Sympathetic trunk

From WikiLectures


The central part is formed by the nuclei of the lateral horns of the spinal cord: nc. intermediomedialis and intermediolateralis within T1-L2.

The superior sympathetic centers in the central nervous system are the formation reticularis, the hypothalamus and the limbic system.

Adrenal medulla can also be classified as sympathetic.

The sympathetic trunk (Truncus sympaticus) forms two types of sympathetic ganglia:

  1. paravertebral – paired truncus sympaticus (dx. et sin.) – a chain of ganglia on the sides of the spine from the cranial base to the sacral bone ( os sacrum),
  2. prevertebral – ganglia as part of the abdominal aortic plexus (plexus aorticus abdominalis) (in front of the aorta at the distance of the large vessels – ggl. coeliaca, ggl. aorticorenalia, ggl. mesentericum superius et inferius)
Truncus sympaticus (view of the ventral side of the spine

Unlike the sympathetic ganglia, the parasympathetic ganglia are stored either in plexuses very close to target organs or directly in their wall (intramural ganglia).

Cervical sympathetic trunk[edit | edit source]

3 types of sympathetic fibers:

a) Rami communicantes grisei - they return back to the spinal nerve, mostly postganglionic fibers

b) Rami viscerales a vasculares - they leave the ganglia and go to the periphery along the blood vessels

c)Fibers to autonomic nerve plexuses and ganglia of internal organs - they meet with the parasympathetic

Thoracic sympathetic trunk[edit | edit source]

  • 10 to 12 pairs of ganglia connected by rami interganglionares, paravertebral to the posterior inner surface of the thorax
  • it lies on the sides of the spine before the heads of the ribs, covered by parietal pleura, the splanchnic nerves (nervi splanchnici (major, minor, imus)) come from it, which then go through the diaphragm and enter the abdominal aortic plexus (plexus aorticus abdominalis)
  • rr. communicantes grisei for the thoracic spinal nerves
  • rr. pulmonales thoracici, rr. oesophageales, r. renalis
  • n. splanchnicus major - by connecting 5.-9. ganglion thoracicum, contains preganglionic fibers - axons of perikarya from the spinal cord
  • n. splanchnicus minor - by connecting 10.-11. ganglion and reaches the celiac plexus
  • n. splanchnicus imus - from the 11th (12th) ganglia to the renal plexus

Lumbar sympathetic trunk[edit | edit source]

  • 4 ganglia connected by rami interganglionares
  • preganglionic fibers from sympathetic perikarya 2.-3. lumbar segment
  • postganglionic continue as:
  • rr. communicantes grisei
  • rr. vasculares into the aortic plexus
  • nn. splanchnici lumbales connected with the aortic plexus, mesentericus inferior and hypogastricus from where they go to the inside of the pelvis
  • Lies inside of the psoas major muscle (left - between the muscle and the aorta, right - behind the vena cava inferior), The nn. splanchnici pelvici come from it into the abdominal aortic plexus

Sacral sympathetic trunk[edit | edit source]

  • 4-6 small ganglia
  • at the height of the coccygeum axis, they connect into ansa sacralis, where an unpaired ganglion impar occurs
  • innervation of the pelvic viscera from the inferior and superior hypogastric plexuses

Prevertebral plexus[edit | edit source]

  • It is divided into 3 contiguous strands located in the retroperitoneum in front of the aorta and continuing into the small pelvis:
  1. plexus aorticus abdominalis – in front of the abdominal aorta, it is divided into two plexuses (they contain the prevertebral ganglia – coeliaca, aorticorenalia, mesentericum superius et inferius):
    • plexus coeliacus – around the truncus coeliacus – the so called plexus solaris,
    • plexus mesentericus – between a. mesenterica sup. et inf.
  2. plexus hypogastricus superior – it goes from the bifurcation of the aorta to the pelvis in front of the "sacral bone", it has two parts:
    • n. praesacralis – a strip of fibers going from the bifurcation of the aorta in front of the promontory to the pelvis where it divides into:
    • n. hypogastricus dx. et sin. – streaks of fibers arising from the division of n. praesacralis.
  3. plexus hypogastricus inferior – the continuation of the nn. hypogastrici on the sides of the rectum and further forward, externally from the pelvic organs (they form plexes around them – plexus rectalis, uterovaginalis, vesicalis…)

Types of fibers in individual plexes[edit | edit source]

  • The above-mentioned plexes contain a sympathetic component coming from the spinal sympathetic nuclei (level C8–L3), parasympathetic it comes through conjunctions from n. vagus (nucleus of the n. vagus in the brainstem) – into the plexus aorticus abdominalis, as well as from the sacral parasympathetic system (spinal parasympathetic nuclei at the S2–S4 level) – into the plexus hypogastricus inferior, meaning:
    • plexus aorticus abdominalis and hypogastricus inferior – Mixed plexes (sympathetic and parasympathetic);
    • plexus hypogastricus superior – only sympathetic.


Sources[edit | edit source]

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