Neurovascular Anatomy — MCQs
Wallenberg syndrome involves which artery?
Which of the following is not a tributary of the cavernous sinus?
Which vessel is most likely damaged in an extradural (epidural) hemorrhage?
In anterior spinal artery syndrome which of the following is spared
All of the following structures lie outside the cavernous sinus except:
Which is correct about the image shown below?
The vein of Galen is formed by which structure?
Which structures are located anterior to the transverse sinus?
A crush injury of the vertebral column can cause the spinal cord to swell. Which structure would be trapped between the dura and the vertebral body by the swelling of the spinal cord?
What constitutes a spinal motion segment?
Neurovascular Anatomy Indian Medical PG Practice Questions and MCQs
Question 1: Wallenberg syndrome involves which artery?
- A. Subclavian artery
- B. Posterior cerebral artery
- C. Posterior inferior cerebellar artery (Correct Answer)
- D. Anterior inferior cerebellar artery
Explanation: ***Posterior inferior cerebellar artery*** - **Wallenberg syndrome**, also known as **lateral medullary syndrome**, is most commonly caused by an infarction in the territory supplied by the **posterior inferior cerebellar artery (PICA)**. - The PICA supplies the **lateral medulla**, which contains several crucial nuclei and tracts, including the nucleus ambiguus, trigeminal nucleus, vestibular nuclei, and spinothalamic tract, leading to the characteristic clinical presentation of Wallenberg syndrome. *Subclavian artery* - The **subclavian artery** is a large artery in the upper thorax that supplies blood to the upper limbs, head, and neck. - While it can be involved in conditions like **subclavian steal syndrome**, it does not directly supply the lateral medulla responsible for Wallenberg syndrome. *Posterior cerebral artery* - The **posterior cerebral artery** primarily supplies the occipital lobe, temporal lobe, and parts of the thalamus and midbrain. - Infarction in the PCA territory typically leads to symptoms like **hemianopia**, visual field defects, and memory deficits, not the constellation of symptoms seen in Wallenberg syndrome. *Anterior inferior cerebellar artery* - The **anterior inferior cerebellar artery (AICA)** supplies the anterior and lateral parts of the cerebellum and the pontomedullary junction, leading to **lateral pontine syndrome** when infarcted. - Symptoms of AICA infarction include ipsilateral facial paralysis, hearing loss, and cerebellar ataxia, which are distinct from Wallenberg syndrome.
Question 2: Which of the following is not a tributary of the cavernous sinus?
- A. Central vein of retina
- B. Sphenoparietal sinus
- C. Inferior cerebral vein (Correct Answer)
- D. Superior ophthalmic vein
Explanation: Detailed anatomical knowledge of the dural venous sinuses is required to answer this question. Venous drainage from the brain by way of the deep veins and dural sinuses typically empties principally into the internal jugular veins, though blood also drains via the ophthalmic and pterygoid venous plexuses [1]. ***Inferior cerebral vein*** - The **inferior cerebral veins** drain the inferior surface of the cerebral hemispheres and typically empty into the **basal vein of Rosenthal**, **transverse sinus**, or other dural sinuses. - They do **not directly drain** into the cavernous sinus, making this the correct answer. - While some small inferior cerebral veins may occasionally communicate with the cavernous sinus, they are not considered standard tributaries. *Central vein of retina* - The **central vein of retina** drains the retina and exits the eye through the optic nerve. - It drains into the **superior ophthalmic vein**, which then empties into the cavernous sinus. - It is an **indirect tributary** via the superior ophthalmic vein, not a direct tributary itself. *Sphenoparietal sinus* - The **sphenoparietal sinus** is a dural venous sinus that runs along the posterior edge of the lesser wing of the sphenoid bone. - It is a **direct tributary** that drains anteriorly into the cavernous sinus. - This is one of the standard tributaries listed in anatomical texts. *Superior ophthalmic vein* - The **superior ophthalmic vein** is the **major tributary** draining orbital structures including the eyeball, extraocular muscles, and eyelids. - It passes posteriorly through the **superior orbital fissure** to drain directly into the cavernous sinus. - This is the most clinically significant tributary, as infections can spread from the face to the cavernous sinus via this route.
