Inferior rectus muscle: Difference between revisions

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[[file:Slide12uu.JPG|thumb|Slide12uu]] [[file:Slide2abaa.JPG|thumb|Slide2abaa|left]] {{Infobox muscle
[[File:Slide12uu.JPG|thumb]] [[File:Slide2abaa.JPG|thumb]] Inferior Rectus Muscle
| Name        = Inferior rectus muscle
| Latin        = musculus rectus inferior bulbi
| Image        = Inferior_rectus.png
| Caption      = Extrinsic eye muscle. [[Inferior rectus muscle]] shown in red.
| Origin      = [[Annulus of Zinn]]
| Insertion    = 6.5 mm inferior to the [[corneal limbus]]
| Blood        = [[Ophthalmic artery]]
| Nerve        = [[Oculomotor nerve]] (inferior branch)
| Action      = [[Depression (kinesiology)|Depresses]], [[adduction|adducts]], and [[extorsion|extorts]] the [[eyeball]]
| Antagonist  = [[Superior rectus muscle]]
}}


The '''inferior rectus muscle''' is one of the six [[extraocular muscles]] that control the movements of the [[eye]]. It is responsible for the downward movement of the eye, as well as its adduction and extorsion.
The '''inferior rectus muscle''' is one of the six extraocular muscles that control the movements of the eye. It is primarily responsible for the downward movement of the eye, also known as depression. This muscle plays a crucial role in ocular motility and is essential for proper visual alignment and function.


== Anatomy ==
== Anatomy ==
The inferior rectus muscle originates from the [[Annulus of Zinn]], a tendinous ring located at the apex of the [[orbit (anatomy)|orbit]]. It inserts approximately 6.5 mm inferior to the [[corneal limbus]].


== Innervation ==
The inferior rectus muscle is located in the orbit, the bony cavity that houses the eye. It originates from the annulus of Zinn, a tendinous ring located at the apex of the orbit. From its origin, the muscle extends forward and slightly downward to insert into the sclera, the white outer layer of the eyeball, approximately 6.5 mm from the limbus, which is the border between the cornea and the sclera.
The muscle is innervated by the inferior branch of the [[oculomotor nerve]] (cranial nerve III).


== Blood Supply ==
=== Innervation ===
The blood supply to the inferior rectus muscle is provided by the [[ophthalmic artery]].
 
The inferior rectus muscle is innervated by the [[oculomotor nerve]] (cranial nerve III). The oculomotor nerve provides motor innervation to most of the extraocular muscles, including the superior rectus, medial rectus, inferior oblique, and levator palpebrae superioris muscles.
 
=== Blood Supply ===
 
The blood supply to the inferior rectus muscle is primarily provided by the inferior muscular branch of the [[ophthalmic artery]], which is a branch of the internal carotid artery. This ensures that the muscle receives the necessary oxygen and nutrients to function effectively.


== Function ==
== Function ==
The primary function of the inferior rectus muscle is to depress the [[eyeball]]. It also contributes to the adduction and extorsion of the eye. The muscle works in opposition to the [[superior rectus muscle]], which elevates the eye.
 
The primary function of the inferior rectus muscle is to depress the eye, moving it downward. Additionally, it contributes to adduction (moving the eye towards the nose) and extorsion (rotating the top of the eye away from the nose). These actions are important for coordinated eye movements and maintaining binocular vision.


== Clinical Significance ==
== Clinical Significance ==
Dysfunction of the inferior rectus muscle can result in [[strabismus]], where the eyes do not properly align with each other. This can lead to double vision and other visual disturbances.


== Related Pages ==
Dysfunction of the inferior rectus muscle can lead to various ocular motility disorders. For example, weakness or paralysis of the muscle, known as inferior rectus palsy, can result in vertical diplopia (double vision) and difficulty in downward gaze. This condition can be caused by trauma, nerve damage, or other neurological disorders.
 
In some cases, surgical intervention may be required to correct misalignment caused by inferior rectus muscle dysfunction. Procedures such as muscle recession or resection can help restore proper eye alignment and improve visual function.
 
== Also see ==
 
* [[Extraocular muscles]]
* [[Extraocular muscles]]
* [[Oculomotor nerve]]
* [[Oculomotor nerve]]
* [[Superior rectus muscle]]
* [[Annulus of Zinn]]
* [[Ophthalmic artery]]
* [[Ophthalmic artery]]
* [[Strabismus]]
* [[Binocular vision]]
* [[Diplopia]]
 
{{Extraocular muscles}}


[[Category:Muscles of the head and neck]]
[[Category:Extraocular muscles]]
[[Category:Eye anatomy]]
[[Category:Ophthalmology]]
[[Category:Ophthalmology]]
{{Muscle-stub}}

Latest revision as of 00:51, 9 December 2024

Inferior Rectus Muscle

The inferior rectus muscle is one of the six extraocular muscles that control the movements of the eye. It is primarily responsible for the downward movement of the eye, also known as depression. This muscle plays a crucial role in ocular motility and is essential for proper visual alignment and function.

Anatomy[edit]

The inferior rectus muscle is located in the orbit, the bony cavity that houses the eye. It originates from the annulus of Zinn, a tendinous ring located at the apex of the orbit. From its origin, the muscle extends forward and slightly downward to insert into the sclera, the white outer layer of the eyeball, approximately 6.5 mm from the limbus, which is the border between the cornea and the sclera.

Innervation[edit]

The inferior rectus muscle is innervated by the oculomotor nerve (cranial nerve III). The oculomotor nerve provides motor innervation to most of the extraocular muscles, including the superior rectus, medial rectus, inferior oblique, and levator palpebrae superioris muscles.

Blood Supply[edit]

The blood supply to the inferior rectus muscle is primarily provided by the inferior muscular branch of the ophthalmic artery, which is a branch of the internal carotid artery. This ensures that the muscle receives the necessary oxygen and nutrients to function effectively.

Function[edit]

The primary function of the inferior rectus muscle is to depress the eye, moving it downward. Additionally, it contributes to adduction (moving the eye towards the nose) and extorsion (rotating the top of the eye away from the nose). These actions are important for coordinated eye movements and maintaining binocular vision.

Clinical Significance[edit]

Dysfunction of the inferior rectus muscle can lead to various ocular motility disorders. For example, weakness or paralysis of the muscle, known as inferior rectus palsy, can result in vertical diplopia (double vision) and difficulty in downward gaze. This condition can be caused by trauma, nerve damage, or other neurological disorders.

In some cases, surgical intervention may be required to correct misalignment caused by inferior rectus muscle dysfunction. Procedures such as muscle recession or resection can help restore proper eye alignment and improve visual function.

Also see[edit]