(b) Ascending or Carotid Branch. — This branch may be reg,arded as a prolongation up wards of the sympathetic cord. It is soft, and presents a more or less greyish-red aspect. On approaching the inferior orifice of the carotid canal in the temporal bone, it com monly divides into two branches which pass along the canal with the internal carotid artery, the one being situated rather to the inner, the other to the outer side of the vessel ; they form numerous intercommunica tions with each other, giving rise to what is termed the internal carotid plexus.
(c) Pharyngeal B ranches. —These, from three to six in number, leave the upper and inner margin of the ganglion, pass inwards and downwards, and unite with the pharyngeal branches of the glossopharyngeal and vagus nerves to form the pharyngeal plexus.
(d) _External lateral Branchcs.—These vary in number ; sometimes there are only two present ; at other times as many as six or eight. They have a greyish-red colour, and from the softness of their texture were termed by Scarpa nervi molles, from their being chiefly distributed to the blood vessels, they were nained by Scemmering vascular branches. They arise from the front of the ganglion, and pass downwards along the internal carotid artery to the point of division of the common carotid, where they give rise to the external carotid plexus. Some filaments also unite with the superior laryngeal nerve.
(e) Superior or long cardiac Nerve, named also the superficial cardiac branch, varies in thickness, and is sometimes absent. It arises from the anterior and lower portion of the superior cervical ganglion, sometimes from the intermediate cord between that and the middle cervical ganglion, and sometimes it derives filaments from both sources. It runs downwards upon the longus colli muscle and to the inner side of the sympathetic cord, and passes behind or in front of the inferior thyroid artery. In its course through the neck it forms communications with the ex ternal laryngeal and descendens noni nerves; it also communicates with the vagus and re current laryngeal nerves, and sometimes with the phrenic. Not unfrequently it is joined by the cardiac branches, which leave the rniddle and inferior cervical ganglion. It passes into the chest in front of or behind the subclavian artery, and along the arteria innominata, to terminate in the cardiac plexus. The nerve
of the left side, after entering the chest, runs along the left carotid artery to the arch of the aorta, passing sometimes in front and sometimes behind that vessel.
(f) Communicating cord between the su perior and middle cervical Ganglia.— The con necting cord between the superior and middle cervical ganglia is commonly single, but occa sionally consists of two distinct portions. It passes from the inferior extremity of the superior cervical ganglion, which sometimes seems to be prolonged downwards into it, along the surface of the rectus capitis antieus major muscle, behind the carotid artery', and rather to the inner side of the pneumogastric nerve, as far as the inferior thyroid artery. Before sinking into the middle cervical gan glion it sometimes divides into two portions, one of which passes in front, the other behind the vessel just mentioned. The communi cating branches with the third, fourth and fifth cervical nerves frequently join it instead of passing to the cervical ganglia. There is also, according to L. F. Meckel, sometimes forrned upon it, above the inferior thyroid artery, a small ganglion termed by some the superior thyroid ganglion, and by others the middle cervical ganglion.
2. Middle cervical ganglion, smaller than the superior ganglia of the same name, pre sents an irregularly oval or triangular shape, and is situated on or near the inferior thyroid artery. Communicating branches pass be tween it and the fifth and sixth cervical nerves; it is also sometimes connected by filaments of communication with the vagus and phrenic nerves. From the inner side of the ganglion several delicate greyish filaments pass ofl which surround the inferior thyroid artery forming a plexus, which is termed the inferior thyroid plexus. These branches communicate with the recurrent and internal laryngeal nerves, as well as with the upper cardiac nerve. The middle cervical ganglion also gives a branch which is sent to the cardiac plexus. This branch, termed the middle or deep cardiac nerve, arises from the ganglion by from two to four roots which unite into a single or double stem. It passes into the chest in front of the subclavian artery, but sometimes behind that vessel, and runs along the arteria innominata to the deep cardiac plexus. On the left side it enters the chest be tween the left carotid and subclavian arteries.