Question 3: Which vessel is most likely damaged in an extradural (epidural) hemorrhage?
- A. Basilar artery
- B. Vertebral artery
- C. Middle meningeal artery (Correct Answer)
- D. Anterior cerebral artery
Explanation: Middle meningeal artery - An extradural (epidural) hemorrhage often results from head trauma, especially to the temporal region, which can cause a fracture across the course of the middle meningeal artery [1]. - This artery runs in a groove on the inner surface of the temporal bone, making it vulnerable to laceration during trauma [1]. Basilar artery - The basilar artery is located at the base of the brainstem and is a common site for strokes, but not typically involved in an extradural hemorrhage. - Damage to the basilar artery usually leads to subarachnoid hemorrhage or ischemic stroke, not an epidural hematoma. Vertebral artery - The vertebral arteries ascend through the cervical vertebrae and join to form the basilar artery, supplying the posterior circulation of the brain. - Damage to these arteries is typically associated with neck trauma or dissection, leading to subarachnoid hemorrhage or ischemia, not an epidural hemorrhage. Anterior cerebral artery - The anterior cerebral artery supplies the frontal lobes and medial aspects of the cerebral hemispheres. - While it can be involved in subarachnoid or intracranial hemorrhages from aneurysm rupture or trauma, it is not the typical source of an epidural hematoma.
Question 4: In anterior spinal artery syndrome which of the following is spared
- A. Lateral spinothalamic tract
- B. Posterior columns (Correct Answer)
- C. Anterior spinothalamic tract
- D. Corticospinal tract
Explanation: ***Posterior columns*** - The **anterior spinal artery** supplies the anterior two-thirds of the spinal cord, leaving the **posterior columns** (dorsal columns) and often the dorsal horns with intact blood supply from the **posterior spinal arteries** [1]. - This sparing results in preserved **fine touch**, **vibration**, and **proprioception** (dorsal column function), which are the defining clinical features distinguishing it from other spinal cord syndromes [1]. *Lateral spinothalamic tract* - This tract, responsible for **pain** and **temperature** sensation, is located within the territory supplied by the **anterior spinal artery** [3]. - Damage to this tract leads to bilateral loss of pain and temperature sensation below the level of the lesion [3]. *Anterior spinothalamic tract* - The **anterior spinothalamic tract** mediates crude touch and pressure and is located anteriorly, within the vascular distribution of the **anterior spinal artery**. - Injury to this tract contributes to the overall sensory deficit observed in anterior spinal artery syndrome. *Corticospinal tract* - The **corticospinal tracts** (also known as the pyramidal tracts), responsible for **voluntary motor control**, are situated in the anterior and lateral funiculi of the spinal cord [2]. - These tracts are supplied by the **anterior spinal artery**, leading to **bilateral motor paralysis** below the lesion in anterior spinal artery syndrome.
Question 5: All of the following structures lie outside the cavernous sinus except:
- A. Sphenoidal air sinus
- B. Maxillary nerve
- C. Internal carotid artery (Correct Answer)
- D. Foramen lacerum
Explanation: ***Internal carotid artery*** - The **internal carotid artery** passes directly through the **venous cavity** of the **cavernous sinus**, surrounded by venous blood. - This anatomical relationship is clinically significant, as trauma to the ICA within the sinus can lead to a **carotid-cavernous fistula**. - The ICA and the **abducent nerve (CN VI)** are the only structures that lie freely within the venous blood of the cavernous sinus. *Sphenoidal air sinus* - The **sphenoidal air sinus** is an air-filled cavity located inferior and anterior to the **cavernous sinus**, separated by a thin bony wall. - It is a distinct anatomical structure completely outside the cavernous sinus. *Maxillary nerve* - The **maxillary nerve (V2)** is located in the **lateral wall** of the cavernous sinus, embedded within the dura mater. - Unlike the ICA, it does **not** lie within the venous cavity itself, but rather within the thickness of the lateral wall. - It exits the skull through the **foramen rotundum** to enter the pterygopalatine fossa. - For the purposes of this question, structures in the lateral wall are considered separate from those within the venous space. *Foramen lacerum* - The **foramen lacerum** is an opening in the base of the skull, inferomedial to the **cavernous sinus**. - It is a bony aperture, not a structure within the cavernous sinus itself. - No major structures fully traverse the foramen lacerum as a completed entity in adults; instead, it is largely filled with fibrocartilage.
