The cervicothoracic ganglion, commonly called the stellate ganglion, is formed by the fusion of the inferior cervical and first thoracic sympathetic ganglia. Located near the C7 and T1 vertebrae, this star-shaped structure serves as a crucial relay station in the sympathetic nervous system.
The stellate ganglion is formed through the anatomical fusion of two separate sympathetic ganglia. The inferior cervical ganglion, located at the seventh cervical vertebra, merges with the first thoracic ganglion at the first thoracic vertebra. This fusion process creates the characteristic star-shaped structure that gives the stellate ganglion its name.
The stellate ganglion serves as a major distribution center for sympathetic nerve fibers. It sends nerve pathways to four primary regions of the body. These include the head and face for controlling pupil dilation and facial sweating, the neck region for vascular control, the upper limb including the arm and hand for blood vessel regulation, and the upper thorax for cardiac and pulmonary functions.
The stellate ganglion controls numerous sympathetic functions throughout its innervation regions. In the eyes, it causes pupil dilation for improved vision in low light. For the cardiovascular system, it increases heart rate and causes vasoconstriction to redirect blood flow. It also reduces sweating in the face and upper limb, and promotes bronchodilation in the lungs to improve airflow during stress responses.
The stellate ganglion has significant clinical importance in modern medicine. Stellate ganglion blocks are commonly performed to treat complex regional pain syndrome, chronic pain conditions, and hyperhidrosis. This procedure involves injecting local anesthetic near the ganglion to temporarily block sympathetic nerve transmission. It's also used in treating certain cardiac arrhythmias and has shown promise in post-traumatic stress disorder therapy by modulating the sympathetic stress response.