Orbicularis oculi muscle

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Orbicularis oculi muscle
Gray379.png
Details
Origin Frontal bone; medial palpebral ligament; lacrimal bone
Insertion Lateral palpebral raphe
Artery Ophthalmic, zygomatico-orbital, angular
Nerve Temporal (orbital, palpebral) and zygomatic (lacrimal) branches of facial nerve
Actions Closes eyelids
Antagonist Levator palpebrae superioris
Identifiers
Latin musculus orbicularis oculi also musculus orbicularis palpebrarum
TA98 A04.1.03.013
TA2 2066
FMA 46779
Anatomical terms of muscle

The orbicularis oculi is a muscle in the face that closes the eyelids. It arises from the nasal part of the frontal bone, from the frontal process of the maxilla in front of the lacrimal groove, and from the anterior surface and borders of a short fibrous band, the medial palpebral ligament.

Contents

From this origin, the fibers are directed laterally, forming a broad and thin layer, which occupies the eyelids or palpebræ, surrounds the circumference of the orbit, and spreads over the temple, and downward on the cheek.

Structure

There are at least 3 clearly defined sections of the orbicularis muscle. However, it is not clear whether the lacrimal section is a separate section, or whether it is just an extension of the preseptal and pretarsal sections. [1] [2]

Orbital orbicularis

The orbital portion is thicker and of a reddish color; its fibers form a complete ellipse without interruption at the lateral palpebral commissure; the upper fibers of this portion blend with the frontalis and corrugator.

Palpebral orbicularis

The palpebral portion of the muscle is thin and pale; it arises from the bifurcation of the medial palpebral ligament, forms a series of concentric curves, and is inserted into the lateral palpebral raphe at the outer canthus (corner) of the eye. [3] The palpebral portion contains the preseptal and pretarsal muscles. The pretarsal orbicularis is thought to be responsible for the spontaneous blink.

Lacrimal orbicularis

The lacrimal part is a small, thin muscle, about 6 mm in breadth and 12 mm in length, 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, and passing behind the lacrimal sac, divides into two slips, upper and lower, which are inserted into the superior and inferior tarsi medial to the puncta lacrimalia; occasionally it is very indistinct. The lacrimal orbicularis facilitates the tear pump into the lacrimal sac. [4]

Function

The muscle acts to close the eye, and is the only muscle capable of doing so. Loss of function for any reason results in an inability to close the eye, necessitating eye drops at the minimum to surgical closure of the eye in extreme cases.

The palpebral portion acts involuntarily, closing the lids gently, as in sleep or in blinking; the orbital portion is subject to conscious control. 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 Levator palpebræ superioris is the direct antagonist of this muscle; it raises the upper eyelid and exposes the front of the bulb of the eye. In addition, the orbital and palpebral portions can work independent of each other, as in the furrowing of the brows by contraction of the orbital to reduce glare while keeping the eyes open by virtue of the relaxation of the palpebral. [3]

Each time the eyelids are closed through the action of the orbicularis, the medial palpebral ligament is tightened, the wall of the lacrimal sac is thus drawn lateralward and forward, so that a vacuum is made in it and the tears are sucked along the lacrimal canals into it. The lacrimal part of the orbicularis oculi draws the eyelids and the ends of the lacrimal canals medialward and compresses them against the surface of the globe of the eye, thus placing them in the most favorable situation for receiving the tears; it also compresses the lacrimal sac. This part comprises two pieces: Horner's muscle and the muscle of Riolan, the latter helps hold the eyelids together to keep the lacrimal passage waterproof. [3]

Associated pathology, such as a lesion of the facial nerve seen in Bell's palsy results in the inability to blink or close the ipsilateral eyelid. Subsequent lack of irrigation increases the risk of corneal inflammation and ulcers.[ citation needed ]

