Neuroanatomy — MCQs
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Which of the following is NOT true about Fanconi's anemia?
A person looking at a window at night becomes frightened, believing a shape resembling a man is present. Upon switching on the light, the shape is revealed to be the window covering. What phenomenon is described?
Which stain is used for Melanin?
Which of the following is NOT a derivative of the ventral mesogastrium?
Which of the following is NOT a feature of the occipital lobe of the brain?
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?
A round to oval cross-section of hair is typically found in which racial group?
By what age does a child typically recognize their own sex?
Which ventricle is represented by the diencephalon?
Russell bodies are accumulations of?
Neuroanatomy Indian Medical PG Practice Questions and MCQs
Question 661: Which of the following is NOT true about Fanconi's anemia?
- A. Defect in DNA repair
- B. Bone marrow hyperplasia (Correct Answer)
- C. Congenital anomaly present
- D. Increased chances of cancer
Explanation: **Explanation:** Fanconi’s Anemia (FA) is a rare, autosomal recessive (primarily) genetic disorder characterized by genomic instability. The correct answer is **Option B** because Fanconi’s anemia leads to **bone marrow hypoplasia (aplasia)**, not hyperplasia. 1. **Why Option B is correct:** FA is the most common cause of inherited **Aplastic Anemia**. The genetic defect leads to a progressive depletion of hematopoietic stem cells, resulting in pancytopenia. Therefore, the bone marrow appears hypocellular (fatty replacement) rather than hyperplastic. 2. **Why Option A is incorrect:** FA is fundamentally a **DNA repair defect**. It involves mutations in the FANC gene family, which are responsible for repairing DNA interstrand cross-links. 3. **Why Option C is incorrect:** Approximately 75% of patients have **congenital anomalies**. Classic signs include radial ray defects (absent/hypoplastic thumb or radius), short stature, microcephaly, and café-au-lait spots. 4. **Why Option D is incorrect:** Due to chromosomal instability, there is a significantly **increased risk of malignancies**, particularly Acute Myeloid Leukemia (AML) and squamous cell carcinomas (head, neck, and anogenital). **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Test:** Chromosomal breakage study using **Diepoxybutane (DEB)** or Mitomycin C (MMC). Cells show increased chromatid breaks. * **Physical Exam Triad:** Short stature + Thumb/Radial defects + Skin hyperpigmentation. * **Treatment:** Bone marrow transplant is the definitive treatment for hematologic complications.
Question 662: A person looking at a window at night becomes frightened, believing a shape resembling a man is present. Upon switching on the light, the shape is revealed to be the window covering. What phenomenon is described?
- A. Illusion (Correct Answer)
- B. Hallucination
- C. Emotion
- D. Loosening of association
Explanation: ### Explanation **Correct Answer: A. Illusion** **1. Why Illusion is Correct:** An **illusion** is defined as a **misinterpretation of a real external sensory stimulus**. In this scenario, there is an actual physical object present (the window covering), but the individual’s brain misinterprets the sensory input due to poor lighting and emotional state (fear), perceiving it as a man. This is a common phenomenon in both normal individuals and certain psychiatric or organic brain conditions (e.g., Delirium). **2. Why the Other Options are Incorrect:** * **B. Hallucination:** This is a sensory perception in the **absence of any external stimulus**. If the person saw a man standing in an empty room where no object existed at all, it would be a hallucination. * **C. Emotion:** This refers to a complex psychological state (e.g., fear, joy, anger). While fear influenced the person's perception in this case, the *phenomenon* of misinterpreting the object is a perceptual error, not an emotion itself. * **D. Loosening of Association:** This is a **disorder of the form of thought** (Formal Thought Disorder) commonly seen in Schizophrenia, where ideas shift from one subject to another in a completely unrelated way. It is not a perceptual disorder. **High-Yield Clinical Pearls for NEET-PG:** * **Pareidolia:** A type of illusion where vague stimuli (like clouds or craters on the moon) are perceived as significant forms (like faces). * **Hypnagogic vs. Hypnopompic:** Hallucinations occurring while falling asleep (Hypna**go**gic = **Go**ing to sleep) vs. waking up (Hypno**pom**pic = **Po**pping out of bed). * **Delirium:** Illusions are highly characteristic of Delirium (Acute Confusional State) due to clouded consciousness. * **Functional vs. Organic:** Hallucinations in psychiatric disorders (Functional) are usually auditory, whereas in organic brain syndromes (like tumors or seizures), they are often visual, olfactory, or gustatory.
