The sympathetic nervous system originates from T1-L2/3. Preganglionic SNS fibers to the upper extremity originate in the first four or five thoracic segments, and synapse in the superior, middle, and inferior (stellate) cervical ganglia. In 80% of people the stellate ganglia is actually made up of both the inferior cervical and first thoracic ganglia. Post-ganglionic nerves from the cervical ganglia extend into the head, neck, upper extremities, heart, and lungs, and carry afferent pain fibers along with them. These SNS fibers allow for vasomotor, pilomotor, secretory, and pupillodilator function.
Upper Extremity Autonomic Innervation
- Presynaptics: T1-T4/5
- Synapse: superior, middle, and inferior (stellate) cervical ganglia
- Function: vasomotor, pilomotor (and secretory, pupillodilator in the head and neck)
Note: Upper extremity SNS fibers carry primary afferent fibers with them