Terminal nerve

Definition
noun, plural: vagus nerves
A small cranial nerve that courses anteriorly along the olfactory tract
Supplement
Cranial nerves are paired nerves that emerge from the brain and the brainstem. They supply the motor pathways between organs in the face and the upper body, and account for detecting and processing various sensations. One of the cranial nerves is the terminal nerve, which is also referred to as the cranial nerve XIII (CN XII) or cranial nerve 0.
The terminal nerve is first described in the brains of sharks by the German scientist, Gustav Fritsch, in 1878.¹ This nerve was then reported to be a common finding in the adult human brain.² It is a small nerve that passes parallel and medial to the olfactory tract. It is initially thought to be part of the olfactory nerve and is regarded by others as vestigial since its structure is thin and easily overlooked unless dissected carefully. Moreover, its function is still under debate although it is thought to possibly be related to the sensing of pheromones.
Synonym(s):

• cranial nerve XIII (CN XIII)
• twelfth cranial nerve
• nerve N
• zero nerve
• cranial nerve zero (cranial nerve 0)
• nervus terminalis

See also:

Reference(s):

¹ Fields, R. D. (2007). “Sex and the Secret Nerve”. Scientific American Mind. 18: 20–7.

² Fuller, G. N. and Burger, P. C. (1990). “Nervus terminalis (cranial nerve zero) in the adult human”. Clinical Neuropathology. 9 (6): 279–83.