NSG Q&A Flashcards
Major branches of the ECA
SALFOPS Max
Superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, superficial temporal, maxillary artery
Classical clinical findings with an occlusion of the anterior choroidal artery
Hemiparesis, hemianesthesia, and hemianopsia
The PCA divides into what two terminal branches?
Parieto-occipital and calcarine arteries
What are Virchow-Robin spaces?
Potential spaces between the blood vessels and the arachnoid and pia layers within the brain and spinal cord
Which sinus courses within the attachment of the tentorium to the petrous ridge?
Superior petrosal sinus
Which large anastomotic vein joins the superior sagittal sinus?
The vein of Trolard (superior anastomotic vein)
Which large anastomotic vein joins the veins of the sylvian fissure with the transverse sinus?
The vein of Labbe
What is the venous angle as seen on a lateral view of a cerebral angiogram?
The angle is formed by the junction of the thalamostriate vein and the internal cerebral veins at the thalamic tubercle.
This area approximates the site of the foramen of Monro
What are the 3 main superficial cerebral veins?
Superior anastomotic vein of Trolard, inferior anastomotic vein of Labbe, superficial middle cerebral vein
Which artery is the most common cause of lateral medullary syndrome (Wallenberg’s)?
Most commonly due to occlusion of the ipsilateral vertebral artery.
This syndrome results from infarct in the region supplied by PICA, which is a branch of the vertebral artery
What is the arterial supply of the thalamus?
Branches of the PCOM arteries, and the perimesencephalic portion of the PCAs
What is the arterial supply of the lateral geniculate nucleus?
It has a dual supply.
Laterally, it receives supply from the anterior choroidal.
Medially, it receives supply from the lateral posterior choroidal
Which artery is most commonly involved in trigeminal neuralgia?
SCA
Which artery is most commonly involved in hemifacial spasm?
AICA
Which artery is most commonly involved in glossopharyngeal neuralgia?
PICA
What is the main arterial supply of the internal capsule?
The lateral lenticulostriate branches from the MCA, the medial striate artery from the ACA, and the direct branches from the ICA
Which vessel has the highest risk of injury in a Chiari decompression?
PICA
Which vessels supply the superior, middle, and inferior cerebellar peduncles?
The SCA, AICA, and PICA, respectively.
Where is the motor strip located in relation to the skull?
4-5.5 cm behind the coronal suture
What sutures make up the asterion?
The lambdoid, parietomastoid, and occipitomastoid sutures.
It is important to define the lower half of the junction of the transverse and sigmoid sinuses.
What are the compartments of the jugular foramen?
Pars venosa (posterolateral), which contains the sigmoid sinus, jugular bulb, CNs X and XI
Pars nervosa (anteromedial), which contains CN IX, and Jacobson’s nerve
What structure does CN VI go through to enter the cavernous sinus?
Dorello’s canal
What structures go through the internal acoustic meatus?
CN VII, CN VIII, and the labyrinthine artery
What structures pass through the annulus of Zinn?
The optic nerve, ophthalmic artery, oculomotor nerve, abducens nerve, and nasociliary nerve
The clivus is formed by which bones?
The occipital and the sphenoid bones
Which cranial nerve nuclei are positioned in the lateral recess near the foramen of Luschka?
The dorsal and ventral cochlear nuclei of CN VIII
What are the cirvumventricular organs?
Pineal gland, subforniceal organ, organum vasculosum of the lamina terminalis, median eminence of the hypothalamus, neurohypophyis, area postrema, and subcommissural organ
The atrium of the ventricle is deep to which cortical structure?
Supramarginal gyrus
Two pairs of small swellings can be seen in the floor of the 4th ventricle, the lateral and medial ridges. What do these structures represent?
The lateral ridges constitute the vagal trigone and indicate the location of the underlying dorsal motor nucleus of the vagus.
The medial ridges constitute the hypoglossal trigone and indicate the location of the underlying hypoglossal nucleus
Where in the brain are the cholinergic neurons found?
The basal nucleus of Meynert.
Abnormalities of this area have been found in patients with Alzheimer’s
Where are the NE-containing neurons found in the brain?
Locus ceruleus
Embryologic origin of the meninges?
The pia and arachnoid layers are formed from ectoderm while the dura is formed from mesoderm.
How much CSF is produced each day?
About 450 mL.
There is only about 150 mL of CSF in the body at any one time.
What separates the interpeduncular cistern from the chiastmatic cistern?
The Liliequist membrane which is an arachnoidal sheet extending from the dorsum sellae to the anterior edge of the mamillary bodies.
Which area of the hippocampus is most vulnerable to hypoxia?
CA1, also called Sommer’s sector.
The CA3 area is relatively resistant to hypoxia
What makes up the neostriatum?
The caudate and putamen
The gustatory area receives input from which nucleus?
The ipsilateral nucleus soliatarius
What deficit would result from a lesion of the right Meyer’s loop?
Left upper quadrantanopia
What clinical finding is seen when there is a lesion of the posterior part of the middle frontal gyrus?
Conjugate eye deviation toward the ipsilateral eye.
This is area 8, the cortical lateral conjugate gaze center.
Stimulation of this area results in eye deviation toward the contralateral side.
The hypothalamus receives fibers from the amygdala via which bundle?
Stria terminalis
Where in the internal capsule do the corticobulbar fibers run?
The genu of the internal capsule
Where in the internal capsule is the corticospinal tract located?
The posterior limb of the internal capsule
What is the main neurotransmitter of the corticothalamic tracts?
Glutamate
Where is the satiety center?
Medial hypothalamus.
Stimulation of this area results in decreased food intake.
Where is vasopressin synthesized?
In the supraoptic and paraventricular nuclei of the hypothalamus
Which part of the hypothalamus acts to lower the body temperature?
The anterior part.
Stimulation of this area causes dilatation of the blood vessels and sweating, which lower body temperature.
Where does the corticospinal tract originate?
The corticospinal tract originates from layer V of the cerebral cortex.
It passes through the corona radiata and posterior limb of the internal capsule.
This tract then runs in the cerebral peduncles and the pyramids of the medulla; it terminates at lamina VII in the spinal cord
What makes up the inferior parietal lobule?
The angular and supramarginal gyri.
The parietal lobe is divided into superior and inferior parietal lobules by the interparietal sulcus.
Damage to which part of the brain causes prosopagnosia?
The temporal association cortex.
Prosopagnosia is the inability to recognize familiar faces; it is caused by the impairment of pathways involved in visual processing
What makes up the inferior frontal gyrus?
The pars orbitalis, pars opercularis, and pars triangularis
Afferent fibers of the pupillary light reflex cross to the contralateral Edinger-Westfall nucleus via which structure?
The posterior commissure
Which cells give rise to the only output of the cerebellar cortex?
Purkinje cells - their signal is inhibitory
What are the middle and superior cerebellar peduncles also called?
Brachium pontis and brachium conjunctiva, respectivley
What is the other name for the inferior cerebellar peduncle?
Restiform body
What is the only afferent tract that runs through the superior cerebellar peduncle?
The ventral spinocerebellar tract.
What syndrome can be caused by a pineal region tumor?
Parinaud syndrome - this consists of upper gaze palsy, dissociated light near response, retraction nystagmus, and an absence of convergence
What is Weber syndrome?
CN III palsy with contralateral hemiparesis
This is due to an infarct in the medial midbrain
Where is the lesion located in Millard-Gubler syndrome?
At the base of the pons – this syndrome includes VII and VI nerve palsy and contralateral hemiplegia
What is the function of the red nucleus?
Maintains flexor muscle tone
Where is the vertical gaze center located?
The rostral interstitial nucleus on the MLF
Crossed nasal retinal visual fibers go to which layer(s) of the lateral geniculate nucleus (LGN)?
Layers 1, 4, and 6.
Fibers from the ipsilateral temporal hemiretina synapse in layers 2,3, and 5
Which trigeminal nucleus receives pain and temperature sensation from the face?
The spinal trigeminal nucleus.
This nucleus extends from the pons to C2 and merges caudally with the substantia gelatinosa.
This nucleus also receives input from CNs VII, IX and X
Which trigeminal nucleus receives proprioception from the face?
The mesencephalic nucleus
What does the lateral lemniscus carry?
The lateral lemniscus is the second order neuron of the auditory pathway.
It ascends in the brainstem to the inferior colliculus.
A lesion of the lateral lemniscus results in partial bilateral deafness
Which CN is most susceptible during CEA?
CN XII
What does hypoglossal nerve palsy suggest in the setting of a skull base tumor?
Hypoglossal nerve palsy may be a manifestation of tumor infiltration into the anterior portion of the ipsilateral occipital condyle
Where does the trochlear nerve decussate?
Within the superior medullary velum
What triggers a glossopharyngeal neuralgia “attack”?
Swallowing, talking, or chewing
What is Hering’s nerve?
A branch of CN IX that is the sensory limb of the carotid body.
When a chemoreceptor detects changes in blood O2 and CO2 concentration, Hering’s nerve is stimulated
What is the significance of an enlarged intervertebral foramen on radiography?
It may suggest a nerve root tumor
At what cervical level is the hyoid bone? Thyroid cartilage? Cricoid?
The hyoid bone is at the level of C3, the thyroid cartilage at C4-5, and the cricoid is opposite C6
Perioral tingling and numbness in syringobulbia is due to compression of which tract?
The spinal trigeminal tract
Which ligament is the primary restraint against atlantoaxial AP translation?
Transverse ligament
Where is the aortic bifurcation usually located?
