Neuroanatomy Practice Questions

Q: All of the following are true about Broca's aphasia except?

Repetition is preserved.. **Explanation:** Broca’s aphasia (Motor or Expressive aphasia) results from damage to **Broca’s area (Brodmann areas 44 and 45)**, located in the posterior part of the inferior frontal gyrus of the dominant hemisphere. **Why "Repetition is preserved" is the correct answer (the false statement):** In Broca’s aphasia, **repetition is significantly impaired**. Repetition requires an intact connection between the receptive (Wernicke’s) and expressive (Broca’s) areas via the arcuate fasciculus, as well as the functional integrity of both areas. Since the motor production of speech is damaged in Broca’s, the patient cannot repeat phrases spoken to them [1]. *Note: If repetition were preserved in a patient with non-fluent speech, the diagnosis would be Transcortical Motor Aphasia.* **Analysis of other options:** * **A. Lesion lies in the frontal lobe:** This is true. Broca’s area is situated in the **inferior frontal gyrus** [1]. * **B. Fluency is impaired:** This is true. It is a **non-fluent** aphasia characterized by "telegraphic speech," slow output, and great effort. * **C. Neologisms are absent:** This is true. Neologisms (creating new, meaningless words) are a hallmark of **Wernicke’s (fluent) aphasia**. Broca’s patients struggle to produce words but generally use existing ones (though often nouns/verbs only). **NEET-PG High-Yield Pearls:** * **Blood Supply:** Broca’s area is supplied by the **superior division of the Middle Cerebral Artery (MCA)**. * **Comprehension:** Remains **intact** (patients are often frustrated because they are aware of their deficit). * **Associated Deficit:** Often accompanied by **contralateral hemiparesis** (due to proximity to the motor cortex) [1]. * **Mnemonic:** **B**roca’s = **B**roken speech (non-fluent).

Q: What is the primary function of microglia in the Central Nervous System?

Phagocytosis. **Explanation:** **Microglia** are the resident macrophages of the Central Nervous System (CNS) [1]. Unlike other glial cells (astrocytes, oligodendrocytes) which are ectodermal in origin, microglia are derived from **mesoderm** (specifically yolk sac macrophages) [1]. **1. Why Phagocytosis is Correct:** Microglia act as the primary immune defense in the brain and spinal cord [1]. When they detect cellular debris, damaged neurons, or infectious agents, they transition from a "resting" (ramified) state to an "activated" (amoeboid) state [2]. In this active form, they perform **phagocytosis**, clearing pathogens and necrotic tissue, and secreting inflammatory cytokines [1]. **2. Why Other Options are Incorrect:** * **Myelin synthesis:** This is the function of **Oligodendrocytes** in the CNS and **Schwann cells** in the Peripheral Nervous System (PNS) [1][2]. * **Fibrosis:** In the CNS, traditional fibrosis (collagen scarring) is rare. Instead, "glial scarring" or **gliosis** is performed primarily by **Astrocytes**, which proliferate and hypertrophy in response to injury. **3. High-Yield Clinical Pearls for NEET-PG:** * **Origin:** Microglia are the only glial cells of **mesodermal origin** (High-yield MCQ) [1]. * **HIV Pathology:** Microglia are the primary targets of HIV in the brain. They fuse to form **Multinucleated Giant Cells**, a pathognomonic finding in HIV-associated dementia [1]. * **Staining:** They can be identified using silver stains (e.g., Rio-Hortega method). * **Gitter Cells:** These are heavily granulated, lipid-laden activated microglia found at the site of liquefactive necrosis in brain infarcts.

Q: What is the root value of the cremasteric reflex?

L1-L2. The **cremasteric reflex** is a superficial reflex elicited by lightly stroking the superior and medial aspect of the thigh. The normal response is the contraction of the cremaster muscle, which pulls the testis ipsilaterally toward the inguinal canal. ### **Explanation of the Correct Answer** The reflex arc involves the following components: * **Afferent Limb:** The **femoral branch of the genitofemoral nerve** (and the ilioinguinal nerve, L1) carries the sensory stimulus to the spinal cord. * **Center:** Spinal segments **L1 and L2**. * **Efferent Limb:** The **genital branch of the genitofemoral nerve** (L1, L2) carries the motor signal to the cremaster muscle [1]. Because both the sensory input and motor output are mediated primarily by the L1 and L2 spinal nerves, **L1-L2** is the definitive root value. ### **Analysis of Incorrect Options** * **L2-L3:** While L2 is involved, L3 is primarily associated with the Patellar (Knee-jerk) reflex (L2-L4). * **S1-S2:** These roots are associated with the **Ankle-jerk reflex** (Achilles reflex). * **L4-L5:** These segments are involved in foot dorsiflexion and the Patellar reflex, but do not contribute to the cremasteric reflex arc. ### **Clinical Pearls for NEET-PG** * **Upper Motor Neuron (UMN) vs. Lower Motor Neuron (LMN):** The cremasteric reflex is absent in both UMN and LMN lesions. * **Testicular Torsion:** This reflex is characteristically **absent** in cases of testicular torsion, making it a vital clinical tool to differentiate torsion from epididymitis (where the reflex is usually preserved). * **L1 Nerve Root:** If a question asks for a single most important root, **L1** is the primary segment.

