Muscle:Orbicularis Oculi

Orbicularis oculi is the circular muscle surrounding the eye, responsible for closing the eyelid. It is one of the very few muscles from which trigger points (TrPs) refer pain to the nose, and the only muscle known to refer pain to the side of the nose and upper lip. Active TrPs can produce a unilateral palpebral fissure narrowing that closely resembles Horner's syndrome, and a characteristic visual disturbance described as "jumpy print."

Anatomy

The orbicularis oculi has two portions:

• Palpebral portion — contained within the eyelids; produces gentle, rapid closure as in blinking
• Orbital portion — surrounds both lids in concentric curves; produces strong, forceful closure of the eye, throwing the skin into folds at the lateral angle of the eyelid

Both portions together form a circular path around the palpebral fissure. The orbital portion forms bony attachments along the superior medial part of the orbit and attaches medially to the medial palpebral ligament.

Like all muscles of facial expression, the fibres lie within the superficial fascia. Fibre diameters are approximately half those of limb muscles (32–40 μm), with a disproportionately high percentage of type IIA fibres. Twitch contraction times are only half as long as limb muscle.

Innervation: Facial nerve (cranial nerve VII), temporal and zygomatic branches.

Primary action: Palpebral portion — gentle eye closure (blinking). Orbital portion — forceful tight closure of the eye.

Functional unit: Closure by the orbicularis oculi is antagonised by the levator palpebrae superioris, which raises the upper lid. The orbicularis oris frequently works in concert with the orbicularis oculi in facial expression.

Referred Pain Pattern

TrPs in the upper orbital portion of the orbicularis oculi refer pain:

• To the side of the nose — ipsilateral (this is one of the very few muscles that refers pain to the nose; no muscle is known to refer pain to the tip of the nose)
• To the cheek close to the nose
• Over the upper lip, homolaterally

Less intense spillover pain may extend into the adjacent cheek. The referral remains on the same side as the active TrP.

Activation and Perpetuating Factors

• Habitual frowning or squinting — due to photophobia, astigmatism, or uncorrected refractive error
• Satellite activation from SCM sternal division TrPs — the sternal division of the sternocleidomastoid refers pain to the orbit; the orbicularis oculi lies within this reference zone and develops satellite TrPs
• Orbicularis oculi TrPs as perpetuating factor for SCM — the relationship is bidirectional; chronic orbital pain activates the frowning and squinting that overloads the orbicularis oculi

Clinical Examination

Patient Examination

Active TrPs in the orbicularis oculi may produce:

• Unilateral palpebral fissure narrowing on the affected side, resembling the ptosis of Horner's syndrome — but without change in pupillary size
• On testing upward gaze, the patient tilts the head backward because they cannot raise the upper eyelid sufficiently to look up

Horner syndrome exclusion:

• Pupils equal and normally reactive — no miosis
• No enophthalmos
• Ciliospinal reflex present
• Extraocular movements full

Symptoms

• Referred pain to the nose, cheek, and upper lip as described above
• "Jumpy print" — when reading text with strong black-and-white contrast, the letters appear to jump, making it difficult to focus. This symptom is pathognomonic of orbicularis oculi TrP involvement and resolves with TrP inactivation.

Trigger Point Examination

TrPs in the upper orbital portion are found by flat palpation:

1. Run the tip of the examining finger crosswise over the muscle fibres above the eyelid, just beneath the eyebrow and against the bone of the orbit
2. Identify a taut band and spot tenderness within it
3. The TrP lies in the upper arc of the orbital portion

Note: Local twitch responses are not readily observed in the orbicularis oculi, probably because it is difficult to place the muscle under sufficient stretch.

Nerve Entrapment

Active TrPs in the medial half of the orbital portion can entrap the supraorbital nerve, producing a unilateral frontal headache with primarily neuritic rather than myofascial pain characteristics. The neuritic quality (tingling, burning, superficial) distinguishes this from the dull aching referred pain of TrP origin. Symptoms resolve on inactivating the responsible frontalis and/or orbicularis oculi TrPs by digital pressure, massage, or injection.

Differential Diagnosis

• Tension headache — the referred pain to the nose and cheek is easily attributed to tension headache without recognition of the facial muscle source
• Sinusitis — nasal and cheek pain overlaps with maxillary sinus distribution; distinguish by absence of nasal congestion, fever, or sinus tenderness on percussion
• Horner's syndrome — palpebral fissure narrowing is the key mimicking feature; excluded by normal pupillary reactivity and absence of enophthalmos (see above)
• Trigeminal neuralgia — distinguished by lancinating paroxysmal pain with trigger zones versus sustained dull aching from TrPs
• Occipital neuralgia — distinguished by superficial scalp tingling and hot prickling (nerve entrapment quality) versus deeper aching TrP referral; patients with nerve entrapment prefer cold (ice pack) and cannot tolerate heat, while TrP patients find moist heat provides relief

Treatment

Trigger Point Release

Spray and stretch is unsatisfactory for the orbicularis oculi because:

• Adequate stretch of the circular muscle is difficult to achieve
• Vapocoolant spray cannot safely be applied near the eye

Trigger point pressure release is the preferred technique:

1. Locate the TrP by flat palpation in the upper orbital arc
2. Roll the TrP progressively between the fingers, squeezing with increasing pressure as the tension releases
3. This can be performed by the clinician or taught to the patient for self-treatment

Trigger Point Injection

1. Locate TrPs by focal tenderness in a taut band palpated in the upper arc of the orbital portion
2. Needle: 16 mm (5/8 inch), 25- or 26-gauge
3. Inject with 0.5% procaine in isotonic saline
4. Warn the patient that ecchymosis may develop in the injected area, causing a temporary "black eye"

Corrective Actions

• Inactivate key TrPs in the clavicular and sternal divisions of the sternocleidomastoid — these are the primary drivers of satellite orbicularis oculi TrPs
• Address refractive error or photophobia that is perpetuating habitual squinting
• Inactivate TrPs in the upper trapezius and other muscles of the head and neck on the same side
• The "jumpy print" symptom resolves with successful inactivation of the orbicularis oculi TrPs — this can be used as a treatment endpoint

Satellite Trigger Points

• Frontalis — frequently develops satellite TrPs in association with SCM clavicular division TrPs; forehead pain
• Zygomaticus major — arc of pain along the nose and forehead; commonly co-active
• Sternocleidomastoid — the primary key TrP muscle driving orbicularis oculi satellites

Related Pages

• Face and Jaw pain region (coming soon)
• Sternocleidomastoid — key driver of satellite orbicularis oculi TrPs
• Zygomaticus major — co-involved facial muscle
• Platysma — co-involved; prickling jaw pain
• Frontalis — co-involved scalp muscle; forehead pain

References

• Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 13.
• Travell J. Identification of myofascial trigger point syndromes: a case of atypical facial neuralgia. Arch Phys Med Rehabil 62:100–106, 1981.