THE CRANIAL OR ENCEPHALIC NERVES 835 



appear to pass to its surface without becoming confounded with it. It is in 

 relation, in front, with the ganglion of Andersch ; behind, it crosses somewhat 

 obliquely the medullary root of the spinal accessory nerve. 



The jugular gangUon is also in relation with the spinal, glosso-pharyngeal, 

 and facial nerve. It communicates with the external root of the spinal accessory 

 nerve by the few radicular filaments indicated above. With the glosso-pharyn- 

 geal it IS connected by : 1. An afferent filament coming from the highest roots 

 of the ninth pair, and which meets it at its antero-internal angle. 2. By an 

 efferent branch it sends to the ganglion of Andersch. 3. Lastly, it is united to 

 the facial by a branch we have named the anastomosing branchy extending from 

 the pneumo gastric to the facial nerve. 



This anastomotic branch, on leaving the jugular ganglion, is somewhat con- 

 siderable in volume, and it has appeared to us that, at times, among its radicles 

 there were some in direct continuity with the sensitive roots of the pneumogastric 

 nerve. This branch is directed forward, above the ganglion of Andersch, crosses 

 Jacobson's branch, traverses the petrous temporal bone, and arrives in the 

 aqueduct of Fallopius ; here it meets the facial nerve, at the point where the 

 latter gives off the chorda tympani. A small number of fibres then lie beside the 

 nerve of the seventh pair in ascending towards the origin of that nerve, where, 

 in our opinion, they constitute a large portion of the great petrosal nerve— that 

 which has at its origin the ganghon. Other fibres descend, on the contrary, in 

 following the proper fibres of the facial nerve, and are lost among these ; but the 

 largest number cross that nerve and continue their course in the substance of 

 the temporalis muscle, to be chiefly distributed to the membrane lining the 

 internal auditory canal. 



Course and relations. — Beyond the jugular ganglion, the trunk of the 

 pneumogastric remains intimately allied with the spinal accessory for about f 

 of an inch ; these two nerves then separate to allow the great hypoglossal nerve 

 to pass between them ; after which the pneumogastric nerve descends alone 

 behind the guttural pouish, in proximity to the superior cervical ganglion. 



Near the origin of the occipital artery it crosses to the inner side of that 

 vessel, and beyond this it is joined in the most intimate manner to the cervical 

 portion of the sympathetic chain ; the single cord resulting from this fusion 

 follows the common carotid artery, above which it is situated, to near the entrance 

 of the thorax. The two nerves then resume their reciprocal independence, the 

 pneumogastric penetrating the thorax a little below the sympathetic, in passing 

 among the lymphatic glands lying between the two first ribs. 



In this course, the two pneumogastrics have nearly the same relations ; though 

 there is something special connected with the left, which is related to the 

 cesophagus towards the lower part of the neck. 



Within the chest, however, these two nerves comport themselves a little 

 differently. The right passes round the axillary artery very obliquely, upwards, 

 outwards, and backwards beneath the mediastinal pleura, to follow the external 

 face of the trachea to above the origin of the bronchi, where this nerve termi- 

 nates. The left also passes below the brachial trunk ; but instead of turning 

 round the trachea, it merely lies beside that tube, and reaches the root of the 

 lung, after crossing, outwardly, the origin of the two aortae. 



When these nerves arrive above the bifurcation of the trachea, they terminate 

 by forming the bronchial plexus and cesophogeal nerves — the latter being prolonged 

 to the stomach and the solar plexus. 



