The cranialnerves are twelve pairs of nerves from the central nervous system. The cranial nerves are loosely based on their functions. In this summary, we discuss the nomenclature of the cranial nerves and supply some background information that might make it easier to understand the nerves and their function.
This summary should read alongside the complete articles for each of the cranial nerves:
The cranial nerve nuclei will be covered in more detail in each cranial nerve article. For now, it is worthwhile knowing that a nucleus refers to a collection of neuronal cell bodies within the central nervous system and they give rise to one of seven major types of fibres (below):
GSA: general somatic afferent – receive sensory information from the skin, skeletal muscles and joints
GVA: general visceral afferent – receive sensory information from the viscera (organs)
SSA: special somatic afferent – receive sensory information from the ectodermal retina, cochlear and vestibular apparatus
SVA: special visceral afferent – receive sensory information from the endodermal nose and tongue
GSE: general somatic efferent – provide motor innervation to skeletal muscles
GVE: general visceral efferent – provide secretomotor function to smooth muscle and glands
SVE: special visceral efferent – provide motor innervation to skeletal muscles of the pharyngeal arches
Afferent fibres carry sensory information back to the brain. Efferent fibres carry motor information away from the brain.
The cranial nerves themselves can be a complex area of anatomy to learn. We have broken the cranial nerves down to their bare essentials. The other cranial nerve articles in this series build on the information presented here.