What are the main components of the abdominal autonomic nervous system?

The abdominal autonomic nervous system consists of two major components: the lumbar sympathetic chains on either side of the lumbar vertebrae and the autonomic plexuses associated with major abdominal vessels and viscera.

What is the lumbar sympathetic chain and where is it located?

The lumbar sympathetic chain is a ganglionated chain that continues from the thoracic sympathetic trunk, located on either side of the lumbar vertebrae, with the right chain overlapped by the inferior vena cava (IVC) and the left chain overlapped by the abdominal aorta.

What are the major autonomic plexuses in the abdomen?

The major autonomic plexuses in the abdomen are organized around the aorta, including the coeliac (solar) plexus around the coeliac trunk and superior mesenteric artery (SMA) origin, and the superior hypogastric plexus in front of the L5 vertebra.

What is the function of the superior hypogastric plexus?

The superior hypogastric plexus functions in parasympathetic control for bladder, urethra, and rectum contraction and vasodilation for erection, and sympathetic control for ejaculation and contraction of structures like the vas deferens and internal urethral sphincter.

What is lumbar sympathectomy and why is it performed?

Lumbar sympathectomy is the surgical removal of L2–L4 ganglia from the lumbar sympathetic chain, performed to treat lower limb ischemia, such as in Buerger's disease, by reducing sympathetic vasoconstriction.

How does visceral pain relate to the abdominal autonomic nervous system?

Visceral pain in the abdomen is triggered by stimuli like stretch, spasm, or ischemia, not by cutting or crushing, and is often referred to somatic areas supplied by the same spinal segments due to shared autonomic pathways.

What are the branches of the lumbar sympathetic chain?

The lumbar sympathetic chain gives off branches including white rami communicantes (L1–L2) for preganglionic motor and sensory fibres, gray rami communicantes for postganglionic fibres, and lumbar splanchnic nerves that join autonomic plexuses.

Abdominal Autonomics – Sympathetic Chain & Plexuses

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