Block 5 Anat, Scalp,Cran,Mening,Brain
(200).webp "Block 5 Anat, Scalp,Cran,Mening,Brain - Quiz")
Questions and Answers
- 1.
Infections may spread from the nasal cavity to the meninges along the olfactory nerves, as its fibers pass from the mucosa of the nasal cavity to the olfactory bulb via the:
- A.
Cribriform plate of the ethmoid
- B.
Crista galli
- C.
Foramen caecum
- D.
Superior orbital fissure
Correct Answer
A. Cribriform plate of the ethmoidExplanation
The olfactory nerve exits the skull through the cribriform plate of the ethmoid bone--an infection in the nasal cavity may be carried to the olfactory bulb by the nerves that are passing through the cribriform plate. The crista galli is a ridge on the ethmoid bone between the two sides of the cribriform plate; it provides an anchor for the falx cerebri. Foramen cecum is a small hole in the frontal bone near the anterior end of the crista galli--it transmits an emissary vein. Finally, the superior orbital fissure is a hole in the sphenoid bone that transmits many cranial nerves: the oculomotor nerve (CN III), the trochlear nerve (CN IV), the ophthalmic division of the trigeminal nerve (CN V1) and the abducens nerve (CN VI) all pass through the superior orbital fissure.Rate this question:
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- 2.
A sixty-four-year old man was diagnosed with an acoustic neuroma (tumor of the VIIIth cranial nerve) where it entered the temporal bone. What other cranial nerve might also be affected since this nerve uses the same foramen as the VIIIth in its course?
- A.
Abducens
- B.
Facial
- C.
Glossopharyngeal
- D.
Trigeminal
- E.
Vagus
Correct Answer
B. FacialExplanation
The facial nerve enters the temporal bone with the vestibulocochlear nerve--both cross into the internal acoustic meatus. Abducens (CN VI) crosses through the superior orbital fissure, along with the oculomotor nerve (CN III), the trochlear nerve (CN IV) and the ophthalmic division of the trigeminal nerve (CN V1). The glossopharyngeal (CN IX), vagus (CN X), and spinal accessory nerve (CN XI) all leave through the jugular foramen. Finally, the three divisions of the trigeminal nerve all leave through different foramina: V1, the ophthalmic division, exits through the superior orbital fissure; V2, the maxillary division, leaves through foramen rotundum; V3, the mandibular division, leaves through foramen ovale.Rate this question:
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- 3.
An 84-year old woman suffers a stroke, with paralysis on the right side of her body. Neurological tests show that the intracerebral hemorrhage has interrupted the blood supply to the posterior part of the frontal, the parietal and medial portions of the temporal lobes of the left cerebral hemisphere. Which vessel was involved?
- A.
Anterior cerebral artery
- B.
Great cerebral vein
- C.
Middle cerebral artery
- D.
Middle meningeal artery
- E.
Posterior cerebral artery
Correct Answer
C. Middle cerebral arteryExplanation
The middle cerebral artery supplies blood to most of the lateral surface of cerebral hemispheres, and the temporal pole, including the frontal, parietal, and medial portions of the temporal lobes. So, the specific damage to the temporal lobe suggests that the middle cerebral artery was disrupted. The other arteries listed do not distribute to the same territory. The anterior cerebral artery supplies the medial and superior surfaces of the brain, including the frontal pole. The posterior cerebral artery supplies the inferior surface of the brain and the occipital pole. Strokes occur in arteries, not veins, so that's one reason why the great cerebral vein is not correct. Veins also drain regions of blood--they don't supply blood to areas. The middle meningeal artery supplies blood to the dura mater and the cranial vault bones--it does not supply blood to the brain.Rate this question:
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- 4.
An infant was diagnosed as having hydrocephalus. It was determined that there was a blockage in the ventricular system of the baby's brain between the third and fourth ventricles. The blockage therefore must have involved the:
- A.
Central canal
- B.
Cerebral aqueduct
- C.
Foramen of Luschka (lateral foramen)
- D.
Foramen of Magendie (medial foramen)
- E.
