Maximus Gage
The orbicularis oculi muscle is situated just beneath the eyelid skin and is responsible for eyelid movement. It extends from the medial to the lateral canthal region, enhancing the eyelid's structural integrity and functionality. The muscle is divided into orbital and palpebral sections, each further subdivided based on function. The orbital portion of the orbicularis oculi facilitates the forceful closure of the eyelids, while the palpebral portion acts involuntarily, closing the lids gently during blinking or sleep. The lacrimal part of the orbicularis oculi, also known as Horner's muscle, facilitates tear drainage and is the only muscle capable of closing the eye.
| Characteristics | Values |
|---|---|
| Name of the muscle that closes the eye | Orbicularis oculi |
| Location | Beneath the eyelid skin |
| Appearance | Flat, broad and thin |
| Shape | Sphincter-like |
| Parts | Orbital, palpebral, deep palpebral, lacrimal, marginal |
| Function | Closes the eyelids, assists with tear drainage, involved in facial expression, ocular protection and reflexes |
| Innervation | Facial nerve (CN7) |
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What You'll Learn
- The orbicularis oculi muscle is a sphincter-like muscle that surrounds the eyelids
- The palpebral portion of the orbicularis oculi muscle controls blinking and sleeping
- The orbital portion of the orbicularis oculi muscle is subject to conscious control
- The lacrimal part of the orbicularis oculi muscle is responsible for tear drainage
- Paralysis of the facial nerve results in an inability to close the eye
The orbicularis oculi muscle is a sphincter-like muscle that surrounds the eyelids
The orbicularis oculi muscle is a thin, flat muscle that sits just beneath the skin of the eyelids. It is a facial expression muscle that surrounds the upper and lower eyelids, extending from the medial to the lateral canthal region. This muscle is responsible for eyelid movement and is the only muscle capable of closing the eyes.
The orbicularis oculi muscle is divided into three parts: the orbital, palpebral, and deep palpebral parts. Each part has its own specific attachments and functions. The orbital portion is thicker and reddish in colour, while the palpebral portion is thin and pale. The orbital part overlays the orbita and blends with the frontalis and corrugator muscles. The palpebral part contains the preseptal and pretarsal muscles, with the latter believed to be responsible for the spontaneous blink.
The palpebral portion of the orbicularis oculi muscle acts involuntarily to close the eyelids gently during sleep or blinking. This protective action helps to keep the eyes moist by distributing tears across the surface of the eyeball. It also facilitates non-verbal communication and expression. The orbital portion, on the other hand, is subject to conscious control. When the entire muscle is brought into action, the eyelids are firmly closed, as in photophobia.
The deep palpebral part of the orbicularis oculi muscle pulls the eyelids and lacrimal papillae medially, facilitating tear drainage across the cornea. It also compresses the lacrimal gland and ducts to improve tear flow. This part of the muscle consists of two sections: the Horner muscle and the muscle of Riolan. The muscle of Riolan helps to hold the eyelids together to maintain a waterproof lacrimal passage.
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The palpebral portion of the orbicularis oculi muscle controls blinking and sleeping
The orbicularis oculi muscle is a sphincter-like muscle in the face that closes the eyelids. It is a flat, broad muscle that forms an ellipse around the circumference of the orbit. The muscle fibres compose the eyelids and extend into the eyebrows, temporal and infraorbital regions. The orbicularis oculi is divided into orbital and palpebral sections, each further subdivided based on function.
The palpebral portion of the orbicularis oculi muscle is thin and pale. It arises from the bifurcation of the medial palpebral ligament and forms a series of concentric curves. The palpebral portion contains the preseptal and pretarsal muscles. The pretarsal orbicularis is responsible for the spontaneous blink. The muscle acts to close the eye, and is the only muscle capable of doing so.
The palpebral portion acts involuntarily, closing the lids gently, as in sleep or in blinking. When the entire muscle is brought into action, the skin of the forehead, temple, and cheek is drawn toward the medial angle of the orbit, and the eyelids are firmly closed, as in photophobia. The skin thus drawn upon is thrown into folds, especially radiating from the lateral angle of the eyelids; these folds become permanent in senescence, and form the so-called "crow's feet".
The deep palpebral part, also known as the lacrimal part, originates from the lateral surface and lacrimal crest (superior part) of the lacrimal bone. The fibres course laterally, passing posterior to the lacrimal sac. Some insert into the superior and inferior tarsi of eyelids, while others continue past the tarsi to insert into the lateral palpebral ligament. The lacrimal orbicularis facilitates the tear pump into the lacrimal sac.
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The orbital portion of the orbicularis oculi muscle is subject to conscious control
The orbicularis oculi muscle is responsible for closing the eyes. This muscle is situated just beneath the eyelid skin and extends from the medial to the lateral canthal region. The muscle is divided into two sections: the orbital portion and the palpebral portion. The orbital portion of the orbicularis oculi muscle is subject to conscious control, meaning that it can be voluntarily contracted to close the eyelids. This is in contrast to the palpebral portion, which acts involuntarily to close the eyelids during blinking or sleep.
