Chapter 2 : Meningen and Cerebrospinal Fluid (3)

Question 1

1. A 25-year-old housewife complains of headaches of 4 months’ duration. She is obese and has bilateral papilledema, and her vision is deteriorating. Her opening cerebrospinal fluid (CSF) pressure is elevated; other CSF findings are normal. Computed tomography (CT) and magnetic resonance imaging (MRl) scans are normal. These signs are due to impairment of CSF egress. Obstruction at which of the following loci is most likely? (A) Arachnoid villi (B) Cerebral aqueduct (C) Foramen of Luschka (D) Foramen of Magendie (E) Foramen of Monro

Answer 1

1-A. This condition, called pseudotumor cerebri (benign intracranial hypertension), is seen primarily in young obese women. Impaired absorptive function of the arachnoid villi is thought to be the cause.

Question 2

2. All of the following statements concerning the arachnoid granulations are correct EXCEPT (A) they are found along the superior sagittal sinus (B) they project into the dural venous sinuses (C) they playa role in the absorption of cerebrospinal ftuid (CSF) (D) they produce CSF (E) they consist of arachnoid villi

Answer 2

2-D. Arachnoid granulations are tufts of pia-arachnoid tissue that extends into the venous lacunae or directly into the venous dural sinuses. Microscopically. they are arachnoid villi and are prominent along the superior sagittal sinus. They playa major role in the absorption of cerebrospinal fluid (CSF).

Question 3

3. All of the following statements concerning the dura mater are correct EXCEPT . (A) it forms the periosteum of the vertebral canal (B) it forms the walls of the venous sinuses (C) it forms the roof of the pituitary fossa (D) it is innervated by two cranial nerves (E) it is continuous with the sclera of the eyeball

Answer 3

3-A. The dura mater forms the walls of the venous sinuses and the diaphragma sellae. which form the roof of the hypophyseal fossa. The dura of the anterior and middle cranial fossae is innervated by the ophthalr lic and maxillarY divisions of the trigeminal nerve (ON V). The in· fratentorial dura of the potiterior cranial fossa is innervated by the vagal nerve (ON X) and the meningeal branches of the upper cervical spinal nerves. The spinal dura consists of one layer. the meningeal dura; it does not form the periosteum of the vertebrae. The dura is continuous with the sclera; it forms the outer connective tissue layer of the optic nerve (CN II).

Question 4

4. All of the following statements concerning the cranial epidural space are correct EXCEPT (A) it contains a branch of the facial artery (B) it contains meningeal veins (C) it usually is associated with arterial hemorrhage (D) it is bounded by two layers of dura (E) it is normally a potential space

Answer 4

4-A. The cranial epidural space is actually a potential intradural space that is created only after trauma and hemorrhage. Epidural hematomas are arterial hemorrhages. The cranial epidural space lies between the periosteal and meningeal dural layers. Meningeal arteries and veins are found in this space.

Question 5

5. All of the following statements concerning the subarachnoid space are correct EXCEPT (A) it communicates via the foramina of Luschka with the fourth ventricle (B) it is found between the arachnoid and the pia mater (C) it extends, in the adult, from’ the conus medullaris to S2 (D) it is lined with ependymal cells (E) it communicates via the median foramen of Magendie with the fourth ventricle

Answer 5

5-0. The subarachnoid space is found between the arachnoid and the pia. It extends in the adult from the conus medullaris to 82. The subarachnoid space is lined with leptomeningeal (mesothe. lial) cells. The subarachnoid space communicates via the foramina of Luschka and the median foramen of Magendie with the fourth ventricle. Ependymal cells line the ventricles.

Question 6

6. All of the following statements concerning meningiomas are correct EXCEPT (A) they are derived from arachnoid cells (B) they are characterized by cellular whorls and p8Smoma bodies (C) they are more frequent in males (D) they are benign, slow-growing, wellcircumscribed tumors (E) they comprise approximately 20% of primary intracranial tumors

Answer 6

6-C. Meningiomas occur more frequently in women (60%) than in men.

Question 7

7. Cerebrospinal ftuid (CSF) .enters the subarachnoid space via whjch of the following structures? (A) Arachnoid villi (B) Cerebral aqueduct (C) Intraventricular foramina of Monro (D) Lateral foramina of Luschka (E) Third ventricle

Answer 7

7-0. Cerebrospinal fluid (CSF) enters the subarachnoid space via the outlet foramina of the fourth ventricle (foramina of Luschka and foramen of Magendie).

Question 8

8. Olive

Answer 8

8-E. The olive is a prominent surface structure of the medulla.

Question 9

9. It contains the trochlear nerve (CN IV)

Answer 9

9-0. The ambient cistern contains the trochlear nerve (CN IV).

Question 10

10. Its stenosis results in hydrocephalus

Answer 10

10-C. Stenosis of the cerebral aqueduct prevents cerebrospinal fluid (CSF) from entering the • fourth ventricle; this results in a noncommunicating hydrocephalus.

Question 11

11. Contains a calcified glomus

Answer 11

11-B. The trigone of the lateral ventricle contains a large tuft of choroid plexus called the glomus. It is usually calcified and highly visible in computed tomography (OT) images.

Question 12

12. Receives cerebrospinal fluid (CSF) from the arachnoid villi

Answer 12

12-A. The superior sagittal sinus receives cerebrospinallluid (CSF) via the arachnoid villi.

Question 13

13. Superior cistern

Answer 13

13-C. The superior (quadrigeminal) cistern overlies the dorsal aspect of the midbrain.

Question 14

14. Blockage results in hydrocephalus

Answer 14

14-B. Blockage of the interventricular foramen of Monro (e.g., due to a colloid cyst of the third ventricle) results in hydrocephalus involving the lateral ventricle.

Question 15

15. Lateral ventricle

Answer 15

15-A. The lateral ventricle is seen between the corpus callosum and the fornix.

Question 16

16. Contains the two foramina of Luschka

Answer 16

16-0. The fourtH ventricle contains the two foramina of Luschka that drain into the two cerebellopontine angle cisterns.

Question 17

17. Receives cerebrospinal fluid (CSF) via the foramen of Magendie

Answer 17

17-E. The cerebellomedullary cistern receives cerebrospinal fluid (CSF) via the foramen of Ma· gendie.