Anatomy - Neuro

Question 1

What is the most common type of cerebellopontine angle tumor? Where would these tumors be located?

Answer 1

Located = Between cerebellum and lateral pons

Most common type - vestibular schwannoma (arising from vestibular portion in vestibulocochlear n.)

Question 2

What Sx are associated with a vestibular schwannoma? What nerves will it compress? What sx?

Answer 2

Unilateral hearing loss
Tinnitus
Unsteadiness and disequilibrium

Compresses CN 5 and 7
5 - Loss of ipsilateral facial sensation
7 - ipsilateral facial muscle paralysis
Loss of corneal reflex

Question 3

How can you tell the difference between spontaneous and inherited vestibular schwannoma? Also what inherited disease is it associated with?

Answer 3

Difference is that the spontaneous version will present with unilateral hearing loss whereas the inherited version will present as bilateral

Associated with NF (neurofibromatosis) type 2

Question 4

Where do crainopharyngiomas arise? Sx?

Answer 4

Arise from remnants of rathke’s pouch in the suprasellar region

Sx = hypothalmic and pituitary dysfunction; possible vision loss

Question 5

Where do germ cell tumors typically arise in the brain? What are the presenting sx?

Answer 5

Pineal gland

Sx - obstructive hydrocephalus, increased ICP, Parinaud syndrome (upward gaze palsy)

Question 6

Aneurysm at what part in the circle of Willis will cause oculomotor palsy? Sx?

Answer 6

Junction near posterior communicating artery

Mydriasis
Diplopia
Ptosis
Down and out eye

Question 7

What causes lateral medullary syndrome? What are the Sx?

Answer 7

Dissection of the vertebral artery leading to PICA occlusion

Vertigo, Nystagmus
Ipsilateral cerebellar signs (ataxia)
Loss of pain/temp in ipsilateral face & contralateral body
Bulbar weakness (dysphonia & dysphagia)
Ipsilateral Horner syndrome (miosis, ptosis, anhidrosis)

Question 8

What nuclei are in the midbrain? pons? medulla? (Generalize)

Answer 8

Midbrain - CN 3 & 4
Pons - CN 5, 6, 7, 9
Medulla - 10, 11, 12

8 = Pons & Medulla

Question 9

Name the cranial n. foramina & what nerves pass through.

Answer 9

Cribriform plate - CN1
Optic canal - CN2
Superior orbital fissure - CN3, 4, 5(1), 6
Foramen rotundum - CN 5(2)
Foramen Ovale - CN 5(3)
Internal acoustic meatus - CN 7, 8
Jugular foramen - CN 9, 10, 11
Hypoglossal canal - CN 12

Question 10

How do you get a cavernous sinus thrombosis? What are the most common organisms? Sx?

Answer 10

Spread of infection from medial 1/3 of face, sinuses, teeth

Staph aureus & streptococci

Sx involving CN 3, 4, 5(1), 6

Question 11

What is Gerstmann syndrome? SX?

Answer 11

Lesion at the angular gyrus of the dominant parietal lobe

Tetrad:
Agraphia
Acalculia
Finger agnosia
Left-right disorientation

Question 12

What Sx would be seen with an ACA stroke?

Answer 12

Supplies medial aspect of frontal and parietal lobes

Will see contralateral lower extremity motor deficits with upper motor neuron signs (hyperreflexia, Babinski sign)

Question 13

What Sx can be seen with an anterior spinal artery stroke?

Answer 13

Bilateral lower extremity weakness with hyporeflexia and loss of pain/temp below level of lesion

Question 14

What artery gives rise to the middle meningeal artery?

Answer 14

Maxillary artery coming off the external carotid

Question 15

You have a pt that comes in with right arm weakness and right miosis and ptosis. Where is the lesion? Why is it there?

Answer 15

The lesion is at the cervical sympathetic ganglia. This is probably because of a Pancoast tumor (from small cell lung carcinoma) near the superior sulcus that has also caused compression of the brachial plexus, which is causing the arm weakness.

Question 16

if you had a cystic lesion in the LEFT CEREBELLAR hemisphere, what Sx are seen? Which side?

Answer 16

Left dysdiadochokinesia (impaired rapid alternating movements)
Limb dysmetria (overshoot/undershoot target) 
Intention tremor

Question 17

What’s the pigmented nucleus found in the posterior postal pons at the later floor of the 4th ventricle? What neurotransmitter is released? What is it responsible for?

