Course
1. Olfactory tract divides into roughly 20 branches
2. Perforates cribriform plate of the ethmoid bone
Physiology
1. Innervates olfactory mucosa
  1. Upper third of the nasal septum
  2. Superior nasal concha
Exam
1. Precautions
  1. Ensure nasal patency
  2. Test one nostril at a time
  3. Avoid testing with noxious odors (e.g Ammonia)
    1. False positives due to Trigeminal Nerve stimulation
2. Ability to identify odors
  1. Coffee
  2. Cloves
  3. Peppermint

Olfactory Nerve (C0028938)
Definition (MSH)	The 1st cranial nerve. The olfactory nerve conveys the sense of smell. It is formed by the axons of OLFACTORY RECEPTOR NEURONS which project from the olfactory epithelium (in the nasal epithelium) to the OLFACTORY BULB.
Definition (CSP)	first cranial nerve; conveys the sense of smell; it is formed by the axons of olfactory receptor neurons which project from the olfactory epithelium (in the nasal epithelium) to the olfactory bulb.
Concepts	Body Part, Organ, or Organ Component (T023)
MSH	D009832
English	cranial nerve I, Cranial Nerve Is, First Cranial Nerve, First Cranial Nerves, Olfactory Nerve, Olfactory nerve structure, Olfactory Nerves, Set of olfactory nerves
Spanish	estructura del nervio olfativo, estructura del nervio olfatorio, filete olfativo, I par craneal, nervio craneal I, nervio olfativo, nervio olfatorio, primer par craneal, primer par craneano
Parent Concepts	Olfactory Pathways (C0028939), Cranial Nerves (C0010268), Set of nerves (C0932025)
Sources	AOD , CSP, LCH, MSH, MTH, NCI, SCTSPA, SNOMEDCT, UWDA Derived from the NIH UMLS (Unified Medical Language System)

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This page was written by Scott Moses, MD, last revised on 10/7/2011 and last published on 12/30/2011.

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Cranial Nerve 1