THE NECK, ANTERIOR. 103 



The Pneumog-astric Nerve. Figs. 10, n, 17, 18. 



This leaves the interior of the skull through the jugular 

 foramen, lying in the central compartment of the same with 

 the ninth and eleventh nerves, passes straight downward 

 behind and between the internal jugular vein and the inter- 

 nal carotid artery, then between the same vein and the 

 common carotid, resting upon the fascia covering the rec- 

 tus capitis anticus major, and longus colli muscles. 



At the base of the neck the right nerve crosses over the 

 front of the subclavian artery and lies between it and the 

 innominate vein. 



On the left side it lies between and behind the subclavian 

 and common carotid arteries. 



For its course and relations in the chest see page 342. 



Just below the skull will be found the enlargement of the 

 pneumogastric called the ganglion of the trunk. To this 

 the hypoglossal nerve is firmly united by connective tissue. 



Branches of the Pneumogastric. The pneumogastric re- 

 ceives branches from the spinal accessory, hypoglossal, 

 superior cervical sympathetic ganglion, and the loop be- 

 tween the two upper cervical nerves. These branches 

 enter the ganglion of the trunk. 



The pneumogastric gives off minute branches to the 

 glossopharyngeal, spinal accessory, hypoglossal, and two 

 upper cervical nerves. 



The branches of distribution, in the neck. 



(a) 'The pharyngeal : May be one or more ; come origi- 

 nally from the spinal accessory branch of communication. 

 They form, with branches from the sympathetic and glosso- 

 pharyngeal, the pharyngeal plexus, from which branches 

 are given to the muscles and mucous membrane of the 

 pharynx. 



(fr) The superior laryngeal : Arises from the lower part 



