Flash card review
What is the origin and branches of the mengingohypophyseal trunk?
Origin: usually arises from the posterior aspect of the central third of the posterior bend of the ICA at the level of the dorsum sella.
Branches: tentorial artery (Bernasconi and Cassinari), the dorsal meningeal artery, and the inferior hypophyseal artery.
Alpha motor neurons are most commonly found in which Rexed lamina?
Rexed lamina IX, which is located in the ventral motor areas of the gray matter.
Fibers in layer 1 (Rexed lamina)
Marginal zone, fast pain (A-delta) and temperature fibers.
Fibers in layer 2 (Rexed lamina)
Substantia gelatinosa, slow pain (C fibers)
Fibers in layer 4 (Rexed lamina)
Nucleus propius, interneurons to thalamus
Fibers in layer 7 (Rexed lamina)
Contains the zona intermedia
Fibers in layer 9 (Rexed lamina)
Alpha and gamma motor neurons
The dentate nucleus receives its blood supply from the:
SCA (also supplies the other deep cerebellar nuclei and SCP)
What is the location of the nucleus accumbens?
The nucleus accumbens is located in the rostral and basal forebrain at the point where the head of the caudate meets the putamen.
What is the line of Gennari?
Subcortical white matter tract in the occipital lobe that carries visual fibers.
Vascular territory of the anterior choroidal artery?
AchA supplies the optic tract and the inferior portion of the posterior limb of the internal capsule
Vascular territory of the ophthalmic artery?
The ophthalmic artery supplies the retina via the central retinal artery and the dura mater of the planumsphenoidale via the ethmoidal branches.
Distal to the brainstem, how many segments does the facial nerve have?
The facial nerve consists of five segments: cisternal, meatal, labyrinthine, tympanic, and mastoid.
Winging of the scapula may result from injury to what 3 nerves and their corresponding muscles?
- Long thoracic nerve - serratus anterior.
- Dorsal scapular nerve - rhomboid.
- Spinal accessory - trapezius.
What is innervated by the dorsal scapular nerve?
Purely motor which supplies the levator scapule and the major and minor rhomboids.
What are the boundaries of the thoracic inlet?
Base: 1st rib.
Anterior: Scalenus anticus.
Posterior: Scalenus medius.
Injury to the radial nerve proximal to the elbow results in what?
- Paralysis of brachioradialis.
- Complete wrist drop.
- Digital extensor paralysis.
- Sensory deficit over dorsum of the radial side of the hand.
What ligament forms the boundary of the cubital tunnel floor?
Ulnar collateral ligament.
What ligament forms the boundary of the cubital tunnel roof?
The roof of the cubital tunnel is the arcuate ligament (aka Osborne’s ligament) connecting the two heads of the flexor carpi ulnaris between the medial epicondyle and the olecranon.
What 3 sites along the median nerve are potential points of compression?
- Between the two heads of the pronator teres.
- Beneath the lacertus fibrosus (bicipital aponeurosis).
- Beneath the tendinous origin of the flexor digitorum superficialis.
Lordosis in the cervical spine approximates:
The normal cervical spine approximately 14.4 degrees of lordosis from C2 to C7.
Arterial supply to the pituitary?
Most pituitary arterial flow is from both the inferior hypophyseal artery (from the meningohypophyseal artery) and the superior hypophyseal artery (from the supraclinoid ICA).
What does the transverse crest separate?
The transverse crest separates the facial nerve and superior vestibular nerve from the cochlear and inferior vestibular nerve.
What does Bill’s bar separate?
Bill’s bar separates the facial nerve from the superior vestibular nerve.
What are the branches off the ICA?
CV MICO SPAAM
- Caroticotympanic artery.
- Vidian artery.
- Meningohypophyseal trunk (posterior trunk) - 3 main branches (tentorial artery of Bernasconi and Casinari, inferior hypophyseal artery, and dorsal meningeal trunk).
- Inferior cavernous sinus artery - lateral trunk.
- Capsular artery of McConnel - medial trunk.
- Ophthalmic branch.
- Superior hypophyseal artery.
- PCOM.
- Anterior choroidal.
