Lesion I Flashcards
paresis
weakness (partial paralysis)
hemiparesis
weakness of one side of the body (face, arm and leg)
palsy
weakness or no movement
paralysis
no movement
hemiplegia
no movement of one side of the body (face, arm and leg)
Weber syndrome deficits
MIDIAL MIDBRAIN SYNDROME
- lesion in ROSTRAL MIDBRAIN basis
- IPSILATERAL oculomotor nerve palsy
- CONTRALATERAL hemiparesis
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
Claude syndrome deficits
CENTRAL MIDBRAIN SYNDROME
- IPSILATERAL oculomotor nerve palsy
- CONTRALATERAL ataxia and tremor of cerebellar origin
Benedikt syndrome deficits
- MEDIAL MIDBRAIN + CENTRAL MIDBRAIN LESIONS
- IPSILATERAL oculomotor nerve palsy
- CONTRALATERAL hemiparesis
- CONTRALATERAL ataxia, tremor, and inoluntary movements
blood supply to the medial portion of the midbrain
- branches of POSTERIOR CEREBRAL artery (PCA)
- Top of basilar artery
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
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
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
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
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
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
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
Occlusion of what vessels which result in Claude sydrome
- Branches of posterior cerebral artery (PCA)
- Top of basilar artery
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
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
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
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
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)
