Medial rectus muscle
Citation, DOI & article data
- innervation: inferior branch of the oculomotor nerve (CN III)
- origin: annulus of Zinn (tendinous ring)
- insertion: globe (anterior, medial surface)
- primary function: one of three ocular adductors
Medial rectus, along with the other rectus muscles, arises from the annulus of Zinn, the common tendinous ring at the apex of the orbit that surrounds the optic canal 1.
The action of the medial rectus is to adduct the eye (see figure 1) 1. Unlike most of the other extraocular muscles, it has no significant contribution to movement in the other ocular axes.
Simultaneous action of the medial rectus muscles of both eyes causes ocular convergence, which is necessary to allow near-field focus, such as when reading.
Rectus comes from the Latin rectos, meaning straight 1.
- 1. Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. (2013) ISBN: 9781451119459
- 2. Netter FH. Atlas of Human Anatomy. (2018) ISBN: 9780323393225
- 3. Imaging of the Head and Neck. Thieme. (2012) ISBN:3131505311. Read it at Google Books - Find it at Amazon
- 4. Gray's basic anatomy. Churchill Livingstone. ISBN:1455710784. Read it at Google Books - Find it at Amazon