Parasympathetic innervation of the neck, thorax, and abdomen (down to the splenic flexure) is provided by the vagus nerve, CN X. During development, the rotation of the foregut structures results in the right vagus nerve becoming the posterior vagal trunk and the left vagus nerve becoming the anterior vagal trunk.
The hindgut, which comprises the colon from the distal third of the transverse colon to the anal canal, is innervated by the pelvic splanchnic nerves. These are parasympathetic fibers arising from the spinal cord at S2-4 levels. |  |
