What Is the Stellate Ganglion?

The stellate ganglion is a knot-like tissue mass consisting of nerve cell bodies that form by the inferior cervical ganglion fusing together with the first thoracic ganglion. The plural term, stellate ganglia, is sometimes used, since the tissue masses can be found on more than one region of the neck's root. Other names for this mass include the the inferior cervical or cervicothoracic ganglion.

Corresponding to the seventh and last cervical vertebra (C7), the stellate ganglion has the vertebra's transverse process — as well as the cervix on the first rib — facing its rear. It is here that the two ganglia, the first thoracic and inferior cervical, join together. The inferior cervical ganglion sends a branch called gray ramus communicans to the spinal nerves for assistance in the transfer of autonomic, motor and sensory signals.

To the front, of the stellate ganglion is one of the subclavian arteries responsible for distributing blood to the neck and arms. Flanking the ganglia are the supreme intercostal vein, superior intercostal artery and ventral ramus of the first thoracic nerve. At the middle, the ganglia has the cylindrical-shaped, largest part of a vertebra called the vertebral body, or body of the vertebra. At the bottom is the dome-shaped area of the pleural cavity that houses the lungs.

This ganglion is part of the sympathetic nervous system (SNS), an area within the nervous system gathers the body's resources in response to stress, which is a function known as fight-or-flight. The stellate ganglion is thus known as sympathetic ganglion. It plays a part in relaying information to the body in relation to threats or danger.

Physicians may cut the stellate ganglion to reduce the symptoms of primary hyperhydrosis, or excessive sweating of the hands, which is linked to a highly active sympathetic nerve. Suppressing the ganglion is also applied for conditions like reflex neurovascular dystrophy (RND). This is variant of the chronic progressive disorder complex regional pain syndrome (CRPS), characterized by joint and skin pain due to inappropriate pain signal transfer to the brain.

A block or mitigation of the ganglion, however, can also lead to certain complications. This includes swallowing difficulty; Horner's syndrome, which is mainly characterized by drooping eyelids and pupil constriction; and pneumothorax, or gas or air accumulation in the pleural cavity. In 2007, a report published by the Scandinavian Society of Anaesthesiology and Intensive Care Medicine suggested that a stellate ganglion block (SGB) can increase radial artery blood flow and prevent radial artery spasm in patients having surgery on their coronary artery.