View source for Template:Cranial nerve deficits

===[[Cranial nerves]]===
[[File:Unilateral hypoglossal nerve injury.jpeg|thumb|Tongue deviation from unilateral hypoglossal nerve injury (CN XII).]]
*'''CN I (Olfactory)'''
**Anosmia + perceived change in taste of food
**Deficit caused by shearing of the nerve ending passing through the cribriform plate usually by closed head trauma
*'''CN II (Optic)'''
**Monocular and binocular visual field defects
**Monocular: [[Giant cell arteritis]], anterior ischemic optic neuropathy, [[glaucoma]], [[optic neuritis]], [[head trauma|trauma]], [[increased ICP]], emboli/arteritis/stenosis leading to retinal ischemia, ophthalmic artery or vein occlusion
**Binocular - Hemianopsia due to bilateral optic nerve disease.
*'''CN III (Oculomotor)''' –See [[Third Nerve Palsy]]
*'''CN IV (Trochlear)'''- See [[Trochlear nerve palsy]]
*'''CN VI (Abducens)'''- See [[Abducens nerve palsy]]
*[[Internuclear ophthalmoplegia]] - Lesion in medial longitudinal fasciculus, cannot adduct in horizontal lateral gaze, but normal convergence. Caused by [[multiple sclerosis]] or [[stroke]]
*'''CN V (Trigeminal)'''
**Jaw weakness and spasm. Jaw closure may be weak and/or asymmetric. +/- Trismus if irritative lesion to motor root.
**See [[trigeminal neuralgia]]
*'''CN VII (Facial)'''
**Upper motor neuron deficit – See [[Stroke (Main)|Stroke]], [[Hemorrhagic  stroke]], [[Multiple sclerosis]], [[Amyotrophic Lateral Sclerosis]] (Upper and lower motor neuron disease)
***Sudden-onset of weakness: forehead sparing, [[facial paralysis|facial droop]]
**Lower motor neuron deficit – See [[Bell's palsy]]
***Ipsilateral to defect: Inability to raise eyebrows, drooping of angle of mouth, incomplete closure of eyelid. No forehead sparing.
*'''CN VIII (Vestibular)'''
**Dysfunction may be characterized by: [[tinnitus]], [[hearing loss|deafness]], [[nausea]], [[vertigo]], balance issues
**See [[vertigo]]
*'''CN IX (Glossopharyngeal)'''
**Dysfunction may be characterized by: [[dysarthria]], [[dysphagia]]
*'''CN X (Vagus)'''
**Dysfunction may be characterized by: [[dysphonia|hoarseness]] (unilateral vocal cord paralysis), [[dyspnea]] and inspiratory [[stridor]] (bilateral). Dysarthria, dysphagia.
*'''CN XI (Accessory)'''
**Dysfunction may be characterized by: Sternocleidomastoid and trapezius [[weakness]] leads to weak head rotation and shoulder shrug
*'''CN XII (Hypoglossal)'''
**Dysfunction may be characterized by: tongue deviation and wasting