Orbicularis Oculi

In short: Orbicularis oculi, the second most powerful facial muscle surrounding the eyes; It consists of three anatomy parts (orbital, palpebral, lacrimal), voluntaria controls closed bite, involuntaria controls blinking and tear pump. As the creator of dynamic crow's feet lines, the primary target in medical aesthetics and Botox applications; Injection depth and protection areas are critical in surgical and aesthetic interventions.

Definition and Historical Perspective

Orbicularis oculi muscle (Latin: orbicularis = "circular", oculi = "eye") is one of the most prominent facial muscles of the human face and is an esphincter-type muscle that surrounds the entire area around the eye. In the 16th century, Andreas Vesalius described the structure of this muscle as "the strong ring that closes the eyelids"; He showed the medial and lateral division of the orbicularis oculi in his detailed anatomy illustrations.

In the 19th and 20th centuries, electromyographic studies revealed the complex functional organization of the orbicularis oculi—functions not only for eyelid closure but also for involuntary blink, lacrimal tract drainage (Horner's muscle), and emotional expression (Duchenne smile). In the 21st century, after botulinum toxin (Botox) became widespread in the field of medical aesthetics, the orbicularis oculi became the primary target of crow's feet (lateral canthus wrinkles) treatment—accounting for approximately 40-50% of aesthetic Botox applications.

Anatomical Structure

Three Parts: Orbicularis oculi is anatomically divided into three parts:

(1) Orbital Part (Pars Orbitalis): The thicker, outer voluntaria is the part that makes a tight closure. It originates medially from the medial palpebral ligament, and superomedially from the frontal bone and frontal process of maxilla. It is located from lateral to lateral palpebral raphe (fibrous band in the lateral canthus). Muscle fibers complete and close the eye socket; The muscle strength of this section is prominent and provides tight eyelid closure (voluntar closure). In the orbital part, fiber orientation is multidirectional, including medial-lateral and superoinferior — this multi-directional organization provides the complex closure mechanism of the eye area.

(2) Palpebral Part (Pars Palpebralis): It is located within the thickness of the upper and lower eyelids. Involuntaria is responsible for the reflex blink and gentle closure function. The normal blinking rate is 15-20 times per minute, and this reflex is triggered through the ophthalmic branch of the trigeminal nerve (CN V). The palpebral section shows a thinner, more sensitive fiber structure in electron microscopy studies stained with the Sihler method.

(3) Lacrimal Part (Pars Lacrimalis - Horner Muscle): Thin muscle bundles located around the most medial, eye canal. It originates from the medial palpebral ligament, monitors the lacrimal sacs and lacrimal ducts (canaliculi), and assists tear drainage through pump action. This part draws tears into the horizontal and vertical channels during blinking; It is critical in normal lacrimal drainage physiology. Patients with lacrimal blockage or experiencing excessive dorsal tear flow (epiphora) after Botox injection have frequently been observed to have blockage or lacrimal system dysfunction.

Innervation (Nerve Transport): Orbicularis oculi is innervated by the temporal and zygomatic branches of the facial nerve (CN VII). The motor enneogram is the most complex of the facial muscle contacts—experimental data show that in the orbital portion both the temporal and zygomatic branches contribute, while in the palpebral portion the zygomatic branch is dominant. This bilateral structure of innervation is a point that should be taken into consideration during Botox injection, and injectors should know the anatomical landmarks well.

Blood Transport (Vascularity): The orbicularis oculi is richly vascularized by branches of the facial artery, superficial temporal artery, and ophthalmic artery. While the medial part is fed by the anterior ethmoid artery and the medial palpebral artery; The lateral part is supplied by the palpebral branches of the superficial temporal artery and the lacrimal artery. This vascular density is important because it increases the risk of hematoma during injection—periorbital purpura is common after Botox injection, especially in anticoagulant users or patients with platelet dysfunction.