- ACA.
- MCA.
What are the branches off the ECA?
SALFOPS I-max
- Superior thyroid.
- Ascending pharyngeal.
- Lingual.
- Facial.
- Occipital.
- Posterior auricular.
- Superficial temporal.
- Internal maxillary artery.
Describe the central artery of Percheron.
The central artery of Percheron arises from the first segment of the PCA and gives rise to bilateral medial thalamic perforators. Occlusion results in bilateral paramedian thalamic infarctions.
These patients typically present with weakness, vestibuloocular and ophthalmoplegic abnormalities. Visual fields remain intact.
What are the borders of Kawase’s triangle?
Anteromedial boundary is formed by the lateral edge of the trigeminal nerve.
Anterolateral boundary is formed by the greater superficial petrosal nerve.
Posterior boundary is formed by the internal auditory canal or a line connecting the hiatus fallopii to the dural ostium of Meckel’s cave.
What are the borders of Trautmann’s triangle?
Located in the posterior fossa.
Medial to the sigmoid sinus.
Superior to the jugular bulb.
Inferior to the superior petrosal sinus.
What are the borders of Macewen’s triangle?
External auditory meatus, inferior temporal line, and the suprameatal line (spine of Henle).
What are the borders of Glasscock’s triangle?
Line from the foramen spinosum to the facial hiatus, the greater superficial petrosal nerve and the mandibular nerve.
What is the most common location for dural AV malformations?
The region of the transverse sigmoid sinus junction accounts for the majority of dural AV malformations (around 63%).
The superior sagittal sinus is a relatively uncommon location (only about 7%).
Borden classification: type 1 dural AV fistulas.
No venous sinus outflow restriction and drain only through sinuses in an anterograde fashion.
Borden classification: type 2 dural AV fistulas.
Some degree of venous restriction that causes some anterograde or retrograde flow and subarachnoid venous drainage.
Borden classification: type 3 dural AV fistulas.
Drain only through subarachnoid veins.
Which cranial nerve(s) pass through the anteromedial pars nervosa?
NERVOUS NINE.
CN IX is located in the anteromedial pars nervosa.
Which cranial nerve(s) pass through the posterolateral pars venosa?
CNs X and XI pass through the posterolateral pars venosa.
Major neurotransmitter in the substantia nigra?
Dopamine
Major neurotransmitter in the dorsal raphe nucleus?
Serotonin
Major neurotransmitter in the locus ceruleus?
Norepinephrine
Major neurotransmitter in the basal nucleus of Meynert?
ACh
Major neurotransmitter in Golgi type II interneurons, substantia innominata?
GABA
Afferent limb of the pupillary reflex?
CN II
Afferent limb of the corneal and tearing reflex?
CN V1
Afferent limb of the gag reflex?
CN IX
Afferent limb of the cough reflex?
CN X
Afferent impulses from the carotid baroreceptor are transmitted primarily to which nucleus?
Afferent impulses from the carotid body are transmitted through the inferior ganglion (petrosal ganglion) to the nucleus tractus solitarius and paramedian nucleus then to nucleus ambiguus and dorsal motor nucleus of CN X for regulation of the heart.
Function of the dorsal motor nucleus of CN X?
The dorsal motor nucleus of CN X provides parasympathetic input to the vagus nerve to the thorax and abdominal viscera up to the splenic flexure of the colon.
Damage to the superior laryngeal nerve causes?
Low tone of voice.
Damage to the recurrent laryngeal nerve causes?
Hoarseness.
The average total brain H20 content is?
Bewteen 70-80%.
What maintains flexor tone?
The rubrospinal tract maintains flexor tone. The red nucleus has input from both cerebral cortices and the contralateral cerebellar interposed nuclei (globse and emboliform).
Output is to rexed laminas V,VI, and VII to inhibit extensor activity.
Neurotransmitters of Renshaw cells?
Glycine.
Principle visceral nucleus of the brainstem?
The nucleus solitarius receives afferent visceral information from the heart, lungs, GI tract, as well as for taste.
What are the circumventricular organs?
