Visceral Innervation Summary

Parasympathetic nerves   (Tips)

Supply structures deep within the head and neck

Originate in the brainstem as preganglionic (GVE) fibers and are components of CN III, VII, IX and X

Postganglionic (GVE) cell bodies are located within MOTOR ganglia which are parasympathetic ONLY

Postganglionic (GVE) fibers of CN III, VII, and part of IX are distributed by CN V (sensory root) near their termination on smooth muscle and glands.  Nerve fibers belong to CN III, VII, and IX not CN V

Sympathetic nerves

Supply viscera superficial and deep within the head and neck

Originate in the IML of the spinal cord as preganglionic (GVE) nerves (T₁ - T₄ or T₆)

Postganglionic (GVE) cell bodies are located within paraverebral ganglia (=superior, middle, inferior [=stellate] sympathetic chain ganglia)

Postganglionic sympathetic (GVE) nerves in the head are distributed by

Internal and external carotid and vertebral arteries and their branches where they form a nerve plexus

Branches of cranial nerves V¹ and V³ (including the motor root) and by an independent nerve called the deep petrosal nerve which joins the greater petrosal nerve (CN VII) to form the nerve of the pterygoid canal.  These postganglionics are distributed by CN V¹ and V².  The sympathetic GVE are not components of the trigeminal (V) nerve

Postganglionics (GVE) in the superficial neck are distributed by grey rami communicantes which join with cervical nerves for distribution

Postganglionics (GVE) in the deep neck are distributed by joining branches of the external carotids and thyrocervical trunk upon which they form a nerve plexus to the thyroid gland and visceral tube.  In contrast, cardiac nerves arise directly from sympathetic ganglia to supply the heart

Referred GVA pain

Pain from glands and smooth muscle in the superficial and deep head and neck is referred to the CNS by the same pathways which distribute sympathetic (GVE) fibers to these viscera.  Cell bodies for pain are located within dorsal root ganglia of T₁ - T₄ or T₆

Afferent (GVA) nerves

Utilize pre-existing pathways in the superficial and deep head and neck to return to the CNS.  They are distributed with autonomic (GVE) fibers

Are components of CN VII, IX, and X involved in reflex control of visceral function and pain

These viscera are deep in the head and neck

Cell bodies are located in ganglia along the course of cranial nerves

CN VII - geniculate ganglion

CN IX and X - inferior ganglion for each

Afferent (SVA) nerves

Taste fibers utilize the same pathways as GVA nerves and are components of CN VII, IX and X

CN VII - geniculate ganglion

CN IX and X - inferior ganglion for each

Smell fibers are components of CN I - olfactory mucosa