44 Questions
A lesion of the Vagus nerve can result in all of the following EXCEPT:
Weakness of the sternocleidomastoid muscle and upper part of the trapezius
Which cranial nerve is responsible for supplying the musculature of the tongue?
Hypoglossal nerve
In Bulbar Palsy syndrome, which group of muscles is NOT typically involved?
Sternocleidomastoids and upper trapezius
What is the main function of the spinal accessory nerve (CN XI)?
Innervate sternocleidomastoid and upper trapezius muscles
If there is a complete lesion of the Hypoglossal nerve, what would happen when protruding the tongue?
The tongue deviates to the healthy side
Which symptom is NOT associated with a lesion of both pharyngeal branches of the Vagus nerve?
Difficulty swallowing liquids leading to coughing
Which division of the trigeminal nerve is responsible for sensory input from the cornea and conjunctiva?
Ophthalmic division (V1)
What type of sensation is primarily associated with the principal sensory nucleus of the trigeminal nerve?
Tactile and light pressure sensation
What characterizes the pain experienced in trigeminal neuralgia?
Sharp, unilateral facial pain
What is the incidence rate of trigeminal neuralgia?
4.3/100,000 persons per year
What age group commonly experiences trigeminal neuralgia in its idiopathic form?
32-35 years
What type of medication is reported to have a positive response in more than half of the cases of trigeminal neuralgia?
Anti-seizure medications
What is the underlying mechanism of trigeminal neuralgia?
Neurovascular compression causing demyelination
What is the preferred imaging method for evaluating trigeminal neuralgia?
Brain MRI with IV contrast and magnetic resonance angiogram
Which is the most common cause of facial nerve palsy?
Herpes simplex virus type I
What is the primary treatment for hemifacial spasm?
Injection of botulinum toxin
What is an aberrant effect observed in patients recovering from facial nerve palsy?
Synkinesis
Which disorder is characterized by painless, irregular clonic contractions of facial muscles on one side?
Hemifacial spasm
What distinguishes glossopharyngeal neuralgia from trigeminal neuralgia?
'Ice pick' pain in the back of the throat vs. facial pain
What symptom is not commonly associated with Bell's Palsy?
'Hyperacusis'
Which treatment has no evidence supporting its effectiveness in Bell's Palsy?
'Antiviral drugs'
'Glossopharyngeal neuralgia' manifests as stabbing pain in which area?
'Root of the tongue and throat'
In a syndrome of Bulbar Palsy, which of the following muscles is NOT typically involved?
Face
If a patient has paralysis on one side of the tongue with slight deviation to the healthy side, which cranial nerve is most likely affected?
Hypoglossal nerve (CN XII)
Which cranial nerve is responsible for weakness of the sternocleidomastoid muscle and upper part of the trapezius when affected?
Accessory nerve (CN XI)
Which condition is characterized by an aberrant effect where patients experience regurgitation of liquids through the nose during swallowing?
Bulbar Palsy
When there is complete paralysis of both sides of the face, which condition should be considered?
Bilateral facial palsy
What is the primary treatment for patients suffering from Hemifacial Spasm?
Botox injections
Which condition is characterized by bilateral facial palsy?
Bulbar Palsy
What is considered a potential cause of secondary trigeminal neuralgia?
Vascular Neoplastic Disease
Which condition may present with paroxysmal, brief, unilateral facial pain similar to trigeminal neuralgia?
Glossopharyngeal Neuralgia
What aberrant effect is commonly observed in patients recovering from facial nerve palsy?
Hemifacial Spasm
Which tumor type could potentially lead to facial nerve palsy?
Schwannoma
What is a common treatment approach for managing hemifacial spasm?
Botox Injections
What is a possible cause of bilateral facial palsy?
HIV infection
Which condition may mimic the symptoms of hemifacial spasm?
Blepharospasm
What is an aberrant effect observed in some patients recovering from facial nerve palsy?
Synkinesis
Which condition is associated with synkinesis and eyelid closure during jaw movements?
Hemifacial Spasm
What may cause painless, irregular clonic contractions of facial muscles on one side?
Tumor
Which disorder involves involuntary tearing whenever the patient salivates?
Hemifacial Spasm
What symptom is NOT commonly associated with hemifacial spasm?
Hoarseness of voice
Which condition may result in contracture with diffuse myokymic activity?
Facial myokymia
What is the main pathological process believed to contribute to hemifacial spasm?
Vascular compression leading to focal demyelination
Which condition can lead to a contraction of the eyelid during jaw movements in the affected side?
