Within that trunk or at the end of that splanchnic nerve, there is a ganglion within which the pre ganglionic sympathetic neuron will synapse with the post ganglionic sympathetic neuron. They will synapse in very small ganglia in or on the target organ. This is old terminology that divided innervation up into general vs. special, visceral vs. somatic, and efferent vs. afferent. The current way of thinking, and the way that this course will be taught, divides innervation up functionally, as described above, with skeletal, sympathetic, and parasympathetic nerves, some of which are efferent and some of which are afferent. Sympathetic fibers reach the lungs via the pulmonary plexuses, which are located along the roots of the lungs.
Pulmonary plexuses are continuous with the cardiac plexus at the tracheal bifurcation.
The esophagus passes through the esophageal hiatus of the diaphragm, which is at the T10 level, to end in the cardiac portion of the stomach. Consider the course, relations, constrictions of the esophagus. For course and relations, see above. Constrictions of the esophagus are found at its beginning, at the tracheal bifurcation, and at the esophageal hiatus. Describe the blood supply and venous drainage of the esophagus.