Interventricular foramen
Correct Answer
B. Cerebral aqueductExplanation
The cerebral aqueduct is the part of the ventricular system that carries cerebrospinal fluid from the third ventricle to the fourth ventricle. So, this must be the part of the ventricular system that was blocked. The central canal is the space where CSF flows through the spinal cord. It is continuous with the 4th ventricle. The foramina of Luschka (lateral aperatures) and foramen of Magendie (median aperature) are small foramina in the 4th ventricle that allow the CSF to leave the ventricular system and enter the subarachnoid space. The interventricular foramina are passages from the lateral ventricles that allow the CSF to enter the 3rd ventricle.Rate this question:
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- 5.
During an intramural baseball game a player is hit in the side of the head, between the eye and the ear. He immediately loses consciousness, wakes up momentarily and then becomes comatose. He is rushed to the ER and is immediately given a CT scan. The scan shows a skull fracture and an accumulation of blood between the dura and the cranial bone on the side of his head, compressing his cerebrum. He is rushed to surgery where a hole is bored into his skull to relieve the pressure. After a few tense hours, he regains consciousness and has an uneventful recovery. The hemorrhage from the fracture would be described as:
- A.
Epidural
- B.
Intracerebral
- C.
Subaponeurotic
- D.
Subarachnoid
- E.
Subdural
Correct Answer
A. EpiduralExplanation
An epidural hemorrhage is a hemorrhage of blood into the space between the dura and the skull. These hemorrhages are usually caused by rupturing the middle meningeal artery, which supplies blood to the dura and the bones of the cranial vault. This hemorrhage results in compression of the dura mater and the brain; if it is not drained, it may result in the brain herniating through the tentorium and death. An intracerebral hemorrhage is a hemorrhage within the cerebral hemispheres. A subaponeurotic hemorrhage could be a collection of blood under the aponeurosis of the scalp, but this is not really a brain hemorrhage and is not as clinically significant as the other answer choices. A subarachnoid hemorrhage is an acute condition where blood collects in the area between the pia mater and arachnoid mater. This is often secondary to a head injury or a ruptured aneurysm. A subdural hemorrhage is characterised by a collection of blood beneath the dura, often caused by a head injury.Rate this question:
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- 6.
The "danger zone" of the scalp is recognized as which of the following layers?
- A.
Galea aponeurotica
- B.
Loose connective tissue
- C.
Pericranium
- D.
Skin
- E.
Subcutaneous connective tissue
Correct Answer
B. Loose connective tissueExplanation
The scalp is comprised of the following layers, from superficial to deep: Skin, Connective tissue, Aponeurosis, Loose connective tissue, and Pericranium. If you take the first letter of each, it spells SCALP. So, now that you know the order of the layers, you need to figure out which one is the danger zone--the place where infections can spread very quickly. And that layer is layer 4, the loose connective tissue. Pus or blood can spread easily in this layer, and infections in this layer can pass into the cranial cavity through emissary veins. So, infections in the loose connective tissue can pass into intracranial structures such as the brain and meninges. Although layer 2 is a connective tissue layer, too, this layer is a bit thicker and is not a place where infections can easily spread.Rate this question:
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- 7.
The presence of blood in a spinal tap taken from an individual with a closed head injury signals arterial bleeding into the:
- A.
Cavernous sinus
- B.
Epidural space
- C.
Subarachnoid space
- D.
Subdural space
Correct Answer
C. Subarachnoid spaceExplanation
Remember back to the spinal cord - when taking cerebrospinal fluid for a spinal tap, you are removing fluid from the subarachnoid space. The subarachnoid space of the spinal cord is continuous with the subarachnoid space around the brain, so you know that the patient must have had a subarachnoid hemorrhage. Subarachnoid hemorrhages are acute events, often caused by an aneurysm or a closed head injury.
In the spinal cord, the epidural space is filled with fat, and the subdural space is really a potential space only - there is no fluid in this area. The cavernous sinus is a venous sinus of the brain, on the lateral surface of the body of the sphenoid bone.Rate this question:
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- 8.
An infection in which scalp layer is likely to spread most readily?
- A.
Skin
- B.
Connective tissue layer
- C.
Aponeurotic layer
- D.
Loose areolar tissue
- E.