The orbital portion of the orbicularis oculi muscle is thicker and has a reddish colour, while the palpebral portion is thin and pale. The orbital portion forms a complete ellipse without interruption at the lateral palpebral commissure, with its upper fibres blending with the frontalis and corrugator muscles. The palpebral portion, on the other hand, arises from the bifurcation of the medial palpebral ligament and forms a series of concentric curves. It is inserted into the lateral palpebral raphe at the outer corner of the eye.
The orbital portion of the orbicularis oculi muscle primarily facilitates the voluntary and forceful closure of the eyelids. It attaches medially to the anterior limb of the medial canthal tendon and the surrounding periosteum. Laterally, it connects to the lateral palpebral raphe. The contraction of the orbital portion draws the skin of the forehead and cheek towards the nose, limiting exposure to potential damaging factors such as bright light or blowing dust.
The palpebral portion of the orbicularis oculi muscle, on the other hand, is responsible for the gentle closure of the eyelids during blinking or sleep. It can also act involuntarily as a reflex mechanism to protect the eyes by spreading tears produced by the lacrimal gland across the surface of the eyeball. The palpebral portion contains the preseptal and pretarsal muscles, with the pretarsal orbicularis being thought to be responsible for the spontaneous blink.
The orbicularis oculi muscle is innervated by the facial nerve (CN7) and is crucial for eyelid movement and tear drainage. It is a facial expression muscle that may be affected by conditions such as Bell's palsy, resulting in an inability to close the eye. Understanding the anatomy and function of this muscle is essential for treating various eye and cosmetic conditions.
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The lacrimal part of the orbicularis oculi muscle is responsible for tear drainage
The orbicularis oculi muscle is responsible for closing the eye. It is a sphincter-like muscle arranged concentrically around the upper and lower eyelids. The muscle is divided into orbital and palpebral sections, with the orbital portion facilitating the forceful closure of the eyelids.
The lacrimal part of the orbicularis oculi muscle is a small, thin muscle, situated behind the medial palpebral ligament and lacrimal sac. It arises from the posterior crest and adjacent part of the orbital surface of the lacrimal bone. This muscle is also known as Horner's muscle, attaching posteriorly to the medial canthal tendon and the posterior lacrimal crest. The lacrimal part of the orbicularis oculi draws the eyelids and the ends of the lacrimal canals medialward, compressing them against the surface of the eye. This action places the lacrimal canals in a favourable position for receiving tears.
The lacrimal part of the orbicularis oculi also compresses the lacrimal sac, creating a vacuum that sucks tears along the lacrimal canals. This process is known as the tear pump, facilitating tear drainage. The muscle acts to close the eye, and it is the only muscle capable of doing so. The palpebral portion of the orbicularis oculi also plays a role in tear drainage by wiping tears produced by the lacrimal gland across the surface of the eyeball, keeping it moist and free of irritating particles.
The orbicularis oculi muscle is innervated by the facial nerve (CN7) and receives arterial blood from three branches of the external carotid artery: the maxillary, superficial temporal, and facial arteries. The ophthalmic artery, a branch of the internal carotid artery, also supplies the muscle. Understanding the anatomy and function of this muscle is essential for treating various eye and cosmetic conditions, such as Bell's palsy and blepharospasm.
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Paralysis of the facial nerve results in an inability to close the eye
The orbicularis oculi muscle, situated just beneath the eyelid skin, is crucial for eyelid movement. This muscle extends from the medial to the lateral canthal region, enhancing the eyelid's structural integrity and functionality. The main function of the orbicularis oculi muscle is to close the eyelids, and it also assists with tear drainage.
Paralysis of the facial nerve can result in an inability to close the eye. Bell's palsy is a condition that causes temporary facial paralysis, usually on just one side of the face. It is caused by inflammation and swelling of the seventh cranial nerve, which controls the facial muscles. This nerve can also be affected by conditions such as Lyme disease, sarcoidosis, and bacterial infections. In some cases, facial paralysis is permanent, but many people may see improvement or a complete recovery with time and/or treatment.
There are several treatments available for facial paralysis, including nonsurgical and surgical options. Nonsurgical treatments include corticosteroids to reduce inflammation, antivirals to fight infection, and botox injections to treat involuntary muscle movements. Surgical options include cosmetic surgery to restore facial balance and symmetry, and eyelid surgery to support eye closure and improve blinking.
The inability to close the eye due to facial nerve paralysis can lead to chronic dry eyes and other complications. As a result, treatments to prevent eye dryness are often recommended, such as eye drops and ointments, taping the eyelids, eye patches, and temporary eyelid closure with sutures.
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Frequently asked questions
The orbicularis oculi muscle, also known as the orbicularis muscle, is responsible for closing the eye.
The orbicularis oculi muscle is divided into orbital, palpebral, and deep palpebral parts. The orbital portion is thick and reddish, while the palpebral portion is thin and pale. The deep palpebral part is involved in tear drainage across the cornea.
Loss of function of the orbicularis oculi muscle results in an inability to close the eye. This can lead to conditions such as dry eye syndrome due to inefficient lubrication. In extreme cases, surgical closure of the eye may be required.
