Neuroanatomy Practice Questions

Q: An unconscious 54-year-old female is admitted to the hospital. A CT scan reveals a tumor in her brain, producing a tentorial herniation. When she regains consciousness, her right eye is directed laterally and downward, with complete ptosis of her upper eyelid and pupillary dilation. Which of the following lobes of the brain is affected by the tumor?

Temporal. **Explanation:** The clinical presentation describes a classic case of **Uncal Herniation**, a subtype of transtentorial herniation. **Why Temporal Lobe is Correct:** The **Uncus** is the innermost part of the **Temporal lobe** (specifically the parahippocampal gyrus). When a tumor or mass effect increases intracranial pressure, the uncus is pushed over the edge of the tentorium cerebelli. This herniation compresses the adjacent **Oculomotor nerve (CN III)**. [1] * **CN III Compression leads to:** 1. **Ptosis:** Paralysis of Levator palpebrae superioris. 2. **

Q: Which ventricle is represented by the diencephalon?

3rd ventricle. The correct answer is **B. 3rd ventricle**. The ventricular system of the brain develops from the central cavity of the neural tube. The **diencephalon** (which includes the thalamus and hypothalamus) develops from the prosencephalon (forebrain). The cavity of the diencephalon persists as the **3rd ventricle**, a narrow, slit-like midline space located between the two thalami. **Analysis of Options:** * **A. Lateral ventricle:** These are the cavities of the **telencephalon** (cerebral hemispheres). They communicate with the 3rd ventricle via the interventricular foramina of Monro. * **C. 4th ventricle:** This is the cavity of the **rhombencephalon** (hindbrain), specifically located between the cerebellum posteriorly and the pons and upper medulla anteriorly. * **D. Cerebral aqueduct (of Sylvius):** This is the narrow channel within the **mesencephalon** (midbrain) that connects the 3rd and 4th ventricles. **High-Yield Facts for NEET-PG:** * **Boundaries of the 3rd Ventricle:** The lateral walls are formed by the medial surfaces of the **thalami** (superiorly) and **hypothalami** (inferiorly), separated by the hypothalamic sulcus. * **Choroid Plexus:** The 3rd ventricle contains a choroid plexus in its roof (tela choroidea) which secretes CSF. * **Clinical Correlation:** Obstruction of the narrow 3rd ventricle or the cerebral aqueduct can lead to **non-communicating (obstructive) hydrocephalus** [1]. * **Recesses:** The 3rd ventricle has several characteristic recesses: optic, infundibular, pineal, and suprapineal.

Q: A male client was involved in a vehicular accident and developed amnesia. Damage to which of the following structures is most likely responsible?

Hippocampus. The **Hippocampus**, located within the medial temporal lobe, is the primary structure responsible for the formation of new memories (encoding) and the consolidation of short-term memory into long-term memory [1]. It is a key component of the **Papez circuit**. Damage to the hippocampus, often seen in traumatic brain injuries or hypoxic insults, characteristically results in **anterograde amnesia** (inability to form new memories), though it can also affect the retrieval of recent memories [1]. **Analysis of Incorrect Options:** * **Hypothalamus:** Primarily functions as the control center for the autonomic nervous system and endocrine system (homeostasis, thirst, hunger, and temperature regulation). While the mammillary bodies (part of the hypothalamus) are involved in memory (e.g., Wernicke-Korsakoff syndrome), the hippocampus is the more definitive site for general post-traumatic amnesia. * **Thalamus:** Acts as the major sensory relay station for the cortex. While specific nuclei (mediodorsal) play a role in memory circuits, it is not the primary site associated with the fundamental process of memory consolidation. * **Cerebrum:** This is too broad a term. While the cerebral cortex stores long-term memories, "amnesia" as a clinical sign specifically points to the limbic structures (hippocampus) rather than the entire cerebrum. **NEET-PG High-Yield Pearls:** * **Klüver-Bucy Syndrome:** Results from bilateral ablation of the **amygdala** (anterior temporal lobe), presenting with hypersexuality, hyperphagia, and visual agnosia [1]. * **Wernicke-Korsakoff Syndrome:** Characterized by damage to the **mammillary bodies** and dorsomedial nucleus of the thalamus due to Thiamine (B1) deficiency. * **Histology:** The hippocampus is one of the few areas in the adult brain capable of **neurogenesis** [1]. It is also highly sensitive to ischemia (Pyramidal cells in Sommer’s sector/CA1).