Pericranium
Correct Answer
D. Loose areolar tissueExplanation
Loose areolar tissue is another name for the loose connective tissue layer of the scalp. Pus or blood can spread easily in this layer, and infections in this layer can pass into the cranial cavity through emissary veins. So, infections in the loose connective tissue can pass into intracranial structures such as the brain and meninges. This can also be called the "danger layer" of the scalp.
Remember--the scalp is comprised of the following layers, from superficial to deep: Skin, Connective tissue, Aponeurosis, Loose connective tissue, and Pericranium. (SCALP!) Although layer 2 is a connective tissue layer, too, this layer is a bit thicker and is not a place where infections can easily spread.Rate this question:
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- 9.
A patient who has sustained a fracture to the middle cranial fossa following a fall from a height, might have any of these nerves injured EXCEPT:
- A.
Trigeminal
- B.
Oculomotor
- C.
Abducens
- D.
Trochlear
- E.
Hypoglossal
Correct Answer
E. HypoglossalExplanation
The middle cranial fossa is the part of the skull that supports the temporal lobes of the brain. It is made of the greater wings of the sphenoid and squamous part of the temporal bones laterally and the petrous part of the temporal bones posteriorly. See Netter Plate 6 and 7 for a better picture of this.
Several cranial nerves enter foramina in the middle cranial fossa; all of these nerves might have been damaged in the fall. The trigeminal nerve (CN V) has three divisions that all leave through spaces in the middle cranial fossa. V1, the ophthalmic division, exits through the superior orbital fissure; V2, the maxillary division, leaves through foramen rotundum; V3, the mandibular division, leaves through foramen ovale. The oculomotor nerve (CN III) crosses through the superior orbital fissure, along with abducens (CN VI), the trochlear nerve (CN IV) and the ophthalmic division of the trigeminal nerve (CN V1). So, all of these nerves might have been damaged in the fall.
The hypoglossal nerve, however, leaves the base of the skull by passing through the hypoglossal canal, which is in the occipital bone and the posterior cranial fossa. It is not likely that this nerve was injured in the fall.Rate this question:
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- 10.
The most likely source of blood in a patient with an epidural hemorrhage is:
- A.
Vertebral artery
- B.
Middle meningeal artery
- C.
Superior cerebral veins
- D.
Anterior cerebral artery
- E.
Circle of Willis
Correct Answer
B. Middle meningeal arteryExplanation
The middle meningeal artery supplies most of the dura mater and the bones of the cranial vault. It is this artery or vein that is usually ruptured in an epidural hemorrhage. The vertebral artery carries blood to the deep neck, cervical spinal cord, and hindbrain. It does not supply blood to the dura. Superior cerebral veins drain blood into the superior sagittal sinus. When injured, they bleed into the subdural space and cause a subdural hematoma. The anterior cerebral artery supplies blood to the frontal pole of the brain. It is not found near the epidural space. Finally, the circle of Willis is an important anastomosis at the base of the brain between the following arteries: posterior cerebral arteries, posterior communicating arteries, internal carotid arteries, anterior cerebral arteries, and anterior communicating arteries.Rate this question:
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- 11.
In a fall from a horse, a rider sustains a severe neck injury at the C6 level. In addition to crushing the spinal cord, the left transverse process of the C6 vertebra is fractured. What artery is endangered?
- A.
Common carotid
- B.
Costocervical
- C.
Inferior thyroid
- D.
Internal carotid
- E.
Vertebral
Correct Answer
E. VertebralExplanation
The paired vertebral arteries travel through the transverse foramina of the C1-C6 vertebrae. So, since the C6 vertebra was damaged, the vertebral artery could also be ruptured. The other arteries are not closely related with the vertebrae. The common carotid arteries come off the brachiocephalic trunk on the right side and the aortic arch on the left side, giving off many arteries that supply the head and neck. The costocervical trunk is a branch of the subclavian artery that supplies the deep neck and the first 2 intercostal spaces. The inferior thyroid artery is a branch of the thyrocervical trunk that supplies the thyroid. Finally, the internal carotid artery is a branch of the common carotid that joins the circle of Willis and supplies the brain.Rate this question:
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- 12.
