Inferior Rectus (Musculus rectus inferior)
Educational content only — not medical advice.
Anatomy
The inferior rectus is an extraocular muscle running along the orbital floor. Arising from the lower limb of the common tendinous ring, it travels forward beneath the eyeball to insert into the anteroinferior sclera. It is the primary depressor of the globe when the eye is abducted, and its fascial sheath contributes to the suspensory ligament of the eye.
Origin & insertion
From the inferior margin of the common tendinous ring to the anteroinferior aspect of the sclera, approximately 6.5 mm posterior to the corneal limbus.
Action
Depresses the eyeball; additionally contributes to extorsion (excyclotorsion) and adduction in secondary gaze angles.
Innervation
Inferior division of the oculomotor nerve (cranial nerve III).
Clinical notes
Entrapment of the inferior rectus muscle within orbital floor blowout fractures leads to mechanical limitation of upward gaze, enophthalmos, and binocular vertical diplopia.
Related structures
Educational references
FAQ
What is the role of the Inferior Rectus?
The inferior rectus is an extraocular muscle running along the orbital floor. Arising from the lower limb of the common tendinous ring, it travels forward beneath the eyeball to insert into the anteroinferior sclera. It is the primary depressor of the globe when the eye is abducted, and its fascial sheath contributes to the suspensory ligament of the eye.
Why is the Inferior Rectus clinically important?
Entrapment of the inferior rectus muscle within orbital floor blowout fractures leads to mechanical limitation of upward gaze, enophthalmos, and binocular vertical diplopia.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details