978 NEUROLOGY 



The communication with the tympanic branch of the glossopharyngeal nerve is 

 effected by the caroticotympanic, which may consist of two or three delicate 

 filaments. 



The cavernous plexus (plexus cavernosus) is situated below and medial to that 

 part of the internal carotid artery which is placed by the side of 'the sella turcica 

 in the cavernous sinus, and is formed chiefly by the medial division of the internal 

 carotid nerve. It communicates with the oculomotor, the trochlear, the ophthalmic 

 and the abducent nerves, and with the ciliary ganglion, and distributes filaments to 

 the wall of the internal carotid artery. The branch of communication with the 

 oculomotor nerve joins that nerve at its point of division; the branch to the troch- 

 lear nerve joins it as it lies on the lateral wall of the cavernous sinus; other filaments 

 are connected with the under surface of the ophthalmic nerve; and a second fila- 

 ment joins the abducent nerve. 



The filaments of connection with the ciliary ganglion arise from the anterior part 

 of the cavernous plexus and enter the orbit through the superior orbital fissure; 

 they may join the nasociliary branch of the ophthalmic nerve, or be continued for- 

 ward as a separate branch. 



The terminal filaments from the internal carotid and cavernous plexuses are 

 prolonged as plexuses around the anterior and middle cerebral arteries and the 

 ophthalmic artery; along the former vessels, they may be traced to the pia mater; 

 along the latter, into the orbit, where they accompany each of the branches of the 

 vessel. The filaments prolonged on to the anterior communicating artery connect 

 the sympathetic nerves of the right and left sides. 



THE CERVICAL PORTION OF THE SYMPATHETIC SYSTEM (PARS 

 CERVICALIS S. SYMPATHICI). 



The cervical portion of the sympathetic trunk consists of three ganglia, distin- 

 guished, according to their positions, as the superior, middle, and inferior ganglia, 

 connected by intervening cords. This portion receives -no white rami communi- 

 cantes from the cervical spinal nerves; its spinal fibers are derived from the white 

 rami of the upper thoracic nerves, and enter the corresponding thoracic ganglia 

 of the sympathetic trunk, through which they ascend into the neck. 



The superior cervical ganglion (ganglion cervicale superius), the largest of the 

 three, is placed opposite the second and third cervical vertebrae. It is of a reddish- 

 gray color, and usually fusiform in shape ; sometimes broad and flattened, and occa- 

 sionally constricted at intervals; it is believed to be formed by the coalescence 

 of four ganglia, corresponding to the upper four cervical nerves. It is in relation, 

 in front, with the sheath of the internal carotid artery and internal jugular vein; 

 behind, with the Longus capitis muscle. 



Its branches may be divided into inferior, lateral, medial, and anterior. 



The Inferior Branch communicates with the middle cervical ganglion. 



The Lateral Branches (external branches') consist of gray rami communicantes to 

 the upper four cervical nerves and to certain of the cranial nerves. Sometimes the 

 branch to the fourth cervical nerve may come from the trunk connecting the 

 upper and middle cervical ganglia. The branches to the cranial nerves consist 

 of delicate filaments, which run to the ganglion nodosum of the vagus, and to the 

 hypoglossal nerve. A filament, the jugular nerve, passes upward to the base of 

 the skull, and divides to join the petrous ganglion of the glossopharyngeal, and the 

 jugular ganglion of the vagus. 



The Medial Branches (internal branches') are peripheral, and are the larnygo- 

 pharyngeal branches and the superior cardiac nerve. 



The laryngopharyngeal branches (rami laryngopharyngei) pass to the side of the 