A 35-year-old man was admitted to the hospital complaining of double vision (diplopia), inability to see close objects, and blurred vision in the right eye. A vertebrobasilar angiogram revealed an aneurysm of the superior cerebellar artery close to its origin on the right side. The doctor attributed the symptoms to the compression of an adjacent cranial nerve by the aneurysm. The compressed nerve is the:
- A.
Abducens (CN VI)
- B.
Oculomotor (CN III)
- C.
Optic (CN II)
- D.
Trigeminal (CN V)
- E.
Trochlear (CN IV)
Correct Answer
B. Oculomotor (CN III)Explanation
Given the patient's symptoms, it seems that some nerve involving vision and the ability to control the eye has been injured. Now, you need to think about which nerve might be damaged by an aneurysm of the superior cerebellar artery. The oculomotor nerve, which innervates the superior rectus, medial rectus, inferior rectus, and inferior oblique muscles, passes between the posterior cerebral artery and the superior cerebellar artery. It could be injured if there was enlargement of or damage to either of these vessels. None of the other cranial nerves are in the right position to be injured from an aneurysm of the superior cerebellar artery.Rate this question:
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- 13.
An elderly patient developed fever and worsening headache a few days after sustaining a scalp laceration and subsequent infection due to a car accident. At the hospital the case was diagnosed as meningitis and superior sagittal sinus thrombosis. The attending physician suggested that infection to the sinus initially spread through one of the scalp layers. The scalp layer involved is:
- A.
Areolar tissue
- B.
Connective tissue
- C.
Epicranial aponeurosis
- D.
Periosteum
- E.
Skin
Correct Answer
A. Areolar tissueExplanation
Areolar tissue is another name for the loose connective tissue layer of the scalp. Pus or blood can spread easily in this layer, and infections in this layer can pass into the cranial cavity through emissary veins. So, infections in the loose connective tissue can pass into intracranial structures such as the superior sagittal sinus, causing conditions like the superior sinus thrombosis.
Remember--the scalp is comprised of the following layers, from superficial to deep: Skin, Connective tissue, Aponeurosis, Loose connective tissue, and Pericranium. (SCALP!) Although layer 2 is a connective tissue layer, too, this layer is thicker and it's not where infections can easily spread.Rate this question:
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- 14.
While riding her bicycle on campus without a helmet a student is hit by a car and falls, hitting her head on the pavement. She is brought to the Emergency Room in an unconscious state with signs of a closed head injury. Tests reveal blood in her cerebrospinal fluid taken from a spinal tap. Diagnosis is of torn cerebral veins as they pass from the brain to the superior sagittal sinus. From which of the following was the bloody fluid taken?
- A.
Cavernous sinus
- B.
Epidural space
- C.
Subarachnoid space
- D.
Subdural space
- E.
Verterbal venous plexus
Correct Answer
C. Subarachnoid spaceExplanation
Remember back to the spinal cord - when taking cerebrospinal fluid for a spinal tap, you are removing fluid from the subarachnoid space. The subarachnoid space of the spinal cord is continuous with the subarachnoid space around the brain, so you know that the patient must have had a subarachnoid hemorrhage. Subarachnoid hemorrhages are acute events, often caused by an aneurysm or a closed head injury.
In the spinal cord, the epidural space is filled with fat, and the subdural space is really a potential space only - there is no fluid in this area. The cavernous sinus is a venous sinus of the brain, lateral to the body of the sphenoid bone. The vertebral venous plexus are the veins that drain the spinal cord - they are valveless veins, so they are an important route that cancer cells can use to metastasize.Rate this question:
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- 15.
You have been asked to assess the neurological deficit that might exist in a patient diagnosed with cavernous sinus thrombosis. You will focus your examination on cranial nerves related to the sinus that includes all the following EXCEPT:
- A.
Abducens (CN VI)
- B.
Facial (CN VII)
- C.
Oculomotor (CN III)
- D.
Ophthalmic division of the trigeminal nerve (CN V1)
- E.