Muscle Fiber Type and Histology: Orbicularis oculi consists of a mixture of Type I (slowly contracting, aerobic) and Type II (fast, anaerobic) fibres; Type II fibers are more abundant in the orbital part (for voluntary force contraction), while the balance is more equal in the palpebral part (for automatic blinking). Muscle fiber diameter is normally in the range of 30-60 microns, and hypertrophy or atrophy may be observed after chronic use (such as bruxism) or Botox injection.

Function and Biomechanics

Eyelid Closure: The primary function of the orbicularis oculi is to close the eyelids. Voluntarian closure (tight, deliberate closure) occurs through strong contraction of the orbital part — this ensures complete closure of the eyelid in contact with the cuticle (conjunctiva) and cornea (cornea). Normal eye blink (involuntary reflex blink) occurs within 0.3 seconds through the smooth, rhythmic contraction of the palpebral part.

Lateral Kanthal Rhytides (Crow's Feet Lines): Contraction of the orbicularis oculi creates dermal folding in the lateral canthus (outer corner of the eye) area—this creates permanent wrinkles over time after repeated contraction cycles. Crow's feet lines are divided into dynamic (appearing during contraction) and static (appearing even in a relaxed position). Aging, sun damage (UV exposure) and repetitive facial movement accelerate the development of static crow's feet. In the field of medical aesthetics, crow's feet treatment is done through Botox injection aimed at lateral orbicularis oculi fiber blocking.

Tear Drainage (Lacrimal Pump Function): During blinking, the lacrimal part (Horner's muscle) contracts and traction is applied to the lacrimal sacks through the medial palpebral ligament; This pump action drains the tears to the naso-lacrimal duct via the lacrimal ducts. The blink sequence is repeated 15-20 times per minute; Thus, tears are continuously absorbed from the surface and drained into the nasopharynx. Depending on this mechanism, orbicularis oculi function is integrated with lacrimal system health; Orbicularis oculi dysfunction (for example: loss of contraction, palsy) may cause epiphora (tears flowing on the face).

Emotional Expression: Orbicularis oculi creates a friendly smile (Duchenne smile), especially during bilateral contraction. In coordination with the zygomatic major muscle, creating characteristic wrinkles around the eyes, this physiognomic pattern has been recognized in sociology and psychology as an indicator of intimate emotional response (AU6—"Cheek Raiser" in Ekman's Facial Action Coding System).

Clinical Significance and Pathological Conditions

Crow's Feet Botulinum Toxin: Orbicularis oculi is the primary target muscle in medical aesthetic interventions. Botox injection into the lateral orbicularis oculi fiber softens lateral canthus wrinkles and sometimes provides "lateral brow elevation" (external brow lift). The injection technique is important: superficial, in 3-4 Units/point in the subdermis layer (1-2 mm deep), 1-1.5 cm laterally from the lateral canthus. Results peak between 2 weeks and 1 month and last for 3-4 months. The risk of "surprised look" or lagophthalmos (exompleat eye closure) due to excessive lateral orbicularis blockade is seen with very high dose injection or incorrect medial placement.

Orbicularis Oculi Palsy (Facial Nerve Neuropathy): Bilateral or unilateral Bell's palsy (7th nerve palsy) causes loss of orbicularis oculi muscle strength. In this case, the eyelid does not close completely (lagophthalmos), creating the risk of keratitis and scarring through corneal exposure. Treatment includes glasses, artificial tears, eye protection ointment, protective taping, and in severe cases, tarrafal nerve transfer or orthosis (eye cover). Botox or fillers are not therapeutic in this case and should be avoided.

Orbicularis Oculi Hypertrophy (Benign): Periorbital muscle hypertrophy (swelling, fullness) may develop due to chronic contraction-spasm (myochemia), stress or caffeine. Eyelid retraction or edema (swelling) may be observed. Treatment: stress management, caffeine reduction, local heat application, myorelaxants (Botox in severe cases).

Myokimia (Involuntary Spasmus): Periorbital myokymia is involuntary, rhythmic twitching of the orbicularis oculi or levator palpebrae superior. It may be benign (idiopathic) or secondary to MS, myasthenia gravis, brain stem lesion. Treatment: mostly conservative (observation, stress reduction, caffeine removal); In severe cases, Botox or myorelaxants may be helpful.

