Neuroanatomy — MCQs

A 40-year-old man presents with a several-month history of chronic cough and fever. Radiography reveals a diffuse reticulonodular pattern. Microscopically, a transbronchial biopsy shows focal areas of inflammation containing epithelioid cell granulomas, Langerhans cells, and lymphocytes. These findings are typically indicative of which of the following types of hypersensitivity immunological responses?

Q1536Medium

Which of the following does not occur at the level of the C6 vertebra?

Q1537Easy

Cerebellar connections to other parts of the brain are projected through which type of cell?

Q1538Easy

Which of the following is NOT included in the cerebellar nuclei?

Q1539Easy

White infarcts are seen in which of the following organs?

Q1540Easy

The floor of the body of the lateral ventricle is formed by which structure?

Neuroanatomy Indian Medical PG Practice Questions and MCQs

Question 1531: All of the following are features of ischemia in the anterior choroidal artery territory except?

A. Hemiparesis
B. Hemisensory loss
C. Homonymous hemianopia
D. Predominant involvement of the anterior limb of the internal capsule (Correct Answer)

Explanation: The **Anterior Choroidal Artery (AChA)** is a small but vital branch of the internal carotid artery. It supplies critical structures in the subcortical region, and its occlusion typically presents with the **"Classic Triple H" syndrome**: Hemiparesis, Hemisensory loss, and Hemianopia. ### Why Option D is the Correct Answer The AChA supplies the **posterior limb of the internal capsule (PLIC)**, not the anterior limb. The anterior limb is primarily supplied by the Medial Striate artery (Heubner’s artery) and branches of the Middle Cerebral Artery (MCA). Therefore, predominant involvement of the anterior limb is not a feature of AChA ischemia. ### Explanation of Incorrect Options * **A. Hemiparesis:** The AChA supplies the posterior limb of the internal capsule, which contains the **corticospinal tract**. Ischemia leads to contralateral motor weakness. * **B. Hemisensory loss:** The artery supplies the **ventroposterolateral (VPL) nucleus** of the thalamus and the sensory fibers in the PLIC, leading to contralateral sensory deficits. * **C. Homonymous hemianopia:** The AChA supplies the **lateral geniculate body (LGB)** and the beginning of the optic radiations. Ischemia results in a contralateral visual field defect (often involving the upper and lower quadrants but sparing the horizontal sector). ### High-Yield Clinical Pearls for NEET-PG * **Origin:** It is a branch of the **Internal Carotid Artery (ICA)**, arising just distal to the posterior communicating artery. * **Supply Summary:** Posterior limb of the internal capsule, Lateral Geniculate Body, Hippocampus, and Choroid plexus of the lateral ventricle. * **The "Triple H" Mnemonic:** **H**emiparesis, **H**emisensory loss, and **H**omonymous hemianopia. * **Distinction:** Unlike MCA strokes, AChA strokes are often "lacunar-like" but involve all three modalities (motor, sensory, and visual) simultaneously.

Question 1532: Which part of the brain is supplied by the anterior cerebral artery?

A. Anterior
B. Lateral
C. Medial (Correct Answer)
D. Posterior

Explanation: The **Anterior Cerebral Artery (ACA)** is a terminal branch of the Internal Carotid Artery. Its primary territory includes the **medial surface** of the cerebral hemispheres, extending from the frontal pole to the parieto-occipital sulcus. [1] ### Why the Correct Answer is Right: * **Medial Surface:** The ACA travels in the longitudinal fissure and curves around the corpus callosum. It supplies the medial aspect of the frontal and parietal lobes, including the **motor and sensory cortex for the lower limb** (paracentral lobule). ### Why the Other Options are Wrong: * **Lateral Surface:** This is primarily supplied by the **Middle Cerebral Artery (MCA)**. The MCA covers the majority of the lateral convexity, including the motor/sensory areas for the face and upper limbs, and the speech areas (Broca’s and Wernicke’s). * **Posterior Surface:** The posterior part of the brain (occipital lobe) and the inferior surface of the temporal lobe are supplied by the **Posterior Cerebral Artery (PCA)**. [1] * **Anterior:** While the name "Anterior" Cerebral Artery suggests an anterior location, in neuroanatomical terms, the blood supply is defined by the **surfaces** (Medial vs. Lateral) rather than just the pole. ### High-Yield Clinical Pearls for NEET-PG: 1. **Stroke Presentation:** An ACA infarct typically presents with **contralateral hemiparesis and hemisensory loss**, specifically affecting the **leg and foot** more than the arm and face. 2. **Frontal Lobe Signs:** ACA occlusion can lead to personality changes, urinary incontinence, and "Gait Apraxia" due to involvement of the prefrontal cortex and paracentral lobule. 3. **Circle of Willis:** The two ACAs are connected by the **Anterior Communicating Artery**, which is the most common site for **Berry Aneurysms**.

