Term
T or F
Hemiparesis and hemiplegia accompanied by sensory (pain and temperature) deficits on the same side is never of spinal cord origin? |
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Definition
True
The lesion causing such deficits would be localized in the brainstem or cerebrum, above the sensory and motor decussations of the major pathways, as shown below with the various brainstem lesions. |
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Term
| Injury to a cranial nerve with a motor component and injury to the corticospinal tract above the motor decussation (which is in the medulla) leads to |
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Definition
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Term
INFERIOR ALTERNATING HEMIPLEGIA
(or Alternating Hypoglossal Hemiplegia) |
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Definition
1. Location: rostral medulla
2. Cause: infarct of branch of the anterior spinal artery.
3. Structures Involved:
A. hypoglossal nerve and/or nucleus
B. Pyramid (Corticospinal Tract)
C. Medial Lemniscus
3. Symptoms:
A. LMN ipsilateral paralysis of tongue (CN XII, hypoglossal)
i. tongue deviates toward side of lesion.
ii. fibrillations and fasciculations of the tongue ipsilaterally
B. UMN paralysis on contralateral side of body
C. Loss of fine touch and conscious proprioception on contralateral side of body
4. If the lesion is at the level of the pyramidal decussation then:
A. UMN paralysis of bilateral body
5. If lesion is at the level of the internal arcuate fibers (DCML crossing) then:
A. Loss of fine touch and conscious proprioception of body bilaterally |
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Term
WALLENBERG'S SYNDROME
or LATERAL MEDULLARY SYNDROME |
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Definition
1. Cause: posterior inferior cerebellar artery infarct in mid-medulla.
2. Structures involved:
A. spinothalamic tract (pain & temperature from the body).
B. spinal trigeminal tract (pain & temperature from the face).
C. CN IX (glossopharyngeal), X (vagus), XI (spinal accessory)
D. reticular formation
E. parts of vestibular nuclei
F. inferior cerebellar peduncle (dorsal spinocerebellar tract, DSCT)
3. Symptoms:
A. loss of pain & temperature sense on opposite of body & back of head (latter is C2 dermatome)
B. ipsilateral loss of pain and temperature on face (CN V, trigeminal tract)
C. difficulty swallowing; hoarse weak voice (CN IX, X)
D. transient tachycardia (CN X)
E. damage to inferior cerebellar peduncle (DSCT) causes poorly coordinated voluntary movements and hypotonia
F. dizziness (Wallenberg's syndrome is an important central cause of dizziness) |
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Term
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Definition
1. Cause: Schwann cell tumor in cerebellopontine angle
2. Structures involved:
A. Cranial nerves VIII (vestibulocochlear), VII (facial)
B. Can progress to involve CN V (trigeminal) as well as the inferior and middle cerebellar peduncles and spinothalamic tract
3. Symptoms:
A. tinnitus
B. abnormal vestibular function (dizziness)
C. nystagmus
D. Bell's palsy (CN VII)
E. Alternating hemianesthesia (ipsilateral loss of pain & temperature sense from the face--CN V trigeminal tract; and contralateral loss of pain & temperature sense from the rest of the body--spinothalamic tract).
F. Hyperacusis (due to damage to CN VII, which innervates the stapedius muscle)
G. Cerebellar symptoms (due to damage of DSCT in inferior cerebellar peduncle)
a. ataxia
b. intention tremor (expressed during voluntary movement; absent during rest--a classic cerebellar lesion sign)
c. dysmetria (overshooting the intended goal; also called post-pointing)
d. hypotonia (insufficient proprioceptive feedback due to DSCT interruption)
e. dysdiadochokinesia (inability to perform rapidly alternating movements; e.g., pronation-supination) |
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Term
| MIDDLE (ABDUCENT) ALTERNATING HEMIPLEGIA |
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Definition
1. Cause: infarct of paramedian and short circumferential branches of basilar artery
2. Structures involved:
A. CN VI (abducens)
B. CN VII (facial) possible
C. Corticospinal tract
D. Medial Lemniscus (possible)
3. Symptoms:
A. ipsilateral adduction of eye (LMN symptom of CN VI damage)
B. body: contralateral UMN signs (spasticity, hyperreflexia, positive Babinski signs due to corticospinal tract damage), contralateral loss of fine touch and conscious proprioception
C. If CN VII (facial) involved,
a. Bell's palsy (inability to close eyelid; mouth droops ipsilaterally)
b. hyperacusis (decreased stapedial reflex)
c. loss of taste, anterior 2/3 of tongue |
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Term
| TRIGEMINAL ALTERNATING HEMIPLEGIA |
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Definition
1. Cause: infarct in lateral mid-pons
2. Structures involved:
A. CN V (trigeminal)
B. Corticospinal tract
C. Lateral lemniscus (auditory pathway)
D. Middle cerebellar peduncle (ponto-cerebellar fibers)
E. Spinothalamic tract
F. Medial lemniscus
3. Symptoms:
A. ipsilateral loss of all sensation from face (CN V)
B. Ipsilateral absence of corneal reflex and sensation (CN V)
C. Inability to bite down (ipsilateral; CN V)
D. Lateral deviation of the protruded jaw toward side of lesion (CN V)
E. Contralateral UMN signs (hyperreflexia, spasticity, positive Babinski sign)
F. Diminution of hearing, especially on contralateral side (lateral lemniscus)
G. Cerebellar signs:
a. hypotonia
b. coarse intention tremor
c. tendency to fall to side of lesion
H. Contralateral loss of pain & temperature sense from body (spinothalamic tract)
I. Contralateral loss of discriminative sense, vibratory sense, touch, pressure from body (medial lemniscus) |
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Term
SUPERIOR ALTERNATING HEMIPLEGIA
(WEBER'S SYNDROME) |
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Definition
1. Cause: infarct of paramedian & short circumferential branches of basilar artery and posterior cerebral artery in midbrain.
2. Structures involved:
A. CN III (oculomotor)
B. Corticospinal & corticobulbar fibers
3. Symptoms:
A. LMN signs
a. ptosis, pupil remains dilated
b. external strabismus (eye abducted; due to denervation of medial rectus)
c. inability to elevate, depress or adduct eye
B. UMN signs
a. paralysis of contralateral side of body; hyperreflexia, spasticity, positive Babinski sign
b. paralysis of contralateral lower face. The lower face motor neurons receive only contralateral UMN input from the corticobulbar tract. The upper face motor neurons receive bilateral UMN input. As a result of this arrangement, and UMN lesion to the corticobulbar tract causes paralysis of muscles of facial expression in the contralateral lower half of the face and bilateral paresis of the upper face. |
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