Editing Autonomic nervous system (section)

=== '''Sympathetic     trunk/chain''' ===

==== '''Cervical      part''' ====

*** Pre-ganglionic fibres all       arise from upper thoracic outflow and ascend in the cervical sympathetic       trunk
*** Most outflow is from T1       level

==== '''Thoracic      part''' ====

*** Paired bundle of nerve       fibres
*** Course
**** Begins at T1 ganglion,        which is usually (80%) fused with the inferior cervical ganglion to        form the '''stellate ganglion''', which lies in front of and below the neck        of the first rib
**** The trunk then passes down        in front of the heads of the ribs, lying in front of all the        intercostal structures in the thorax (apart from the supreme        intercostal vein)
**** Exits from the thorax        beneath the medial arcuate ligament
*** Supply
**** Cardiac plexus -        sympathetic fibres from cervical and upper thoracic ganglia
**** Trachea and oesophagus        receive branches
**** There are usually 12        ganglia corresponding to each intercostal nerve, with each ganglion        giving off one grey and one white ramus to each intercostal nerve
**** Upper limb is mostly T2        and T3, but some T1, T4 and T5
**** Splanchnic nerves come        from the lower eight ganglia - see below
*** Removal of thoracic ganglia       4-12 bilaterally is theorised to remove pain fibres from the abdominal       viscera

==== '''Lumbar part''' ====

*** Comprises inputs from lower       thoracic ganglia and L1-L2 nerve roots
*** Left part along the left       margin of aorta, and right part behind IVC
*** The trunk passes down       across the pelvic brim to become the sacral part of the trunk
*** Just behind the medial       arcuate ligament, medial to psoas major
*** Lumbar splanchnic nerves       pass downwards and form the superior hypogastric plexus