Hemifacial Spasm
Study Notes
Cranial Nerve Palsies
- Lesion of the Vagus Nerve:
- Soft palate droops on the ipsilateral side and does not rise in phonation
- Uvula often deviates to the normal side on phonation
- Loss of the gag reflex on the affected side and of the curtain movements of the lateral wall of the pharynx
- Voice is hoarse, often nasal
- Lesion of the Hypoglossal Nerve:
- Supplies the musculature of the tongue
- Complete interruption of the nerve results in paralysis on one side of the tongue
- Tongue curves slightly to the healthy side as it lies on the mouth
- Deviates to the affected side on protrusion of the tongue
- Syndrome of Bulbar Palsy:
- Result of weakness or paralysis of muscles that are supplied by the motor nuclei of the lower brainstem (5th, 7th and 9th-12th cranial nerves)
- Involved muscles: face and jaw, sternocleidomastoids and upper part of the trapezii, muscles of the tongue, pharynx, and larynx
Trigeminal Nerve
- Anatomy:
- Mixed sensory and motor
- Sensory: greater part of the head and face, mucous membranes of the nose, mouth and paranasal sinuses, cornea and conjunctiva, dura in the anterior and middle cranial fossa
- Gasserian or semilunar ganglion: cell body; largest sensory ganglion
- 3 sensory nuclei: principal sensory nucleus (tactile and light pressure sensation), mesencephalic nucleus (proprioception), spinal trigeminal nucleus (pain and temperature sensation)
- 3 sensory divisions: ophthalmic division (V1), maxillary division (V2), mandibular division (V3)
- Motor: masseter and pterygoid muscles; motor nucleus in the midpons
- Trigeminal Neuralgia:
- Tic douloureux; incidence rate: 4.3/100,000 persons per year
- Higher in women than men (ratio of 3:2) and elderly
- Mean age of onset: 52-58 years in idiopathic form, 32-35 years in symptomatic form
- Characteristic features:
- Paroxysmal, brief, unilateral facial pain
- Tendency to involve V2 or V3
- Pain intensity makes the patient grimace or wince (tic)
- Presence of a trigger point on the face
- Lack of demonstrable sensory or motor deficit
- Response in more than half of the cases to anti-seizure medications
- Trigeminal Neuropathy:
- Numbness in one or more branches of the trigeminal nerve, sometimes associated with paresthesia or neuropathic pain
- Etiologies: facial and cranial injuries, postherpetic neuralgia, numb chin syndrome, compression by tumors
Facial Nerve
- Anatomy:
- Mainly a motor nerve
- Muscles of facial expression
- Sensory component (small): nervus intermedius of Wrisberg; taste sensation from the anterior two-thirds of the tongue; cutaneous sensation from the anterior wall of the external auditory canal
- Superior salivatory nucleus: secretomotor fibers to the lacrimal gland and sublingual and submaxillary glands
- Bell's Palsy:
- Most common disease of the facial nerve
- Incidence rate: 23 per 100,000 people annually
- Probably more common in diabetic and hypertensive patients
- A viral agent has long been suspected as a causative agent (Herpes simplex virus type I)
- Onset is acute
- One-half of cases attain maximum paralysis within 48 hours and all within 3 or 4 days
- Clinical features:
- Peripheral type of facial paralysis
- Pain behind the ear may precede the paralysis by a day or two
- Taste impairment is present in most patients
- Rarely persists beyond the second week of paralysis
- Hyperacusis (paralysis of the stapedius muscle)
- A report by the patient of fullness or numbness of the face
- Course:
- Fully 70% of patients recover completely within a month or two
- 85% achieve near-normal facial function
- Recovery of taste precedes recovery of motor function
- If taste returns in the first week, it is a good prognostic sign
- Early recovery of some motor function in the first 5-7 days is the most favorable sign
- Recurs in approximately 8%
- Treatment:
- Protection of the eye during sleep
- No evidence that surgical decompression of the facial nerve is effective
- Prednisone (40-60 mg/day) during the first week to 10 days after onset
- Evidence fails to support the use of antiviral drugs
- Other Causes of Palsy:
- Lyme disease
- HIV infection
- Leprosy
- Sarcoidosis
- Ramsay Hunt syndrome
- Herpes zoster of the geniculate ganglion
- Facial palsy + vesicular eruption of the external auditory canal + 8th cranial nerve involvement
- Tumors
- Bilateral facial palsy: Guillain-Barre syndrome, Lyme disease, HIV infection, sarcoidosis, Melkersson-Rosenthal syndrome (triad of recurrent facial paralysis, facial edema, and plication of the tongue)
- Aberrant Effects of Recovery from Facial Nerve Palsy:
- Contracture with diffuse myokymic activity
- Aberrant regeneration of the facial nerve
- Synkinesis
- Eyelid closure during contraction of the orbicularis oris
- Crocodile tears: anomalous tearing whenever the patient salivates
- Jaw-winking phenomenon: jaw movements cause an involuntary closure of the eyelid ipsilateral to the movement
Test your knowledge on the anatomy and functions of the cranial nerves with a focus on the trigeminal nerve. Explore information about the sensory and motor components as well as key anatomical structures and their functions.
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