Question 663: Which stain is used for Melanin?
- A. Oil red
- B. Gomori methamine silver stain
- C. Masson Fontana stain (Correct Answer)
- D. PAS stain
Explanation: The correct answer is **Masson Fontana stain**. This stain is based on the **argentaffin reaction**. Melanin is a reducing agent that can reduce silver nitrate to metallic silver without the need for an external reducing agent. When applied to tissue, the melanin granules appear black against a pink or red background. **Analysis of Options:** * **Masson Fontana (Correct):** Specifically used to demonstrate melanin and argentaffin granules (found in carcinoid tumors). * **Oil Red O:** This is a fat-soluble dye used to demonstrate **neutral lipids** and triglycerides in frozen sections. It is not used for pigments like melanin. * **Gomori Methenamine Silver (GMS):** While this also uses silver, it is primarily used to visualize **fungal elements** (like *Pneumocystis jirovecii*) and basement membranes. It requires an oxidation step (chromic acid) which is not the mechanism for melanin staining. * **PAS (Periodic Acid-Schiff):** Used to detect **glycogen**, mucopolysaccharides, and basement membranes. It stains these structures magenta. **High-Yield Clinical Pearls for NEET-PG:** * **Melanin Identification:** Apart from Masson Fontana, melanin can be identified by the **Schmorl’s reaction** (turns blue) and can be "bleached" using hydrogen peroxide or potassium permanganate. * **Dopa Reaction:** Used to identify the enzyme tyrosinase in melanocytes (useful in diagnosing albinism). * **IHC Markers:** For malignant melanoma, the most specific immunohistochemical markers are **S-100, HMB-45, and Melan-A**. * **Argentaffin vs. Argyrophil:** Argentaffin cells (like those containing melanin) can reduce silver themselves; Argyrophil cells require an external reducer.
Question 664: Which of the following is NOT a derivative of the ventral mesogastrium?
- A. Falciform ligament
- B. Coronary ligament
- C. Lesser omentum
- D. Gastrosplenic ligament (Correct Answer)
Explanation: ### Explanation The development of the peritoneal folds depends on their origin from either the **ventral mesogastrium** or the **dorsal mesogastrium**. The stomach is initially suspended in the midline by these two mesenteries. **1. Why Gastrosplenic Ligament is the Correct Answer:** The **Gastrosplenic ligament** is a derivative of the **dorsal mesogastrium**. During development, the spleen arises as a mesenchymal condensation within the dorsal mesogastrium. This divides the dorsal mesentery into two parts: the portion between the stomach and spleen (Gastrosplenic ligament) and the portion between the spleen and the posterior abdominal wall (Lienorenal/Splenorenal ligament). **2. Why the Other Options are Incorrect:** The ventral mesogastrium exists only in the upper abdomen (above the umbilicus) and is divided into two main parts by the development of the **liver** [1]: * **Lesser Omentum (Option C):** Formed from the part of the ventral mesogastrium connecting the stomach/duodenum to the liver (Hepatogastric and Hepatoduodenal ligaments) [1]. * **Falciform Ligament (Option A):** Formed from the part connecting the liver to the anterior abdominal wall [1]. * **Coronary Ligament (Option B):** Formed by the reflection of the ventral mesogastrium from the liver onto the diaphragm [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Ventral Mesogastrium Derivatives:** Falciform ligament, Lesser omentum, Coronary ligaments, and Triangular ligaments of the liver [1]. * **Dorsal Mesogastrium Derivatives:** Greater omentum, Gastrosplenic ligament, Lienorenal ligament, and the Mesentery of the small intestine. * **The Vagus Nerve:** The left vagus nerve supplies the anterior surface of the stomach, while the right vagus supplies the posterior surface, due to the 90-degree clockwise rotation of the stomach during development [2].
