Examination

Motor function: The character of the voice and the ability to swallow provide information

about the branchiomotor functions of the vagus.

Clinical implications:

A unilateral vagal lesion causes weakness of the soft palate, pharynx, and larynx. Acute

lesions may produce difficulty swallowing both liquids and solids and hoarseness or a nasal

quality to the voice. Sensory change is anesthesia of the larynx due to involvement of the

superior laryngeal nerve. The gag reflex is absent on the involved side. Autonomic reflexes

(vomiting, coughing, and sneezing) are not usually affected.

Bilateral complete vagal paralysis is incompatible with life. It causes complete paralysis

of the palate, pharynx, and larynx, with marked dysphagia and dysarthria; tachycardia; slow,

irregular, and respiration; vomiting; and gastrointestinal atonia.

Disorders of Cranial Nerve X

Unilateral supranuclear lesions generally cause no dysfunction because of bilateral

innervation.

Bilateral supranuclear lesions, as from pseudobulbar palsy, cause dysphagia and

dysarthria.

Extrapyramidal disorders may produce difficulty with swallowing and talking. Patients with

Parkinson’s disease typically have a hypokinetic dysarthria. Laryngeal spasm with stridor

may occur in Parkinson’s disease.

Nuclear lesions bulbar ALS, syringomyelia, and some neoplasms, may cause

fasciculations in the palatal, pharyngeal, and laryngeal muscles.

Infranuclear Extramedullary and intracranial involvement can occur in processes involving

the meninges, extramedullary tumors, aneurysms, trauma, sarcoidosis, and skull fractures.

Lesions at the jugular foramen or in the retroparotid space usually involve some

combination of IX, X, XI, XII, and the cervical sympathetics.

Palatal myoclonus: Seen in lesions at Mollaret triangle.

Jacobson’s neuralgia: Involvement of tympanic branch of CN 9.

Recurrent laryngeal nerve palsy:

Causes:

Unilateral:

Mitral stenosis

Bronchogenic carcinoma

Aortic aneurysm

Hodgkin’s disease

Bilateral:

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Guillain–Barré syndrome

Thyroidectomy

Lymphomas

CRANIAL NERVE XI—SPINAL ACCESSORY

The spinal accessory (SA) nerve, cranial nerve XI (CN XI), is actually two nerves that run

together in a common bundle for a short distance [Fig. 6D(iii).68].

Cranial part (ramus internus): The smaller cranial portion is a special visceral efferent

(SVE) accessory to the vagus. It emerges from the medulla laterally as four or five rootlets

caudal to the vagal filaments. The cranial root runs to the jugular foramen and unites with

the spinal portion, traveling with it for only a few millimeters to form the main trunk of CN XI.

The cranial root communicates with the jugular ganglion of the vagus, and then exits

through the jugular foramen separately from the spinal portion. It is distributed principally

with the recurrent laryngeal nerve to sixth branchial arch muscles in the larynx.

Fig. 6D(iii).68: Anatomy of spinal accessory nerve.

Spinal part (ramus externus): The major part of CN XI is the spinal portion. Its function is

to innervate the sternocleidomastoid (SCM) and trapezius muscles. The fibers of the spinal

root arise from SVE motor cells in the SA nuclei in the ventral horn from C2 to C5, or even

C6. These unite into a single trunk, which ascends between the denticulate ligaments and

the posterior roots. The nerve enters the skull through the foramen magnum, ascends the

clivus for a short distance, and then curves laterally. The spinal root joins the cranial root for

a short distance, probably receiving one or two filaments from it. It exits through the jugular

foramen in company with CNs IX and X.

C1-2 supplies sternocleidomastoid.

C3-4 supplies trapezius.

Testing the Spinal Accessory Nerve

Cranial Part

The functions of the cranial portion of CN XI cannot be distinguished from those of CN X,

and examination is limited to evaluation of the functions of the spinal portion.

Spinal Part

Testing SCM [Figs. 6D(iii).69 and 6D(iii).70]:

Testing one muscle at a time: To assess SCM power, have the patient turn the head fully

to one side and hold it there, then try to turn the head back to midline, avoiding any tilting or

leaning motion. The muscle usually stands out well, and its contraction can be seen and

felt. Significant weakness of rotation can be detected if the patient tries to counteract firm

resistance.