POSS MAN
Pineal gland. Organum vasculosum of the lamina terminalis. Subforniceal organ. Subcommissural organ. Median eminence of the hypothalamus. Area postrema. Neurohypophysis.
Neural tube closure initiates at the:
During neurulation (post ovulation day 21) the neural crest starts to close at the caudal rhombencephalon and form the neural tube.
Complete neural tube closure generally occurs by 18 weeks gestation.
Schwann cells are derived from?
Neural crest cells.
Neural crest cells also give rise to ganglion satellite cells, most of the neurons of the peripheral nervous system, melanocytes, and part of the cranial mesenchyme.
During gastrulation the formation of the notochordal process begins with cells invaginating through:
Hensen’s node (primitive node) is the regional thickening of cells anterior to the primitive streak, through which gastrulating cells migrate anteriorly to form tissues in the future head and neck.
The metopic suture generally ossifies during the:
Second year of life.
The coronal suture is usually obliterated and ossifies around:
24 years of age.
The resting membrane potential is determined mainly by what ion?
Potassium.
Neurotransmitter that is found in a postganglionic sympathetic nerve terminal?
ACh and NE.
Hexamethonium blocks what receptor?
Hexamethonium is a nicotinic ACh receptor antagonist, acts by preventing ACh from binding to the cholinergic receptor.
Anterograde transport is mediated by what protein?
Kinesins.
Retrograde transport is mediated by what protein?
Dynein.
Describe the difference in the BBB in the choroid plexus compared to elsewhere.
In the choroid plexus, the BBB is primarily epithelial.
This is in contrast to the endothelial BBB that exists elsewhere.
What is the rate limiting enzyme in dopamine synthesis?
Tyrosine hydroxylase is the rate limiting enzyme for the synthesis of dopamine from tyrosine.
It is an oxidase that converts tyrosine to L-DOPA.
What neurotransmitter(s) is synthesized within synaptic vesicles?
Norepinephrine is the only neurotransmitter synthesized within synaptic vesicles.
NE is the neurotransmitter of most POST-ganglionic sympathetic neurons and also in the locus ceruleus.
What is the second messenger of all norepinephrine receptors?
All NE receptors are metabotropic receptors that use G proteins and the second messenger cAMP.
What is the rate limiting enzyme in serotonin synthesis?
Tryptophan hyrdroxylase is the rate limiting enzyme for serotonin synthesis.
Serotonergic neurons are located primarily in the raphe nuclei.
What is the mechanism of action of the cholera toxin?
Activates Gs.
What is the mechanism of action of the pertussis toxin?
Inactivates Gi.
What is the mechanism of action of lithium?
Activates Gs.
What is the mechanism of action of the tetanus toxin?
Inhibits glycine and GABA release.
What neurotransmitter is released by Renshaw cells?
Renshaw cells are inhibitory interneurons in the spinal cord.
They release glycine.
Description of Meissner capsules.
Rapidly adaptive, touch receptors.
Description of Merkel receptors.
Slowly adaptive, touch and pressure receptors.
Description of free nerve endings.
Pain receptors.
Description of Ruffini corpuscles.
Rapidly adaptive, vibration receptors.
Description of Pacinian corpuscles.
Slowly adaptive, heavy pressure receptors.
What are some potential complications of intrathecal baclofen pump overdose?
Moderate complications include hallucinations, seizure, confusion and psychotic behavior.
Severe complications include respiratory depression, coma and hypotension.
What percentage of acute SCI are associated with cervical spine fractures?
39%.
What percentage of thoracic spine injuries result in concurrent spinal cord injury?
10%.
Lundberg ‘A’ waves are a result of what?
The brain’s normal compensatory response to an increase in cerebrovascular volume secondary to dilation of vasculature.
What type of edema predominates in the early stages of TBI?
In the earliest stages of acute head injury, cytotoxic edema is the major factor responsible for intracranial hypertension.
Cytotoxic edema occurs minutes to hours after injury and is the manifestation of cellular swelling.
Vasogenic edema occurs hours to days after acute head injury and is the result of extracellular fluid permeating the disrupted endothelial lining in the brain’s capillary network.
What medical treatment options are most effective for essential tremor?