At the mid body of L3
Loss of sensation over the webspace between the first and second toes is associated with what injury?
Injury to the deep peroneal nerve
What are the radiographic findings in acute transverse myelitis?
Radiographic findings are usually normal, possibly with increased T2 signal
What are some radiographic findings that can help distinguish infection from tumor in the spine?
A characteristic radiographic finding is that destruction of the disk space is highly suggestive of infection, whereas in general the tumor will affect primarily the body and will not cross the disk space
What is the unique feature of a far lateral disk herniation?
Unlike the usual disk herniation, a far lateral herniation impinges against the upper nerve root
Ex: a L4-5 far lateral disk herniation will produce a L4 nerve root radiculopathy
What is Spurling’s sign?
Radicular pain reproduced when the examiner exerts downward pressure on the vertex while tilting the head toward the symptomatic side.
This causes narrowing of the intervertebral foramen and reproduces the symptoms.
How dot he sympathetic fibers exit the spinal cord?
Via the ventral roots by way of the white rami communicantes
What are the symptoms of posterior interosseous neuropathy?
Finger extension weakness including the thumb with no wrist drop or sensory loss.
The posterior interosseous nerve may be entrapped at the arcade of Frohse, which is a fibrous band that the nerve goes through when it dives into the supinator muscle
Where is the site of entrapment of the suprascapular nerve?
Within the suprascapular notch beneath the transverse scapular ligament.
Entrapment results in atrophy of the infra- and supraspinatus muscles as well as deep, poorly localized shoulder pain.
This is due to the fact that this nerve carries sensation from the posterior joint capsule, but has no cutaneous representation.
Which nerve roots are usually affected in true neurogenic thoracic outlet syndrome?
The C8 and T1 nerve roots.
Thoracic outlet syndrome is most commonly due to a cervical rib or to an enlarged C7 transverse process.
What are the symptoms of anterior interosseous syndrome?
Weakness of flexion of distal phalanges of the thumb (flexor pollicis longus), index, and middle finger (flexor digitorum profundus 1 and 2).
This give the characteristic “pinch sign”.
There is no sensory loss as this is a pure motor branch of the median nerve.
What must be ruled out in a patient with wrist drop?
Lead poisoning
Where is the ligament of Struthers, what nerve may it compress, and what syndrome can compression of this nerve mimic?
The ligament of Struthers is present in a small percentage of the population and is found crossing the cubital fossa above the medial intermuscular septum.
In this area it may cause compression of the median nerve, which can mimic carpal tunnel syndrome.
In cases of median nerve compression by the ligament of Struthers, thenar numbness is more pronounced than in carpal tunnel syndrome (where the palmar cutaneous branch is spared).
Where is the arcade of Struthers, and what nerve may it compress?
The arcade of Struthers is located at the elbow near the medial head of the triceps.
It may compress the ulnar nerve at this location.
It is important in ulnar nerve transposition that the arcade of Struthers, when present, is released to prevent kinking of the ulnar nerve.
How does magnesium prevent excitotoxicity in brain injury?
Magnesium readily crosses the BBB and blocks various subtypes of calcium and NMDA channels.
What is the most abundant excitatory neurotransmitter in the brain?
Glutamate
What cellular elements compose the BBB?
Endothelial cells, astrocyte endfeet, and pericytes.
The capillary endothelial cells are connected together by tight junctions.
What happens to platelet function after SAH?
It is enhanced, leading to an increase in platelet aggregates in the cerebral microcirculation.
What happens to CBF immediately after a SAH?
It decreases.
It is thought that a disturbed balance between which peptide and molecule plays a major role in the development of vasospasm?
Endothelin-1 (vasoconstriction) and NO (vasodilatation)
What is deferoxamine?
An iron chelator.
Because ICH may result in iron toxicity to the brain, iron chelation may help to reduce brain damage in these cases.
What is S100B and how is it related to TBI?
S100B is a protein belonging to a multigenic family of low-molecular weight calcium-binding S100 proteins abundant in astrocytes.
After TBI, S100B protein is released by astrocytes - this protein may be neuroprotective and/or neurotrophic.
What is the (intracranial) Windkessel phenomenon?
The Windkessel phenomenon is the ability of the of the cerebral vasculature to expand and the ability of the CSF and venous blood to translocate to accommodate arterial pulsations and provide a smooth capillary flow in the brain.
What is the ischemic penumbra?
The term ischemic penumbra has been used to define a region in which CBF reduction has passed the threshold that leads to failure of electrical but not membrane function.
The neuron is functionally disturbed, but remains structurally intact.
What are the functions of transforming growth factor beta (TGF-B)?
TGF-B is a multifunctional polypeptide implicated in the regulation of various cellular processes including growth, differentiation, apoptosis, adhesion, and motility.
Abnormalities in the TGF-B signaling pathways are implicated in the development and progression of brain tumors.
What is the causative mutation in Crouzon syndrome?
Crouzon syndrome is caused by mutations in fibroblast growth factor receptor 2 (FGFR2) leading to constitutive activation of receptors in the absence of ligand binding.
This syndrome is characterized by premature fusion of the cranial sutures that leads to abnormal cranium shape, restricted brain growth, and increased ICP.
How does baclofen work?
Baclofen is an agonist of GABA; it reduces the release of presynaptic neurotransmitters in excitatory spinal pathways.
What is hypsarrhythmia?
A chaotic, high-amplitude, generalized EEG pattern characteristic of infantile spasms.
What is “subsidence” in relation to the aging spine?
Subsidence is the loss of vertebral column height that occurs normally with aging; it may also refer to the loss of graft height after surgery.
The use of dynamic plates allows normal subsidence to occur and may help bony fusion resulting in decreased incidence of construct failures.
What is the genetic defect in Gorlin syndrome?
Gorlin syndrome is an autosomal dominant disorder resulting from mutations in the patched (PTCH) gene that predisposes to neoplasias and widespread congenital malformations.
What is the composition of a PEEK cage?
Polyetheretherketone (PEEK) spacers have a modulus of elasticity close tot hat of cortical bone.
PEEK is a strong polymer that is able to withstand the compressive load of the vertebral column.
Its hollow center allows for packing of autologous bone.
What are common areas of leptomeningeal dissemination of tumors?
The most common areas of leptomeningeal dissemination of CNS tumors are the basilar cisterns, Sylvian fissures, and cauda equina, most likely because of both gravity and slower rate of CSF flow in these areas.
How does hypocalcemia lead to tetany?
When there is less calcium in the interstitial fluid, the Na opens sooner, so the membrane is more excitable.
In other words, hypocalcemia causes a lower threshold of membrane depolarization and action potential initiation.
How can hyperventilation induce seizures?
Hyperventilation causes a respiratory alkalosis, which increases the pH.
Increasing pH increases the membrane excitability and can induce seizures.
What are the two types of acetylcholine receptors?
Nicotinic - located in the neuromuscular junction and preganglionic endings of both sympathetic and parasympathetic fibers.
Muscarinic- found in all postganglionic parasympathetic endings and the postganglionic sympathetic endings of sweat glands.
What are the two main inhibitory neurotransmitters of the CNS?
GABA and glycine
What is hyperaglia?
This is increased sensitivity to pain (decreased pain threshold).
This can occur by either increased sensitivity of the receptors, by facilitation in the spinal cord, or thalamic lesions.
What is thalamic pain syndrome?
AKA Dejerine-Roussy syndrome.
This is usually due to a posteroventral thalamic stroke and its abnormal subsequent facilitation of the medial thalamic nucleus.
These patients usually have a contralateral hemianesthesia at first, with increased pain in that area in the following weeks to months.
What does a muscle spindle detect?
It detects length and velocity of change in the length of the muscle.
It is in parallel with the muscle fibers and is stimulated by stretching.
It increases firing with muscle stretch and decreases firing with muscle contraction.
What causes decerebrate posturing?
This is caused by a lesion between the pons and the midbrain.
This results in blockage of normal stimulation input to the medullary reticular formation from the red nucleus, basal ganglia, and cortex.
As a result, there is unopposed antigravity muscle tone that is stimulated by the lateral vestibular nucleus and pontine reticular nucleus.
What is the MOA of the nitrosoureas (BCNU, CCNU)?
These widely used chemotherapy agents in patients with malignant brain tumors are alkylating agents.
They alkylate DNA in multiple locations causing cross-links and often produce single or double stranded DNA breaks, which eventually lead to tumor cell death.
How does temozolamide work?
Temozolamide works by attaching a methyl group to the DNA base guanine.
This attachment prevents proper DNA replication and leads to cell death.
What is MGMT?
MGMT is a DNA repair enzyme that can remove the methyl group placed by temozolamide, thereby negating the cytotoxic effects of temozolamide.
Therefore, patients who express low levels of MGMT respond better to temozolamide.
What is the effect of sleep deprivation on the autonomic system?
Sleep deprivation increases sympathetic output and decreases parasympathetic output.
What is the Hering-Breuer inflation reflex?
This is a reflex that is stimulated by stretch receptors in the bronchi and bronchioles.
The afferent arm of the reflex is via the vagus nerve and inhibits the dorsal respiratory nucleus in the dorsal medulla to stop inspiration if the lungs are overly distended.
What causes vasogenic edema?
Vasogenic edema is caused by increased BBB permeability to proteins and macromolecules.
This type of edema is extracellular and is caused by vessel damage and inflammation.
What causes cytotoxic edema?
Cytotoxic edema is caused by an impaired Na/K pump as occurs in ischemia.
Water and electrolytes accumulate inside the cells.
It is an intracellular type of edema.