Q: Left sided facial weakness with a right hemisphere lesion most likely indicates a lesion at which location?

Internal capsule. **Explanation:** The question describes a **contralateral facial weakness** (left-sided weakness with a right-sided lesion). This pattern is characteristic of an **Upper Motor Neuron (UMN)** lesion. **Why Internal Capsule is correct:** The facial nerve nucleus (located in the pons) receives bilateral innervation for the upper face but only **contralateral** innervation for the lower face via the **corticobulbar tract**. These fibers descend through the **genu of the internal capsule** [1]. A lesion in the right internal capsule interrupts these descending UMN fibers before they reach the left facial nucleus, resulting in paralysis of the muscles of the lower left quadrant of the face (sparing the forehead). **Why other options are incorrect:** * **Pons:** A lesion in the pons typically involves the facial nerve nucleus or its exiting fibers. This results in an **ipsilateral Lower Motor Neuron (LMN)** palsy (Bell’s palsy type), affecting both the upper and lower face on the same side as the lesion. * **Medulla:** The facial nerve (CN VII) originates in the pons. A medullary lesion would affect lower cranial nerves (IX, X, XI, XII) but not the facial nerve. * **Amygdala:** This is part of the limbic system involved in emotional processing; it does not mediate voluntary motor control of facial muscles. **High-Yield Clinical Pearls for NEET-PG:** * **UMN vs. LMN:** In UMN lesions (e.g., Internal Capsule/Cortex), the **forehead is spared** because the upper face receives bilateral cortical input [1]. In LMN lesions (e.g., Pons/Stylomastoid foramen), the **entire half of the face** is affected. * **Rule of 4s:** CN V, VI, VII, and VIII are associated with the **Pons**. * **Internal Capsule Anatomy:** Remember the mnemonic "Genu for Genuflect" (Kneel/Face)—the **Genu** contains corticobulbar fibers (Head/Face), while the **Posterior Limb** contains corticospinal fibers (Body) [1].

Q: What is the blood supply of the spinal cord?

One anterior and two posterior spinal arteries. ### Explanation The blood supply of the spinal cord is derived from longitudinal arteries that originate from the **vertebral arteries** and are reinforced by segmental medullary arteries. **1. Why Option A is Correct:** The spinal cord is supplied by three primary longitudinal vessels: * **One Anterior Spinal Artery:** Formed by the union of two branches from the intracranial portion of the vertebral arteries. It runs in the anterior median fissure and supplies the **anterior two-thirds** of the spinal cord (including the motor tracts and anterior horns). * **Two Posterior Spinal Arteries:** These arise either directly from the vertebral arteries or the posterior inferior cerebellar arteries (PICA). They run along the posterolateral sulci and supply the **posterior one-third** of the cord (including the dorsal columns). **2. Why Other Options are Incorrect:** * **Options B & C:** These are anatomically incorrect. There is never more than one anterior spinal artery in a normal human anatomy. * **Option D:** This is incorrect because the posterior aspect requires two distinct arteries to cover the bilateral dorsal columns and horns, whereas the anterior aspect is served by a single midline vessel. **3. Clinical Pearls for NEET-PG:** * **Artery of Adamkiewicz (Arteria Radicularis Magna):** This is the largest segmental medullary artery, usually arising from the left side between **T9 and L2**. It is crucial for supplying the lower two-thirds of the spinal cord. * **Vulnerability:** The **T4–T8 segments** are considered "watershed areas" with relatively sparse blood supply, making them highly susceptible to ischemic injury during surgery or hypotension. * **Anterior Spinal Artery Syndrome:** Characterized by loss of motor function (corticospinal tract) and pain/temperature sensation (spinothalamic tract) below the level of the lesion, while **sparing** fine touch and proprioception (dorsal columns).

Q: All of the following are supplied by the anterior cerebral artery except?

