sympathetic division (coronary plexuses)
Last reviewed 01/2018
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