Answer 17

Locus ceruleus
Norepinephrine
RAS - sleep/wake cycle; arousal; mood; cognition; autonomic control (blood pressure)

Pts may present with coma and abnormally high blood pressure

Question 18

Where are dopamine, dynorphin, histamin, orexin formed? What are they responsible for?

Answer 18

Dopamine - ventral tegmental area and substantia nigra pars compacta (MIDBRAIN) = cognition, behavior, voluntary movement, inhibiting prolactin secretion

Dynorphin - Periaqueductal gray, rostral central medulla, spinal cord (dorsal horn) = pain modulation

Histamine and orexin - posterior hypothalamus = arousal and wakefulness

Question 19

What nerve do parotid gland tumors occlude?

Answer 19

Facial nerve!

Question 20

Where is the best place for a femoral nerve block? Where are the locations of a pudendal nerve block, saphenous nerve block, and obturator nerve block?

Answer 20

Below the inguinal canal

Pudendal - Tip of the ischial spine
Saphenous - adductor canal, medial tibial condyle
Obturator - obturator canal

Question 21

Explain how direct and consensual pupillary responses work.

Answer 21

The optic nerve carries fibers to the lateral geniculate nucleus and eventually synapses at the pretectal nucleus at the level of the superior colliculus. The PN then send fibers to the edinger-Westphal nucleus bilaterally, which have fibers of the oculomotor n. These preganglionic parasympathetic fibers will run to the ciliary ganglion, which sends postganglionic fibers to the pupillae sphincter m.

Question 22

Describe the direct pathway of the basal ganglia.

Answer 22

Overall, thalamus releases glutamate to excite the cerebral cortex to initiate movement. The GPi and the SNpr continuously release GABA to inhibit movement.

When movement is initiated, the cerebral cortex excites the glutamate neurons to excite the striatum. The striatum will then inhibit GPi/SNpr through GABA neurons, inhibiting the inhibition, and allowing movement to occur.

Question 23

Describe the indirect pathway of the basal ganglia.

Answer 23

The cerebral cortex does 2 different excitatory things. 1) excites the striatum, which will inhibit the GPe, which stops its inhibition the subthalamic nucleus. 2) excites the subthalamic nucleus, which sends inhibitory neurons to the thalamus, which cannot excite movement via the cerebral cortex.

This prevents unwanted movements (ex: Hemiballismus) from occurring.

Question 24

What Sx are seen with a lesion at the VPM/VPL of the thalamus? Lentiform nucleus? Caudate? Internal capsule?

Answer 24

VPL/VPM = contralateral sensory loss (thalamic syndrome = stabbing burning pain over contralateral aspect of body)

Lentiform nucleus (GP and putamen) = lesion seen in Wilson’s dz= liver + psychiatric + neurologic deficits

Caudate = Huntington - chorea, dementia, and behavior abnormalities

Internal capsule = contralateral pure motor and sensorimotor sx

Question 25

From where do VPL and VPM receive input? Where do they project? What Sx are seen?

Answer 25

VPL receives input from spinothalamic tract and dorsal columns. VPM - trigeminal pathway. They both send somatosensory projections the cortex via thalamocortical pathway.

Complete contralateral sensory loss (touch, pain/temp, vibration/propriception). Also possible unsteady gait.

Question 26

What sensory sx could you expect with an infraorbital francture?

Answer 26

Will result in lesion of the infraorbital nerve which will cause loss of sensation of upper cheek/lip/gingiva

Question 27

Where are the 2 common location of an intracranial germinoma? Which is the most common? What Sx are seen with this?

Answer 27

Pineal gland (most common) - papilledema + parinaud syndrome 
Suprasellar region - endocrinopathies

Question 28

What are the symptoms seen with a pineal gland tumor?

Answer 28

Papilledema - increased intracranial pressure and papilladema resulting from obstructive hydrocephalus from obstruction of cerebral aqueduct

Parinaud (dorsal midbrain) syndrome - Limited vertical gaze, bilateral eyelid retraction, light near dissociation

Question 29

What does medial medullary syndrome cause?

Answer 29

Contralateral spastic paralysis
Contralateral loss of vibration and proprioception
Ipsilateral flaccid paralysis of tongue (CN 12)