Autonomic Nerves in Neck

The cervicothoracic (stellate) ganglion is formed by the fusion of the seventh and eighth cervical ganglia with the first and/or second thoracic ganglia. It is an irregularly fusiform structure with many radiating branches. The cervicothoracic ganglion is situated posterior to the first part of the subclavian artery, the origin of the vertebral artery, the vertebral vein, and the apex of the lung. It lies anterior to the last cervical transverse process, the neck of the first rib, and the anterior primary ramus of the eighth cervical nerve as it passes outward to unite with the corresponding ramus of the first thoracic nerve to form the inferior trunk of the brachial plexus. The vertebral vessels run over the upper pole of the ganglion, and the superior intercostal vessels run lateral to it at the level of the neck of the first rib. An aponeurotic slip from the scalene muscles spreads out to become attached to the suprapleural membrane and may veil the ganglion during the anterior operative approach. If a scalenus minimus is present, it may also obscure the ganglion.

The cervicothoracic ganglion receives white rami communicantes from the first and second thoracic nerves and sends gray rami communicantes to the eighth cervical and first thoracic nerves and, occasionally, to the seventh cervical and second thoracic nerves. These rami carry efferent and afferent sympathetic fibers to and from the brachial plexus and the uppermost intercostal nerves, thus helping to innervate vessels, sweat glands, arrectores pilorum, bones, and joints in the upper limbs and superior parts of the chest wall. The ganglion or the ansa subclavia invariably communicate with the ipsilateral phrenic nerve, and almost constantly with the vagus or the recurrent laryngeal nerve. Fibers are supplied to the heart, esophagus, trachea, and thymus. Some vascular fibers from the ganglion pass directly to the large vessels in the cervicothoracic inlet, but most of the sympathetic fibers for the upper limb structures enter the inferior trunk of the brachial plexus. They pass mainly into the medial cord of the plexus and then into the median and ulnar nerves and, to a lesser extent, into the axillary, radial, musculocutaneous, and other branches of the plexus. Vasomotor and sudomotor disturbances, or causalgia, are therefore most likely to follow irritation or injury to the inferior trunk of the brachial plexus or to the ulnar or median nerves.

Most of the preganglionic fibers for the upper limbs emerge through the anterior rami of the second to sixth or seventh thoracic nerves, and the second and third nerves probably contain the majority of the fibers.

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