A number of auxiliary muscles assist in cooperating with the eyelid muscles. For example, the corrugator supercilii pulls the eyebrows to the bridge of the nose, making a roof over the middle of the forehead and forehead wrinkles, used mainly to protect the eyes from excess sunlight. The procerus (pyramidalis) muscles, in the bridge of the nose, arise from the lower nasal bone to the lower forehead, on each side of the midline. The procerus muscles pull the skin into horizontal wrinkles. The frontalis muscle, which runs from the upper forehead, halfway between the coronal suture (which traverses the top of the skull) and the top edge of the orbit, attaches to the eyebrow skin. Since it pulls the eyebrows upward, it is the antagonist of the orbicularis oculi. It is used in looking up, and increasing vision if there is insufficient light or when objects are far away. [3]

Clinical significance

It is involved in the corneal reflex, part of the assessment of the function of the facial nerve. This can be used to examine the facial nerve even in unconscious patients.

Related Research Articles

Articles related to anatomy include:

Blinking is a bodily function; it is a semi-autonomic rapid closing of the eyelid. A single blink is determined by the forceful closing of the eyelid or inactivation of the levator palpebrae superioris and the activation of the palpebral portion of the orbicularis oculi, not the full open and close. It is an essential function of the eye that helps spread tears across and remove irritants from the surface of the cornea and conjunctiva.

<span class="mw-page-title-main">Eyelid</span> Thin fold of skin that covers and protects the eye

An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. "Palpebral" means relating to the eyelids. Its key function is to regularly spread the tears and other secretions on the eye surface to keep it moist, since the cornea must be continuously moist. They keep the eyes from drying out when asleep. Moreover, the blink reflex protects the eye from foreign bodies. A set of specialized hairs known as lashes grow from the upper and lower eyelid margins to further protect the eye from dust and debris.

<span class="mw-page-title-main">Procerus muscle</span> Small pyramidal slip of muscle deep to the superior orbital nerve, artery and vein

The procerus muscle is a small pyramidal slip of muscle deep to the superior orbital nerve, artery and vein. Procerus is Latin, meaning tall or extended.

<span class="mw-page-title-main">Ophthalmic artery</span> Artery of the head

The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some structures in the nose, face, and meninges. Occlusion of the ophthalmic artery or its branches can produce sight-threatening conditions.

<span class="mw-page-title-main">Corrugator supercilii muscle</span> Muscle near the eye

The corrugator supercilii muscle is a small, narrow, pyramidal muscle of the face. It arises from the medial end of the superciliary arch; it inserts into the deep surface of the skin of the eyebrow.

<span class="mw-page-title-main">Frontalis muscle</span>

The frontalis muscle is a muscle which covers parts of the forehead of the skull. Some sources consider the frontalis muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscle along with the occipitalis muscle.

<span class="mw-page-title-main">Ophthalmic nerve</span> Sensory nerve of the face

The ophthalmic nerve (CN V1) is a sensory nerve of the head. It is one of three divisions of the trigeminal nerve (CN V), a cranial nerve. It has three major branches which provide sensory innervation to the eye, and the skin of the upper face and anterior scalp, as well as other structures of the head.

<span class="mw-page-title-main">Tarsus (eyelids)</span>

The tarsi or tarsal plates are two comparatively thick, elongated plates of dense connective tissue, about 10 mm (0.39 in) in length for the upper eyelid and 5 mm for the lower eyelid; one is found in each eyelid, and contributes to its form and support. They are located directly above the lid margins. The tarsus has a lower and upper part making up the palpebrae.

<span class="mw-page-title-main">Lacrimal artery</span> Artery of the orbit

The lacrimal artery is an artery of the orbit. It is a branch of the ophthalmic artery. It accompanies the lacrimal nerve along the upper border of the lateral rectus muscle, travelling forward to reach the lacrimal gland. It supplies the lacrimal gland, two rectus muscles of the eye, the eyelids, and the conjunctiva.

<span class="mw-page-title-main">Lacrimal canaliculi</span> Small channels in each eyelid that drain lacrimal fluid

The lacrimal canaliculi are the small channels in each eyelid that drain lacrimal fluid, from the lacrimal puncta to the lacrimal sac. This forms part of the lacrimal apparatus that drains lacrimal fluid from the surface of the eye to the nasal cavity.