Question 6: Which is correct about the image shown below?
- A. A = Choroidal fissure, B= Body of fornix
- B. A = Internal capsule, B= Body of fornix
- C. A = Insula, B= Body of fornix
- D. A = Septum pellucidum, B= Body of fornix (Correct Answer)
Explanation: ***A = Septum pellucidum, B= Body of fornix*** - The image displays a coronal section of the brain. **A** points to the **septum pellucidum**, which is a thin, triangular membrane that separates the anterior horns of the lateral ventricles and extends from the corpus callosum to the fornix. - **B** points to the **body of the fornix**, a C-shaped bundle of nerve fibers in the brain that acts as the major output tract of the hippocampus. *A = Choroidal fissure, B= Body of fornix* - The **choroidal fissure** is the gap between the fornix and the thalamus, where the choroid plexus is located; it is not indicated by A. - While B is correctly identified as the body of the fornix, A is clearly a septal structure. *A = Internal capsule, B= Body of fornix* - The **internal capsule** is a white matter structure located deep within the brain, medial to the lentiform nucleus and lateral to the caudate nucleus and thalamus; it is not A. - The structure indicated by A is a thin membrane separating the lateral ventricles, not the dense white matter of the internal capsule. *A = Insula, B= Body of fornix* - The **insula** is a portion of the cerebral cortex folded deep within the lateral sulcus, which separates the frontal and parietal lobes from the temporal lobe; it is not indicated by A. - A is a midline structure, whereas the insula is a lateral structure deep in the cerebrum.
Question 7: The vein of Galen is formed by which structure?
- A. Internal cerebral veins (Correct Answer)
- B. Basal veins of Rosenthal
- C. Inferior sagittal sinus
- D. Superior sagittal sinus
Explanation: ***Internal cerebral veins*** - The **great cerebral vein of Galen** is formed by the union of two **internal cerebral veins** and two **basal veins of Rosenthal**. - It plays a crucial role in draining the deep venous system of the brain, including the **thalamus**, **basal ganglia**, and **choroid plexus**. - While both internal cerebral veins and basal veins contribute to its formation, "internal cerebral veins" is the most commonly tested answer. *Basal veins of Rosenthal* - The **basal veins of Rosenthal** also contribute to forming the great cerebral vein of Galen along with the internal cerebral veins. - However, in most examination contexts, the internal cerebral veins are considered the primary answer. - The basal veins primarily drain structures in the midbrain, thalamus, and insula. *Inferior sagittal sinus* - The **inferior sagittal sinus** does not form the great cerebral vein. - Instead, it merges with the **great cerebral vein** to form the **straight sinus**. - The inferior sagittal sinus runs along the lower border of the falx cerebri. *Superior sagittal sinus* - The **superior sagittal sinus** does not form the great cerebral vein. - It drains into the **confluence of sinuses** (torcular Herophili), which then connects to the transverse sinuses. - It runs along the superior border of the falx cerebri and drains the superior aspects of the cerebral hemispheres.
Question 8: Which structures are located anterior to the transverse sinus?
