Question

1. What would you assess for if there is damage to cranial nerve VII? 2. What is the difference between a stroke and Bell's PalsyIs cranial nerve Vll affected?

please type your work.
subject: medical Surgical.

Answer 1

Examination of Cranial Nerve VII

Inspect the face for droop or asymmetry. Ask the patient to look up, so that the forehead wrinkles, and observe if there is a loss of wrinkling on one side. Push down on each side of the forehead. ... They are not useful in localizing lesions or assessing facial nerve function.

The 7th (facial) cranial nerve is evaluated by checking for hemifacial weakness. Asymmetry of facial movements is often more obvious during spontaneous conversation, especially when the patient smiles or, if obtunded, grimaces at a noxious stimulus; on the weakened side, the nasolabial fold is depressed and the palpebral fissure is widened. If the patient has only lower facial weakness (ie, furrowing of the forehead and eye closure are preserved), etiology of 7th nerve weakness is central rather than peripheral.

Taste in the anterior two thirds of the tongue can be tested with sweet, sour, salty, and bitter solutions applied with a cotton swab first on one side of the tongue, then on the other.

Hyperacusis, indicating weakness of the stapedius muscle, may be detected with a vibrating tuning fork held next to the ear.

ASSESSMENT OF CRANIAL NERVE 7

Cranial Nerve VII: Facial

1. Begin by observing the patient. If there is facial asymmetry, determine which side is affected, which may not be immediately obvious. Remember that most people have a slight bony facial asymmetry. Smoothing of the nasolabial folds or widening of a palpebral fissure on one or both sides could be subtle signs of facial weakness.
2. The following maneuverstest the motor function of the facial nerve. Peripheral facial palsy (Bell's palsy) manifests with unilateral weakness of both the upper and lower facial muscles, unlike central facial palsy (such as seen in stroke) where the upper facial muscles are not affected by weakness because of the bilateral cortical innervation of the forehead.
   1. Ask the patient to raise the eyebrows. Look for an inability to wrinkle the forehead on the involved side.
   2. Tell the patient to smile or show teeth, which will accentuate the weakness on the involved side, as the patient may not be able to fully raise the ipsilateral upper lip, resulting in a crooked appearance.
   3. Ask the patient to close the eyes tightly against resistance applied by the examiner. You can also assess if the patient buries the eyelashes equally on both sides.
   4. Ask the patient to blow up the cheeks and try to push the air out against pursed lips.
3. Bell's palsy may result in an ipsilateral loss of taste on the anterior 2/3 of the tongue. Therefore, special testing of the taste sensation can be performed.
   1. Tell the patient to stick out the tongue.
   2. Hold the tip of the tongue with a gauze pad.
   3. Swab the side of the tongue with the solution of sugar water.
   4. Ask the patient to identify the taste.
   5. Ask the patient to rinse out the mouth with water, and repeat the testing on the other side. Ask the patient to compare the sense of taste on each side of the tongue.

2.A stroke is caused by a blood clot that stops blood flow to the brain or by a blood vessel that ruptures in the brain, while Bell's palsy is linked to facial nerve damage.

Bell's palsy (also called idiopathic facial paralysis) is the most common cause of unilateral facial paralysis. It has the following features:

• Acute onset of unilateral upper AND lower facial paralysis
• Flattening of the forehead and inability to raise eyebrows on affected side
• On smiling the face lateralizes to the opposite (normal side)
• Hyperacusis
• Changes in taste
• Impaired eyelid closure

The above symptoms are thought to occur as a result of the injury, swelling, and/or ischemia of the facial nerve (CN VII) as a result of compression as it passes through the facial canal. While the exact cause is unknown, it appears that viral infection (herpes virus) is associated.  

Bell's Palsy is a peripheral nerve effect whereas a ischemic stroke is a central process. As shown in the diagram, the forehead receives motor innervation from both hemispheres of the cerebral cortex. A stroke that compromised motor innervation of the face would therefore only result in paralysis of the lower half of the face - the forehead still receiving innervation from the unaffected hemisphere. A peripheral lesion, such as Bell's Palsy, interrupts the innervation after the motor commands from both hemispheres have joined, so that the forehead is paralyzed.