Trunk nerves (intercostal, sympathetic, vagus nerve)
Sympathetic trunk (chain)
Truncus sympathicus (dexter et sinister)
- Origin
- Paired bilateral nerve cord extending from the base of the skull (superior cervical ganglion) down to the coccyx (ganglion impar)
- Insertion
- Runs paravertebrally over the heads of the ribs in the thorax and on the anterolateral lumbar vertebral bodies, connected to spinal nerves via white and gray rami communicantes
- Function
- Primary conduit for the sympathetic nervous system mediating 'fight-or-flight' responses: pupillary dilation, tachycardia, bronchodilation, vasoconstriction, sudomotor activation, and GI inhibition
- Innervation
- Receives preganglionic myelinated inputs from the intermediolateral cell column (T1-L2)
- Movement & chain
- Continuous sympathetic vascular and visceral tone
- Palpation
- Not palpated directly
- Clinical
- Horner's syndrome (triad of ptosis, miosis, and facial anhidrosis caused by disruption of the cervical sympathetic chain by apical Pancoast lung tumor or carotid dissection), endoscopic thoracic sympathectomy (ETS) for refractory palmar hyperhidrosis.
- Segmental innervation
- T1-L2 spinal cord levels
- In clinical practice
- Triaging Horner's syndrome in apical chest pain, counseling regarding compensatory sweating following endoscopic thoracic sympathectomy
- Region in the model
- Trunk nerves (intercostal, sympathetic, vagus nerve)