Cranial Pair 0: The Nervus Terminalis

Area of Science:

• Neuroscience
• Embryology
• Human Anatomy

Background:

• The nervus terminalis, identified in elasmobranchs in 1878, is now recognized as cranial pair zero.
• Its origin is primarily the olfactory placode, with potential neural crest contribution.
• This nerve is prominent in human embryos but less distinct in adults.

Purpose of the Study:

• To review current knowledge on the nervus terminalis.
• To focus on the anatomical and clinical relevance of this nerve.
• To incorporate original illustrations of the nerve during development.

Main Methods:

• Literature review of existing studies on the nervus terminalis.
• Analysis of anatomical pathways and cellular components.
• Examination of developmental stages from embryonic to adult human forms.

Main Results:

• The nervus terminalis fibers traverse the cribriform plate to connect with the telencephalon.
• Ganglion cells, forming the ganglion of the nervus terminalis, are typically located at the crista galli base.
• The nerve's fibers may facilitate luteinizing hormone-releasing hormone cell migration, impacting the hypothalamic-gonadal axis.

Conclusions:

• The nervus terminalis plays a role in the development of the hypothalamic-gonadal axis.
• Alterations in this nerve's function may be associated with conditions like Kallmann's syndrome.
• Further understanding of its anatomy and function is crucial for clinical relevance.