What are the visual field findings in patients with ischemic optic neuropathy?
Ischemic optic neuropathy is the most common cause of painless monocular blindness in the elderly.
This is caused by occlusion of the central retinal artery.
This causes an altitudinal field deficit.
What medications increase the level of Dilantin?
Cimetidine, coumadin, isoniazid, and sulfa drugs.
What is ideomotor apraxia?
This is the inability to perform a complex motor task despite the awareness of the task.
These patients can perform many complex tasks automatically, but cannot perform the same acts on command.
This condition is caused by a lesion of the supramarginal gyrus of the dominant parietal lobe.
What lesions can produce a head tilt?
CN IV palsy, anterior vermis lesion, tonsilar herniation.
In myasthenia, the head tilts back.
What is the term for the vermicular movement of the face in a patient with pontine demyelination?
Myokymia
What disorders can benefit from DBS of the ventral intermediate thalamic nucleus?
Essential tremor and parkinsonian tremor
What region of the internal capsule may be affected in a patient with dysarthria and clumsy-hand syndrome?
The genu
What do lesions of the bilateral hippocampi produce?
Recent memory impairment
What is the name of the area involved with cortical inhibition of bladder and bowel voiding that is damaged in NPH?
The paracentral lobule
If there is a problem with pupillary response, where is the lesion in relation to the lateral geniculate body?
Anterior to the lateral geniculate body
What are some causes of circumoral paresthesia?
Hypocalcemia, hyperventilation, syrignobulbia, and neurotoxin fish poisoning
What diseases may manifest as facial myokymia?
Intrinsic brainstem glioma or MS
What are the major signs and symptoms of lateral medullary infarction?
Vertigo, nausea, vomiting, intractable hiccups, diplopia, dysphagia, dysphonia, ipsilateral sensory loss of facial pain and temperature, ipsilateral Horner’s, contralateral pain and temperature loss of the limbs and trunk
What differentiates ptosis from CN III palsy from ptosis in Horner’s?
Horner syndrome ptosis is partial and disappears on looking up
What are conditions that may result in upgaze palsy?
Tumor on the quadrigeminal plate or pineal region (Parinaud syndrome), hydrocephalus or other causes of elevated ICP, Guillain-Barre, myasthenia, botulism, hypothyroidism
What is the diagnosis (until proven otherwise) of an adult patient who presents with recurrent meningitis without any other predisposing conditions?
CSF fistula.
Recurrent meningitis in an infant may be a manifestation of basal encephalocele.
A cherry red spot in the retina is seen in which conditions?
Tay-Sachs
Niemann-Pick
Pseudo-Hurler syndrome
Retinitis pigmentosa is seen in which conditions?
Friedreich ataxia
Refsum disease
Cockayne syndrome
Kern-Sayre syndrome
What is Melkersson-Rosenthal syndrome?
Triad of recurrent orofacial edema, recurrent CN VII palsy, and lingua plicata.
What is Ramsay-Hunt syndrome?
Herpes zoster oticus
Third most common cause of CN VII palsy
What is Heerfrodt syndrome?
Uveoparotid fever
CN VII palsy in sarcoidosis
Bilateral CN VII palsy is indicative of which disease?
Lyme disease
What is Millard-Gubler syndrome?
Ipsilateral CN VI and VII palsy and contralateral hemiparesis
What is Brissaud-Sicard syndrome?
Ipsilateral CN VII hemispasm and contralateral hemiparesis
What is Foville syndrome?
Ipsilateral CNs VI and VII involvement and horizontal gaze paralysis with contralateral hemiparesis
What is Panayiotopoulous syndrome?
Benign occipital lobe epilepsy in children
What is the most common side effect of mannitol?
Renal failure
What is the most common cause of SAH?
Head trauma
What is the most common cause of CSF leakage?
Head trauma
Having a skull fracture doubles the patient’s risk of CSF leak.
How can one differentiate if nasal drainage is CSF or nasal secretion?
The primary distinction is the glucose level.
Glucose is present in the CSF (at 50% of serum levels) and not present in nasal drainage.
Beta-2 transferrin can confirm the presence of CSF
What is the major cause of spontaneous intracranial hypotension?
Spontaneous CSF leaks.
Diffuse pachymeningeal enhancement on MRI is the most common finding.
What are the areas most prone to DAI after head trauma?
Corpus callosum and superior cerebellar peduncle.
What range of cerebral perfusion pressures are accommodated by cerebral autoregulation?
60-160 mmHg
CPP should be maintained above what number after a severe head injury?
70 mmHg
Where on the carotid artery is the most common location for a traumatic aneurysm?
Most traumatic aneurysms of the carotid artery are located on the segment between the proximal and distal dural rings.
They are pseudyaneurysms that may project medially into the sphenoid sinus.
They may present with the classic triad of head injury with basal skull fracture, unilateral visual loss, and epistaxis.
What are the prerequisites for a growing skull fracture?
- The skull fracture occurs in infancy or early childhood
- There is a dural tear at the time of the fracture
- There is brain injury at the time of the fracture with displacement of leptomeninges and possibly brain through the dural defect
- There is subsequent enlargement of the fracture to form a cranial defect
What are some cases where hyperemia of the brain can occur?
Head trauma, after CEA or stenting, and after excision of an AVM
What is the most common site of hypertensive cerebral hemorrhage?
Putamen
What are the signs and symptoms of Addisonian crisis?
Addisonian crisis is an adrenal insufficiency emergency with symptoms of mental status changes and muscle weakness.
Signs of postural hypotension, shock, hyponatremia, hyperkalemia, hypoglyecemia, and hyperthermia may be seen.
What is neurogenic pulmonary edema?
Neurogenic pulmonary edema is associated with SAH, head trauma, and seizure disorder.
It is caused by an increased capillary permeability in the lungs associated with an increased sympathetic discharge.
What is the name of a cystic tumor of the suprasellar region that arises from neuroectodermal remnants of Rathke pouch?
Craniopharyngioma
What preoperative medication can lessen general and cardiac risks in patients with a GH secreting tumor?
Somatostatin analogue
Which type of lesion can present with calcification in the sella area and erode through the posterior clinoids?
Craniopharyngioma
Erosion of the posterior clinoids may also occur from chronic increases in ICP.
What type of tumor can erode the internal acoustic meatus?
Acoustic schwannoma
What type of tumor can erode the petrous apex?
Trigeminal schwannoma
What type of tumor can erode the clivus?
Chordoma
What type of tumor can erode the sellar floor?
Large pituitary tumors
What type of tumor can erode the orbital foramen?
Optic nerve glioma
What type of tumor can erode the jugular foramen?
Glomus jugular tumor
What disease may produce generalized bone erosion? Generalized hyperostosis?
Multiple myeloma produces generalized bone erosion.
Paget disease usually results in generalized hyperostosis.
Meningiomas results in focal hyperostosis.
What is the most common extradural neoplasm involving the clivus?
Chordoma
What is the most common site of origin for chordomas?
Sacrum
What is the second most common site of origin for chordomas?
Clivus
Prophylactic cranial irradiation may be considered part of the standard treatment of patients with what disease?
Small cell lung carcinoma
Where are colloid cysts found?
The anterior roof of the 3rd ventricle
What is the most common intraorbital tumor found in adults?
Cavernous hemangioma.
These are benign, slow-growing vascular lesions.
They manifest as a painless, progressive proptotic eye.
What is the second most common type of intracranial schwannoma?
Trigeminal schwannoma
What is the most common presentation of a choroid plexus tumor?
Intracranial hypertension
What are the differences in location of a choroid plexus papilloma between an adult and a child?
Choroid plexus papillomas are rare benign tumors of the CNS that occur mostly in children.
These tumors are usually found in the left lateral ventricle in children and the 4th ventricle in adults.
What is the significance of elevated choline peaks and reduced NAA levels in spectroscopic evaluation of brain tumors?
Increased choline levels indicate increased membrane turnover.
NAA (which reflects neuronal integrity) is reduced in tumors.
What CSF tumor marker is positive in germinomas?
Placental alkaline phosphatase
Which pineal region tumor is most sensitive to radiation?
Germinoma
What serum marker should you look for in a patient with a pineal region tumor?
B-HCG and AFP because these neoplasms are of germ cell origin.
B-HCG is elevated in choriocarcinomas.
AFP is elevated in embryonal carcinomas and yolk sac tumors.
What are the 3 most common focal brain lesions in HIV?
Toxoplasmosis, primary lymphoma, and progressive multifocal leukoencephalopathy (PML)
What modality can distinguish primary lymphoma of HIV from other focal mass lesions associated with HIV?
A 18-FDG PET scan.
Lymphomas have a higher uptake than toxoplasmosis or PML.
What diagnostic test is recommended for a pediatric patient with a posterior fossa tumor?
MRI of the spine to rule out drop mets
What is Collin’s law?
Collin’s law (or rule) states that a congenital tumor may be considered cured if it does not recur within a period equal to the person’s age plus 9 months after surgery.
Where do meningiomas arise from?
Arachnoid cap cells present in the arachnoid granulations (convexity meningiomas) and in the arachnoid layers of the meninges (for non-convexity meningiomas)
How do meningiomas of the foramen magnum present?
Pyramidal weakness initially affecting the ipsilateral arm, followed by the ipsilateral leg, spreading to the contralateral limbs when the tumor enlarges.
What is the chromosomal abnormality found in meningiomas?
Over 70% of these tumors have monosomy 22.
From where do convexity meningiomas derive their blood supply?
The external carotid artery branches
Which hormone receptors do meningiomas exhibit?