Testing two muscle at a time: The two SCM muscles can be examined simultaneously by

having the patient flex his neck while the examiner exerts pressure on the forehead or by

having the patient turn the head from side to side. Flexion of the head against resistance

may cause deviation of the head toward the paralyzed side.

Fig. 6D(iii).69: Examination of sternocleidomastoid muscle (testing one muscle at a time).

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Fig. 6D(iii).70: Examination of sternocleidomastoid (testing both muscles at a time).

Interpretation: With unilateral paralysis, the involved muscle is flat and does not contract or

become tense when attempting to turn the head contralaterally or to flex the neck against

resistance. Weakness of both SCMs causes difficulty in anteroflexion of the neck, and the

head may assume an extended position.

Testing trapezius muscle (Fig. 6D(iii).71):

Inspection: With trapezius atrophy, inspection findings include:

Depression or drooping of the shoulder contour

Flattening of the trapezius ridge

Sagging of the shoulder

Fig. 6D(iii).71: Traditional method of assessing trapezius muscle (shrugging shoulders

against resistance).

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The resting position of the scapula shifts downward

The upper portion of the scapula tends to fall laterally while inferior angle moves inward

(this scapular rotation and displacement are more obvious with arm abduction).

Palpation:

Traditional method: The strength of the trapezius is traditionally tested by having the

patient shrug the shoulders against resistance. However, much of shoulder shrugging is due

to the action of the levator scapulae.

Newer methods:

For upper trapezius: Resisting the patient’s attempt to approximate the occiput to the

acromion. Impairment of upper trapezius function causes weakness of abduction beyond

90°.

For middle and lower trapezius: Place the patient’s abducted arm horizontally, palm up,

and attempt to push the elbow forward. Muscle power should be compared on the two

sides. Weakness of the middle trapezius muscle causes winging of the scapula.

Clinical implication: Weakness of the muscles supplied by CN XI may be caused by

supranuclear, nuclear, or infranuclear lesions.

Supranuclear involvement: Irritative supranuclear lesions may cause head turning away

from the discharging hemisphere. This turning of the head (or head and eyes) may occur

as part of a controversive, ipsiversive, or Jacksonian seizure and is often the first

manifestation of the seizure. Extrapyramidal lesions may also involve the SCM and

trapezius muscles, causing rigidity, akinesia, or hyperkinesis.

Nuclear involvement of the SA nerve may occur in motor neuron disease, syringobulbia,

and syringomyelia. In nuclear lesions, the weakness is frequently accompanied by

atrophy and fasciculations.

Infranuclear or peripheral lesions—either extramedullary but within the skull, in the

jugular foramen, or in the neck—are the most common causes of impairment of function

of the SA nerve. Tumors in the foramen magnum, lesions of the cerebellopontine angle,

basal skull fractures, and meningitis.

“Dropped Head Syndrome”/Floppy Head Syndrome/Broken Neck Sign

This syndrome, characterized by weakness of the extensor muscles of neck with or without

involvement of neck flexors, can be caused by:

Myasthenia gravis

Inflammatory myopathy—polymyositis

Guillain–Barré syndrome

Amyotrophic lateral sclerosis (ALS)/Bulbar polio

Facio-scapulo-humeral dystrophy

Neurotoxic snake bite/Organophosphorous compound poisoning.

CRANIAL NERVE XII—HYPOGLOSSAL NERVE

Function: CN XII supplies the intrinsic muscles, and all of the extrinsic muscles of the

tongue except the palatoglossus.

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Anatomy [Fig. 6D(iii).72]: Nucleus located in medial medulla. Distribution of fibers from

rostral to caudal, the innervation is intrinsic tongue muscles, then genioglossus, hyoglossus,

and styloglossus.

Fig. 6D(iii).72: Location of hypoglossal nerve.

Examination

The clinical examination of hypoglossal nerve function consists of evaluating the strength,

bulk, and dexterity of the tongue—looking especially for weakness, atrophy, abnormal

movements (particularly fasciculations), and impairment of rapid movements.

Inspection:

Tongue deviation: To look for tongue deviation by asking the patient to protrude the

tongue and also to move the tongue to either sides.

