NERVES 157 



ganglia of sympathetic, forming the posterior pulmonary 

 plexus. 



CEsophageal : to oesophagus, forming a plexus (plexus gulae) 



Gastric : the right nerve is distributed to posterior part of 

 stomach, and ends in the solar, splenic and left renal plexuses. 

 The left supplies the anterior surface and ends in the left 

 hepatic plexus. 



THE IITH or SPINAL ACCESSORY NERVE. Origin Super- 

 ficial: the accessory part from the lateral tract below vagus, 

 the spinal part from the side of the cord as low down as the 

 5th cervical nerve. Deep : anterior horn of grey matter of 

 medulla, and of cord as low as 5th cervical nerve. 



Course. The accessory part passes out of the jugular foramen 

 close to the pneumogastric, and sends one or two branches to 

 the ganglion of the root. It does not blend with the ganglion 

 of the trunk, but joins vagus below. The principal part joins 

 pharyngeal and superior laryngeal branches, but offsets are 

 sent to the cardiac and inferior laryngeal branches. The 

 spinal part enters skull through foramen magnum and passes 

 to jugular foramen ; it is enclosed in the same sheath of dura 

 mater as the vagus. Issuing from the foramen, it passes down- 

 wards between internal carotid artery and internal jugular 

 vein, and then backwards superficial to the internal jugular 

 vein to upper part of sterno-mastoid, which it pierces, at the 

 same time communicating with the branch to the muscle 

 from the cervical plexus. Crossing the occipital part of the 

 posterior triangle, it enters the under surface of the trapezius, 

 where it joins with branches of the 3rd and 4th cervical 

 nerves to form a plexus in the substance of the muscle. 



Distribution. Supplies sterno-mastoid and trapezius muscles. 



THE I2TH or HYPOGLOSSAL NERVE. Origin Superficial: 

 by ten or twelve filaments, from the groove between the 

 olivary body and anterior pyramid. Deep: nucleus beneath 

 trigonum hypoglossi in floor of 4th ventricle. 



Course. The nerve passes in two bundles through anterior 

 7ondyloid foramen, then downwards and forwards between 

 vagus and spinal accessory, between internal carotid artery 

 and internal jugular vein to the lower border of the digastric 

 muscle ; curving round the occipital artery, it crosses the 

 external carotid and lingual arteries, and passing between 

 the mylo-hyoid and hyo-glossus muscles, ends by dividing 

 into branches on the genio-hyo-glossus. 



Branches : 



Communicating. To the ganglion of the trunk of pneumo 

 gastric 