Blepharitis and Dermatitis (Inflammation): Inflammation and edema develop in the orbicularis oculi area after eyelid dermatitis, atopic or seborrheic dermatitis, and contact allergy. This can affect blinking and lead to lacrimal dysfunction.

Orbicularis Retaining Ligament (ORL) and Blepharoplasty Landmark: In eyelid surgery, the orbicularis retaining ligament is the fiber band between the preseptal and postseptal of the lower eyelid. During blepharoplasty (eyelid surgery), the ORL must be preserved because cutting it can cause senescent eyelid ptosis and a "hollow eye" appearance.

Comparison: Facial Expression Muscles

Orbicularis oculi is one of the most complex facial muscles. Comparison with other eye-surrounding muscles:

1. Orbicularis Oculi (Eye Contour): Esphincter, 3 parts, voluntaria + involuntaria, without mimic expression and lacrimal pump.

2. Corrugator Supercilii (Eyebrow Retractor): Inner eyebrow recession, frown lines, medial depressor (Batch 5 peer).

3. Frontalis (Forehead Muscle): Eyebrow lifter, horizontal forehead lines, agonist-antagonist relationship orbicularis oculi (Batch 5 peer).

4. Procerus (Between the Eyebrows): Contribution to brown lines, medial lower brow depressor (Batch 5 peer).

Functional Synergy: Authentic smile is formed by the coordination of orbicularis oculi (Duchenne's marker) + zygomaticus major + levator labii superioris. In botox injection strategies, this synergistic relationship should be taken into consideration and the risk of over-correction should be minimized.

Developmental and Changes with Age

Fetal and Neonatal Period: Orbicularis oculi develops embryologically from mesodermal tissue originating from the pharyngeal arch in the facial nerve (CN VII) innervation region. At birth, the orbicularis oculi is functional, the newborn's protective eye closure reflex (corneal reflex) is present and the blink reflex is anatomically ready.

Childhood and Adolescence (0-18 years): The orbicularis oculi grows parallel to the eyelid size during growth and development. In children and early adolescence, dynamic crow's feet lines are minimal because skin elasticity is high and muscle-skin contact is better. During puberty, as hormonal changes and solar exposure increase, the first fine lines (dynamic crow's feet) begin to appear in the 20s and 30s.

Adulthood (25-45 years): Orbicularis oculi contraction frequency (mimic frequency) varies depending on professional and social activities. In people with sunny, outdoor work and intense sun exposure, static crow's feet lines develop earlier (even in their 30s). The use of Botox has become widespread in this age group.

Middle Age (45-60 years): Dermal collagen and elastin loss is evident in the orbicularis oculi area. Eyelid skin elasticity decreases, static crow's feet lines deepen, and periorbital hollowness develops. During this period, the combination of Botox and fillers is frequently preferred — Botox + hyaluronic acid filler synergy addresses volume loss and dynamic wrinkles at the same time.

Old age (60+ years): Orbicularis oculi atrophy, skin sagging, and upper and lower eyelid ptosis develop. Lacrimal dysfunction (dry eye syndrome) is common because the contraction efficiency of the lacrimal part of the orbicularis is reduced. Surgical blepharoplasty can be performed for functional and aesthetic indications; However, Botox use should be done more gently in this age group (lower dose, medial-focused placement), because the risk of levator palpebrae palsy is higher and the healing capacity is low.

Treatment Options and Interventions

1. Botulinum Toxin (Botox) — Crow's Feet Injection: The most common, non-invasive treatment method. Injection technique: 1-1.5 cm laterally from the lateral canthus, preseptal muscle, subdermis (1-2 mm depth), 3-4 Units/point, typically 3 Units applied to 3-4 points = total 9-12 Units/side. It softens dynamic crow's feet lines by blocking the lateral orbicularis oculi fiber. Result: 2 weeks-1 month. Duration: 3-4 months. Complications: lagophthalmos, "surprised look", ptosis (rare, from incorrect placement).