Trochlear (CN IV)
Correct Answer
B. Facial (CN VII)Explanation
The cavernous sinus is a venous sinus of the brain, lateral to the body of the sphenoid bone. All of the cranial nerves and vessels that pass out of the skull at the superior orbital fissure pass through the cavernous sinus. This includes the oculomotor nerve, the trochlear nerve, the ophthalmic division of the trigeminal nerve, and the abducens nerve. The internal carotid artery also passes through the cavernous sinus. Since three of the nerves in the cavernous sinus control the motions of the extraocular muscles, testing eye movements would be a good way to see if nerves in the cavernous sinus were disrupted. The ophthamic division of the trigeminal nerve, which supplies cutaneous sensation to the skin of the upper face, could be tested by evaluating the sensations on the forehead.
The facial nerve is not associated with the cavernous sinus. It passes through the internal acoustic meatus and exits the skull through the stylomastoid foramen. So, you would not need to test to see if the facial nerve was intact.Rate this question:
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- 16.
The glossopharyngeal nerve exits the skull via what opening?
- A.
Foramen ovale
- B.
Carotid canal
- C.
Jugular foramen
- D.
Hypoglossal canal
- E.
Stylomastoid foramen
Correct Answer
C. Jugular foramenExplanation
The glossopharyngeal nerve (CN IX), vagus (CN X) and accessory nerve (CN XI) exit the skull at the jugular foramen. The posterior meningeal artery enters the skull through this space. The mandibular division of the trigeminal nerve (V3) exits the skull through foramen ovale. The carotid canal is the place where the internal carotid artery and the internal carotid nerve plexus enter the skull. The hypoglossal canal is where the hypoglossal nerve (CN XII) leaves the skull. The stylomastoid foramen is the hole that the facial nerve (CN VII) uses to exit the skull.Rate this question:
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- 17.
An infant was found to have hydrocephalus. Studies revealed that the hydrocephalus was caused because CSF could not get out of the third ventricle. The passage blocked was the:
- A.
Central canal
- B.
Cerebral aqueduct
- C.
Interventricular foramen
- D.
Lateral foramen (of Luschka)
- E.
Medial foramen (of Magendie)
Correct Answer
B. Cerebral aqueductExplanation
For CSF to travel from the third ventricle to the 4th ventricle and the central canal of the spinal cord, it must pass through the cerebral aqueduct. So, this is the passageway that must be blocked. The central canal is the space where CSF flows through the spinal cord. It is continuous with the 4th ventricle. The foramen of Luschka and foramen of Magendie are small foramina in the 4th ventricle that allow the CSF to leave the ventricular system and enter the subarachnoid space. The interventricular foramina are passages in the lateral ventricles that allow the CSF to leave the lateral ventricles and enter the 3rd ventricles. See Netter Plate 102 for a diagram of the ventricles of the brain.Rate this question:
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- 18.
A person develops a cavernous sinus thrombosis. Because of its relationship to the sinus, which cranial nerve might be affected?
- A.
Abducens
- B.
Facial
- C.
Mandibular V3
- D.
Olfactory
- E.
Optic
Correct Answer
A. AbducensExplanation
The cavernous sinus is a venous sinus of the brain, lateral to the body of the sphenoid bone. All of the cranial nerves and vessels that pass out of the skull at the superior orbital fissure pass through the cavernous sinus. This includes the abducens nerve, the oculomotor nerve, the trochlear nerve, and the ophthalmic division of the trigeminal nerve. Any of these nerves might be affected by a cavernous venous sinus thrombosis.
The facial nerve is not associated with the cavernous sinus. It passes through the internal acoustic meatus and exits the skull through the stylomastoid foramen. The mandibular division of the trigeminal nerve (V3) exits the skull through foramen ovale. The olfactory nerves enter the skull through the cribriform plate of the ethmoid bone. The optic nerve exits the skull through the optic canal. None of these nerves are associated with the cavernous sinus.Rate this question:
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- 19.
Blockage of the flow of cerebrospinal fluid (CSF) within the cerebral aqueduct (of Sylvius) normally would result in the enlargement of all of the following ventricular spaces except the:
- A.
Fourth ventricle
- B.
Interventricular foramen (of Monro)
- C.
Lateral ventricle
- D.
