Bell's palsy is the paralysis of the nerve?

Appeared in: SCTIMST Staff Nurse - 2016

Explanation

Bell's palsy is defined as an idiopathic, unilateral paralysis of the muscles of facial expression.
These muscles are innervated by the Facial nerve, which is the seventh cranial nerve (CN VII).
The inflammation of CN VII leads to compression and ischemia, causing the characteristic facial droop, inability to close the eye, and loss of forehead wrinkles on one side of the face.
The image provided shows the classic clinical presentation of Bell's palsy, confirming the involvement of the facial nerve.

Option A: The Trigeminal nerve (CN V) is primarily responsible for facial sensation and controlling the muscles of mastication (chewing).
Option B: The Optic nerve (CN II) is a purely sensory nerve that transmits visual information from the retina to the brain.
Option D: The Oculomotor nerve (CN III) controls most of the eye's movements, pupil constriction, and eyelid elevation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Identification of the cranial nerve affected in Bell's palsy as background academic context rather than a clinical decision trigger.
The highest priority in nursing care for a patient with Bell's palsy is protecting the cornea of the affected eye from abrasion and ulceration due to incomplete eyelid closure.
Nurses must provide psychosocial support, as the sudden change in facial appearance can be distressing for the patient.
Patient education is crucial, emphasizing that recovery is likely (80% of patients recover within weeks to months) and teaching how to perform facial massage and exercises to maintain muscle tone.

How to Approach the Question

First, identify the core condition in the question: 'Bell's palsy'.
Recall the fundamental definition of Bell's palsy, which is the paralysis of a specific cranial nerve.
Analyze the provided image. Observe the signs of unilateral facial paralysis: drooping mouth, flattened skin folds, and an inability to close the eye. These signs point to weakness in the muscles of facial expression.
Consider the functions of the cranial nerves listed in the options.
Match the observed signs (paralysis of facial expression muscles) to the function of the correct cranial nerve.
Eliminate the other options based on their distinct functions: Trigeminal (sensation/chewing), Optic (vision), and Oculomotor (eye movement). This process will lead you to the correct answer.

Concept Tested & Keywords

Concept Tested: Identification of the cranial nerve affected in Bell's palsy.
Stem keywords: Bell's palsy, paralysis, nerve
Lead-in keywords: BEST, MOST RELEVANT CLUE
Clinical cues: Image showing unilateral facial droop, flattened nasolabial fold, and inability to close one eye.
Negative lead-in flag: false

Q3TqGhzG--C8V5jSHg59w7

E6 Medicine Harrison 22e Part 2 pp. 1458-1460, 1459-1461

E6 Nursing Brunner Adult Health 3SA Vol 2 Part 2 p. 143-145

Practise the full SCTIMST Staff Nurse - 2016

Attempt every question from this paper in a timed mock, then review the full solution for each one.