Progesterone and estrogen.
This may explain why meningiomas are more common in women and why they tend to grow with pregnancy and breast CA.
What is Foster-Kennedy syndrome?
Optic atrophy in one eye and papilledema in the other eye with anosmia.
This syndrome is sometimes seen with olfactory groove meningiomas.
Any patient younger than 40 years with a unilateral acoustic neuroma should also be evaluated for what condition?
NF2
What do brainstem auditory evoked potentials show in a patient with acoustic neuroma?
A delay of wave V latency on the affected side
What medication may shrink a neurosarcoid mass at the skull base?
Corticosteroid
What is the most common primary skull neoplasm?
Osteoma
Which malignancies are associated with NF1?
Malignant peripheral nerve sheath tumors, pheochromocytoma, and leukemia
What osseous lesion and condition are usually seen with NF1?
Sphenoid dysplasia and thinning of long bones
What is the mode of inheritance of NF2?
AD on chromosome 22
Where are chordomas found?
Almost all chordomas occur near the clivus or sacrum
What is the difference between an osteoid osteoma and an osteoblastoma?
Size, these are benign bone tumors.
When the lesion is 2cm or less, it is called an osteoid osteoma.
If greater than 2cm, it is called an osteoblastoma
What is Gardner syndrome?
Gardner syndrome is characterized by intestinal polyposis with frequent malignant degeneration, benign soft tissue neoplasms, and multiple osteomas of the skull and mandible.
What is the most common location for epidermoid tumors?
CPA
What are some cerebral mets in pediatric patients?
Neuroblastoma, rhabdomyosarcoma, and Wilm’s tumor
What are the radiosensitive cerebral mets?
Small cell lung CA, multiple myeloma, germinoma, lymphoma, and leukemia
Where do brain mets appear?
Gray-white junction
Which brain lesion is associated with gelastic seizures?
Hypothalamic hamartomas
Besides a brain MRI, which other diagnostic procedures are needed in a patient with an ependymoma?
A spinal MRI and a lumbar puncture (if not contraindicated)
What are the most common tumors of the jugular foramen?
Also called glomus jugular tumors, paragangliomas are the most common, followed by schwannomas and meningiomas.
What is the most common presenting sign of a glomus tumor?
Unilateral hearing loss due to invasion of the middle ear.
What is the most common vessel supplying a glomus jugulare tumor?
The ascending pharyngeal artery
What is the differential diagnosis for a cerebral ring-enhancing lesion?
Glioma, lymphoma, infection, demyelinating plaque, radiation necrosis, resolving hematoma, cysticercosis, sarcoid, or granulomatous disease.
What tumor marker is useful for differentiating between renal cell carcinoma and hemangioblastoma?
Epithelial membrane antigen is not present in hemangioblastomas, but is present in renal cell carcinoma.
What pitfall must be avoided in treating a patient with Parkinson disease and malignant melanoma?
Levodopa should not be given because dopamine is a precursor of melanin; giving levodopa may stimulate tumor growth.
What is gliomatosis cererbri?
Diffusely enlarged cerebral hemisphere filled with tumor.
This also refers to diffuse enlargement of the cerebellum or brainstem.
There are no focal masses.
What is the most common benign primary intraorbital tumor?
A cavernous hemangioma
Patients with what type of tumor of the CNS exhibit polycythemia?
Hemangioblastoma (10%)
Chromosome 22 is associated with which disorders?
Meningiomas, ependymomas, NF2, and metachromatic leukodystrophy
Which common pediatric tumor arises from the floor and which one arises from the roof of the 4th ventricle?
Medulloblastoma: roof of the 4th ventricle (vermis)
Ependymoma: floor of the 4th ventricle
What kind of visual deficit is feared in temporal lobectomy?
Contralateral superior temporal visual field deficit
On which chromosome is the VHL gene located?
3p
What are the CNS manifestations of VHL disease?
Hemangioblastomas of the retina, brainstem, cerebellum, spinal cord, and nerve roots; endolymphatic sac tumors
Which skull base tumor ascends into the cranial cavity via perineural spread?
An adenocystic carcinoma
What are the cardinal symptoms of a vestibular schwannoma?
Unilateral hearing loss, tinnitus, vertigo, and unsteadiness
What is the eponym for dysplastic gangliocytoma of the cerebellum?
Lhermitte-Duclos disease
The Epstein-Barr virus is associated with which carcinomas?
Burkitt lymphoma and nasopharyngeal carcinoma
What is Eaton-Lambert syndrome?
This is a paraneoplastic syndrome in which Ig antibodies to the presynaptic voltage-gated Ca channel are produced.
This decreases the number of ACh quanta released.
It causes proximal limb fatigue, but unlike myasthenia, this syndrome spares ocular muscles.
About 60% of cases are associated with pulmonary oat cell (small cell) carcinoma.
Where does esthesioneuroblastoma originate from?
The olfactory epithelium.
What is the most common presenting symptom of esthesioneuroblastoma?
Nasal obstruction, followed by epistaxis.
What are the symptoms of adrenal insufficiency?
Fatigue, weakness, arthralgia, anorexia, nausea, hypotension, orthostatic dizziness, hypoglycemia, and dyspnea
What does a persistently elevated GH level suggest after transphenoidal resection for a GH producing tumor?
Persistent tumor or damage to the pituitary stalk
What suprasellar aneurysm could mimic a pituitary tumor on a CT scan?
A superior hypophyseal artery aneurysm.
What parts of the visual fields are affected initially by a suprasellar mass?
Superior temporal quadrants
What is happening when a patient with a known pituitary tumor has a sudden headache, CN III palsy, and a contralateral CN IV palsy?
Pituitary apoplexy.
Expansion of the mass accounts for the CN findings on opposite sides.
Which nerve is most commonly involved by a tumor in the cavernous sinus?
The oculomotor nerve (followed by abducens and then trochlear)
What is an easy way to differentiate CSW from SIADH?
This can be done by measuring plasma volume and looking for signs and symptoms of dehydration.
SIADH patients will have high plasma volumes, increased weight, and high CVP.
CSW patients will have low plasma volumes, decreased weight, low CVP and may have orthostatic hypotension.
What is the most common cause of Cushing syndrome?
Exogenous administration of glucocorticoids for chronic inflammation.
What nerve innervates the diaphragma sella?
The first division of the trigeminal nerve
What types of lesions can exhibit calcification near the sellar area?
Meningioma, aneurysm, craniopharyngioma, pituitary adenoma, and chondrosarcoma
Describe a pituitary pseudotumor in the setting of thyroid disease?
With chronic primary hypothyroidism, there is secondary hyperplasia of the pituitary, which can mimic a pituitary mass on MRI.
Loss of negative feedback from thyroid hormones causes increased TRH release from the hypothalamus producing secondary hyperplasia of thyrotropic cells in the adenohypophysis.
What is the most common intrinsic tumor of the hypothalamus?
Astrocytoma
What is the DDx for thickening of the pituitary stalk?
Lymphoma, lymphocytic hypophysitis, granulomatous disease, or hypothalamic glioma.
What is the “stalk effect”?
Elevation of prolactin due to decreased dopamine from compression on the pituitary stalk from a non-prolactinoma.
The prolactin level is usually under 150, whereas in prolactinomas the level is above that.
What is Nelson syndrome?
This occurs when there is pituitary enlargement after an adrenalectomy that was performed to treat Cushing syndrome.
Patients usually have hyperpigmentation due to MSH that is overproduced along with ACTH.
What is the difference between Cushing syndrome and Cushing disease?
Cushing syndrome is a constellation of findings caused by hypercortisolism.
The most common cause is exogenous steroid administration.
Cushing disease is endogenous hypercortisolism due to an ACTH-secreting pituitary adenoma.
What is pituitary apoplexy?
Pituitary apoplexy is acute hemorrhagic necrosis of a pituitary adenoma when it outgrows its blood supply.
This can be an emergency as the acute expansion of the tumor that can develop, may compress the optic apparatus and may cause blindness.
Treatment is with surgery and/or steroids.
Which medication is used to temporarily lower cortisol levels?
Ketoconazole
What serum marker is measured in a GH-secreting pituitary adenoma?
Somatomedin C.
It is synthesized in the liver and produces IGF-1.
What visual field deficit is usually found in suprasellar masses?
Bitemporal hemianopsia from compression of the optic chiasm.
Cells are most resistant to radiation therapy in which phase of the cell cycle?
The S phase (DNA synthetic phase).
This is thought to be due to the cells increases ability in this part of the cell cycle to repair damaged DNA from radiation.
At what age is it safe to use brain radiation?
Radiation is avoided in children below 5 years of age.
On average, how long after radiation treatment is radiation necrosis seen?
18 months.
Radiation necrosis affects mostly the white matter; the neurons are relatively resistant.
Treatment is usually with steroids.
Besides the risk of radiation necrosis, what is one major drawback to treating AVMs of the brain with SRS?
It takes about 2 years for the radiation to obliterate the AVM.
During the time, the patient may have an increased risk of hemorrhage.
Radiation is best reserved for lesions less than 3cm in size.
What empiric medications should be given to all HIV-positive patients with a CNS mass lesion?
A 2 week trial of toxoplasmosis medications, pyrimethamine and sulfadiazine.
What should be done with a patient if herpes simplex encephalitis is suspected?
Start acyclovir immediately.
What should be at the top of the DDx in a patient who presents with a suboccipital dimple and an attack of infectious meningitis?
A posterior fossa dermoid cyst with a cutaneous fistula.
What type of venous thrombosis may occur with mastoiditis?