- A. Right atrium
- B. Left atrium
- C. Right pulmonary artery
- D. Aorta (Correct Answer)
Explanation: ***Aorta*** - The **transverse sinus of the pericardium** is a passage within the pericardial cavity that separates the great arteries (aorta and pulmonary trunk) anteriorly from the atria and great veins posteriorly. - The **ascending aorta** and **pulmonary trunk** are both located anterior to the transverse sinus. - This anatomical relationship is clinically important during cardiac surgery, as the transverse sinus can be used to pass ligatures around the great vessels. *Right atrium* - The **right atrium** is located posterior to the transverse sinus. - It forms part of the posterior wall of the pericardial cavity and receives the superior and inferior venae cavae. - The transverse sinus separates the atria from the anteriorly positioned great arteries. *Left atrium* - The **left atrium** is also positioned posterior to the transverse sinus. - It forms the base of the heart and receives the pulmonary veins. - Like the right atrium, it lies behind the plane of the transverse sinus. *Right pulmonary artery* - The **right pulmonary artery** is a branch of the pulmonary trunk that passes to the right lung. - While the **pulmonary trunk** itself is anterior to the transverse sinus, the **right pulmonary artery** branch courses laterally and posteriorly, passing behind the ascending aorta and superior vena cava. - Therefore, the right pulmonary artery is NOT considered anterior to the transverse sinus in the same way the main great vessels (aorta and pulmonary trunk) are.
Question 9: A crush injury of the vertebral column can cause the spinal cord to swell. Which structure would be trapped between the dura and the vertebral body by the swelling of the spinal cord?
- A. Alar Ligament
- B. Cruciform Ligament
- C. Anterior Longitudinal Ligament
- D. Posterior Longitudinal Ligament (Correct Answer)
Explanation: ***Anterior Longitudinal Ligament*** - The **anterior longitudinal ligament** is located on the anterior aspect of the vertebral bodies and disks, *not* within the vertebral canal where the spinal cord and dura are situated [1]. - While robust, its position makes it unlikely to be directly trapped *between the dura and the vertebral body* due to spinal cord swelling in the posterior compartment. *Alar Ligament* - The **alar ligaments** connect the dens to the occipital condyles and are crucial for the stability of the craniocervical junction. - These ligaments are located superiorly in the cervical spine and are not found along the general length of the vertebral column to be trapped by swelling lower down. *Cruciform Ligament* - The **cruciform ligament** is located in the upper cervical spine, consisting of the transverse ligament of the atlas and longitudinal bands connecting to the occiput and axis. - Its position is high in the cervical region, and it would not be trapped between the dura and a vertebral body in a general crush injury of the vertebral column. *Posterior Longitudinal Ligament* - The **posterior longitudinal ligament** is situated *within the vertebral canal*, running along the posterior surfaces of the vertebral bodies and intervertebral discs, anterior to the spinal cord and dura [1]. - If the spinal cord swells, it would expand posteriorly towards the dura and anteriorly towards this ligament, causing the ligament to be directly compressed *between the swollen spinal cord (and dura)* and the vertebral body.
Question 10: What constitutes a spinal motion segment?
- A. A disc and the vertebrae above and below, including their interlocking facet joints. (Correct Answer)
- B. A disc and the facet joints at that level.
- C. A vertebral body and the disc above.
- D. A section of the spine involved in a physiological curve with the similar function (i.e. thoracic kyphosis).
Explanation: ***A disc and the vertebrae above and below, including their interlocking facet joints.*** - A **spinal motion segment** or **functional spinal unit** is defined as two adjacent vertebrae and the intervertebral disc between them. - This unit includes all the associated **ligaments**, **capsules**, and especially the **facet joints**, which together allow for complex movements. *A disc and the facet joints at that level.* - This definition is incomplete as it misses the crucial component of the **vertebral bodies** themselves. - The vertebral bodies provide the main structural support and articulation points for the disc and facet joints. *A vertebral body and the disc above.* - This partial definition describes only a fraction of the components required for a functional segment. - It omits the **inferior vertebral body** and the critical **facet joints** that enable motion. *A section of the spine involved in a physiological curve with the similar function (i.e. thoracic kyphosis).* - This option describes a broader **region** of the spine rather than a single, functional motion unit. - A physiological curve involves multiple motion segments working in concert, not a single segment.
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