Fourth nerve palsy

Fourth Cranial Nerve Palsy
Trochlear nerve
Specialty	Ophthalmology

Fourth cranial nerve palsy also known as Trochlear nerve palsy, is a condition affecting Cranial Nerve 4 (IV), the Trochlear Nerve, which is one of the Cranial Nerves that causes weakness or paralysis to the Superior Oblique Muscle that it innervates. This condition often causes vertical or near vertical double vision as the weakened muscle prevents the eyes from moving in the same direction together.

Because the fourth cranial nerve is the thinnest and has the longest intracranial course of the cranial nerves, it is particularly vulnerable to traumatic injury.

To compensate for the double-vision resulting from the weakness of the superior oblique, patients characteristically tilt their head down and to the side opposite the affected muscle.

When present at birth, it is known as congenital fourth nerve palsy.

See also

• Trochlear nerve


• Harada-Ito procedure

References

External links

Classification	D ICD-10: H49.1 ICD-9-CM: 378.53 MeSH: D020432
External resources	eMedicine: oph/697

v t e Diseases of the human eye (H00–H59 360–379)
Adnexa Eyelid Inflammation Stye Chalazion Blepharitis Entropion Ectropion Lagophthalmos Blepharochalasis Ptosis Blepharophimosis Xanthelasma Eyelash Trichiasis Madarosis Lacrimal apparatus Dacryoadenitis Epiphora Dacryocystitis Xerophthalmia Orbit Exophthalmos Enophthalmos Orbital cellulitis Orbital lymphoma Periorbital cellulitis Conjunctiva Conjunctivitis allergic Pterygium Pinguecula Subconjunctival hemorrhage
Globe Fibrous tunic Sclera Scleritis Episcleritis Cornea Keratitis herpetic acanthamoebic fungal Corneal ulcer Photokeratitis Thygeson's superficial punctate keratopathy Corneal dystrophy Fuchs' Meesmann Corneal ectasia Keratoconus Pellucid marginal degeneration Keratoglobus Terrien's marginal degeneration Post-LASIK ectasia Keratoconjunctivitis sicca Corneal neovascularization Kayser–Fleischer ring Haab's striae Arcus senilis Band keratopathy Vascular tunic Iris Ciliary body Uveitis Intermediate uveitis Hyphema Rubeosis iridis Persistent pupillary membrane Iridodialysis Synechia Choroid Choroideremia Choroiditis Chorioretinitis Lens Cataract Congenital cataract Childhood cataract Aphakia Ectopia lentis Retina Retinitis Chorioretinitis Cytomegalovirus retinitis Retinal detachment Retinoschisis Ocular ischemic syndrome / Central retinal vein occlusion Central retinal artery occlusion Branch retinal artery occlusion Retinopathy diabetic hypertensive Purtscher's of prematurity Bietti's crystalline dystrophy Coats' disease Macular degeneration Retinitis pigmentosa Retinal haemorrhage Central serous retinopathy Macular edema Epiretinal membrane (Macular pucker) Vitelliform macular dystrophy Leber's congenital amaurosis Birdshot chorioretinopathy Other Glaucoma / Ocular hypertension / Primary juvenile glaucoma Floater Leber's hereditary optic neuropathy Red eye Globe rupture Keratomycosis Phthisis bulbi Persistent fetal vasculature / Persistent hyperplastic primary vitreous Persistent tunica vasculosa lentis Familial exudative vitreoretinopathy
Pathways Optic nerve Optic disc Optic neuritis optic papillitis Papilledema Foster Kennedy syndrome Optic atrophy Optic disc drusen Optic neuropathy Ischemic anterior (AION) posterior (PION) Kjer's Leber's hereditary Toxic and nutritional Strabismus Extraocular muscles Binocular vision Accommodation Paralytic strabismus Ophthalmoparesis Chronic progressive external ophthalmoplegia Kearns–Sayre syndrome palsies Oculomotor (III) Fourth-nerve (IV) Sixth-nerve (VI) Other strabismus Esotropia / Exotropia Hypertropia Heterophoria Esophoria Exophoria Cyclotropia Brown's syndrome Duane syndrome Other binocular Conjugate gaze palsy Convergence insufficiency Internuclear ophthalmoplegia One and a half syndrome Refraction Refractive error Hyperopia Myopia Astigmatism Anisometropia / Aniseikonia Presbyopia Vision disorders Blindness Amblyopia Leber's congenital amaurosis Diplopia Scotoma Color blindness Achromatopsia Dichromacy Monochromacy Nyctalopia Oguchi disease Blindness / Vision loss / Visual impairment Anopsia Hemianopsia binasal bitemporal homonymous Quadrantanopia subjective Asthenopia Hemeralopia Photophobia Scintillating scotoma Pupil Anisocoria Argyll Robertson pupil Marcus Gunn pupil Adie syndrome Miosis Mydriasis Cycloplegia Parinaud's syndrome Other Nystagmus Childhood blindness
Infections Trachoma Onchocerciasis

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