The muscular branches of the ophthalmic artery provide the most important blood supply to the EOMs. The lateral muscular branch supplies the lateral rectus, superior rectus, superior oblique, and levator palpebrae superioris muscles; the medial muscular branch, the larger of the 2, supplies the inferior rectus, medial rectus, and inferior oblique muscles.
The lateral rectus muscle is partially supplied by the lacrimal artery; the infraorbital artery partially supplies the inferior oblique and inferior rectus muscles. The muscular branches give rise to the anterior ciliary arteries accompanying the rectus muscles; each rectus muscle has 1–4 anterior ciliary arteries. These pass to the episclera of the globe and then supply blood to the anterior segment. The commonly held notion that the lateral rectus has fewer ciliary vessels than the other rectus muscles has been challenged by anatomical work showing that the number of ciliary vessels is similar for the lateral rectus and the other rectus muscles and that these vessels may, in fact, contribute substantially to the blood supply of the anterior segment.
Johnson MS, Christiansen SP, Rath PP, et al. Anterior ciliary circulation from the horizontal rectus muscles. Strabismus. 2009;17(1):45–48.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.