The cervical sympathetic consists of two large ganglia united by an intervening cord. The ganglia are distinguished as the superior and the inferior cervical. Sometimes there are three. The superior cervical ganglion, situated beneath the atlas, gives blanches to those nerves in its vicinity - ■ the glossopharyngeal, spinal accessory, pneumogastric and hypoglossal, and the lower branch of the first cervical nerve.
The efferent branches, or those which pass from the ganglion, are filaments to the internal carotid artery, others to the three divisions of the common carotid, and to the guttural pouch and pharynx. The branches which accompany the internal carotid into the cranium form the carotid and cavernous plexuses, and are connected with the fifth cranial nerve.
The sympathetic cervical cord passes down the neck in company with the pneumogastric, which it leaves on entering the chest and joins the inferior cervical ganglion. In its course down the neck no filaments are received or given off by it.