What are the thoracic sympathetic trunks?

The thoracic sympathetic trunks are paired ganglionated chains that run along either side of the vertebral column. They are part of the autonomic nervous system, connecting above to the cervical chain and below to the lumbar chain.

How many ganglia are in the thoracic sympathetic trunk?

Typically, there are 11 thoracic ganglia (sometimes 10). The first thoracic ganglion often fuses with the inferior cervical ganglion to form the stellate (cervicothoracic) ganglion.

What are the main branches of the thoracic sympathetic trunks?

The branches are divided into medial (visceral) and lateral (somatic) groups. Medial branches include preganglionic fibers forming splanchnic nerves and postganglionic fibers to visceral plexuses. Lateral branches supply the skin for functions like sweating and vasomotor control.

What is the clinical significance of the thoracic sympathetic trunks?

They are involved in procedures like sympathectomy to treat conditions such as severe hypertension or Raynaud's disease. Damage can lead to Horner’s syndrome, and their paralysis in spinal anesthesia can cause hypotension.

How do the thoracic sympathetic trunks connect to other parts of the nervous system?

They are continuous above with the cervical sympathetic chain and below with the lumbar sympathetic chain (via the medial arcuate ligament). This allows them to integrate autonomic functions across the thorax and abdomen.

What is the role of splanchnic nerves from the thoracic sympathetic trunks?

Splanchnic nerves carry preganglionic fibers to abdominal structures. Key nerves include the greater splanchnic nerve (T5–T9) to celiac ganglion and adrenal gland, lesser splanchnic nerve (T10–T11) to celiac ganglion, and least splanchnic nerve (T12) to renal plexus.

Thoracic Sympathetic Trunk – Ganglia & Splanchnic Nerves