Q: Which of the following statements about Horseshoe kidney is true?

Fused at the lower pole and lies in front of L4.. **Explanation:** **1. Why Option D is Correct:** Horseshoe kidney is the most common renal fusion anomaly. In 90% of cases, the kidneys are **fused at the lower poles** by an isthmus of renal or fibrous tissue. During embryological development, the kidneys normally ascend from the pelvis to the lumbar region. However, in a horseshoe kidney, the central isthmus gets trapped under the **Inferior Mesenteric Artery (IMA)**, which arises from the aorta at the level of **L3**. Consequently, the kidney is arrested in its ascent and typically lies at the level of **L4-L5**, anterior to the lower lumbar vertebrae. **2. Why Other Options are Incorrect:** * **Options A & C:** Fusion at the upper pole is extremely rare (less than 10%). The standard presentation involves lower pole fusion. * **Options B & C:** While the kidney is lower than normal, it does not remain "in the pelvis" (which would be a pelvic kidney); it ascends until it hits the IMA. The level of L1 is the normal anatomical position of the renal hilum, which a horseshoe kidney cannot reach due to the IMA obstruction. **3. High-Yield Clinical Pearls for NEET-PG:** * **Vascular Obstruction:** The **Inferior Mesenteric Artery** is the key structure that prevents the ascent. * **Ureteric Course:** Ureters pass **anterior** to the isthmus, often leading to urinary stasis and an increased risk of **stones (nephrolithiasis)** and infections. [1] * **Associated Risks:** Increased incidence of **Renal Pelvis Tumors** (Transitional Cell Carcinoma) and **Wilms tumor** in children. * **Radiology:** On an IVP (Intravenous Pyelogram), look for the **"Handshaking sign"** or reversed "Flower vase" appearance of the calyces.

Q: What is the primary treatment for influenza?

Oseltamivir. **Explanation:** Influenza is caused by the Influenza A and B viruses. The primary treatment strategy involves inhibiting the viral enzyme **Neuraminidase**, which is essential for releasing newly formed viral particles from the host cell membrane. **Why Oseltamivir is Correct:** **Oseltamivir** (Tamiflu) is a potent Neuraminidase inhibitor. By blocking this enzyme, it prevents the cleavage of sialic acid receptors, thereby trapping the virus within the infected cell and limiting its spread to adjacent respiratory epithelial cells. It is effective against both Influenza A and B and is the drug of choice when administered within 48 hours of symptom onset. **Analysis of Incorrect Options:** * **Amantadine:** This is an M2 ion channel blocker that prevents viral uncoating. It is only active against Influenza A. However, due to widespread resistance (>99% of circulating strains), it is no longer recommended for primary treatment. * **Ribavirin:** A guanosine analog used primarily for Hepatitis C (in combination) and Respiratory Syncytial Virus (RSV) in severe pediatric cases. It is not the standard treatment for influenza. * **Cidofovir:** A DNA polymerase inhibitor used primarily for Cytomegalovirus (CMV) retinitis in HIV patients and occasionally for severe adenovirus or poxvirus infections. It has no activity against the RNA-based influenza virus. **High-Yield Clinical Pearls for NEET-PG:** * **Zanamivir:** Another neuraminidase inhibitor; administered via inhalation (avoid in asthmatics due to risk of bronchospasm). * **Baloxavir Marboxil:** A newer agent that inhibits the "cap-snatching" endonuclease activity of the viral RNA polymerase. * **Chemoprophylaxis:** Oseltamivir can be used for post-exposure prophylaxis in high-risk individuals.

Q: The appendix of the testis arises from which embryonic structure?

Paramesonephric duct. **Explanation:** The **Appendix of the Testis** (Hydatid of Morgagni) is a small, sessile vestigial remnant located at the upper pole of the testis. It is the cranial remnant of the **Paramesonephric duct (Müllerian duct)** in males. In females, the paramesonephric ducts develop into the fallopian tubes, uterus, and upper part of the vagina; however, in males, the secretion of Anti-Müllerian Hormone (AMH) by Sertoli cells causes these ducts to regress, leaving behind only the appendix testis and the prostatic utricle. **Analysis of Options:** * **A. Mesonephric duct (Wolffian duct):** In males, this duct forms the epididymis, vas deferens, seminal vesicles, and ejaculatory ducts. Its vestigial remnant in males is the **Appendix of the Epididymis**. * **C. Mesonephric tubules:** These give rise to the efferent ductules of the testis. Vestigial remnants include the **paradidymis** (Organ of Giraldés). * **D. Genital Tubercle:** This is a precursor of the external genitalia, forming the glans penis in males and the glans clitoris in females. **High-Yield Clinical Pearls for NEET-PG:** * **Torsion of the Appendix Testis:** This is a common cause of acute scrotum in prepubertal boys. It presents with a pathognomonic **"Blue Dot Sign"** (a blue-colored nodule visible through the scrotal skin). * **Prostatic Utricle:** This is the other significant male remnant of the Paramesonephric duct, often referred to as the "male uterus." * **Gartner’s Duct:** The female remnant of the Mesonephric duct (found in the broad ligament/vaginal wall).