Third ventricle
Correct Answer
A. Fourth ventricleExplanation
If the cerebral aqueduct was blocked, CSF would not flow from the third ventricle into the fourth ventricle and the central canal. So, all the spaces proximal to the blockage would enlarge, while all the spaces distal to the blockage would be normal. The third ventricle, lateral ventricle, and interventricular foramen are proximal to the blockage of CSF; fluid circulates from the lateral ventricles, through the interventricular foramen, to the third ventricle before reaching the cerebral aqueduct. This means that all of these spaces should be enlarged with fluid. The fourth ventricle, however, needs the cerebral aqueduct to be open so that it can receive fluid--it would not become distended from the blockage in the aqueduct.Rate this question:
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- 20.
All of the following nerves exit the cranial cavity by way of bony openings located in the middle cranial fossa EXCEPT:
- A.
Abducens
- B.
Trochlear
- C.
Oculomotor
- D.
Trigeminal
- E.
Facial
Correct Answer
E. FacialExplanation
The middle cranial fossa is the part of the skull that supports the temporal lobes of the brain. It is made of the greater wings of the sphenoid and squamous parts of the temporal bones laterally and the petrous parts of the temporal bones posteriorly. See Netter Plate 6 and 7 for a better picture of this.
Several cranial nerves enter foramina in the middle cranial fossa. The abducens (CN VI) crosses through the superior orbital fissure, along with the oculomotor nerve (CN III), trochlear nerve (CN IV) and ophthalmic division of the trigeminal nerve (CN V1). The trigeminal nerve (CN V) has three divisions that all leave through spaces in the middle cranial fossa. V1, the ophthalmic division, exits through the superior orbital fissure; V2, the maxillary division, leaves through foramen rotundum; V3, the mandibular division, leaves through foramen ovale.
The facial nerve, however, leaves the base of the skull by passing through the internal acoustic meatus, which is in the part of the temporal bone that is in the posterior cranial fossa.Rate this question:
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- 21.
During childbirth, an excessive anteroposterior compression of the head may tear the anterior attachment of the falx cerebri from the tentorium cerebelli. The bleeding that follows is likely to be from which of the following venous sinuses?
- A.
Occipital sinus
- B.
Sigmoid sinus
- C.
Straight sinus
- D.
Superior sagittal sinus
- E.
Transverse sinus
Correct Answer
C. Straight sinusExplanation
The straight sinus drains the deep cerebrum--it lies within the junction of the falx cerebri and tentorium cerebelli. This is exactly the location that was damaged in birth, so this is the correct answer. The occipital sinus drains the cerebellum--it lies within the dura mater at base of falx cerebelli. It is inferior to the straight sinus. The sigmoid sinus drains the blood from the brain into the internal jugular vein--it lies within sigmoid groove, covered by dura mater. The superior sagittal sinus drains the cerebral hemispheres--it lies superiorly within falx cerebri, near the superior border of the skull. The transverse sinus lies within the attachment of tentorium cerebelli to the inner surface of the calvaria. When trying to understand these sinuses, a picture is really worth a thousand words, so take a look at Netter 97 and 98!Rate this question:
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- 22.
The inferior sagittal sinus is found in the free edge of what structure?
- A.
Diaphragma sellae
- B.
Falx cerebelli
- C.
Falx cerebri
- D.
Filum terminale
- E.
Tentorium cerebelli
Correct Answer
C. Falx cerebriExplanation
The falx cerebri is a crescent-shaped, sagittally-oriented fold of dura mater lying between cerebral hemispheres. The inferior sagittal sinus runs in the inferior margin of the falx cerebri. The falx cerebelli is a small fold of dura mater lying between cerebellar hemispheres--it is the location of the occipital sinus. The diaphragma sellae is a piece of dura mater which forms the roof of the hypophyseal fossa; it is pierced by the stalk of the hypophysis. The tentorium cerebelli is a tent-like sheet of dura mater covering of cerebellum, oriented somewhat transversely. The straight sinus is found in the junction of the falx cerebri and tentorium cerebelli. The filum terminale is an extension of the pia mater below the end of the spinal cord at L2. It is a structure of the spinal cord, not the brain.Rate this question:
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