Alcohol, primidone, beta-blockers.
What is the mechanism of action of Botox?
Toxin enters the nerve terminal via endocytosis, interacts with SNARE proteins, and inhibits the vesicular release of ACh at the neuromuscular junction.
What signs/symptoms are seen in cardiogenic shock?
Increased HR, decrease in CO, decrease in SVR.
Cardiac index less than 1.8L/min/m2.
Pulmonary capillary wedge pressure greater than 18mmHg.
What organism is most likely to cause meningitis following traumatic skull fracture?
Streptococcus pneumoniae is responsible for 50-70% of all cases of meningitis occurring after traumatic skull fracture.
Describe Hallervorden-Spatz syndrome.
Involves the deposition of iron especially in the globus pallidus and retina.
Presents with dystonia, rigidity, and neurobehavioral changes.
Pathogenesis of Dandy-Walker malformation.
Malformation associated with hypoplasia of the vermis, pseudocystic 4th ventricle, upward displacement of the tentorium, torcula and lateral sinuses, and AP enlargement of the posterior fossa.
Common locations for arachnoid cysts.
Sylvian fissure (54%), CPA (17.5%), parasellar or convexity (15% each).
Galassi’s classification for Sylvian fissure arachnoid cysts: type 1.
Temporal tip, biconvex shape, communicates with subarachnoid space.
Galassi’s classification for Sylvian fissure arachnoid cysts: type 2.
Quadrilateral shape, moderate mass effect, delayed uptake of iodine contrast after cisternography.
Galassi’s classification for Sylvian fissure arachnoid cysts: type 3.
Large, rounded, severe compression with shift, no communication with subarachnoid space.
Describe a primary vein of Galen malformation.
Rare form of embryonic AV shunt located in the midline in the choroidal fissure.
It consists of multiple feeding arteries, principally the anterior and posterior choroidal arteries and the ACA, draining directly into an enlarged venous pouch.
Describe a secondary vein of Galen malformation.
Deep midline true AV malformation that drain selectively into the great vein of Galen thereby causing distention and enlargement of the vein.
These malformations result from persistent adjacent dural and parenchymal AV shunts, which lead to secondary dilation of a normally developed vein of Galen.
Mneumonic for MRI appearance of hemoglobin by stages.
Acute, subacute, chronic.
T1 - George Washington Bridge (gray, white, black).
T2 - oreo cookie (black, white, black).
Describe the arterial pathophysiology of chronic HTN.
Serum proteins accumulate in the basement membrane and cause collagen deposition, hyalinization of the media, atrophy of the muscularis layer, vessel dilatation or stenosis, and fatty macrophage accumulation occurs commonly (lipohyalinosis).
Common sites for hypertensive intraparenchymal hemorrhage.
Putamen (60%), thalamus (20%), pons (10%), cerebellum (5%), and subcortical (2%).
Ocular manifestation of putamen hemorrhages.
Eyes deviate toward the lesion.
Ocular manifestation of thalamic hemorrhages.
Persistent downgaze.
Ocular manifestation of cerebellar hemorrhages.
Eyes deviate away from the lesion.
Ocular manifestation of pontine hemorrhages.
Fixed, pinpoint pupils.
What is the most common site of origin for juvenile angiofibromas?
Posterior nasopharynx.
The fossa of Rosenmuller is a well established site of origin of angiofibromas.
Describe cavernous angiomas.
Benign tumors commonly present with seizures, hemorrhage, and stroke.
Angiographically occult.
Hamartomatous vascular anomalies characterized by densely packed and grossly enlarged immature capillaries without intervening neural tissue.
Mnemonic for sellar/parasellar masses.
TACHMOS.
Teratoma, adenoma/aneurysm, craniopharyngioma, hypothalamic glioma/hamartoma, mets, optic glioma, sarcoid.
Tumors associated with gelastic seizures.
Hypothalamic hamartomas.
Most common location of central neurocytomas.
About 3/4 occur in the lateral ventricles along the septum pellucidum with the foramen of Monro.
Other 1/4 occur in the 3rd ventricle.
Immunohistochemistry stain that is positive in central neurocytomas.
