Peripheral nervous system

**Definition:** The stellate ganglion is a collection of sympathetic nerves located in the neck, specifically near the first rib and the seventh cervical vertebra. It's formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion. This ganglion plays a role in the sympathetic nervous system, which controls various involuntary functions like heart rate, blood flow, and sweating, particularly in the head, neck, and upper limbs.