2. Hyaluronic Acid Filler (Dermal Filler): For periorbital hollowness or volume loss. It is injected into the middle dermis, around the lateral canthus ("tear trough") and into the temporal region. Dose: 0.3-0.5 mL/side. Result: immediate (peak after 3-5 days of edema). Duration: 9-12 months. Technique: ultra-fine cannula, periosteal placement to avoid vascular occlusion (lateral canthal artery risk).

3. Radiofrequency (RF) and Microneedling: It softens fine lines through collagen remodeling. Course: 1-2 sessions per week, 4-6 weeks. Gradual improvement, natural-looking results; but it is not as fast as Botox.

4. Fractionated Laser Resurfacing (CO2, Erbium:YAG): Epidermis and dermal rejuvenation. Meticulous application is required on the orbicularis oculi. Downtime: 1-2 weeks. Risks: postinflammatory hyperpigmentation, persistent erythema.

5. Blepharoplasty (Surgery): In functional (sagging eyelid, visual obstruction) or aesthetic (appearance of the area) indication. Preseptal + postseptal dissection, fat hernia removal, ORL preserve. Orbicularis oculi should be preserved (not partial resection, full preserve), and the retaining ligament should remain intact.

Pathological Differential Diagnosis — Periorbital Bulging and Twitching

Status	finding	Etiology	Diagnosis	treatment
Dynamic Crow's Feet (Dynamic Wrinkles)	Lateral canthus lines during smiling/blinking	Orbicularis oculi contraction, aging, UV exposure	Clinical observation, resting vs dynamic assessment	Botox 9-12 U/side, sunscreen, retinoid
Static Crow's Feet (Static Wrinkles)	Lateral canthus lines visible in resting position, external eyebrow linea de bolt	Chronic sun damage, collagen loss, orbicularis hypertrophy	clinical appearance	Botox + filler (tear trough) + laser resurfacing
Periorbital Edema (Swelling)	Swelling around the eyes, "puffy eyes"	Allergic reaction, contact dermatitis, sinusitis, sleep disorder, fluid retention	History (allergy exposure, sleep deprivation), visual examination, imaging (CT sinus)	Allergen avoidance, topical steroid, cool compress, address underlying cause
Periorbital Myokimia	Involuntaria eyelid twitching, rhythmic spasmus	Stress, caffeine, benign idiopathic; MS, secondary to myasthenia gravis	History, clinical exam, EMG (in doubt)	Stress reduction, caffeine removal, warm compress, Botox (heavy), serology/imaging secondary cause rule-out
Bell's Palsy (CN VII Palsy)	Loss of eyelid closure, lagophthalmos, corneal exposure	Facial nerve neuropathy (viral, traumatic, tumor)	Clinical (coronal frown loss, eye closure asymmetry), EMG, NCS, imaging (MRI nerve)	Steroid (acute), artificial tears, eye ointment, protective eyewear, eyelid weight/tarsal strips, nerve transfer (chronic recovery poor)
Levator Palpebrae Palsy (Ptosis)	Upper eyelid sagging, visual obstruction, unilateral/bilateral	CN III (oculomotor) palsy, myasthenia, myogenic atrophy, aging, Botox iatrogenic	Margin reflex distance (MRD), levator function test, imaging (MRI orbit)	Müller muscle resuspension, levator aponeurosis plication (surgery), eyelid crutch (temporary), Botox injection antagonist muscle (lateral brow lift auxiliary)
Blepharospasm (Involuntary Eyelid Closure)	Orbicularis oculi involuntarya sustained contraction, forced eye closure	Benign essential blepharospasm (idiopathic), secondary (dystonia, Parkinson's, light sensitivity)	Clinical exam, EMG, MRI (secondary cause rule-out)	Botox injection orbicularis oculi (therapeutic — 20-25 U/side), antihistamine, sunglasses, behavioral therapy
Periorbital Xanthelasma (Lipid Deposit)	Yellowish nodule medial canthus, usually bilateral	Hypercholesterolemia, lipid metabolism disorder	Clinical appearance, lipid panel	Statin therapy, topical retinoid, surgical excision (aesthetics), chemical cauterization
Lagophthalmos (Exsompleat Eye Closure)	The eyelid does not close completely, strip exposure on the cornea	CN VII palsy, orbicularis oculi weakness, eyelid retraction, iatrogenic Botox	Clinical (Bell's test — try to close the eye, the sclera is visible), forward gaze lagophthalmos index	Artificial tears, eye ointment, protective eyewear, lower lid weight, upper eyelid gold weight implant (chronic), orbicularis oculi repair/transfer (surgery)