Q: What does Grade 1 lymphedema signify?

Edema that disappears after overnight rest. Lymphedema is classified based on the severity of lymphatic dysfunction and the resulting tissue changes. The grading system (often referred to as the **International Society of Lymphology (ISL) Stages**) is a high-yield topic for NEET-PG. ### **Explanation of the Correct Answer** **Grade 1 (Stage I) Lymphedema** is characterized by **reversible edema**. At this stage, the protein-rich fluid has accumulated, but there is no significant tissue fibrosis. The hallmark of this stage is that the swelling is **pitting** in nature and, most importantly, **disappears or significantly reduces with limb elevation or overnight rest**. ### **Analysis of Incorrect Options** * **Options A & B (Pitting up to ankle/knee):** These describe the *anatomical extent* of edema rather than the *grade*. Grading is determined by the pathophysiology of the tissue (reversibility and fibrosis) rather than just the height of the swelling. * **Option C (Non-pitting edema):** This signifies **Grade 2 (Stage II)** or **Grade 3 (Stage III)** [1]. In these later stages, chronic inflammation leads to the deposition of connective tissue and fat (fibrosis). Because the tissue becomes "hardened," it no longer pits when pressure is applied [1]. ### **Clinical Pearls for NEET-PG** * **Stage 0 (Latent):** Impaired lymph transport exists, but no visible edema is present. * **Stage I (Spontaneously Reversible):** Pitting edema; subsides with elevation [2]. * **Stage II (Spontaneously Irreversible):** Non-pitting edema; significant fibrosis; does not resolve with elevation [1][2]. * **Stage III (Lymphostatic Elephantiasis):** Severe non-pitting edema with trophic skin changes (acanthosis, warty overgrowths, and thickening) [1]. * **Stemmer’s Sign:** Inability to pinch the skin on the dorsal surface of the base of the second toe. A positive sign is diagnostic of lymphedema.

Question 1

The hippocampal formation is part of the______ lobe?

Accepted Answer

Limbic

Answer

Frontal

Answer

Insular

Answer

Occipital

Question 2

All of the following are true about Broca's aphasia except?

Accepted Answer

Repetition is preserved.

Answer

Lesion lies in the frontal lobe.

Answer

Fluency is impaired.

Answer

Neologisms are absent.

Question 3

What is the primary function of microglia in the Central Nervous System?

Accepted Answer

Phagocytosis

Answer

Myelin synthesis

Answer

Fibrosis

Answer

All of the above

Question 4

What is the root value of the cremasteric reflex?

Accepted Answer

L1-L2

Answer

L2-L3

Answer

S1-S2

Answer

L4-L5

Question 5

A patient has an invasive tumor in the cavernous sinus. Which of the following signs is NOT typically present in such a patient?

Accepted Answer

Weakness in screwing the eyes up tightly

Answer

A dilated pupil

Answer

A drooping eyelid

Answer

A deviated eye looking down and laterally

Question 6

Which of the following statements about Horseshoe kidney is true?

Accepted Answer

Fused at the lower pole and lies in front of L4.

Answer

Fused at the upper pole and lies in the pelvis.

Answer

Fused at the lower pole and lies in the pelvis.

Answer

Fused at the upper pole and lies in front of L1.

Question 7

What does the Node of Ranvier represent?

Accepted Answer

A gap between two adjacent Schwann cells.

Answer

An indentation of a Schwann cell due to the synapsing of an adjacent unipolar neuron.

Answer

Gaps between dendrites and Schwann cells.

Answer

Gaps between the Schwann cell and the axon.

Question 8

What is the primary treatment for influenza?

Accepted Answer

Oseltamivir

Answer

Amantidine

Answer

Ribavirin

Answer

Cidofovir

Question 9

The appendix of the testis arises from which embryonic structure?

Accepted Answer

Paramesonephric duct

Answer

Mesonephric duct

Answer

Mesonephric tubule

Answer

Genital Tubercle

Question 10

What does Grade 1 lymphedema signify?

Accepted Answer

Edema that disappears after overnight rest

Answer

Pitting edema up to the ankle

Answer

Pitting edema up to the knee

Answer

Non-pitting edema

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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