Lateral sinus thrombosis may be secondary to mastoiditis due to the proximity of this sinus to the mastoid bone.
What is the proper medical treatment of a Nocardia brain abscess?
TMP-SMX
What is the most common etiology of subdural empyema?
Frontonasal sinusitis
What is the rate of immediate mortality in stroke?
In cerebral hemorrhage, immediate mortality is about 50%.
In cerebral infarction, immediate mortality is about 20%.
What are some causes of hemorrhagic stroke?
HTN, amyloid vasculopathy, aneurysm, AVM, neoplasm, coagulation disease, anticoagulant therapy, vasculitis, drug abuse, trauma.
What is the meaning of luxury perfusion?
The area adjacent to an ischemic area receives more blood flow than normal due to the vasodilation of the arteriolar bed in response to local lactic acidosis.
What is Bow Hunter’s disease?
Bow hunter’s stroke results from vertebrobasilar insufficiency caused by mechanical occlusion or stenosis of the vertebral artery at the C1-2 level with head rotation.
Until proven otherwise, what is a headache in an elderly patient who presents with pain when talking and/or chewing and a high ESR?
Giant cell (temporal) arteritis
Dissecting aneurysms that cause SAH typically arise from which artery?
Vertebral artery
Where is a likely location of a traumatic aneurysm due to previous transsphenoidal surgery?
The anterior aspect of the carotid siphon.
What is the name of the test whereby manual compression on the carotid artery is performed with vertebral angiography to asses the size of the PCOMM artery?
The Allcock test
In what percentage of AVMs are aneurysms also found?
10-20%
What is a pretruncal nonaneurysmal SAH (also called benign perimesencephalic hemorrhage)?
It is the term given for subarachnoid blood in the prepontine or interpeduncular cisterns from rupture of small perimesencephalic veins and/or capillaries.
The blood is inferior to the Liliequist membrane (the membrane that separates the interpeduncular cistern from the chiasmatic cistern).
A repeat angiogram may not be needed with this particular type of SAH, and the M&M of this type of bleeding is significantly lower than classic SAHs.
What percentage of patients with aneurysmal SAH have multiple aneurysms confirmed by an angiogram?
About 20-30%
What clues can guide the surgeon in determining which aneurysm has bled in a patient with multiple aneurysms?
Looking for the pattern of blood on a CT scan, looking for focal spasm on an angiogram, considering the larger or more irregularly shaped aneurysm, examining the patient for focal neurological signs, consider repeating the angiogram and looking for changes in size and shape of the aneurysms, choosing the aneurysm that has the highest chance of rupture (ACOM).
What size is needed for an aneurysm to be considered a “giant” aneurysm?
2.5 cm and greater
How can one clinically differentiate carotid occlusion from innominate artery occlusion?
The BP in the right arm may be diminished with innominate artery occlusion.
What is the cumulative risk of rebleeding in an untreated aneurysm?
20% at 2 weeks and 30% at 1 month after initial rupture
If a CT scan is done for cerebral ischemia, at what time could one expect to see a hyperdense artery sign?
Between 12-24 hours.
Following an AComm artery aneurysm clipping from the left side, a patient awakens with hemiparesis and aphasia. What artery was most likely inadvertently coagulated or clipped?
The recurrent artery of Heubner.
In the treatment of Acomm artery aneurysms, great care must be taken to avoid unnecessary manipulation or occlusion of the Heubner artery.
Occlusion may cause hemiparesis with facial and brachial predominance because of compromise of that branch supplying the anterior limb of the internal capsule, and aphasia if the artery is on the dominant side.
What are some intracranial and extracranial complications of aneurysm rupture?
Intracranial complications include rebleeding, vasospasm, hydrocephalus, hematoma formation, and seizures.
Extracranial complications include myocardial irritation or infarction, neurogenic pulmonary edema, and gastric ulceration.
What area on the circle of Willis is most commonly hypoplastic?
The A1 segment of the anterior cerebral artery.
How is the arterial anatomy defined when the Pcomm artery is larger than the P1?
Fetal PComm
In what percentage of patients are the PCAs supplied on one or both sides by the carotid circulation?
About 20% of patients have a fetal circulation.
How can an Acomm artery aneurysm result in subarachnoid blood in the 3rd ventricle? What Fisher grade would this represent?
Rupture through the lamina terminalis.
Fisher grade 4.
How can an aneurysm result in 4th ventricular blood?
Rupture of a PICA aneurysm through the foramen of Luschka
What is the leading cause of death or morbidity after SAH?
Vasospasm is a leading cause of death or morbidity after SAH.
What value of MCA velocity in cm per second defines vasospasm?
A value of 120-200 indicates mild vasospasm, and over 200 cm/s indicates severe spasm.
What is the Lindegaard ratio?
The ratio of velocity of MCA flow to ICA flow, it is used to assess vasospasm.
A ratio of greater than 6 indicates severe vasospasm, less than 3 is normal.
What is central DI?
DI is a complication caused by a deficiency of ADH that may occur after a SAH, usually from an aneurysm near the anterior circulation.
Polyuria is the most prominent feature.
The diagnosis is confirmed by finding high volumes of dilute urine, of very low osmolality, at the same time as high serum osmolality, with hypernatremia in severe cases.
In what neurosurgical situations is DI commonly seen?
Following transsphenoidal surgery, brain death, craniopharyngioma, Acomm artery aneurysm, head injury, basal skull fractures, encephalitis, and meningitis.
What arteries supply lenticulostriates? Thalamoperforators?
Lenticulostriates are from the M1 segment of the MCA.
Thalamoperforators are from the P1 segment of the PCA.
In MCA occlusion in the dominant hemisphere, how can one have hemiplegia without aphasia in one case, and receptive aphasia without hemiplegia in another case?
Occlusion of the superior trunk of the MCA results in a sensory-motor hemiplegia without a receptive aphasia.
Occlusion of the inferior division of the MCA results in a receptive aphasia in the absence of hemiplegia.
When is surgery for venous angiomas warranted?
Bleeding or intractable seizures.
However, venous angiomas are usually benign and should be managed nonoperatively.
How can a vein of Galen aneurysm cause obstructive hydrocephalus?
Compression of the sylvian aqueduct.
What types of lesions can cause a pulse-synchronous tinnitus?
Carotid-cavernous fistula, dural AVM, glomus jugulare tumor, and a vascular lesion of the petrous bone/skull base.
What diagnosis must be excluded when one encounters a red, pulsatile, retrotympanic mass in a patient with conductive hearing loss and pulsatile tinnitus?
Glomus jugulare tumor
What is Vernet syndrome?
Palsies of CNs IX, X and XI at one time.
Which locations of dural vascular malformations carry a high risk of cerebral hemorrhage?
Dural malformations involving the anterior cranial fossa or the tentorial incisura carry a high risk of cerebral hemorrhage as part of their natural history.
In addition, the identification of cortical venous drainage by angiography appears to be predictive of hemorrhage.
What are the symptoms of verbtebrobasilar insufficiency and what is the risk of a stroke in the first year after a vertebrobasilar TIA?
Drop attack, diplopia, dysarthria, visual defect, and dizziness.
The risk of CVA is 22% in the first year after a TIA.
Until proven otherwise, what is acute retroorbital pain with a Horner’s syndrome indicative of?
Carotid artery dissection.
What is Binswanger encephalopathy?
Subcortical arteriosclerotic encephalopathy (SAE), which is a rare disorder in which progressive dementia and pseudobulbar palsy are associated with diffuse hemisphere demyelination.
A CT scan shows areas of periventricular low attenuation.
What are some signs and symptoms of cavernous sinus thrombosis?
Cavernous sinus thrombosis can spread from an infection on the face via draining veins or paranasal sinuses.
It is characterized by painful ophthalmoplegia, proptosis, and chemosis with edema of periorbital structures.
There may also be facial numbness and fevers.
What is the most common tumor of the cavernous sinus?
Meningioma
How does carotid dissection present?
Sudden neck pain, ipsilateral Horner’s syndrome, and sometimes lower cranial nerve palsies.
Type 1 AVF (Borden classification)
Via meningeal artery - drains anterograde to the venous sinus.
Type 2 AVF (Borden classification)
Via meningeal artery - drains anterograde to the venous sinus and sinus drains retrograde to subarachnoid veins.
Type 3 AVF (Borden classification)
Via meningeal artery - drains retrograde to subarachnoid veins.
According the Borden classification, which type of AVFs have a higher change of bleed?
The fistulas with a retrograde flow into subarachnoid veins have high pressure into veins and carry an increased chance of intracranial bleed and hence, require treatment.
What is the classification for spinal AVMs?
Type 1: dural AVF Type 2: intramedullary AVM Type 3: juvenile AVM Type 4: perimedullary AVF Type 4a: artery of Adamkiewicz Type 4b: multiple feeders
What is the usual location of cavernous malformations of the brain?
70% are supratentorial and 30% occur in the cerebellum, brainstem and spinal cord
What is the effect of the arteriopathy in moyamoya disease?
Progressive occlusion of the terminal ICA as well as the ACA or MCA.
This occurs while lenticulostriate collaterals form (moyamoya vessels) at the base of the brain.
What are the common symptoms and signs of a Chiari 1 malformation?
Symptoms: headache (sometimes worse with cough), neck pain, weakness, numbness, unsteadiness.
Signs: hyperactive LE reflexes, downbeat nystagmus, loss of temperature sensation, gait disturbance, hand atrophy, UE weakness.
What is often cited as the cutoff below which one may consider tonsillar herniation a Chiari I malformation?
