Sphincter pupillae muscle

From WikiMD's Wellness Encyclopedia

Sphincter Pupillae Muscle

File:Sphincter pupillae.png
Sphincter pupillae muscle (Image courtesy of Gray's Anatomy)

The Sphincter pupillae muscle is a muscle in the human eye that controls the size of the pupil. It is a circular muscle that forms a ring around the pupil, and is responsible for constricting the pupil in response to bright light.

Structure[edit | edit source]

The sphincter pupillae muscle is located in the iris of the eye. It is a smooth muscle that forms a ring around the pupil. The muscle fibers are arranged in a circular pattern, allowing the muscle to constrict the pupil when it contracts.

Function[edit | edit source]

The primary function of the sphincter pupillae muscle is to control the size of the pupil. It does this by constricting the pupil in response to bright light, a process known as miosis. This helps to protect the retina from damage caused by excessive light exposure.

Clinical significance[edit | edit source]

Damage to the sphincter pupillae muscle can result in a condition known as mydriasis, which is characterized by an abnormally dilated pupil. This can occur as a result of injury, disease, or the use of certain drugs.

See also[edit | edit source]

References[edit | edit source]


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Contributors: Prab R. Tumpati, MD