<span class="mw-page-title-main">Lacrimal sac</span> Upper, dilated end of the nasolacrimal duct

The lacrimal sac or lachrymal sac is the upper dilated end of the nasolacrimal duct, and is lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla. It connects the lacrimal canaliculi, which drain tears from the eye's surface, and the nasolacrimal duct, which conveys this fluid into the nasal cavity. Lacrimal sac occlusion leads to dacryocystitis.

The anterior lacrimal crest is a bony projection on the frontal process of the maxilla. It creates the lateral margin of the lacrimal sac fossa and is continuous with the orbital margin. The medial palpebral ligament is attached to anterior lacrimal crest. It is an important structure to avoid damaging during rhinoplasty.

<span class="mw-page-title-main">Medial palpebral ligament</span> Ligament connecting the maxilla and the lacrimal bone to the eyelids

The medial palpebral ligament is a ligament of the face. It attaches to the frontal process of the maxilla, the lacrimal groove, and the tarsus of each eyelid. It has a superficial (anterior) and a deep (posterior) layer, with many surrounding attachments. It connects the medial canthus of each eyelid to the medial part of the orbit. It is a useful point of fixation during eyelid reconstructive surgery.

<span class="mw-page-title-main">Frontal process of maxilla</span> Plate which forms part of the lateral boundary of the nose

The frontal process of the maxilla is a strong plate, which projects upward, medialward, and backward from the maxilla, forming part of the lateral boundary of the nose.

<span class="mw-page-title-main">Angular artery</span> Artery of the face

The angular artery is an artery of the face. It is the terminal part of the facial artery. It ascends to the medial angle of the eye's orbit. It is accompanied by the angular vein. It ends by anastomosing with the dorsal nasal branch of the ophthalmic artery. It supplies the lacrimal sac, the orbicularis oculi muscle, and the outer side of the nose.

<span class="mw-page-title-main">Medial palpebral arteries</span>

The medial palpebral arteries are arteries of the head that contribute arterial blood supply to the eyelids. They are derived from the ophthalmic artery; a single medial palpebral artery issues from the ophthalmic artery before splitting into a superior and an inferior medial palpebral artery, each supplying one eyelid.

<span class="mw-page-title-main">Zygomatic branches of the facial nerve</span> Nerves of the face

The zygomatic branches of the facial nerve (malar branches) are nerves of the face. They run across the zygomatic bone to the lateral angle of the orbit. Here, they supply the orbicularis oculi muscle, and join with filaments from the lacrimal nerve and the zygomaticofacial branch of the maxillary nerve (CN V2).

<span class="mw-page-title-main">Lateral palpebral raphe</span> Ligamentous band at the lateral edge of the eyelids

The lateral palpebral raphe is a ligamentous band near the eye. Its existence is contentious, and many sources describe it as the continuation of nearby muscles. It is formed from the lateral ends of the orbicularis oculi muscle. It connects the orbicularis oculi muscle, the frontosphenoidal process of the zygomatic bone, and the tarsi of the eyelids.

<span class="mw-page-title-main">Accessory visual structures</span> External parts of the eye including eyebrow, eyelid, and lacrimal apparatus

The accessory visual structures are the protecting and supporting structures (adnexa) of the eye, including the eyebrow, eyelids, and lacrimal apparatus. The eyebrows, eyelids, eyelashes, lacrimal gland and drainage apparatus all play a crucial role with regards to globe protection, lubrication, and minimizing the risk of ocular infection. The adnexal structures also help to keep the cornea moist and clean.

References

PD-icon.svgThis article incorporates text in the public domain from page 380 of the 20th edition of Gray's Anatomy (1918)

  1. ↑ Eyelid Anatomy at eMedicine
  2. ↑ http://vmede.org/sait/content/Anatomija_bili4_t1/4_files/mb4_216.jpeg%5B%5D
  3. 1 2 3 4 "Eye, Human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2010
  4. ↑ Becker, Bruce B. (1992). "Tricompartment Model of the Lacrimal Pump Mechanism". Ophthalmology. 99 (7): 1139–45. doi:10.1016/S0161-6420(92)31839-1. PMID   1495795.
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