Lateral rectus muscle
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The lateral rectus muscle is one of the 6 extraocular muscles that control eye movements. It is responsible for abduction and is the only muscle that is innervated by the abducens nerve (CN VI). It should normally measure 2.9 ± 0.6 mm.
Summary
- innervation: abducens nerve (CN VI)
- origin: annulus of Zinn (tendinous ring)
- insertion: globe (anterior, lateral surface)
- primary function: one of three ocular abductors
Gross anatomy
Origin
Lateral 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 canal1.
Insertion
Lateral rectus runs anteriorly on the medial surface of the eye and inserts into the lateral surface of the sclera just posterior to the junction of cornea and sclera 2.
Arterial supply
Branches of the ophthalmic artery, itself a branch of the internal carotid artery.
Innervation
Lateral rectus is unique among the extraocular muscles in being supplied by the abducens nerve.
Action
The action of the lateral rectus is to abduct 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.
Etymology
Rectus comes from the Latin rectos, meaning straight 1.
Related pathology
-
secondary function: none- as the lateral rectus and superior oblique muscles are the only extraocular muscles not supplied by the oculomotor nerve, the unopposed force generated by these muscles results in depression and abduction of the affected eye
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tertiary function: none- as the lateral rectus is the primary ocular abductor, abducens nerve palsy results in adduction of the affected eye, due to unopposed effect primarily of the medial rectus muscle
- because of its long subarachnoid course and location in the Dorello canal, abducens nerve palsy can be an early sign of increased intracranial pressure
See also
-<p>The <strong>lateral rectus muscle</strong> is one of the 6 <a href="/articles/extraocular-muscles-1">extraocular muscles</a> that control <a href="/articles/eye-movements">eye movements</a>. It is responsible for abduction and is the only muscle that is innervated by the <a href="/articles/abducens-nerve">abducens nerve (CN VI)</a>. It should normally measure 2.9 ± 0.6 mm.</p><h4>Summary</h4><ul>- +<p>The <strong>lateral rectus muscle</strong> is one of the 6 <a href="/articles/extraocular-muscles-1">extraocular muscles</a> that control <a href="/articles/eye-movements">eye movements</a>. It is responsible for abduction and is the only muscle that is innervated by the <a href="/articles/abducens-nerve">abducens nerve (CN VI)</a>.</p><h4>Summary</h4><ul>
- +</ul><h4>Gross anatomy</h4><h5>Origin</h5><p>Lateral 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 <a href="/articles/optic-canal">optic canal</a> <sup>1</sup>.</p><h5>Insertion</h5><p>Lateral rectus runs anteriorly on the medial surface of the eye and inserts into the lateral surface of the <a href="/articles/sclera">sclera</a> just posterior to the junction of <a href="/articles/cornea">cornea</a> and sclera <sup>2</sup>.</p><h4>Arterial supply</h4><p>Branches of the <a href="/articles/ophthalmic-artery">ophthalmic artery</a>, itself a branch of the <a href="/articles/internal-carotid-artery-1">internal carotid artery</a>.</p><h4>Innervation</h4><p>Lateral rectus is unique among the extraocular muscles in being supplied by the <a href="/articles/abducens-nerve">abducens nerve</a>.</p><h4>Action</h4><p>The action of the lateral rectus is to abduct the eye (see figure 1) <sup>1</sup>. Unlike most of the other extraocular muscles, it has no significant contribution to movement in the other ocular axes.</p><h4>Etymology</h4><p>Rectus comes from the Latin <em>rectos</em>, meaning straight <sup>1</sup>.</p><h4>Related pathology</h4><ul>
-<strong>secondary function</strong>: none</li>- +<a href="/articles/oculomotor-nerve-palsy">oculomotor nerve palsy</a><ul><li>as the lateral rectus and <a href="/articles/superior-oblique-muscle">superior oblique muscles</a> are the only extraocular muscles not supplied by the oculomotor nerve, the unopposed force generated by these muscles results in depression and abduction of the affected eye</li></ul>
- +</li>
-<strong>tertiary function</strong>: none</li>- +<a href="/articles/abducens-nerve-palsy-1">abducens nerve palsy</a><ul>
- +<li>as the lateral rectus is the primary ocular abductor, abducens nerve palsy results in adduction of the affected eye, due to unopposed effect primarily of the <a href="/articles/medial-rectus-muscle">medial rectus muscle</a>
- +</li>
- +<li>because of its long subarachnoid course and location in the <a href="/articles/dorello-canal">Dorello canal</a>, abducens nerve palsy can be an early sign of increased intracranial pressure</li>
- +</ul>
- +</li>
References changed:
- 1. Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. (2013) <a href="https://books.google.co.uk/books?vid=ISBN9781451119459">ISBN: 9781451119459</a><span class="ref_v4"></span>
- 2. Netter FH. Atlas of Human Anatomy. (2018) <a href="https://books.google.co.uk/books?vid=ISBN9780323393225">ISBN: 9780323393225</a><span class="ref_v4"></span>
- 3. Imaging of the Head and Neck. Thieme. (2012) ISBN:3131505311. <a href="http://books.google.com/books?vid=ISBN3131505311">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/3131505311">Find it at Amazon</a><span class="ref_v3"></span>
- 4. Gray's basic anatomy. Churchill Livingstone. ISBN:1455710784. <a href="http://books.google.com/books?vid=ISBN1455710784">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/1455710784">Find it at Amazon</a><span class="auto"></span>
- 1. Imaging of the Head and Neck. Thieme. (2012) ISBN:3131505311. <a href="http://books.google.com/books?vid=ISBN3131505311">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/3131505311">Find it at Amazon</a><span class="ref_v3"></span>
- 2. Gray's basic anatomy. Churchill Livingstone. ISBN:1455710784. <a href="http://books.google.com/books?vid=ISBN1455710784">Read it at Google Books</a> - <a href="http://www.amazon.com/gp/product/1455710784">Find it at Amazon</a><span class="auto"></span>
Images Changes:
Image 8 Annotated image (Coronal non-contrast) ( create )
Image 9 Annotated image (Coronal bone window) ( create )
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