Olfactory Nerve

Structure

• The olfactory nerve, or cranial nerve I, is unique among cranial nerves. It's composed of sensory nerves for smell. Origin Originates in the olfactory epithelium in the upper part of the nasal cavity. Pathway Axons pass through the cribriform plate of the ethmoid bone. They end in the olfactory bulb on the inferior surface of the frontal lobe. Olfactory Bulb The olfactory bulb is part of the brain where the olfactory nerves begin. It processes odor information and sends it to the brain. Intracranial Course From the olfactory bulb, the olfactory tract extends posteriorly. The tract divides into medial and lateral striae. Central Connections The medial striae connect to the contralateral olfactory area. The lateral striae project to the ipsilateral primary olfactory cortex. Clinical Significance Anosmia, loss of smell, can occur with damage to the olfactory nerves. Important in assessing frontal lobe lesions and skull base fractures.