5 mm below the foramen magnum
Chiari II malformation nearly always is associated with what spinal lesion?
Myelomeningocele.
All infants with myelomeningocele have MRI criteria of Chiari II malformation.
Hydrocephalus is nearly always present in these patients.
What are some common features of Chiari II malformation?
Downward displacement of the medulla, 4th ventricle, and cerebellum into the cervical spinal canal, elongation of the pons and 4th ventricle, dysgenesis of the corpus callosum, and medullary kinking.
What is the most common suprasellar tumor in children?
Craniopharyngioma
What hereditary conditions are associated with cerebral aneurysms?
Marfan’s, Ehlers-Danolos, pseudoxanthoma elasticum, polycystic kidney disease, tuberous sclerosis, hereditary hemorrhagic telangiectasia, Anderson-Fabry disease, and NF
What genetic disorder is associated with an imperfection of the vessel wall and increased incidence of cerebral AVMs?
Rendu-Osler-Weber disease (AKA hereditary hemorrhagic telangiectasia)
What disease should be considered in a child with multiple cerebral AVMs, recurrent epistaxis, and/or cerebral abscesses?
Rendu-Osler-Weber disease (AKA hereditary hemorrhagic telangiectasia)
What congenital diseases may present with seizures?
Tuberous sclerosis and Sturge-Weber
What are the manifestations of Sturge-Weber syndrome?
Unilateral port wine stain in the ophthalmic division of CN V, seizures, contralateral hemisensory and motor deficit, and cortical tramline calcification on CT.
Where is the most common location of germ cell tumors in the CNS?
The pineal region.
These are most common in children and adolescents, with a peak incidence around 12 years.
What is the most common presenting symptom of patients with choroid plexus papillomas?
Headache from increased ICP.
These tumors produce communicating hydrocephalus by overproducing CSF.
Other symptoms of increased ICP may be present such as nausea/vomiting, and craniomegaly.
What classic radiographic signs are seen in a CT of a patient with Sturge-Weber disease?
Tram track cortical calcifications and ipsilateral calvarial thickening.
What is the most common brain tumor that arises from patients with tuberous sclerosis?
Giant cell astrocytoma.
It occurs in about 10% of patients.
What is the classic triad seen in patients with tuberous sclerosis?
Mental retardation, seizures, and adenoma sebacum
What is the most common cutaneous manifestation of tuberous sclerosis?
Ash-leaf hypopigmented macules.
What is the most common childhood orbital lesion?
Retinoblastoma
These tumors arise from photo-receptor precursors.
What is the most common primary CNS tumor to exhibit extraneural spread?
Medulloblastoma
What is the difference in the location of a medulloblastoma in an adolescent (or adult) from that of a very young child?
Medulloblastomas may be present in the cerebellar hemisphere more often in adolescents and adults.
They are more often found in the midline in children.
What are the common findings in McCune-Albright syndrome?
Endocrine abnormalities, unilateral cafe au lait spots with jagged edges, fibrous dysplasia, and precocious puberty (in females)
How does a cerebellar pilocytic astrocytoma appear on a non-enhanced CT scan?
It appears as a hypodense mass lesion in almost 3/4s of the cases and is isodense to the white matter in the rest.
This is a helpful differentiating feature from medulloblastomas that are hyperdense on a non-enhanced CT scan.
What is the classic triad on neurologic examination at presentation in children with brainstem gliomas?
Ataxia, long tract signs, cranial nerve palsies.
What are the features of Aicardi syndrome?
Agenesis of the corpus callosum, infantile spasms, mental retardation, and chorioretinopathy.
Which pediatric brain tumor typically exhibits high serum and CSF levels of placental alkaline phosphatase?
Germinoma.
What is the Mt. Fuji sign?
A characteristic finding of two frontal poles surrounded by air on a CT scan indicative of pneumocephalus.
What diagnosis must be kept in mind when a young woman presents with bilateral trigeminal neuralgia?
MS
What is meant by the term allodynia?
Pain causes by a normally non-noxious stimuli
What is most often the offending vessel in trigeminal neuralgia?
The superior cerebellar artery.
Other nonvascular cases are a posterior fossa tumor and a MS plaque.
What areas are targeted in DBS to help with essential tremor? Parkinsonian tremor?
DBS of the VIM thalamic nucleus helps to improve essential tremor.
DBS of the subthalamic nucleus helps with parkinsonian tremor.
What is considered the best target of choice for dystonia?
Globus pallidus internus
What are the only involuntary movement disorders that persist during sleep?
Hemifacial spasm and palatal myoclonus.
What is the main difference between facial myokymia and hemifacial spasm?
Facial myokymia is a continuous facial spasm and may be a manifestation of an intrinsic brainstem glioma or MS.
Hemifacial spasm is intermittent, unilateral, and starts in the orbicularis oculi and slowly progresses down the entire side of the face.
Define radiculopathy.
Irritation of the LMN due to a mechanical or chemical insult to the nerve root in a single spinal level.
It can result in burning pain and numbness along with weakness and loss of reflexes in the corresponding nerve’s motor and sensory distribution.
What is the Lasegue sign?
The straight leg raise test.
In the cervical spine, which nerve root will be affected in case of a disk herniation?
The lower nerve root will be affected.
For example, if there is a disk herniation at C4-5, the C5 root will be affected.
What is a Spurling test?
In cases of radiculopathy, cervical extension with axial compression and rotation of the head of the pathology side decreases the size of the neural foramen and compresses the exiting nerve root resulting in increased pain or symptoms along the arm.
In lateral recess stenosis, is a SLR positive or negative?
Negative
What nerve roots are tensed by a SLR maneuver?
L5 and S1
What type of nerves are contained in the dorsal ramus of the nerve root?
The dorsal ramus contains nerves that serve the dorsal portions of the trunk carrying visceral motor, somatic motor, and sensory information to and from the skin, and muscles of the back.
What type of nerve root is located in the ventral ramus of the nerve root?
The ventral ramus contains nerves that serve the remaining ventral parts of the trunk and the upper and lower limbs carrying visceral motor, somatic motor, and sensory information to and from the ventrolateral body surface, structures in the body wall and the limbs.
How is the pain from lateral recess stenosis and herniated lumbar disk affected by sitting?
Lateral recess stenosis pain is relieved by sitting, whereas herniated disk pain is exacerbated by sitting.
Why does a C5 radiculopathy follow anterior or posterior decompression in a minority of cases even if the case was done without any obvious complication?
A C5 radiculopathy (deltoid weakness) may be related to traction on the nerve root from posterior migration of the cord after decompression because the C5 nerve has the shortest length from the foramen to muscle ending.
Which spinal tract is most responsible for lower limb subconscious proprioception from muscles, joints, and skin?
Spinocerebellar pathways.
What conditions may have L’Hermitte phenomenon as part of the patient’s history?
MS, cervical myelopathy, and subacute combined degeneration
What type of nystagmus is present in compressive lesions of the craniocervical border?
Downbeat nystagmus
What type of traumatic spinal lesion results in a cape-like sensory deficit?
A central cord lesion damages the second sensory neuron crossing to join the lateral spinothalamic tract.
Pain and temperature sensations are impaired bilaterally.
Because sacral fibers are located most peripherally in the lateral spinothalamic tract, there is sometimes sacral sparing with central cord lesions.
As the lesion expands, anterior horn cells may become involved and weakness may result.
Which type of spondylolisthesis is thought to result from a stress fracture of the pars interarticularis?
Isthmic spondylolithesis
What are the main causes of thoracic myelopathy from degenerative disease?
Herniated disks, ossification of the PLL, ossification of the ligamentum flavum, and posterior bone spurs.
How long must elective surgery wait for a patient who has been taking Plavix?
At least 7-10 days.
What is the cervical level of the inferior edge of the mandible, the hyoid bone, thyroid cartilage, and cricoid ring?
Inferior edge of the mandible: C2
Hyoid bone: C3
Thyroid cartilage: C4-5
Cricoid ring: C6
Which nerves arise from the lateral cord?
The lateral pectoral nerve to the pectoralis major muscle, the musculocutaneous nerve that innervates the biceps, and partly the median nerve.
During a thoracolumbar spine procedure, dissection of the psoas muscle should take into account which nerve on the anterior surface of the muscle?
The genitofemoral nerve
What is a superficial abdominal reflex?
They are performed by stroking each four quadrants of the abdomen and the normal response is the movement of the umbilicus toward the stroked segment.
It is an UMN reflex and asymmetry suggests intraspinal (UMN) pathology.
What ligaments serve as the ventral extent of safe dissection to avoid injury to the spinal nerve root during exposure and decortication of the transverse process?
The intertransverse ligaments
Where is the best place near the nerve root to expose an intervertebral herniated disk?
The shoulder of the nerve root is the best place to expose and remove the disk.
An extruded disk may sometimes be found in the axilla of the nerve root.
In which groove is the recurrent laryngeal nerve located?
The tracheoesophageal groove
Where is the best place to insert an intrathecal baclofen pump?
The tip of the catheter is placed at the level corresponding with the therapeutic indication: T10-12 for spastic diplegia, C5-T2 for spastic tetraplegia, and C1-4 for generalized secondary dystonia.
What is the critical distance of dens displacement above which open reduction and internal fixation should be considered?
6 mm. If the dens is displaced 6 mm or more, internal fixation is recommended because of the high rate of nonunion associated with widely displaced type II fractures.
If the dens is displaced less than 6mm, a halo brace is adequate.
What sensations are lost and retained in syringomyelia?
Pain and temperature sensation are lost.