Related Terms and Cross-References

Crow's Feet Botox — Orbicularis oculi lateral fiber Botox treatment, technique, results, crow's feet lift.

Botox (Botulinum Toxin) — General botox physiology, injection technique, adverse effects.

Frontalis Muscle — Eyebrow lifter, orbicularis oculi agonist-antagonist relationship (Batch 5 peer).

Corrugator Supercilii — Inner eyebrow puller, glabellar frown; coordination with orbital orbicularis (Batch 5 peer).

Fox-Eye Lift — Lateral orbicularis disinsertion, poor results, technique.

Masseter Muscle — Anatomy peer, Batch 4 reference (AnatomicalStructure).

Forehead Botox — Frontalis treatment, adjacent to lateral brow lift.

Frequently Asked Questions (FAQ)

1. When do crow's feet lines appear?

   Dynamic crow's feet lines (appearing when smiling or blinking) typically begin to appear in the 20s to 30s; It occurs earlier, especially in cases of high UV exposure or expressive mimic habits. Static crow's feet (which also appear in the resting position) become more noticeable at age 40+ due to loss of dermal collagen.

2. How effective is Botox for crow's feet?

   Botox is very effective for dynamic crow's feet lines (80-90% improvement). On static lines, Botox alone may have limited effect; In this case, a combination of fillers (hyaluronic acid) or laser resurfacing gives better results.

3. Can Botox damage the eyelid during injection?

   It is rare, and in case of incorrect placement (injection towards the medial or too deep), ptosis (upper eyelid droop) may develop through diffusion to the levator palpebrae superior. A talkative and experienced injector minimizes this risk; Attention should be paid to anatomical landmarks and superficial injection depth (1-2 mm).

4. What is a "surprised look" and how does it occur?

   When very high doses of Botox are injected into the lateral orbicularis oculi, the lateral eyebrow elevation becomes excessive and the facial expression appears "surprised." This is an aesthetic problem and is corrected after 3-4 months as the Botox effect decreases; The dose should be reduced in the second application.

5. What is the risk of lagophthalmos after Orbicularis oculi Botox?

   Lagophthalmos (eyelid incomplete closure) is seen in excessive orbicularis oculi blockage or levator palpebrae posterior diffusion; However, crow's feet is very rare with standard dosage (9-12 U/side) and technique. The risk increases with very high doses (20+ U), medial placement, pre-existing eyelid weakness or CN VII palsy.

6. Does filler (filler) help with crow's feet lines?

   Hyaluronic acid filler is effective in the treatment of periorbital hollowness and tear trough. The lateral canthus plays a limited auxiliary role in filler the fine lines; Instead, the combination of Botox + atrazine-targeted resurfacing is more effective.

7. Why does orbicularis oculi contraction (myochemia) occur and what is the treatment method?

   Benign idiopathic myokymia frequently develops due to stress, caffeine, and sleep deprivation. Treatment: stress management, caffeine reduction, heat application. In severe, persistent cases, secondary cause (MS, myasthenia) rule-out with Botox (10-15 U/side orbicularis) or serology/imaging is required.

8. What is the function of the lacrimal pump (Horner's muscle)?

   The lacrimal part of the orbicularis oculi pulls the sacks through the medial palpebral ligament during blinking, draining the tears into the lacrimal duct and naso-lacrimal duct. This may cause loss of pump function (orbicularis paralysis, dry eye reflex), epiphora (tears flowing on the face) or rhinitis after epiphora.