Fasciculations: Ask the patient to open the mouth and with the tongue inside the mouth

look for the fasciculations.

Palpation:

Hold the tongue with gauze and palpate the tongue with gloved finger to examine the

consistency of the tongue [Fig. 6D(iii).73].

To examine the power of the tongue patient is instructed to push the tongue against the

cheek while giving the counter resistance from outside [Fig. 6D(iii).74].

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Fig. 6D(iii).73: Palpation of tongue.

Fig. 6D(iii).74: Examining the motor power of tongue.

Interpretation

On inspection:

Tongue deviation [Fig. 6D(iii).75]: When unilateral weakness is present, the tongue deviates toward

the weak side on protrusion because of the action of the normal genioglossus. And also there is

impairment of the ability to deviate the protruded tongue toward the opposite side.

Fasciculations: Presence of fasciculations suggests LMN paralysis of the 12th cranial nerve.

On palpation:

Small and stiff tongue: Suggestive of UMN type of 12th nerve palsy.

Flabby tongue with fasciculations: Suggestive of LMN type of 12th nerve palsy.

Other clinical aspects: The neck-tongue syndrome, consisting of pain in the neck and numbness or

tingling in the ipsilateral half of the tongue on sharp rotation of the head, has been attributed to damage

to lingual afferent fibers traveling in the hypoglossal nerve to the C2 spinal roots through the atlantoaxial

space.

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Fig. 6D(iii).75: Tongue deviation to the left suggestive of weakness of left hypoglossal muscle.

Bulbar palsy Pseudobulbar palsy

Etiology:

Motor neuron disease

Syringobulbia

Guillain-Barré syndrome

Poliomyelitis

Subacute meningitis (carcinoma and

lymphoma)

Neurosyphilis

Brainstem CVA

Etiology:

The most common cause is bilateral CVAs affecting the internal capsule

Other causes include:

Multiple sclerosis

Motor neuron disease

High brainstem tumors

Head injury

Bilateral damage or injury of the nerve

nuclei of cranial nerves IX, X, XI, and

XII

Lower motor neuron palsy of the

respective muscles

Gag reflex—absent

Tongue—wasted, fasciculations

“Wasted, wrinkled, thrown into folds,

and increasingly motionless”

Palatal movement—absent

Jaw jerk—absent or normal

Speech—nasal “Indistinct (flaccid

dysarthria), lacks modulation, and has a

nasal twang”

Emotions – normal

Other—signs of the underlying cause,

e.g. limb fasciculations

Bilateral damage or injury of corticobulbar tracts to nerve nuclei of cranial nerves V,

VII, X, XI, and XII

Upper motor neuron palsy of the respective muscles

Gag reflex—increased or normal

Tongue—spastic

“It cannot be protruded, lies on the floor of the mouth and is small and tight”

Palatal movement—absent

Jaw jerk—increased

Speech—spastic: “A monotonous, slurred, high-pitched, ‘Donald Duck’, dysarthria”

that “sounds as if the patient is trying to squeeze out words from tight lips”. “Hot

potato voice”

Emotions—labile

Other—bilateral upper motor neuron (long tract) limb signs. Bilateral extensor

plantar and bilateral exaggerated reflexes

MULTIPLE CRANIAL NERVE PALSIES

Cranial

nerve

Cavernous

sinus

thrombosis

Superior

orbital

fissure

syndrome

Orbital

apex

syndrome

Jaccoud’s

(retro-sphenoid

space)syndrome

Petrous

apex

gradinigo

syndrome

TolosaHunt,

lateral

cavernous

sinus

syndrome

CP

angle

tumor

Vernet

jugular

foramen

syndrome

Villaret,

postretroparotid

syndrome

sy

II ✓ ✓

III ✓ ✓ ✓ ✓ ✓

IV

✓

✓

✓

✓

✓

V

1

✓

✓

✓

✓

✓

V

2

✓

✓

✓

✓

V

3

✓

✓

VI ✓

✓

✓

✓

✓

✓

✓

VII ✓ VIII ✓ IX

✓

✓

X

✓

✓

XI ✓

✓

XII ✓ Horner ✓ ✓ NOTES

1.

2.

3.

4.

5.

6.

7.

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