 

 and the pharynx to near the base of the skull, where it ends in ends at 

 pharyngeal and meningeal branches. Its offsets are numerous, but sku11 : 

 small : 



a. Prevertebral branches pass to the longus colli and recti antici branches 

 muscles, supplying also the nerves and lymphatic glands of this SbSi vei 

 region. 



b. Pharyngeal branches supply the wall of the pharynx, the soft pharyngeal, 

 palate and the tonsil. The highest of these, one of the terminal 

 branches of the artery, ramifies in the superior constrictor, the 

 Eustachian tube, and the levator and tensor palati muscles : this 