Broca's area. **Explanation:** The **Anterior Cerebral Artery (ACA)** is a major branch of the internal carotid artery that primarily supplies the medial aspect of the cerebral hemispheres. **Why Broca’s Area is the correct answer:** Broca’s area (Brodmann areas 44 and 45) is located in the inferior frontal gyrus of the **lateral surface** of the frontal lobe [1]. The lateral surface of the brain, including the motor speech area (Broca's) and the sensory speech area (Wernicke's), is supplied by the **Middle Cerebral Artery (MCA)**. Therefore, an ACA stroke will not typically result in Broca’s aphasia. **Analysis of incorrect options:** * **Anterior and Medial Cerebrum:** The ACA curves around the genu of the corpus callosum to supply the medial surface of the frontal and parietal lobes, as well as the anterior portion of the superior frontal gyrus. * **Paracentral Lobule:** This area on the medial surface controls the motor and sensory functions of the **contralateral lower limb and perineum**. It is a classic high-yield territory supplied by the ACA. **NEET-PG High-Yield Pearls:** 1. **ACA Stroke Clinical Presentation:** Characterized by contralateral motor and sensory loss specifically affecting the **leg and foot** (due to paracentral lobule involvement), sparing the face and arms. 2. **Urinary Incontinence:** Often seen in ACA infarcts due to involvement of the frontal micturition center. 3. **Recurrent Artery of Heubner:** A major branch of the ACA (A2 segment) that supplies the head of the caudate nucleus and the anterior limb of the internal capsule. 4. **MCA vs. ACA:** Remember: **M**CA = **M**ost of the lateral surface (Face/Arm); **A**CA = **A**ll of the medial surface (Leg/Foot).

Question 1

Which of the following is NOT a feature of the occipital lobe of the brain?

Accepted Answer

It is the only area in the brain activated by visual stimuli.

Answer

Visual cortex lies in relation to the calcarine fissure.

Answer

Brodmann's area 17 corresponds to the visual cortex.

Answer

Geniculocalcarine fibres from the medial half of the lateral geniculate terminate on the superior lip of the calcarine fissure.

Question 2

An unconscious 54-year-old female is admitted to the hospital. A CT scan reveals a tumor in her brain, producing a tentorial herniation. When she regains consciousness, her right eye is directed laterally and downward, with complete ptosis of her upper eyelid and pupillary dilation. Which of the following lobes of the brain is affected by the tumor?

Accepted Answer

Temporal

Answer

Parietal

Answer

Occipital

Answer

Frontal

Question 3

Which ventricle is represented by the diencephalon?

Accepted Answer

3rd ventricle

Answer

Lateral ventricle

Answer

4th ventricle

Answer

Cerebral aqueduct

Question 4

A 15-year-old girl presents with a sore throat. She is prescribed an antibiotic that can enter most body tissues but cannot penetrate the blood-brain barrier. Which cell type is primarily responsible for the blood-brain barrier?

Accepted Answer

Endothelial cell

Answer

Astrocyte

Answer

Glial cell

Answer

Macrophage

Question 5

Damage to the sixth cranial nerve will produce which deficit in eye movement?

Accepted Answer

Inability to move the eyes laterally (away from the midline)

Answer

Inability to move the eyes in a vertical up-and-down motion

Answer

Inability to rotate the eyes within the eye socket

Answer

Inability to move the eyes medially (towards the midline)

Question 6

A male client was involved in a vehicular accident and developed amnesia. Damage to which of the following structures is most likely responsible?

Accepted Answer

Hippocampus

Answer

Hypothalamus

Answer

Thalamus

Answer

Cerebrum

Question 7

Which of the following cerebellar pathways does NOT pass through the inferior cerebellar peduncle?

Accepted Answer

Posterior spinocerebellar pathway

Answer

Pontocerebellar pathway

Answer

Cuneocerebellar pathway

Answer

Anterior spinocerebellar pathway

Question 8

Left sided facial weakness with a right hemisphere lesion most likely indicates a lesion at which location?

Accepted Answer

Internal capsule

Answer

Pons

Answer

Medulla

Answer

Amygdala

Question 9

What is the blood supply of the spinal cord?

Accepted Answer

One anterior and two posterior spinal arteries

Answer

Two anterior and one posterior spinal arteries

Answer

Two anterior and two posterior spinal arteries

Answer

One anterior and one posterior spinal artery

Question 10

All of the following are supplied by the anterior cerebral artery except?

Accepted Answer

Broca's area

Answer

Anterior cerebrum

Answer

Medial cerebrum

Answer

Paracentral lobule

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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