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Flashcards in lesion II Deck (16)
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1
Q

What cranial nerves and tracts are closely located to midline of pons

A
  • TRACTS

–> pyramidal tract

–> medial lemniscus

CRANIAL NERVES (level of lesion is localized by CN)

–> OCULOMOTOR (CNIII) = UPPER alternating hemiplegia

–> ABDUCENT (CN VI) = MIDDLE alternating hemiplegia

–> HYPOGLOSSAL (CN XII) = LOWER alternating hemiplegia

2
Q

define alternating hemiplegia

A
  • includes syndrome in which

–> CRANIAL NERVE MOTOR deficits are exhibited on ONE SIDE

WHEREAS

–> DESCENDING LONG MOTOR TRACT deficits are exhibited on the OPPOSITE SIDE

3
Q

What tracts are located laterally

A
  • Spinothalamic tract
  • spinal tract of V
4
Q

What cranial nerves located laterally

A
  • Trigeminal (CN V) = midpons
  • Facial (CN VII) = caudal pons
  • Vestibulocochlear (CN VIII) = caudal pons, medulla
  • Glossopharyngeal (CN IX) = medulla
  • Vagus (CN X) = medulla

*Horner’s syndrome = IPSILATERAL TO LESION

*CEREBELLAR SIGNS = ATAXIA, ipsilateral to lesion

5
Q

Describe Dysarthria hemiparesis (pure motor hemiparesis) syndrome

A
  • CAUSED BY Basilar artery (PARAMEDIAN BRANCHES)
  • Structures affected:

–> CORTICONUCLEAR tract (UMN) = CONTRALATERAL lower face weakness and DYSARTHRIA

–> CORTICOSPINAL tract (UMN) = deficits in CONTRALATERAL upper and lower limb weakness

6
Q

Define Dysarthria

A
  • Motor speech disorder due to weakness/paralysis of the mouth (lips, tongue and lower face)
7
Q

Describe ataxic Hemiparesis Syndrome

A
  • Caused by occlusion in PARAMEDIAN BRANCHES (ventral territory of the pons)

–> CORTICONUCLEAR tracts (UMN) = CONTRALTERAL lower face weakness and DYSARTHRIA

–> CORTICOSPINAL tract (UMN) = CONTRALATERAL upper and lower limb weakness (motor hemiparesis)

–> PONTINE NUCLEI/PONTOCEREBELLAR FIBERS = CONTRALATERAL ATAXIA

8
Q

Describe FOVILLE’S SYNDROME

A
  • Occluded PARAMEDIAN BRANCHES (ventral and dorsal territories of pons)
  • CORTICONUCLEAR tract = CONTRALATERAL lower face weakness and DYSARTHRIA
  • CORTICOSPINAL tract = CONTRALATERAL upper and lower weakness
  • FACIAL COLLICULUS (LMN)

–> abducen nucleus/paramedian pontine reticular formation (PPRF) = ipsilateral horizontal (lateral) gaze paralysis

–> facial nerve root fascicles = IPSILATERAL face paralysis

9
Q

Pontine Wrong-way Eyes syndrome

A
  • Caused by OCCLUDED Paramedian branches (supply ventral and dorsal territories of pons
  • STRUCTURES AFFECTED

–> Corticonuclear tract = Dysarthria and CONTRALATERAL lower face weakness

–> corticospinal tract = CONTRALATERAL upper and lower limb weakness

  • Abducens nucleus or Paramedian pontine reticular formation (PPRF) = IPSILATERAL lateral gaze paralysis
10
Q

Millard-Gubler syndrome

A
  • Caused by Paramedian branch occlusion
  • STRUCTURE

–> corticonuclear tract = CONTRALATERAL lower face weakness and dysarthria

–> Corticospinal tract = CONTRALATERAL upper and lower limb weakness

–> Facial nerve fascicles (LMN) = IPSILATERAL facial weakness

11
Q

What regions are variably invovled in Lesion in Medial Pontine basis and tegmentum

A
  • Caused by occlusion of paramedian branches
  • STRUCTURES
  • -> Medial lemniscus = CONTRALATERAL decreased proprioception, vibratory sense and tactile discrimination

–> Medial longitudinal fasciculus (MLF) = internuclear ophthalmoplegia (INO)

12
Q

describe the lesion of the lateral caudal pons (AICA syndrome)

A
  • caused by AICA occluded

–> Middle cerebellar peduncle = IPSILATERAL ataxia

–> Vestibular nuclei = vertigo and nystagmus

–> Trigeminal nucleus/tract = IPSILATERAL facial decreased pain and thermal sense

–> spinothalamic tract = CONTRALATERAL body decreased pain and thermal sense

–> Descending sympathetic fibers = IPSILATERAL horner’s syndrome

13
Q

describe lesion in DORSOLATERAL rostral pons (superior cerebellar artery syndrome)

A
  • Caused by occlusion in superior cerebellar artery
  • SUPERIOR cerebellar peduncle and cerebellum = IPSILATERAL ataxia and cerebellar origin
14
Q

Medial medullary syndrome

A
  • Lesion in medial medulla caused by occlusions of anterior spinal artery (paramedian branches) or vertebral artery (paramedian branches)
  • structures affected (infarction)

–> corticospinal tract = weakness in CONTRALATERAL upper and lower limbs (contralateral hemiparesis)

–> hypoglossal nerve and nucleus (LMN) = weakness/paralysis of the IPSILATERAL tongue and ATROPHY of the IPSILATERAL tongue muscles

–> Medial lemniscus = CONTRALATERAL decreased vibratory and proprioceptive sensation and discriminatory (fine) touch sensation

15
Q

Describe the cause Lateral medullary syndrome (WALLENBERG syndrome)

A
  • Lesion in Lateral medulla
  • Caused by vertebral artery (thombosis) or PICA (thrombosis)
16
Q

What structuers are affected in Wallenberg’s syndrome (lateral medullary syndrome)

A
  • Inferior cerebellar peduncle = Ipsialteral ataxia
  • vestibular nuclei = unsteady gait, vertigo, nausea, vomiting
  • spinothalamic tract = decrease/loss of pain and thermal sense from CONTRALATERAL side
  • spinal tract/nucleus of V = decrease/loss of pain and thermal sense from IPSILATERAL face
  • Descending sympathetic fibers = ISPILATERAL Horner’s syndrome
  • nucleus ambiguus = dysphonia, dysphagia, ispilateral decrease of gag reflex
  • nucleus solitarius = decrease in taste sensation IPSILATERAL tongue
  • Loss of vertical orientation = perceives world as it is upside down or turned sideways