Question 665: Which of the following is NOT a feature of the occipital lobe of the brain?
- A. Visual cortex lies in relation to the calcarine fissure.
- B. Brodmann's area 17 corresponds to the visual cortex.
- C. Geniculocalcarine fibres from the medial half of the lateral geniculate terminate on the superior lip of the calcarine fissure.
- D. It is the only area in the brain activated by visual stimuli. (Correct Answer)
Explanation: ### Explanation **Why Option D is the correct answer:** The statement is incorrect because visual processing is not restricted solely to the occipital lobe. While the primary visual cortex (V1) is located there, visual information is transmitted via two major pathways to other lobes: the **Dorsal Stream** (the "Where" pathway) to the **parietal lobe** for spatial awareness, and the **Ventral Stream** (the "What" pathway) to the **temporal lobe** for object recognition [3]. Additionally, subcortical structures like the superior colliculus and pretectal nucleus also process visual stimuli [2]. **Analysis of Incorrect Options:** * **Option A:** The primary visual cortex is indeed located on the medial surface of the occipital lobe, buried within the walls of the **calcarine fissure** [1]. * **Option B:** **Brodmann’s area 17** is the histological designation for the primary visual cortex (striate cortex). Areas 18 and 19 represent the visual association areas. * **Option C:** The lateral geniculate body (LGB) maintains a precise retinotopic map. Fibers from the **medial half** of the LGB (representing the superior retinal quadrants/inferior visual field) terminate on the **superior lip** of the calcarine fissure [1]. Conversely, the lateral half (Meyer’s loop) terminates on the inferior lip. **High-Yield Clinical Pearls for NEET-PG:** * **Macular Sparing:** Lesions of the occipital lobe (e.g., PCA stroke) often result in contralateral homonymous hemianopia with macular sparing due to the dual blood supply (PCA and MCA) to the occipital pole [1]. * **Meyer’s Loop:** Fibers representing the superior visual field loop through the temporal lobe; a lesion here causes "pie in the sky" (superior quadrantanopia). * **Anton’s Syndrome:** A condition where a patient with cortical blindness (bilateral occipital lobe damage) denies their blindness (confabulation).
Question 666: 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?
- A. Parietal
- B. Temporal (Correct Answer)
- C. Occipital
- D. Frontal
Explanation: **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. **
Question 667: A round to oval cross-section of hair is typically found in which racial group?
- A. Negroid
- B. Mongoloid
- C. Caucasoid (Correct Answer)
- D. All of the above
Explanation: The cross-sectional shape of a hair shaft is a key anthropometric and forensic indicator used to differentiate between racial groups. This shape is primarily determined by the geometry of the hair follicle. **1. Why Caucasoid is correct:** In individuals of **Caucasoid** (European) descent, the hair follicle is typically straight or slightly curved, resulting in a hair shaft that is **round to oval** in cross-section. This shape allows the hair to be straight, wavy, or curly, with a medium diameter and an even distribution of pigment granules. **2. Why the other options are incorrect:** * **Negroid (African):** The hair follicles are often spiraled or "kidney-shaped." This produces a **flat, elliptical, or ribbon-like** cross-section. This structural asymmetry causes the hair to be tightly coiled or kinky. * **Mongoloid (Asian):** The follicles are perfectly circular and oriented perpendicular to the scalp. This results in a **large, circular (round)** cross-section. Mongoloid hair is typically the thickest and straightest among the three groups. **High-Yield Clinical Pearls for NEET-PG:** * **Medullary Index:** In humans, the medulla (the innermost layer of hair) is generally narrow, occupying less than one-third of the shaft diameter. In animals, it is usually wider (more than half). * **Growth Phase:** The **Anagen** phase is the active growth phase (80-90% of scalp hair), while **Telogen** is the resting phase. * **Forensic Significance:** Hair cross-section is a classic "Forensic Medicine" topic often integrated with Anatomy. Remember: **Round = Mongoloid; Oval = Caucasoid; Flat/Elliptical = Negroid.**
Question 668: By what age does a child typically recognize their own sex?