Question 1533: Which of the following is not a labile cell?

A. Bone marrow
B. Epidermal cells
C. Small intestine mucosa
D. Hepatocytes (Correct Answer)

Explanation: ### Explanation The classification of cells based on their regenerative capacity (Labile, Stable, and Permanent) is a fundamental concept in pathology and neuroanatomy. **1. Why Hepatocytes is the Correct Answer:** Hepatocytes are classified as **Stable (Quiescent) cells**. These cells are normally in the $G_0$ phase of the cell cycle and have a low level of replication. However, they retain the ability to rapidly enter the cell cycle ($G_1$ phase) in response to stimuli, such as a partial hepatectomy or chemical injury. Because they are not "continuously" dividing under normal physiological conditions, they are not labile cells. [1] **2. Why the Other Options are Incorrect:** **Labile (Continuously Dividing) cells** are those that follow the "die and replace" rule. They are constantly being lost and replaced by maturation from stem cells and by proliferation of mature cells. * **Bone Marrow (Option A):** Hematopoietic cells in the bone marrow are classic labile cells, constantly producing new blood cells to replace those that have reached the end of their lifespan. * **Epidermal Cells (Option B):** The stratified squamous epithelium of the skin is a labile tissue that undergoes constant desquamation and renewal. [2] * **Small Intestine Mucosa (Option C):** The columnar epithelium of the gastrointestinal tract has one of the highest turnover rates in the human body, making it a labile tissue. [3] **3. High-Yield Clinical Pearls for NEET-PG:** * **Permanent Cells:** These cells have left the cell cycle and cannot undergo division (e.g., **Neurons**, Cardiac myocytes, and Skeletal muscle). Injury to these tissues results in scarring (fibrosis), not regeneration. * **Stable Cells:** Besides hepatocytes, other examples include proximal renal tubular cells, pancreatic acinar cells, and mesenchymal cells (fibroblasts/smooth muscle). * **Cell Cycle Phase:** Labile cells are always in the cycle; Stable cells are in $G_0$ but can be recruited; Permanent cells have permanently exited the cycle.

Question 1534: Which nerve pierces the thyroid gland?

A. Superior laryngeal nerve
B. Inferior laryngeal nerve
C. Recurrent laryngeal nerve (Correct Answer)
D. Posterior laryngeal nerve

Explanation: The **Recurrent Laryngeal Nerve (RLN)** is the correct answer because of its intimate anatomical relationship with the thyroid gland and the inferior thyroid artery. As the RLN ascends in or near the tracheoesophageal groove, it passes deep to the pretracheal fascia [1]. Before entering the larynx behind the cricothyroid joint, it frequently passes through the **suspensory ligament of Berry** (which connects the thyroid gland to the trachea) [2]. In many individuals, the nerve may actually pierce the posterior part of the thyroid gland's capsule or be embedded within the glandular tissue itself, making it highly vulnerable during thyroidectomy [1]. **Analysis of Incorrect Options:** * **Superior Laryngeal Nerve (SLN):** This nerve divides into internal and external branches. The internal branch pierces the thyrohyoid membrane, and the external branch supplies the cricothyroid muscle [3]. Neither branch pierces the thyroid gland. * **Inferior Laryngeal Nerve:** This is simply the terminal continuation of the Recurrent Laryngeal Nerve after it passes the lower border of the inferior constrictor muscle. While technically the same nerve, "Recurrent Laryngeal Nerve" is the standard anatomical term for the segment related to the gland. * **Posterior Laryngeal Nerve:** This is not a standard anatomical term in human neuroanatomy regarding the thyroid region. **NEET-PG High-Yield Pearls:** 1. **Ligament of Berry:** The RLN is most commonly injured here during surgery [2]. 2. **Arterial Relation:** The RLN is closely related to the **Inferior Thyroid Artery**, while the External Laryngeal Nerve is related to the **Superior Thyroid Artery** [1, 4]. 3. **Function:** The RLN supplies all intrinsic muscles of the larynx *except* the cricothyroid (supplied by the External Laryngeal Nerve). 4. **Injury:** Unilateral RLN injury causes hoarseness; bilateral injury causes stridor and airway emergency.

