Cranial nerves examination

There are 12 pairs of cranial nerves although the optic nerve is really an extension of the brain rather than a peripheral nerve. The ability to test them swiftly, efficiently and to interpret the findings should be a core competency for general practitioncer. | Cranial nerves examination There are 12 pairs of cranial nerves although the optic nerve is really an extension of the brain rather than a peripheral nerve. The ability to test them swiftly efficiently and to interpret the findings should be a core competency for general practitioncer. Olfactory bulb Longitudinal cerebral fissure Temporal pole Lateral sulcus fissure Infundibulum I Midbrain ------ Pons ------------ Middle cerebellar peduncle Junction of pons and medulla Choroid plexus of 4th ventricle Lateral recess of -4th ventricle Medulla I-------- Hypoglossal------- nerve CN XII Cerebellum ------- Olfactory nerves fila collectivety comprising olfactory nerve CN 1 Olfactory tract Optic nerve CN II Optic tract I To forebrain I Oculomotor nerve CN III Trochlear nerve CN IV Sensory root I Trigeminal Motor root I nerve CN V Abducent nerve CN VI facial nerve CN VII -Intermediate nerve Vestibulocochlear nerve CN VIII Glossopharyngeal nerve CN IX Vagus nerve CN X c Spinal accessory nerve CN Xl d I . Cranial nerve I - Olfactory nerve 1 . Anatomy The olfactory nerves CN I have sensory fibers concerned with the special sense of smell. The olfactory receptor neurons are in the olfactory epithelium olfactory mucosa in the roof of the nasal cavity. The central processes of the olfactory receptor neurons ascend through foramina in the cribriform plate of the ethmoid to reach the olfactory bulbs in the anterior cranial fossa. These nerves synapse on neurons in the bulbs and the processes of these neurons follow the olfactory tracts to the primary and associated areas of the cerebral cortex. 2 . Examination Test the sense of smell by presenting the patient with familiar and nonirritating odors. First be sure that each nasal passage is open by compressing one side of the nose and asking the patient to sniff through the other. The patient should then close both eyes. Occlude one nostril and test smell in the other with such substances as cloves coffee soap or vanilla. Ask if the .