Sympathetic division (coronary plexuses)

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