Question 1535: A 40-year-old man presents with a several-month history of chronic cough and fever. Radiography reveals a diffuse reticulonodular pattern. Microscopically, a transbronchial biopsy shows focal areas of inflammation containing epithelioid cell granulomas, Langerhans cells, and lymphocytes. These findings are typically indicative of which of the following types of hypersensitivity immunological responses?

A. Type I
B. Type II
C. Type III
D. Type IV (Correct Answer)

Explanation: **Explanation:** The clinical presentation of chronic cough, fever, and reticulonodular patterns, combined with the histological finding of **epithelioid cell granulomas** and **Langhans giant cells**, is a classic description of **Tuberculosis** or **Sarcoidosis**. These conditions are mediated by a **Type IV (Delayed-type) Hypersensitivity reaction**. **Why Type IV is Correct:** Type IV hypersensitivity is a cell-mediated immune response (not antibody-mediated). It involves **CD4+ T-lymphocytes (Th1 cells)** which, upon encountering an antigen, release cytokines like IFN-γ. This activates macrophages, transforming them into **epithelioid cells**. These cells can fuse to form **Langhans giant cells**, ultimately resulting in the formation of a granuloma to sequester the indigestible antigen. **Why Other Options are Incorrect:** * **Type I (Immediate):** Mediated by IgE and mast cell degranulation (e.g., Anaphylaxis, Asthma). It does not form granulomas. * **Type II (Antibody-mediated):** Involves IgG/IgM binding to fixed cell-surface antigens, leading to complement activation or ADCC (e.g., Rheumatic fever, Goodpasture syndrome). * **Type III (Immune-complex):** Caused by the deposition of antigen-antibody complexes in tissues, leading to neutrophil recruitment (e.g., SLE, Post-streptococcal glomerulonephritis). **High-Yield NEET-PG Pearls:** * **Granuloma Components:** Epithelioid cells (modified macrophages), lymphocytes, and giant cells (Langhans type in TB; Foreign body type in non-immunological reactions). * **Key Cytokine:** **IFN-γ** is the most critical cytokine for macrophage activation in Type IV reactions. * **Classic Examples:** Mantoux test (PPD), Contact dermatitis, and chronic infections like Leprosy and Tuberculosis.

Question 1536: Which of the following does not occur at the level of the C6 vertebra?

A. The trachea bifurcates. (Correct Answer)
B. The pharynx ends.
C. The esophagus begins.
D. The larynx ends.

Explanation: The **C6 vertebra** is a critical anatomical landmark in the neck, representing the transition point between several respiratory and gastrointestinal structures. ### 1. Why the Correct Answer is Right **Option A: The trachea bifurcates.** The trachea begins at the lower border of the cricoid cartilage (C6) but does **not** bifurcate there. Tracheal bifurcation (the carina) occurs at the level of the **T4-T5 vertebrae** (the Sternal Angle of Louis). In a living subject in the erect position, this bifurcation can descend as low as T6 due to gravity and respiration. ### 2. Analysis of Incorrect Options (Events at C6) The following events occur at the level of the lower border of the cricoid cartilage, which corresponds to the **C6 vertebra**: * **Option B & C: The pharynx ends and the esophagus begins.** The muscular tube of the pharynx transitions into the esophagus at this level. This is also the site of the cricopharyngeal sphincter (the narrowest part of the esophagus). * **Option D: The larynx ends.** The larynx transitions into the trachea at the lower border of the C6 vertebra. ### 3. High-Yield Clinical Pearls for NEET-PG * **Palpation:** The **Carotid Tubercle** (Chassaignac’s tubercle) is the prominent anterior tubercle of the transverse process of C6. It is used as a landmark to compress the carotid artery to control bleeding. * **Middle Cervical Ganglion:** Located at the level of C6. * **Vertebral Artery:** Usually enters the foramen transversarium at the level of **C6** (not C7). * **Omohyoid:** The intermediate tendon of the omohyoid muscle crosses the carotid sheath at the level of C6.

