Anatomy - Neuro Flashcards
What is the most common type of cerebellopontine angle tumor? Where would these tumors be located?
Located = Between cerebellum and lateral pons
Most common type - vestibular schwannoma (arising from vestibular portion in vestibulocochlear n.)
What Sx are associated with a vestibular schwannoma? What nerves will it compress? What sx?
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
How can you tell the difference between spontaneous and inherited vestibular schwannoma? Also what inherited disease is it associated with?
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
Where do crainopharyngiomas arise? Sx?
Arise from remnants of rathke’s pouch in the suprasellar region
Sx = hypothalmic and pituitary dysfunction; possible vision loss
Where do germ cell tumors typically arise in the brain? What are the presenting sx?
Pineal gland
Sx - obstructive hydrocephalus, increased ICP, Parinaud syndrome (upward gaze palsy)
Aneurysm at what part in the circle of Willis will cause oculomotor palsy? Sx?
Junction near posterior communicating artery
Mydriasis
Diplopia
Ptosis
Down and out eye
What causes lateral medullary syndrome? What are the Sx?
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)
What nuclei are in the midbrain? pons? medulla? (Generalize)
Midbrain - CN 3 & 4
Pons - CN 5, 6, 7, 9
Medulla - 10, 11, 12
8 = Pons & Medulla
Name the cranial n. foramina & what nerves pass through.
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
How do you get a cavernous sinus thrombosis? What are the most common organisms? Sx?
Spread of infection from medial 1/3 of face, sinuses, teeth
Staph aureus & streptococci
Sx involving CN 3, 4, 5(1), 6
What is Gerstmann syndrome? SX?
Lesion at the angular gyrus of the dominant parietal lobe
Tetrad: Agraphia Acalculia Finger agnosia Left-right disorientation
What Sx would be seen with an ACA stroke?
Supplies medial aspect of frontal and parietal lobes
Will see contralateral lower extremity motor deficits with upper motor neuron signs (hyperreflexia, Babinski sign)
What Sx can be seen with an anterior spinal artery stroke?
Bilateral lower extremity weakness with hyporeflexia and loss of pain/temp below level of lesion
What artery gives rise to the middle meningeal artery?
Maxillary artery coming off the external carotid
You have a pt that comes in with right arm weakness and right miosis and ptosis. Where is the lesion? Why is it there?
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.
if you had a cystic lesion in the LEFT CEREBELLAR hemisphere, what Sx are seen? Which side?
Left dysdiadochokinesia (impaired rapid alternating movements) Limb dysmetria (overshoot/undershoot target) Intention tremor
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?
Locus ceruleus
Norepinephrine
RAS - sleep/wake cycle; arousal; mood; cognition; autonomic control (blood pressure)
Pts may present with coma and abnormally high blood pressure
Where are dopamine, dynorphin, histamin, orexin formed? What are they responsible for?
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
What nerve do parotid gland tumors occlude?
Facial nerve!
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?
Below the inguinal canal
Pudendal - Tip of the ischial spine
Saphenous - adductor canal, medial tibial condyle
Obturator - obturator canal
Explain how direct and consensual pupillary responses work.
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.
Describe the direct pathway of the basal ganglia.
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.
Describe the indirect pathway of the basal ganglia.
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.
What Sx are seen with a lesion at the VPM/VPL of the thalamus? Lentiform nucleus? Caudate? Internal capsule?
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
