Facial paralysis: what it is and how it differs from asymmetry
Quick facts
- Definition
- Total or partial loss of movement of the muscles of facial expression.
- Types
- Peripheral (facial nerve injury, affects the whole face on one side) and central (injury in the brain, spares the forehead).
- Key sign
- A forehead that does not wrinkle indicates peripheral paralysis; a preserved forehead suggests a central cause.
- Action
- Sudden onset is a medical emergency; assessment comes before any aesthetic procedure.
Facial paralysis is the total or partial loss of movement of the muscles of expression. Depending on the extent, the patient cannot frown, close the eye or smile on one side. The orofacial harmonization (HOF) professional does not treat paralysis, but needs to recognize it, tell it apart from asymmetry and know when to stop the appointment.
What are the types?
The most useful way to think about it is by the location of the injury.
| Type | Where the injury is | Forehead | Examples |
|---|---|---|---|
| Peripheral | In the facial nerve or its branches | Affected, does not wrinkle | Bell's palsy, trauma, infection |
| Central | In the brain | Usually preserved | Stroke, tumor |
The difference comes from the fact that the forehead receives commands from both sides of the brain. A central injury on one side spares forehead movement, and a peripheral injury affects it along with the rest.
How do you tell it apart from asymmetry?
In static facial asymmetry, the patient moves the muscles on both sides, just unevenly, and the condition is long-standing or gradual. In paralysis, there is loss of movement. The practical way to assess is to ask the patient to:
- raise the eyebrows
- close the eyes tightly
- smile showing the teeth
- whistle or puff out the cheeks
Any movement missing on one side, especially if the condition is recent, is a reason to refer. For the patient, the statement "it has always been like this" is clinical information that should be recorded together with photo and video.
Why does this matter before treating?
- Botulinum toxin: it reduces muscle contraction and can accentuate an existing asymmetry or mask the progression of a condition. See botulinum toxin.
- Branch injury: the temporal and marginal mandibular branches of the facial nerve are known for their vulnerability in surgery and trauma, which is why the history of prior procedures matters.
- Eye protection: if the patient cannot close the eye (lagophthalmos), the cornea is at risk and ophthalmologic follow-up is part of the care.
Also known as: facial nerve paralysis, prosopoplegia.
Frequently asked questions
How do you tell facial paralysis from asymmetry?
In static asymmetry, the muscles move, just unevenly. In paralysis there is loss of movement on one side. If the condition is recent or sudden, it is a medical emergency.
When should a central cause be suspected?
When the forehead moves normally and there is weakness in an arm or leg, altered speech or confusion. That combination calls for emergency care.