Ch 1: Questions Flashcards
A tumor is growing the third ventricle. Which of the following parts of the CNS might be compressed? A- mesencephalon B-hypothalamus C-adenohypophysis D-hippocampus E-superior colliculi
B- hypothalamus (part of diencephalon)
- colliculi are part of mesencephalon and adjacent to cerebral aqueduct
- adenohypophysis is not near a ventricle
- hippocampus is adjacent to inferior horn of lateral ventricle
Excessive use of alcohol during a pregnancy causes fetal alcohol syndrome, which affect the development of neural crest cells. Which of the following might be evident in the newborn infant?
A. There may be fewer neuron cell bodies in the gray matter of the CNS.
B. The sulci that separate cortical gyri may be wider than normal.
C. The fetus may have anencephaly.
D. The optic nerves may be absent.
E. There may be fewer postganglionic autonomic neurons.
E
Of the choices given, the postganglionic autonomic neurons are the only neurons that are derived from neural crest cells. Gray matter and the optic nerve are derived from the neural tube, and anencephaly is a neural tube defect not directly associated with neural crest cells.
Imaging reveals that your patient has a form of hydrocephalus that has resulted in an enlarged lateral ventricle in the right hemisphere. All of the other ventricles appear to be of normal size. Where might there be an obstruction? A. At an arachnoid granulation B. In the third ventricle C. At the foramen of Magendie D. At the foramen of Monro on the right E. At a foramen of Luschka on the right
What form of hydrocephalus is present? A. A normal pressure hydrocephalus B. A noncommunicating hydrocephalus C. A communicating hydrocephalus D. Hydrocephalus ex vacuo
D: Based on the direction of CSF flow, an enlarged ventricle should be proximal to an obstruction. An obstruction at the foramen of Magendie or a foramen of Luschka may result in an enlargement of all ventricles; an obstruction in the third ventricle might enlarge both lateral ventricles. An obstruction at an arachnoid granulation may not result in any ventricular enlargement.
B: A noncommunicating hydrocephalus results from an obstruction to CSF flow inside the ventricles or the channels that interconnect them.
A young male child is born with a cystlike protrusion in the dorsal midline of the back at the level of the lower lumbar spine. Imaging and diagnostic testing reveal that the cyst contains CSF, and the spinal cord is displaced into the cyst. You diagnose the condition as:
A. Spina bifida with meningomyelocele
B. Spina bifida occulta
C. Rachischisis
D. Spina bifida with meningocele
E. Anencephaly
A: In spina bifida cystica with meningomyelocele, the most common form of spina bifida cystica, the dura and arachnoid line the cyst, and the spinal cord is displaced into the cyst.
An infant is born with a congenital herniation of the tonsils and vermis of the cere-
bellum inferiorly through the foramen magnum. What else might be evident in the patient?
A. Syringomyelia
B. Hirschsprung’s disease
C. Anencephaly
D. Absence of the basal plate
E. Spina bifida occulta
A: The infant has an Arnold-Chiari malformation, which results from a congenital herniation of the tonsils and vermis of the cerebellum inferiorly through the foramen magnum. The Arnold-Chiari malformation is commonly seen with a cavitation of the central canal in the spinal cord or caudal medulla (a syringomyelia) and with spina bifida with meningomyelocele.
The telencephalon has failed to develop properly. Which part of the brain may be ad-
versely affected?
A. The mammillary bodies
B. The hippocampus
C. The neurohypophysis
D. The thalamus
E. The pineal gland
B
All other choices are derived from the diencephalon.
An evaluation of a fetus during pregnancy reveals elevated levels of alpha-fetoprotein
during amniocentesis, polyhydramnios, and a neural tube defect. Which of the fol-
lowing defects might the fetus have?
A. Spina bifida with meningocele
B. Dandy-Walker syndrome
C. Anencephaly
D. Rachischisis
E. Arnold-Chiari malformation
C:
Spina bifida with meningocele and rachischisis are caudal neural tube defects that may be associated with elevated levels of alpha-fetoprotein during
pregnancy, but polyhydramnios is evident only in the event of the rostral neural tube defect. Dandy-Walker syndrome and Arnold-Chiari malformation are caudal defects that would not be causes of polyhydramnios.
An ultrasound image of a fetus reveals the presence of spina bifida occulta. Which of the following statements might apply to this congenital defect?
