sympathetic division (coronary plexuses)

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The sympathetic division of the coronary plexuses can be divided into:

  • post-ganglionic efferent motor fibres:
    • preganglionic fibres originate from the lateral horn of the upper five thoracic segments
    • on each side the preganglionic fibres pass to the superior three cervical ganglia and superior five thoracic ganglia
    • cell bodies are within these ganglia
    • cervical cardiac branches of these ganglia pass to the coronary plexuses
    • stimulation produces positive inotropy, chronotropy and dilates the coronary arteries
  • pre-ganglionic afferent pain fibres:
    • on each side pass within the sympathetic nerves to the three cervical and upper thoracic ganglia but the majority are destined for the inferior cervical and first thoracic ganglia
    • pass via spinal nerves and white rami communicantes to the T1 to T5 spinal segments, particularly on the left side
    • hence, pain may be referred to the cutaneous distribution of these segments despite nerve signals originating in the heart - myocardial ischaemia may present with left sided upper thoracic or inner arm pain

Last reviewed 01/2018