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extraocular muscles

Also called EOMs, extrinsic ocular muscles, eye muscles

The extraocular muscles are the six muscles that move each eye: four rectus muscles (medial, lateral, superior and inferior) and two oblique muscles (superior and inferior). The four recti arise from the annulus of Zinn at the back of the orbit and insert in front of the equator, while the two obliques reach the globe from the front of the orbit and insert behind the equator on the temporal side.1,2

Each muscle has one primary action in primary position and subsidiary actions that depend on where the eye is pointing. The oculomotor nerve supplies four of the six, the trochlear nerve supplies the superior oblique, and the abducens nerve supplies the lateral rectus.1

To test a single muscle, the examiner places the eye where that muscle acts alone, about 23 degrees outward for the vertical recti and about 51 degrees inward for the obliques.3

More detail

The rectus insertions sit at increasing distances from the cornea, 5.5 mm for the medial, 6.5 for the inferior, 6.9 for the lateral and 7.7 for the superior, and this pattern is known as the spiral of Tillaux.3 The recti pull the globe backward and toward the nose, while the obliques pull it forward and toward the nose.1 In primary position the horizontal recti only adduct or abduct. The superior rectus elevates, then intorts and adducts, and the inferior rectus depresses, then extorts and adducts. The superior oblique intorts, then depresses and abducts, and the inferior oblique extorts, then elevates and abducts.4 The superior division of the oculomotor nerve serves the superior rectus and the levator of the lid, and its inferior division serves the medial rectus, inferior rectus and inferior oblique.1 A seventh orbital muscle, the levator, lifts the upper lid and shares the nerve supply of the extraocular muscles, but it does not move the eye.2

Sources (4)
  1. von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 3
  2. Adler's Physiology of the Eye, ch. 7
  3. Kanski, Clinical Ophthalmology (2024), ch. 18
  4. Pickwell's Binocular Vision Anomalies, ch. 17, Table 17.1

Reviewed October 2026

Related terms

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