Light touch, vibration and position sense are retained.
This is termed a “dissociated sensory loss”.
What condition constitutes the triad of cephaliga, hyperhidrosis, and cutaneous vasodilation, and at what level of the spinal cord is the injury?
Autonomic hyperreflexia occurs with a spinal cord lesion above T6.
What are the most important structures in maintaining atlantooccipital stability?
The tectorial membrane and the alar ligaments.
How can Collet-Sicard syndrome occur from trauma?
Lower CN injury (9-12) from an occipital condyle fracture, infection, carotid artery dissection, GSW, and possibly neoplasia.
Collet-Sicard syndrome is a collective term for involvement of CNs IX, X, XI and XII producing paralysis of the vocal cords, palate, trapezius, and SCM with secondary loss of the sense of taste in the back of the tongue, and anesthesia of the larynx, pharynx, and soft palate.
Where does conus medullaris syndrome occur? Cauda equina syndrome?
Patients with conus medullaris syndrome usually have injuries from T11-L1 where the spinal cord is usually terminating into the cauda equina.
Therefore, cauda equina syndrome is seen in injuries from L1 down through the sacral levels.
What are the main clinical differences between conus medullaris and cauda equina syndrome?
Conus medullaris syndrome involves a symmetric motor deficit and preserved knee reflex; cauda equina patients have asymmetric motor and sensory loss with decreased knee reflex.
Pain is prominent in cauda eqina syndrome and rare in conus medullaris syndrome.
Both conditions have a flaccid bladder with overflow incontinence.
What are the most common contributors to secondary injury in spinal cord trauma?
Untreated hypotension, hypoxia, patient mishandling with regards to spinal instability and immobilization
What are some associated conditions seen with acute transverse myelitis?
Trauma, SLE, Sjogren syndrome, herpes zoster, CMV, and schistosomiasis
Increased interpediculate distance indicates failure of which column?
The middle column.
Recall that the middle column is the posterior half of the disk and vertebral body and the PLL.
What are the most common instances where a neck fracture is treated with a halo?
An unstable Jefferson fracture, type II and III odontoid fractures, an unstable hangman fracture.
What is autonomic hyperreflexia?
Exaggerated autonomic response to normally innocuous stimuli occurring in patients with spinal cord lesions above T6.
Stimuli for autonomic hyperreflexia are bladder distention, colorectal stimulation, skin infections, and DVTs.
The classic triad is seen in 85% of cases and includes headache, hyperhidrosis, and cutaneous vasodilation.
What is spinal shock?
It occurs after acute spinal trauma when all the reflex activities of the spinal cord are depressed below the injured level, usually present for 24-48 hours after the injury.
Return of the reflexes below the injury level signifies the end of spinal shock.
The return of which reflex usually indicates the end of spinal shock?
Bulbocavernosus
What are the side effects of TCAs?
Daytime sedation, dry mouth, urinary retention, constipation, weight gain, blurry vision, and orthostatic hypotension.
What is the most common reason for lumbar spine surgery in people older than 65 years of age?
Lumbar spinal stenosis
What are some common intermediate and delayed complications after a lumbar laminectomy?
CSF leakage, infection, hematoma, nerve injury, and post-laminectomy spondylolisthesis
What are some of the common causes of AA instability?
RA, Down syndrome, trauma, tumors, errors of metabolism, infection
What does canal elongation indicate in spondylolisthesis?
Canal elongation indicates fractures of the pars interarticularis in spondylolisthesis.
Degenerative spondylolisthesis presents with spinal stenosis and an intact pars.
Diminished sensation over the medial malleolus suggests nerve root compromise at which level?
L4
In acute cervical disk herniation, movement of the head in which direction accentuates the radicular pain?
In acute cervical disk herniation, lateral flexion of the head toward the side of the pain usually increases radicular pain because this motion aggravates the irritated nerve root by further decreasing the size of the intervertebral foramen.
What vertebral segment is most commonly affected with ossification of the PLL?
C5 is most commonly affected, followed by C4 and C6
What is the most common location of a spinal epidural abscess?
The thoracic spine.
The majority are located posterior to the spinal cord.
Spinal epidural abscess should be considered in any patient who presents with backache, fever, and spine tenderness.
What is the most common organism found in an spinal epidural abscess?
S. aureus
What is the most common location of vertebral osteomyelitis?
The lumbar spine.
Vertebral osteomyelitis is seen in IV drug abusers, patients with diabetes, and hemodialysis patients.
What part of the vertebra does Pott disease have a predilection for?
Tuberculous spondylitis has a predilection for the vertebral body and spares the posterior elements.
What is suggested when a spinal lesion is destroying the disk space?
A characteristic radiographic finding that helps distinguish infection from metastatic disease is that destruction of the disk space is highly suggestive of infection, whereas in general, a tumor will not cross the disk space.
What is Grisel syndrome?
Spontaneous subluxation of the AA joint secondary to parapharyngeal infection. It is thought to occur through direct hematogenous spread from the inflammatory exudates to the AA articulations.
What is the most common intramedullary spinal cord tumor?
An ependymoma.
Astrocytoma is a close second.
What types of nerves do neurofibromas generally arise from?
The sensory nerve roots.
Sometimes it is necessary to sacrifice the dorsal rootlets involved with the tumor.
Until proven otherwise, a mass behind the dens is what?
A chordoma must be ruled out.
However, in a patient with a history of RA, a benign pannus is also in the DDx.
What are some characteristics of chordoma?
Chordomas are slowly growing, expansile tumors that infiltrate local bone and adjacent soft tissues, with a high chance of local recurrence or seeding after resection.
What CN palsy can be present with a chordoma?
Chordomas presenting with CN VI palsies are not uncommon.
What is the most common primary spinal tumor?
Chordoma is the most common primary malignancy found in the adult spine, placing osteosarcoma second.
When should you consider selective arteriography and embolization in the treatment of spinal tumors?
Selective arterial embolization is employed in the treatment of highly vascular lesions, aneurysmal bone cyst, angiosarcoma, arterial vascular malformations, renal cell carcinoma mets, schwannoma, or other neural tumors requiring sacrifice of the vertebral artery.
What are some features of osteosarcomas?
Most patients have local pain, and plan radiographs of the spine show osteoblastic and osteolytic activity.
Tumors frequently start in the vertebral body and extend posteriorly.
What type of mass frequently involves the posterior elements and can present as a palpable soft tissue mass?
Chondrosarcoma
Where do chordomas commonly occur?
Sacrococcygeal region (50%), cranial base (35%), or vertebra (15%)
Chordomas are remnants from which embryonic tissue?
The notochord.
What type of bone tumor has radiographic features of septations and fluid levels?
Aneurysmal bone cyst.
What are some masses that grow in the sacrum?
Chordoma, giant cell tumor, mets, myeloma, neurofibromas, aneurysmal bone cyst, chondrosarcoma, osteoblastoma, and osteosarcoma.
What bone tumors grow in the posterior elements of the spine?
Aneurysmal bone cyst, osteoid osteoma, osteoblastoma.
Aneurysmal bone cysts may display a fluid level, indicative of hemorrhage and sedimentation.
Aneurysmal bone cysts are highly vascular lesions that may be cured with surgery and bone curettage.
Most cases of osteoid osteoma present in what part of the vertebra?
In the lamina and/or pedicle.
Where in the spinal do osteochondromas seem to grow more often?
At C2.
When growing from the posterior, elements may present as a palpable mass; when growing anteriorly they may present as dysphagia and hoarseness, with vascular involvement.
What are the most common neoplasms seen at the filum terminale?
Myxopapillary ependymoma and less commonly, paraganglioma.
What is the most common tumor to seed along the subarachnoid space in children?
Medulloblastoma
Which is the most common site for spinal meningiomas?
Thoracic (80%) and cervical (15%)
What is the defining feature of a malignant meningioma?
Invasion of neural tissue.
What cranial nerve is usually the earliest one affected in a case of glomus jugular tumor?
The facial nerve.
Back pain at night should be treated as what condition until proven otherwise?
Tumor invasion of the spine.
Osteoid osteoma is defined as a bone tumor less than what size in diameter?
Two cm.
Any lesion larger than this is defined as an osteoblastoma.
In what bone tumors may angiography be helpful?
Aneurysmal bone cyst and hemangioma.
These tumors can be treated with embolization.
What type of bone tumors can involve the sacrum?
Giant cell tumor, chordoma, and Ewing sarcoma.
What is the most common spinal vascular malformation?
The dural AV fistula
What is Cobb syndrome?
Cobb syndrome is a rare, non-inherited disorder that involves the association of spinal angiomas or AVMs with congenital, cutaneous vascular lesions in the same dermatome.
Where is the watershed zone of the spinal cord?
The mid-thoracic region (T6) has a tenuous vascular supply and is described as the “watershed zone” of the spinal cord.
Thrombosis of which artery produces the unique syndrome of ipsilateral hypoglossal palsy and crossed hemiplegia?
Thrombosis of the anterior spinal artery.
What part of the embryo develops into the dorsal root ganglia?
Neural crest cells
At approximately what days of gestation do the anterior and posterior neuropore close?
24 and 26 days, respectively.
What is the difference between hydromyelia and syringomyelia?
Hydromyelia refers to dilations of the central canal that are at least partially lined by ependymal cells.
Syringomyelia refers to all other cavities of the spinal cord outside of the central canal.
What other problems may go unnoticed in a newborn with an incomplete evaluation of myelomeningocele?
Diastematomyelia and/or thickened filum terminale.
What are the MRI criteria for spinal cord tethering?
