What is the Difference Between UMN and LMN Facial Palsy?
🆚 Go to Comparative Table 🆚The main difference between upper motor neuron (UMN) and lower motor neuron (LMN) facial palsy lies in the involvement of the forehead muscles. In UMN facial palsy, the forehead is not affected, and the patient can fully raise the eyebrow on the affected side. In contrast, LMN facial palsy involves the forehead muscles, and the patient is unable to raise the eyebrow on the affected side.
Some key differences between UMN and LMN facial palsy include:
- Location of damage: UMN facial palsy is caused by damage to the facial nerve (cranial nerve VII) that supplies the muscles of the face, while LMN facial palsy is caused by damage to the facial.
- Causes: UMN facial palsy can be caused by stroke, subdural hemorrhage, multiple sclerosis, or neoplasm (e.g., primary brain malignancy), presenting with forehead sparing. LMN facial palsy can be caused by conditions such as Bell's palsy, Ramsay Hunt syndrome, and others.
- Symptoms: In UMN facial palsy, the patient can raise the eyebrow fully on the affected side, while in LMN facial palsy, the patient is unable to raise the eyebrow on the affected side.
- Severity grading: The House-Brackmann classification is used to grade the severity of facial nerve palsy, with higher grades indicating more severe dysfunction.
To differentiate between UMN and LMN facial palsy, testing facial movements will help. If the forehead is not affected (i.e., the patient is able to raise fully the eyebrow on the affected side), then the facial palsy is likely to be UMN lesion. On the other hand, paralysis that includes the forehead, such that the patient is unable to raise the affected eyebrow, is an LMN lesion.
Comparative Table: UMN vs LMN Facial Palsy
The difference between UMN (upper motor neuron) and LMN (lower motor neuron) facial palsy lies in the affected muscles and their corresponding motor neurons. Here is a table summarizing the differences between UMN and LMN facial palsy:
| Feature | UMN Facial Palsy | LMN Facial Palsy |
|---|---|---|
| Forehead Affected | Yes (spared) | No |
| Able to Raise Eyebrow on Affected Side | Yes | No |
| Frontalis and Orbicularis Oculi Muscle Sparing | Yes | No |
| Characterized By | Unilateral facial palsy, some sparing of frontalis and orbicularis oculi muscles | Unilateral paralysis of all muscles of facial expression |
UMN facial palsy is characterized by unilateral facial palsy with some sparing of the frontalis and orbicularis oculi muscles, while LMN facial palsy is characterized by unilateral paralysis of all muscles of facial expression. In UMN facial palsy, the patient is able to raise the eyebrow fully on the affected side, but in LMN facial palsy, the patient is unable to raise the eyebrow on the affected side. The forehead is not affected in UMN facial palsy, while the forehead is affected in LMN facial palsy.
- UMN vs LMN
- Bell’s Palsy vs Facial Palsy
- Bell’s Palsy vs Stroke
- Bell’s Palsy vs Cerebral Palsy
- Bell’s Palsy vs Ramsay Hunt Syndrome
- Upper vs Lower Motor Neuron
- ALS vs MND
- Multiple Sclerosis vs Motor Neuron Disease
- Paresis vs Paralysis
- Motor Neuron Disease vs Muscular Dystrophy
- Erb’s Palsy vs Klumpke’s Palsy
- Muscular Dystrophy vs Myasthenia Gravis
- Polio vs Paralysis
- Lagophthalmos vs Ptosis
- Diplegia vs Paraplegia
- ALS vs MS (Multiple Sclerosis)
- Ptosis vs Pseudoptosis
- Parkinson’s vs Myasthenia Gravis
- Myasthenia Gravis vs Lambert Eaton Myasthenic Syndrome