Synaptophysin.
Describe age and common location for pleomorphic xanthoastrocytomas.
Mainly affects children and young adults, and is most commonly found in the temporal lobe.
Describe age and common location for desmoplastic infantile gangliogliomas.
They occur before 18 months. Typically present as massive frontal cystic lesions.
Most common presentation of mesial temporal sclerosis.
Complex partial seizures.
DWI and ADC signals in arterial occlusion and ischemia.
Hyperintense on DWI, hypointense on ADC.
DWI and ADC signals in venous occlusion and thrombosis.
Hypointense on DWI, hyperintense on ADC.
DDx for solitary lytic lesions in the skull.
Metastatic lesion, myeloma, fibrous dysplasia, TB, trauma, histiocytosis X, osteomyelitis, leptomeningeal cyst, and epidermoid/dermoid.
Appearance of eosinophilic granuloma in the skull.
Lytic lesion with well delineated non-sclerotic margins and beveled edges.
Most common tumor of pineal recess?
Germinoma.
What tumor can be followed with B-HCG levels?
Choriocarcinoma.
What tumor can be followed by APF levels?
Endodermal sinus tumor.
What tumor can be followed by CEA levels?
Teratomas.
What are the 3 distinct anatomic locations of brainstem gliomas?
- Pontine (diffuse intrinsic 50%).
- Tectal (exophytic, 20%).
- Cervicomedullary (focal 20, 10%).
Damage to the upper motor neuron pathway for CN VII causes…
Weakness in the CONTRALATERAL lower face.
“Forehead sparing” is due to the bilateral innervation of the superior face.
Damage to the lower motor neuron pathway for CN VII causes…
Weakness in the entire IPSILATERAL face.
Cerebellar proprioception is under what control?
The cerebellum is responsible for UNCONSCIOUS proprioception.
It receives input from the dorsal nucleus of Clark (Rexed’s layer 7). This info travels through the ipsilateral dorsal spinocerebellar tract.
What system is responsible for conscious proprioception?
The dorsal column-MLF system.
Function of the superior olive.
The superior olivary nucleus’ primary input is derived from the bushy cells of bilateral anterior ventral cochlear nuclei. This input occurs primarily via the ventral acoustic stria. Its output is to the lateral lemnisci.
The superior olivary nucleus is the first point where binaural input is combined.
Wave forms in brainstem auditory evoked responses.
Wave 1 - auditory nerve. Wave 2 - cochlear nuclei (pons). Wave 3 - superior olivary complex. Wave 4 - lateral lemniscus. Wave 5 - inferior colliculus. Wave 6 - medial geniculate nucleus. Wave 7 - auditory radiations (cortex).
What system is monitored via somatosensory evoked potentials?
Dorsal column system.
Erb’s point for somatosensory evoked potentials.
N9 (supraclavicular region).
What tract regulates extensor tone?
The lateral vestibulospinal tract regulates extensor tone through the lateral vestibular nucleus.
The vestibulospinal tract arises from the lateral vestibular nucleus (i.e. Deiter’s nucleus) and descends bilaterally in the anterior part of the lateral funiculus.
What tract regulates flexor tone?
Flexor activity is regulated by the rubrospinal tract from the red nucleus.
The rubrospinal tract arises from magnocellular neurons in the red nucleus and crosses at the ventral tegmental decussation. Stimulation of the red nucleus leads to excitation of contralateral flexor alpha motor neurons and inhibition of extensor alpha motor neurons.
The predominant neurotransmitter of the pedunculopontine nucleus is?
Acetylcholine.
Function of the pedunculopontine nucleus?
One of the main components of the reticular activating system.
Functions include arousal, attention, learning, reward, and locomotion. Also implicated in the generation and maintenance of REM sleep.
Nimodipine blocks what calcium channel?
L-type.
What level should be measured to check for acromegaly?
Elevated IGF-1 levels almost always suggest acromegaly.
Treatment of the rhythmic involuntary movements seen in chorea?
Decreasing dopaminergic tone.
What is the most common endocrinologic abnormality associated with lymphocytic hypophysitis?
