Neuro2 Flashcards
Can a Pineal tumor affect the pons?
No. the pineal body is at the level of the midbrain. The pons is too far caudal to be affected by a pineal tumor
What is primarily contained in the superior cerebellar peduncle?
Efferent projections from the cerebellum
What clinical symptoms would result from damage to the superior cerebellar peduncle?
Cerebellar signs: e.g., intention tremor, dysmetria (lack of coordination of movement)
What is parinaud sundrome?
paralysis of conjugate verticle gaze due to a lesion in the superior colliculi.
This can be due to a pinealoma
Function of superior colliculi
conjugate vertical gaze center
Function of inferior colliculi
auditory
Function of Pineal gland
melatonin secretion, circadian rhythms
Physical exam shows paralysis of upward gaze, bilateral papilledema, and pupils that react to accomodation, but not to direct light. CT scan shows a tumor.
What is this clinical sydrome?
Parinaud’s Syndrome.
The papilledema is do to compression of the cerebral aqueduct by the pinealoma that is causing the syndrome, leading to non-communicating hydrocephalus.
What structures form the cerebellopontine angle?
the cerebellum, upper medulla, and middle cerebellar peduncle.
What nerves pass through the cerebellopontine angle?
CN VII and VIII
facial and vestibulocochlear
What are the most common nerves in the cerebellopontine angle?
acoustic neuromas (80%) and meningiomas (20%)
Result of lesion of the optic tract
Homonymous hemianopia of the contralateral visual field
Result of lesion of the left lateral geniculate nucleus
Right homonymous hemianopia
Result of lesion in the left temporal lobe?
Upper right quadrantinopia
Meyer’s loop is located in the temporal lobe
Result of lesion in the left parietal lobe?
Lower right quadrantinopia
dorsal optic radiation is located in the parietal lobe
Part of the ear supplied: auriculotemporal nerve
anterior half of the external ear canal
Part of the ear supplied: auricular branch of the vagus nerve
posterior half of the external ear canal
Part of the ear supplied: greater auricular nerve
lower part of the auricle
Part of the ear supplied: lesser occipital nerve
upper part of the auricle
Part of the ear supplied: vestibulococclear nerve
hearing and motion sense
What structure is adjacent to the lateral ventricles, and would be affected by a choroid plexus papilloma in the lateral ventricle?
The caudate nucleus
What brain structure overlies the fourth ventricle?
The cerebellum
What brain structure forms part of the floor of the fourth ventricle?
The pons
What part of the ventricular system does the hypothalamus sit next to?
The third ventricle
What part of the ventricular system is the hippocampus near?
It is adjacent to the inferior (temporal) horn of the lateral ventricle.
A 32 year old woman comes to the physician because of double vision that is worse when she looks to the right. She states that when she closes one eye, her vision returns to normal. An MRI of the brain shows a demyelinating lesion in the brain stem. She says that earlier in the year, she experienced tingling in her arm. What is her likely diagnosis?
The combination of diplopia with a demyelinating central nervous system lesion identified on MRI, coupled witha history of other neurologic symptoms separated by space and time is strongly suggestive of
MS
What are the two horizontal gaze centers?
(1) Frontal eye fields (contralateral gaze)
2) PPRF (paramedian pontine reticular formation; ipsilateral gaze
Describe the path required for both eyes to look to the right
Left frontal eye field –> right PPRF –> right abducens nucleus –> (1) abducens of right eye, and (2) decussates to form left MLF (medial longitudinal fasciculus) –> left oculomotor nucleus –> left eye medial rectus
What is right INO (internuclear opthalmoplegia)?
A lesion of the right MLF.
This would result in an inability to adduct the right eye during left conjugate gaze.
However, convergence is intact: The right eye can adduct during non-conjugate gaze. This fact distinguishes an INO from a medial rectus (CN III) palsy.
In a right INO, you will also observe nystagmus in the left eye when the patient attempts to look left
Where would the lesion be if both eyes were unable to look right when attempting right conjugate gaze, and instead remained looking straight forward?
What is often seen with this condition?
The right PPRF – the center responsible for ipsilateral conjugate gaze
The PPRF is located within the abducens nucleus
A complete ipsilateral facial paralysis is often seen with lesions in this area because the facial nerve loops around the abducens nucleus
Where would the lesion be if neither eye can look to the right, and instead both eyes drift to the left
The left frontal eye field (controls (contralateral) horizantal gaze to the right)
Because the activity of the right frontal eye field is unopposed, the eyes slowly drift to the left (the side of the lesion)
The middle meningeal artery is a branch of what artery?
Maxillary artery
Tear of the middle meningeal artery results in what?
An epidural hematoma
What openings are found in the middle cranial fossa?
- -optic canal
- -superior orbital fissure
- -foramen rotundum
- -foramen ovale
- -foramen spinosum
What runs through the optic canal?
CN II
opthalmic artery
central retinal vein
What runs through the superior orbital fissure?
CN III, IV, V1, VI
opthalmic vein
sympathetic fibers
What runs through the foramen rotundum?
CN V2
What runs through the formen ovale?
CN V3`
What runs through the foramen spinosum?
Middle Meningeal Artery
What openings are found in the posterior cranial fossa?
- -internal auditory meatus
- -jugular foramen
- -hypoglossal canal
- -foramen magnum
What runs through the internal auditory meatus?
CN VII, VIII
What runs through the jugular foramen?
CN IX, X, XI, jugular vein
What runs through the hypoglossal canal?
CN XII
What runs through the foramen magnum?
- -brain stem
- -spinal roots of CN XI
- -vertebral arteries
