What is the cervical portion of the sympathetic system?

What it is

• The cervical portion of the sympathetic trunk consists of three ganglia, distinguished, according to their positions, as the superior, middle, and inferior ganglia, connected by intervening cords. This portion receives no white rami communicantes 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 vertebræ. It is of a reddishgray color, and usually fusiform in shape; sometimes broad and flattened, and occasionally 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.