Termination of the conus below the L3 vertebral body and filum thicker than 2 mm.
In patients with demonstrated low-lying conus, the presence of fat within the filum is suggestive of cord tethering.
When the thickened filum and low-lying conus are demonstrated, surgical release of the tethered cord is justified even in the absence of neurologic impairments.
What is the accepted diameter of a congenitally narrow cervical canal?
Any cervical canal diameter less than 12 mm.
What is congenital kyphosis type I? Type II?
Congenital kyphosis type I involves failure of vertebral body formation, most commonly in the thoracolumbar transition area of T11-12.
Congenital kyphosis type II results from failure of vertebral segmentation.
Which skeletal abnormalities can be seen with a Chiari I malformation?
Platybasia, basilar invagination, and Klippel-Feil syndrome.
What determines the prognosis for encephalocele patients?
The prognosis is directly proportional to the amount of brain found within the defect.
Because about half of these patients have hydrocephalus, early CSF diversion is critical in preventing CSF leakage and infection.
What are some types of occult spinal dysraphism?
Diastematomyelia, neurenteric cyst, lipomyelomeningocele, lipoma, dermoid cyst, dermal sinus tract, and tethered cord.
What is a type I split cord malformation?
Type I split cord malformation refers to two hemicords each housed within its own dural tube separated by a dural, sheathed, rigid, osseocartilaginous septum.
What is a type II split cord malformation?
Type II split cord malformation refers to two hemicords housed within a single dural sheath separated only by a non-rigid fibrous sheath.
What is the common CT finding in both pseudotumor cerebri and in VP shunt overdrainage?
Slit-like ventricles.
What is the angiographic finding of mass effect due to a brain tumor on an AP view?
The pericallosal arteries are seen as a bayonet or stairstep-shaped bend under the falx cerebri. This phenomenon is called square shift. The same type of shift is observed in the displacement of callosmarginal artery under the anterior falx .
What is the most common nontumor MRI finding in patients with complex partial epilepsy?
Chronic temporal lobe seizures are typically associated with atrophy of the hippocampus and less commonly, the parahippocampal gyrus. This type of atrophy is associated with sclerosis most of the time.
In what forms can hemangioblastomas appear on CT or MRI?
Vascular nodule on the side of the cyst, vascular nodule encompassing the cyst, or solid vascular mass are the types encountered on contrast-enhanced CT or MRI.
What can be seen in the anterior vascular MRI/MRA in relation to a presellar vs a postsellar tumor?
A presellar localization causes elevation of A1 segments of the ACA, wherewas a postsellar tumor does not generally displace them.
What is the DDx for a spherical hypointense mass in the suprasellar region in the MRI?
The most important two are Rathke cleft cyst and aneurysm due to the flow void.
What is the enhancement pattern of a pituitary adenoma with contrast relative to a normal gland?
Normal gland will enhance immediately after the contrast injection as opposed to adenoma that remains unchanged; however, 30 minutes post injection, the normal gland loses its enhancement and the tumor enhances.
What are the MRI signs of acute intracranial hypotension?
Diffuse pachymeningeal enhancement, bilateral subdural effusion/hematomas, downward displacement of brain, enlargement of the pituitary gland, engorgement of the dural venous sinuses, prominence of spinal epidural venous plexus, venous sinus thrombosis, and isolated cortical vein thrombosis.
What type of imaging is most helpful to detect DAI?
DAI is notorious for poor visualization on CT. When it is non-hemorrhagic, it is best demonstrated with T2 MRI. When it is hemorrhagic, GRE MRI shows the injury best.
What are the findings of Dandy-Walker malformation on a coronal T2 MRI?
Dandy-Walker malformation is characterized by cystic dilatation of the 4th ventricle, complete or partial agenesis of the cerebellar vermis, and an enlarged posterior fossa.
What are the best diagnostic clues for Sturge-Weber syndrome in MRI?
Cortical calfication, atrophy and enlarged ipsilateral choroid plexus are the typical MRI findings. In skull radiography, tram-tack calcifications are a typical sign.
What are the diagnostic clues on CT and MRI in a patient with suspected traumatic carotid-cavernous fistula?
Enlarged superior ophthalmic vein on contrast CT and dilated cavernous sinus as flow voids on T1, along with marked proptosis and swelling of eyelids.
What are the image characteristics of multiple sclerosis on MRI?
Multiple perpendicular callososeptal hyperintensities along the penetrating venules (Dawson fingers), bilateral asymmetric ovoid FLAIR hyperintensities, and transient enhancement during active demyelination.
How is a CPA arachnoid cyst differentiated from an epidermoid cyst?
Epidermoid cysts present restricted diffusion in DWI whereas arachnoid cysts do not.
What is the term “Medusa head” used to describe on MRI or angio?
A developmental venous anomaly is characterized by dilated medullary veins that course in the white matter, resembling “caput medusa” or “medusa head”. These anomalous venous structures tend to coincide with cavernomas.
What are the MRI findings of Wilson disease?
Wilson disease is suggested mainly in T2 images by brain atrophy (focal/diffuse), high signal intensity at the lentiform nuclei with bilateral symmetrical and concentric lamella putaminal pattern, thalamic and caudate nuclei, substantia nigra, periaqueductal gray matter, pontine tegmentum, and cerebellum
What is the best imaging tool for cavernous malformations and what the most common findings?
T2 GRE is the best tool for cavernous malformations. Hypointense “blooming” and numerous punctate hypointense foci (black dots) if the lesion is greater than 3cm are the most common findings on T2 GRE.
What are the commonly accepted angiographic criteria for AVMs with a relatively higher risk of bleeding?
Stenotic venous drainage, single draining vein, intranidal aneurysm, smaller nidus, and deep location are the features in the AVMs that are more likely to bleed.
What is the chronologic order of angiographic findings in moyamoya disease?
A narrowing of the circle of Willis and the ICA is the earliest finding. Then, lenticulostriate and thalamoperforator collaterals develop in the intermediate phase. Transdural EC-IC collaterals emerge in the late phase of the disease.
What is the differential diagnosis for false-positive empty delta sign?
An empty delta sign is typical contrast CT or MRI evidence for a superior sagittal sinus thrombosis. This is caused by enhancing dura surrounding a clot in the thrombosed sinus. Subdural hematoma, subdural empyema, or arachnoid granulations can commonly mimic this appearance with a false-positive empty delta sign.
What is the angiographic finding associated with high risk of hemorrhage in Cognard grading system for dural AV fistula?
Reflux (retrograde drainage) into cortical veins is associated with higher hemorrhage risk compared with those that do not have this type of drainage. In the grading system, type IIB, IV, V involve this angiographic feature.
What are the characteristic MRI findings of infectious spondylitis?
The destruction of two adjacent endplates and intervening disk associated with large paraspinal masses are the characteristic MRI findings of infectious spondylitis. The paraspinal masses are the abscess formations and are usually with calcfications.
How is the neuroradiologic assessment for the integrity of atlantoaxial (transverse) ligament?
Atlantodental distane > 3 mm on lateral C-spine or the sum overhang distance of both C1 lateral masses on C2 > 7mm on an open-mouth odontoid XR indicates transverse ligament disruption.
What are modic changes?
Vertebral body marrow changes at the endplates. They are typically associated with degenerative or inflammatory conditions. There are three types: type 1 shows increased signal only on T2 and is associated with bone edema or acute inflammation. Type 2 shows increased signal on both T1 and T2 and signifies replacement of marrow by fat. Type 3 shows decreased signal on both T1 and T2 and suggests osteosclerosis. Both types 2 and 3 are chronic changes.
What are the 5 types of spondylolisthesis?
Isthmic (pars interarticularis defect), degenerative, dysplastic (congenital), traumatic, pathologic.
What are the radiographic indications for surgical fusion of the lumber spine in a patient with an L2 burst fracture?
Canal compromise of greater than 50%, loss of height of greater than 50% and/or kyphosis greater than 30 degrees.
What is the rule of Spence?
When looking at an AP odontoid view of the C-spine XR, the sum of the lateral overhang of the C1 lateral masses from the C2 vertebra should not exceed 7mm. If the distance is 7mm or more, there is a transverse ligament rupture.
What is the Steele rule of thirds?
The dens, subarachnoid space, and spinal cord each occupy one third of the area of the canal at the level of the atlas.
What is the normal thickness of the prevertebral soft tissue anterior to the cervical spine on plain XR lateral images?
At C2, it is 6mm.
At C6, it is 22mm.
What is McGregor’s line?
The McGregor line is an imaginary line drawn from the posterior edge of the hard palate to the most inferior point of the occiput on a sagittal view. It is used in conditions such as RA to determine vertical settling of the odontoid process. There should not be more than 4.5 mm of protrustion of the odontoid process above this line.
What are the three types of occipital condyle fractures?
- Impacted fracture of the occipital condyle.
- Basilar skull fracture that extended into the occipital condyle.
- Avulsion of the occipital condyle.
What is the most common cause of spinal cord compression in patients with cancer?
Metastatic tumor in the epidural space.
What is usually the earliest indication of spinal cord compression in a cancer patient?
Central back pain.
What are the two most common intramedullary spinal cord tumors?
Ependymomas and astrocytomas.
What are the two most common intradural-extramedullary spinal tumors?
Meningiomas and schwannomas.
What are the two most common extradural spinal tumors?
Mets and bone tumors.
Where do myxopapillary ependymomas occur?
At the conus or filum terminale.
Which intramedullary tumors most commonly present with a cyst?
Hemangioblastomas followed by ependymomas and astrocytomas.