Low ACTH secretion.
Dopamine secretion is stimulated by what?
Thyroid releasing hormone, prolactin, and vasoactive intestinal peptide (VIP).
What symptom/sign is not found in variant CJD but is found in sporadic CJD?
Periodic sharp wave complexes on EEG.
What scan can be used when deciding whether Horner’s syndrome is congenital?
Family albumin tomography (FAT Scan).
Lack of sensory loss, presence of a “pinch sign” and hand weakness is characteristic of what?
Anterior interosseus syndrome.
Anomic aphasia.
Characterized by the inability to recall proper names and names of objects.
Conduction aphasia.
Characterized by relatively impaired repetition of speech, accompanied by some difficulty in naming and some comprehension impairment.
Transcortical sensory aphasia.
Comprehension is impaired, output is fluent and may even include jargon, and repetition is relatively good.
Transcortical motor aphasia.
Comprehension and repetition are very good, but spontaneous speech output is impaired.
Definition of echolalia.
The near mandatory tendency to repeat what has just been said by another person.
Definition of palilalia.
Repetition of the last word.
Definition of logoclonia.
Repetition of the last syllable.
Definition of logorhea.
Meaningless outpouring of words.
Definition of phatosomia.
Persistent “medicine-like” smell present even in the absence of a stimulus.
It is typically seen after head injury.
Definition of cacosmia.
Imagining of unpleasant odors, particularly putrefactive odors.
Definition of parosmia.
Distortion of the sense of smell, as in smelling odors that are absent.
Symptoms of Millard-Gubler syndrome.
Abducens and facial nerve paralysis as well as contralateral hemiplegia of the extremities.
It involves unilateral damage to the inferior pons, commonly by pontine infarction or hemorrhage.
Difference between akathisia and tardive dyskinesia.
Akathisia is a subjective disorder characterized by a desire to be in constant motion resulting in an inability to sit still and a compulsion to move. It develops early in treatment (days). It is reversible and can be treated with benztropine and trihexyphenidyl.
Tardive dyskinesia is an involuntary disorder characterized by repetitive purposeless movements which typically involve the buccolingual masticatory areas. Presents weeks to months after treatment and is usually irreversible.
Tardive dyskinesia is caused by blockage of what receptor?
Dopamine.
What are risk factors for pseudotumor cerebri?
- Plump females.
- Tetracycline.
- Cyclosporine.
- Steroid withdrawal.
Describe PML.
PML is a subacute demyelinating disease of the CNS caused by the JC virus.
Progressive FND is the clinical hallmark.
Extremity weakness and disturbance of speech are the most common symptoms.
Describe cavernous malformations.
May be inherited or sporadic and consist of variable sized sinusoids or cavernous spaces between capillaries.
Unlike AVMs and capillary telangiectasias, they have NO intervening brain tissue between the vascular spaces.
When can fibrillations be seen on EMG after nerve transection?
10-25 days after axon death.
In neuropathic disorders the motor unit potentials on EMG would most likely show what?
Motor unit potentials in neuropathic disorders are polyphasic and show prolonged duration.
In myopathic disorders the motor unit potentials on EMG would most likely show what?
Motor unit potentials in myopathic disorders show large numbers of fibers with early recruitment and decreased amplitude.
Can be polyphasic (secondary to reinnervation).
Common location of aneurysms arising from PCOM?
Aneurysms almost always arise from the superior medial aspect of the PCOM.
What part of the cord is most resistant to traumatic injury?
Lateral spinal cord.
This explains why some trauma patients have sacral sparing, since the sacral fibers are more laterally located and are relatively protected by the pedicles.
Definition of isthmic spondylolisthesis.
Fracture of the pars interarticularis (2 subtypes, A and B).
What is a type IIA isthmic spondylolisthesis?
Stress fractures of the pars interarticularis.
What is a type IIB isthmic spondylolisthesis?
Also occurs from micro-fractures of the pars, however in contrast to type IIA, the pars remain intact but stretched out as the fractures fill in with new bone.
An elongated pars interarticularis would cause greater stress possibly resulting in further microfractures of the pars and thus repeating the process.