- A. 2 years
- B. 3 years (Correct Answer)
- C. 4 years
- D. 5 years
Explanation: **Explanation:** The development of gender identity is a significant milestone in pediatric neurodevelopment and psychology. By the age of **3 years**, most children can consistently identify themselves as a boy or a girl. This is known as **Gender Identity**, the internal sense of being male, female, or another gender. * **Why 3 years is correct:** According to Kohlberg’s stages of gender development and standard pediatric milestones (often tested in both Anatomy/Neuroanatomy and Pediatrics), children begin to categorize themselves and others by gender around age 2, but it is by age 3 that they can clearly verbalize and recognize their own sex. * **A. 2 years:** At this age, children are beginning to become aware of physical differences between sexes and can point to "boys" or "girls" in pictures, but their own self-identity is not yet firmly established or consistently verbalized. * **C. 4 years:** By this age, gender identity is well-established. Waiting until age 4 to recognize one's sex would be considered a slight delay in typical social-cognitive development. * **D. 5 years:** By age 5 to 7, children reach **Gender Constancy**—the understanding that sex remains the same regardless of external changes like clothing, hair length, or activities. **High-Yield Clinical Pearls for NEET-PG:** * **Gender Identity (3 years):** Ability to label oneself correctly. * **Gender Stability (4 years):** Understanding that they will grow up to be a man or a woman. * **Gender Constancy (5–7 years):** Understanding that gender is a permanent biological trait. * **Clinical Correlation:** Delays in reaching these milestones or significant gender dysphoria may be evaluated during routine pediatric developmental screenings.
Question 669: Which ventricle is represented by the diencephalon?
- A. Lateral ventricle
- B. 3rd ventricle (Correct Answer)
- C. 4th ventricle
- D. Cerebral aqueduct
Explanation: 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.
Question 670: Russell bodies are accumulations of?
- A. Cholesterol
- B. Lipoprotein (Correct Answer)
- C. Immunoglobulin
- D. Phospholipid
Explanation: The correct answer is **B. Lipoprotein**. [1] In the context of **Neuroanatomy**, Russell bodies (also known as **Russell’s bodies of the cerebellum**) are small, eosinophilic, refractile granules found within the cytoplasm of the **Purkinje cells** of the cerebellum. These bodies are histologically identified as accumulations of **lipoproteins**. They are considered a normal physiological feature or a sign of aging in the cerebellar cortex and should not be confused with pathological inclusions. [1] **Analysis of Options:** * **A. Cholesterol:** While cholesterol is a component of neural membranes, it does not form the discrete cytoplasmic inclusions known as Russell bodies in the cerebellum. * **C. Immunoglobulin:** This is a common **distractor**. In **General Pathology**, "Russell bodies" refer to eosinophilic inclusions of condensed **immunoglobulins** found in the rough endoplasmic reticulum of plasma cells (seen in chronic inflammation or Multiple Myeloma). However, in the specific context of **Neuroanatomy/Neurohistology**, they refer to the lipoprotein granules in Purkinje cells. * **D. Phospholipid:** Although lipoproteins contain phospholipids, the specific histological classification for these cerebellar inclusions is lipoprotein. **Clinical Pearls for NEET-PG:** * **Purkinje Cells:** These are the only output cells of the cerebellar cortex and are inhibitory (GABAergic). * **Confusing Terminology:** Always check the context of the question. If the question refers to **Plasma cells/Inflammation**, the answer is **Immunoglobulin**. If it refers to **Neuroanatomy/Purkinje cells**, the answer is **Lipoprotein**. * **Negri Bodies:** Another high-yield cerebellar inclusion, but these are viral (Rabies) and found in the cytoplasm of Purkinje cells.
Practice by Chapter
Organization of the Nervous System
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Spinal Cord Anatomy
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Brainstem Anatomy
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Cerebellum
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Diencephalon
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Cerebral Cortex
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Basal Ganglia
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Limbic System
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Cranial Nerves
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Autonomic Nervous System
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Neural Pathways and Tracts
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Neurovascular Anatomy
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