9. Why is orbicularis oculi important during blepharoplasty?

   During blepharoplasty, it is critical to preserve the orbicularis retaining ligament (ORL); Cutting it off may cause postoperative "hollow eye" appearance, risk of ectropion, and senescent ptosis. Additionally, anteroinferior displacement of the orbicularis oculi muscle may create the appearance of preseptal fat hernia.

10. What is the connection between UV exposure and crow's feet?

    Chronic solar UV exposure accelerates dermal collagen and elastin degradation, especially around the delicate periorbital area. UV damage itself deepens dynamic wrinkles and triggers the formation of static crow's feet. Consistent use of Sunscreen SPF 30+ is essential in Crow's Feet Prevention.

11. Can Orbicularis oculi Botox cause facial asymmetry?

    If bilateral Botox dose and placement are not symmetrical, facial asymmetry (one side eyebrow higher, the other side lower) may occur. Experienced injectors minimize this by using mirror anatomy and bilateral palpation-guided placement. Asymmetry decreases in 4-6 weeks (Botox absorbs), touch-up can be done after 2 weeks for the necessary correction.

Op. Dr. Hamza Gemici Comment

From a Plastic and Reconstructive Aesthetic Surgery perspective, the orbicularis oculi is the central structure in the treatment of crow's feet and periorbital aging. In my 20+ years of clinical experience, I have observed that the "light up" of the eyes is directly related to the youthful, non-wrinkled eye area. 40-50% of Botox applications focus on the orbicularis oculi lateral fiber.

In terms of technique, crow's feet Botox is one of the most meticulous applications in the field of medical aesthetics. By using superficial injection depth (1-2 mm), precise lateral placement (1-1.5 cm lateral from the lateral canthus), and conservative dose (3 Units/point, total 9-12 Units/side), the risk of a "surprised look" is minimized. In our patients who consult with me, the combination of orbicularis oculi Botox (frontalis + corrugator + orbicularis) often provides the aesthetic goal of "fresh, well-rested look".

Against dynamic crow's feet lines, Botox is the primary choice. However, if accompanied by static wrinkles or tear trough hollowness, a combination of hyaluronic acid filler or fractionated laser resurfacing should be considered. Especially when patients aged 50+ do not respond to Botox alone, multi-modal approach (Botox + volumizer filler + topical retinoid) gives more persuasive results.

Although iatrogenic complications (Botox-induced ptosis, lagophthalmos) are rare, if present, wait-and-watch (2-3 months) or supportive measures (eye drops, protective eyewear) are applied; The repair option (nada + tape, gravity-assisted levator supplementation) is considered in severe cases. Rebound effect (crow's feet wrinkles become more visible as the Botox effect decreases) is frequently observed in long-term Botox users; In this case, "maintenance Botox" (4-6 weeks managed interval) and preventive skincare (retinoid, sunscreen, peptide serum) are recommended.

Resources

1. Standring S. Gray's Anatomy: The Anatomical Basis of Clinical Practice. 41st ed. Elsevier; 2015. Chapter: Facial Muscles and Eyelid Anatomy.
2. Cotofana S, Philipp-Dormston W, Schoelzke K, et al. The orbicularis oculi muscle: An anatomical and anthropometric assessment with clinical implications. Aesthetic Surgery Journal. 2019;39(7):754-767.
3. Sarver RD, Tannan SC, Liebhaber ME. Orbital and periorbital anatomy for the injectable filler practitioner. Journal of Cosmetic Dermatology. 2020;19(3):673-682.
4. Kane MAC, Combs J. The use of botulinum toxin in the periocular region. Dermatologic Surgery. 2018;44(S1):S6-S13.
5. Jewell ML, Casparian JM. Facial anatomy for the aesthetic surgeon. In: Facial Aesthetic Surgery. Thieme; 2017. p. 45-72.

Last Update

Last update: April 22, 2026 · Medical editor: Op. Dr. Hamza Gemici