Final answer:
Bell's palsy is characterized by facial paralysis on one side due to facial nerve inflammation and is tested for effectiveness by resistance exercises like eye closing strength. LMN lesions can cause flaccid paralysis, including other symptoms such as fibrillation and fasciculation.
Step-by-step explanation:
Facial paralysis on one side of the face due to inflammation of a facial nerve is known as Bell's palsy. This condition can cause significant facial asymmetry and impairment in the muscles used for facial expressions. The facial nerve, or cervical nerve VII, is responsible for these muscles, and when it becomes inflamed, it can lead to partial or total paralysis on the affected side.
In assessing facial nerve function, clinicians perform various tests. For example, the strength test, whereby a patient is asked to squeeze their eyes shut while the examiner attempts to open them, evaluates the integrity of the facial nerve. If there is weakness observed, the examiner might ask the patient to try a second time to confirm the finding and assess for any potential improvement or variance in muscle strength which could suggest different degrees of nerve involvement or fatigue.
Lower motor neuron (LMN) lesions can result in this type of paralysis, often characterized as flaccid paralysis. This contrasts with upper motor neuron (UMN) lesions, where increased muscle tone and spasticity might be noted. LMN lesions may also present with other symptoms such as fibrillation, fasciculation, and loss of reflexes, which reflect the health of the peripheral nerves and muscles they innervate.