CN and Sensory System Examination Flashcards
(32 cards)
CN I Origin/ Course
Olfactory nerves —> cribriform plate —> olfactory bulb —> olfactory tract —> anterior perforated subtrance —> lateral olfactory stria (—> parahippocampal gyrus) and medial olfactory stria (—> limbic system)
CN II Origin/ Course
Retinal ganglion cells —> optic disk —> optic nerve —> orbit —> optic canal —> optic chiasm —> optic tract —> lateral geniculate body (—> optic radiation —> occipital lobe) and superior colliculi (—> pretectal area)
CN III Origin/ Course
Midbrain —> interpeduncular fossa —> between superior cerebellar artery and posterior cerebellar arter —> tentorial edge —> cavernous sinus —> medial orbital fissure —> oculomotor nerve, superior division (levator palpebrae and superior rectus muscle) and inferior division (medial and inferior rectus and inferior oblique muscles) or parasympathetic fibers —> ciliary ganglion
CN IV Origin/ Course
Midbrain —> dorsal brainstem below the inferior colliculi —> around the cerebral peduncle —> lateral wall of the cavernous sinus —> orbital fissure —> superior oblique muscle
CN V Origin/ Course
Pons —> ca.50 root fulaments —> petrous apex —> through the dura mater —> trigeminal ganglion —> foramen rotundum —> foramen ovale
CN VI Origin/ Course
Posterior margin of pons —> up the clivus —> dura mater —> petrous apex —> lateral to internal carotid artery —> orbital fissure —> lateral rectus muscle
CN VII Origin/ Course
Pons above the olive —> internal acoustic meatus —> petrous pyramid —> geniculum of facial nerve —> medial wall of the tympanic cavity —> stylomastoid foramen —> muscles of facial expression
CN VIII Origin/ Course
Lateral to CN VII —> vestibular nerve, cochlear nerve
CN IX Origin/ Course
Medulla —> jugular foramen —> bet carotid artery and internal jugular vein —> root of the tongue
CN X Origin/ Course
Posterolateral sulcus of the medulla —> jugular foramen —> internal organs
CN XI Origin/ Course
Cranial and spinal roots —> trunk of accessory nerve —> jugular foramen —> internal organs
CN XII Origin/ Course
Medulla —> hypoglossal canal —> tongue muscles
May be absent when patient has colds
CN I
May be absent when there is an inferior frontal brain tumor
CN I
Tested by visual confrontation
Peripheral vision/ visual fields
CN II
The use of a Snellen or Jaeger chart testing eyes one at a time is used for the test of
Central vision/ visual acuity
CN II
Distance when using a Snellen chart
20 ft or 6m
Distance when using a Jaeger chart
14 inches or 35.5 cm
Innervates the Lateral Recti
CN VI
Innervates the Superior Oblique Muscles
CN IV
Innervates the medial recti, superior and inferior recti and the inferior oblique muscles
CN III
When testing for cranial nerves III, IV and VI the target should slowly trace
a large letter H
Muscles of of mastication
Masseter, temporalis, pterygoids
Most common ailment affecting CN V
Trigeminal Neuralgia
