Lesion I Flashcards Preview

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Flashcards in Lesion I Deck (23):
1

paresis

weakness (partial paralysis)

2

hemiparesis

weakness of one side of the body (face, arm and leg)

3

palsy

weakness or no movement

4

paralysis

no movement

5

hemiplegia

no movement of one side of the body (face, arm and leg)

6

Weber syndrome deficits

MIDIAL MIDBRAIN SYNDROME

- lesion in ROSTRAL MIDBRAIN basis

- IPSILATERAL oculomotor nerve palsy

- CONTRALATERAL hemiparesis

7

A lesion in the rostral midbrain basis on the LEFT, results in...

- oculomotor nerve palsy on LEFT

- Weak lateral pterygoid on RIGHT

- Weak facial muscles on LOWER RIGHT

- weak musculus uvulae on RIGHT

- weak genioglossus on RIGHT

- weak extremtiies on RIGHT

8

Claude syndrome deficits

CENTRAL MIDBRAIN SYNDROME

- IPSILATERAL oculomotor nerve palsy

- CONTRALATERAL ataxia and tremor of cerebellar origin

9

Benedikt syndrome deficits

- MEDIAL MIDBRAIN + CENTRAL MIDBRAIN LESIONS

- IPSILATERAL oculomotor nerve palsy

- CONTRALATERAL hemiparesis

- CONTRALATERAL ataxia, tremor, and inoluntary movements

10

blood supply to the medial portion of the midbrain

- branches of POSTERIOR CEREBRAL artery (PCA)

- Top of basilar artery

11

What structures are involved in Weber syndrome (medial midbrain syndrome)

- Exiting root of OCULOMOTOR NERVE (contains GSE + GVE) = Ipsilateral

- Corticonuclear fibers (basis pedunculi) = (UMN) weakness/paralysis (contralateral)

- Corticospinal fibers in basis pedunculi (above the pyramidal decussation) = CONTRALATERAL weakness (hemiparesis) of the extremities

12

describe lesion to oculomotor nerve

- contains GSE + GVE fibers

- oculomoter NERVE innervates the IPSILATERAL eye

--> IPSILATERAL paralysis of the LPS (PTOSIS)

--> EYE cannot move medially or vertically (EYE DEVIATED DOWN and OUT)

--> IPSILATERAL DILATION of the pupil/fixed (MYDRIASIS), lens is flat

13

Describe lesion to Cortiocnuclear fibers

- located in basis pedunculi (prior to their distribution

- LESION that damages the corticonuclear (UMN) tract in the LEFT rostral midbrian RESULTS in WEAKNESS/PARALYSIS in CONTRALATERAL side

- TRIGEMINAL MOTOR NUCLEUS = (midpons)

- FACIAL NUCLEUS

- NUCLEUS AMBIGUUS

- HYPOGLOSSAL NUCLEUS

14

Lesion to the tigeminal motor nucleus

- Affected in MEDIAL MIDBRAIN SYNDROME (WEBER SYNDROME)

- located in midpons

- receives BILATERAL UMN projections; EXCEPT for the LMN that innervate lateral pterygoid muscle (receive CONTRALATERAL projections)

- CONTRALATERAL WEAKNESS/PARALYSIS of the lateral pterygoid muscle = RIGHT lateral pterygoid will be affected/weak, jaw will deviate to the RIGHT (weak side) on protrusion

15

Lesion to the facial nucleus

- Damaged in Medial midbrain syndrome (weber syndrome)

- upper 1/2 receives BILATERAL UMN projections

- lower 1/2 receives CONTRALATERAL projections

- CONTRALATERAL weakness/paralysis of the muscles of the LOWER FACE

- RIGHT LOWER facial muscles will be affected and show weakness/paralysis

16

Lesion to the nucleus ambiguus

- Damaged in medial midbrain syndrome (weber syndrome)

- receives BILATERALY (primarily contralateral) UMN projections

- CONTRALATERAL weakness/paralysis of MUSCULUS UVULAE

- RIGHT MUSCULUS UBULAE will be affected, uvula will be PULLED to innervate/intact side to DEVIATE to left when saying AHHH

 

17

lesion to the Hypoglossal nucleus

- Damaged in Medial midbrain syndrome (webers syndrome)

- Receives BILATERAL UMN projections, EXCEPT FOR LMN's that INNERVATE GENIOGLOSSUS, which receives ONLY contralteral projections

- CONTRALATERAL WEAKNESS/PARALYSIS of GENIOGLOSSUS MUSCLE

--> innervated/intact side PUSHES tongue to deviate toward the WEAK side (to the right if lesion on left) UPON PROTRUSION

18

Occlusion of what vessels which result in Claude sydrome

- Branches of posterior cerebral artery (PCA)

- Top of basilar artery

19

What structures are affected in Central midbrain syndrome (midbrain tegmentum)

- Oculomotor nerve fascicles = oculomotor NERVE innervates the IPSILATERAL EYE

- Red nucleus

- Cerebellothalamic fibers = CONTRALATERAL ataxia and tremor of cerebellar origin

20

Lesion to the oculomotor nerve fascicles

- Affected in Central midbrain syndrome (Claude syndrome)

- Oculomotor nerve innervates the IPSILATERAL EYE

- IPSILATERAL PARALYSIS OF THE LPS = PTOSIS

- Extraocular muscles (ipsilateral oculomotor nerve palsy) EXCEPT the LR6SO4

--> eye cannot move medially or vertically (EYE DEVIATED DOWN AND OUT, diplopia)

- IPSILATERAL DILATION of the pupil/fixed (MYDRIASIS), lens is flat

21

describe cerebellothalamic fibers

- Cerebellum fibes rise to OUTPUT fibers called CEREBELLOTHALAMIC FIBERS

- Exit the cerebellum and ASCEND to the midbrain via the SCP

--> DECUSSATE in the CAUDAL MIDBRAIN in the decussation of the SCP (at level of the inferior colliculus)

- fibers continue to the thalamus which project to motor cortex

- CONTROLS MOVEMENT OPPOSITE SIDE OF THE BODY

- LESION just ROSTRAL to the SCP decussation on the RIGHT, damaging the cerebellothalamic fibers carrying informatino from the CONTRALATERAL (LEFT) cerebellum

--> DEFICITS INCLUDE = CONTRALATERAL ataxia and tremor of cerebellar origin

22

 substantia nigra

- Output frmo the RIGHT basal ganglia and projected to the RIGHT thalamus which projects to the RIGHT motor cortex

- Right motor cortex controls MOVEMENT of the LEFT SIDE

- Movement of the left side of the body is INFLUENCED by the RIGHT BASAL GANGLIA

- control contralateral INVOLUNTARY movement

23

Lesion in CAUDAL MIDBRAIN

- CAUSED BY DEMYELINATING DISEASE (Multiple sclerosis)

- Cerebellothalamic fibers (from superior cerebellar peduncles) = DEFICITS IN RIGHT LIMBS)

- LEFT TROCHLEAR NUCLEUS = RIGHT eye is deviated upward (HYPERTROPIC and slightly EXTORTED)

- LEFT MEDIAL LONGITUDINAL FASICULUS (MLF) = LEFT INTERNUCLEAR OPHTHALMOPLEGIA (INO) (left eye does NOT turn medially on gase to the right)