NERVES 177 



then goes either behind or in front of the subclavian artery, 

 and, coursing along the innominate, ends in the deep cardiac 

 plexus behind the arch of the aorta. In the middle of the 

 neck it communicates with the external laryngeal, lower down 

 with the upper cardiac branches of the pneumogastric, in the 

 thorax with the recurrent laryngeal, and with other sympa- 

 thetic branches in its whole course. 



The left upper cardiac nerve has the same connections in the 

 neck as the right nerve. On entering the thorax, it passes 

 along left common carotid artery, and, crossing the arch of 

 the aorta, joins the superficial cardiac plexus. 



Branches to Vessels. Branches are given to the external 

 carotid artery, which are prolonged to its branches. 



Ascending or carotid branch lies behind internal carotid 

 artery, enters carotid canal, and divides into: 



(a) External division : distributed to internal carotid ; 



communicates with tympanic branch of glosso- 

 pharyngeal, and forms the carotid plexus. 



(b) Internal division : distributed over internal carotid 



artery, thus communicating with the external 

 division, and prolonged to form the cavernous 

 plexus. 



The carotid plexus lies on the outer side of the internal 

 carotid artery at its 2nd bend. 



Branches : 



Connecting : to the 6th nerve and Gasserian ganglion. 



The large deep petrosal nerve passes from the plexus through 

 the hiatus Fallopii, to join the large superficial petrosal nerve 

 at the Vidian canal, the junction of the two forming the 

 Vidian nerve. 



The small deep petrosal nerve passes backwards in a small canal 

 in the processus cochleariformis, to join the tympanic plexus. 



The cavernous plexus lies below and to the inner side of 

 last bend of the internal carotid artery. 



Branches : 



Connecting : to the 3rd, 4th, and ophthalmic division of 5th 

 nerve. 



Ganghonic : the sympathetic root of the ophthalmic or lenti- 

 cular ganglion passes into the orbit. It is generally joined to 

 the branch of the 3rd nerve supplying the inferior oblique. 



Pituitary : to that body. 



2. The MIDDLE CERVICAL GANGLION generally lies on the 

 inferior thyroid artery, opposite the 6th cervical vertebra. 



Branches : 



Connecting : to the 5th and 6th cervical nerves. 



Thyroid: to the thyroid body, communicating with external 



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