A. At birth there may be neurological deficits in the lower limbs.
B. Amniocentesis during pregnancy may reveal higher than expected levels of alpha-fetoprotein.
C. The defect is caused by failure of the rostral end of the neural tube to close.
D. Polyhydramnios may be evident during the pregnancy.
E. The neural tube has failed to induce the formation of the neural arch at lumbosacral vertebral levels.
E: In spina bifida occulta, the caudal neuropore closes normally, alpha-fetoprotein and amniotic levels are normal, and there are no neurological deficits.
Your patient develops transient blindness in the right eye that clears after several min-
utes. What was the most likely cause?
A. A berry aneurysm compressing the optic chiasm
B. Emboli in the central artery of the retina on the right
C. A lacunar stroke involving the right posterior cerebral artery
D. A watershed infarct in the right MCA–PCA territory
E. A thrombus in the basilar artery
B: TIAs that result from small emboli shed from a plaque in the internal carotid commonly involve retinal branches of the ophthalmic artery, the first branch of the internal carotid.
Your patient has suffered from a small lacunar infarct of the thalamus. Occlusion of which of the following vessels might cause the infarct?
A. Medial striate artery
B. Deep branch of the PCA
C. Recurrent artery of Heubner
D. Lenticulostriate artery
E. Anterior choroidal artery
B
All of the other choices may be involved in a lacunar stroke but not specifically to the thalamus.
A 49-year-old male patient is brought to the emergency room by his wife because he has difficulty raising his right arm. He is able to make a fist with his right hand and hold objects with no weakness. He complains of numbness on the right side of his trunk and thigh, and he has some weakness of the anterior thigh muscles. A carotid
bruit indicates that the left internal carotid artery is stenotic. The patient’s signs and symptoms may have resulted from:
A. Bleeding from an AVM
B. A subarachnoid hemorrhage
C. A watershed infarct in the MCA–ACA territory
D. A lacunar stroke
E. An embolus in the MCA
C:
The patient has “person in a barrel” syndrome with involvement of cortical areas supplied by both the ACA and the MCA.
A patient vomits violently in response to toxins present in CSF. What area of the CNS responded to the toxins and initiated the reflex vomiting?
A. Organum vasculosum
B. Area postrema
C. Subfornical organ
D. Median eminence
E. Pineal gland
B:
The area postrema is a circumventricular organ in the wall of the fourth ventricle and responds to circulating toxins by inducing vomiting.
A patient develops a choroid plexus papilloma that results in an oversecretion of CSF.Which of the following might be a location of the papilloma?
A. Posterior horn of the lateral ventricle
B. Cerebral aqueduct
C. Central canal
D. Anterior horn of the lateral ventricle
E. Inferior horn of the lateral ventricle
E
None of the other choices contain choroid plexus.
A patient has valvular heart disease that gives rise to an embolus, which enters an internal carotid artery. In which branch of the anterior circulation is the embolus most likely to become lodged?
A. The anterior communicating artery
B. An MCA
C. A posterior communicating artery
D. An ACA
E. A vertebral artery
B
The MCA is the larger of the 2 branches of the anterior circulation. The PCA and vertebral artery are part of the posterior circulation, and the posterior communicating artery links the 2 cerebral circulations.
A 22-year-old male college student suffers head trauma after being thrown from a motorcycle and briefly loses consciousness. A neurological exam given in the emergency room is normal, and the patient is discharged. Several hours later, he is takenback to the emergency room because he has become drowsy and confused. His right pupil is 5 mm, but his left pupil is only 3 mm in diameter; both react to light. Muscle stretch reflexes are elevated in the left lower limb, and on his return to the emergency room, the patient’s left lower limb seemed weaker than the right. A computed
tomography scan reveals intracranial bleeding that forms a lens-shaped hematoma between the skull and the lateral aspect of the right hemisphere and subsequent herniation of brain tissue. How would you characterize the intracranial bleeding?
A. Subdural hematoma B. Rupture of an AVM C. Epidural hematoma D. Subarachnoid hemorrhage E. Intraventricular hematoma
How would you characterize the herniation in this patient? A. Subfalcine B. Arnold-Chiari C. Tentorial D. Tonsillar E. Kernohan’s
C: Skull trauma has lacerated a middle meningeal artery and caused a biconvex, lens-shaped epidural hematoma adjacent to a hemisphere.
C. The epidural hematoma has compressed the lateral part of the right hemisphere and caused a tentorial herniation. In a tentorial herniation, the uncus, the most medial part of the temporal lobe, herniates through the tentorial notch of the dura and compresses the midbrain and the oculomotor nerve.
