extraocular

DEFINITION of extraocular

The term most frequently appears in the clinical context of the extraocular muscles (EOMs) — the seven muscles extrinsic to the eyeball that govern its movements and the position of the upper eyelid. Six of these muscles move the eyeball itself (four recti and two obliques), while the seventh — the levator palpebrae superioris — elevates the upper eyelid. These are distinct from the intraocular (intrinsic) muscles inside the eye (e.g., the ciliary muscle, pupillary sphincter, and dilator). The EOMs work in coordinated, paired fashion (Sherrington’s law of reciprocal innervation: when an agonist contracts, its antagonist relaxes), enabling smooth, precise binocular gaze. They are innervated by three cranial nerves: CN III (oculomotor), CN IV (trochlear), and CN VI (abducens). Beyond muscles, extraocular can also describe any structure, disease, or implant located outside the globe itself.

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ETYMOLOGY of extraocular

greek A modern compound formed from two classical roots: Latin extra- — “outside of, beyond, except,” from exter (“outward”), from Proto-Indo-European h₁eǵʰs (“out”)Latin oculus — “eye,” from PIE okʷ- (“to see”), the same root as Greek ops/ophthalmos; Latin -ar (-aris) — adjectival suffix meaning “pertaining to” Literally: “pertaining to that which is outside the eye.”

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THE SEVEN EXTRAOCULAR MUSCLES

Muscle	Cranial Nerve	Primary Action
Superior rectus	CN III (oculomotor)	Elevation
Inferior rectus	CN III (oculomotor)	Depression
Medial rectus	CN III (oculomotor)	Adduction (inward)
Lateral rectus	CN VI (abducens)	Abduction (outward)
Superior oblique	CN IV (trochlear)	Incyclotorsion, depression, abduction
Inferior oblique	CN III (oculomotor)	Excyclotorsion, elevation, abduction
Levator palpebrae superioris	CN III (oculomotor)	Upper eyelid elevation

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RELATED TERMS

• Intraocular: Situated inside the eyeball — contrasts directly with extraocular (e.g., intraocular pressure, intraocular lens).
• Strabismus: Misalignment of the eyes due to extraocular muscle imbalance; umbrella term for esotropia, exotropia, hypertropia.
• Ophthalmoplegia: Paralysis of extraocular muscles; can be partial or complete.
• EOM palsy / Cranial nerve palsy: CN III, IV, or VI palsies directly impair specific extraocular muscles, producing diplopia and abnormal eye position.
• Thyroid eye disease (TED) / Graves’ orbitopathy: Autoimmune condition causing extraocular muscle inflammation and enlargement.
• Strabismus surgery: Surgical tightening (resection) or loosening (recession) of extraocular muscles to correct misalignment.
• Diplopia: Double vision; a hallmark symptom of extraocular muscle dysfunction.
• Congenital fibrosis of the extraocular muscles (CFEOM): Rare genetic disorder replacing EOM tissue with fibrous tissue.
• Exophthalmos / proptosis: Forward protrusion of the eyeball, often from extraocular/orbital pathology.
• Nystagmus: Involuntary, rhythmic eye movements involving abnormal extraocular muscle activity.

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DERIVATIONS of extraocular

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Query functionality

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FROM #medterm 
WHERE length(filter(definition, (word) => econtains([[]].definition, word))) > 0 AND file.name != [[]].file.name

Med roots Appendix A Prefixes Appendix B Combining Forms Appendix C Suffixes Appendix D Suffix forms