Question 1537: Cerebellar connections to other parts of the brain are projected through which type of cell?

A. Golgi cells
B. Basket cells
C. Purkinje cells (Correct Answer)
D. Oligodendrocytes

Explanation: ### Explanation The cerebellum functions as a major coordination center, receiving vast sensory input and sending out motor corrections. The key to understanding its circuitry lies in identifying the **sole output** of the cerebellar cortex. **Why Purkinje Cells are Correct:** Purkinje cells are the functional units of the cerebellar cortex [1]. They are large, flask-shaped neurons located in the middle layer of the cortex. Crucially, they represent the **only cells whose axons leave the cerebellar cortex** [1]. These axons project primarily to the **Deep Cerebellar Nuclei** (Dentate, Emboliform, Globose, and Fastigial) and occasionally directly to the vestibular nuclei. From these nuclei, information is projected to the thalamus, red nucleus, and brainstem, thereby connecting the cerebellum to the rest of the brain [2]. These projections are **inhibitory (GABAergic)** in nature [1]. **Why Other Options are Incorrect:** * **Golgi cells:** These are inhibitory interneurons located in the granular layer. They function within a local feedback loop to inhibit granule cells; they do not project outside the cerebellum [1]. * **Basket cells:** These are inhibitory interneurons in the molecular layer that provide lateral inhibition to Purkinje cells [1]. Their influence is strictly local. * **Oligodendrocytes:** These are non-neuronal glial cells responsible for myelinating axons in the Central Nervous System (CNS). They do not transmit neural signals or form projections. **High-Yield Clinical Pearls for NEET-PG:** * **All cells** in the cerebellar cortex are inhibitory (GABAergic) **except Granule cells**, which are excitatory (Glutamatergic) [1]. * **Afferent inputs** to the cerebellum are of two types: **Climbing fibers** (from Inferior Olivary Nucleus) and **Mossy fibers** (from all other sources) [1]. * **Clinical Sign:** Damage to Purkinje cells or their projections leads to **ipsilateral** cerebellar ataxia, dysmetria, and intention tremors.

Question 1538: Which of the following is NOT included in the cerebellar nuclei?

A. Dentate nuclei
B. Emboliform nuclei
C. Fastigial nuclei
D. Caudate nuclei (Correct Answer)

Explanation: The cerebellum contains four pairs of deep nuclei embedded within its white matter. These nuclei are the primary output centers of the cerebellum. **Why Caudate Nucleus is the correct answer:** The **Caudate nucleus** is a component of the **Basal Ganglia** (specifically part of the corpus striatum), located in the forebrain (telencephalon) [1]. It plays a vital role in motor planning and the reward system, but it is anatomically and functionally distinct from the cerebellum. **Explanation of the Cerebellar Nuclei (Incorrect Options):** The deep cerebellar nuclei can be remembered by the mnemonic **"Don’t Eat Greasy Foods"** (Lateral to Medial): * **Dentate Nucleus (A):** The largest and most lateral nucleus; it resembles a crumpled bag. It connects with the cerebrocerebellum and is involved in planning and initiation of voluntary movements [2]. * **Emboliform Nucleus (B):** Located medial to the dentate; it is part of the nucleus interpositus. * **Globose Nucleus:** Also part of the nucleus interpositus (not listed in options but part of the group). * **Fastigial Nucleus (C):** The most medial nucleus, associated with the vestibulocerebellum; it regulates balance and eye movements [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Phylogenetic Classification:** The Dentate is the "Neo-cerebellum," while the Fastigial is the "Archi-cerebellum." * **Blood Supply:** The deep nuclei are primarily supplied by the Superior Cerebellar Artery (SCA) and Anterior Inferior Cerebellar Artery (AICA). * **Lesion Sign:** Damage to the deep nuclei (especially the Dentate) results in **ipsilateral** motor deficits, such as intention tremors and dysmetria [3].

Question 1539: White infarcts are seen in which of the following organs?

A. Kidney
B. Spleen
C. Heart
D. All the above (Correct Answer)

Explanation: ### Explanation Infarction is categorized into two types based on the color and the nature of the blood supply to the organ: **White (Anemic) Infarcts** and **Red (Hemorrhagic) Infarcts**. **Mechanism of White Infarcts:** White infarcts occur in **solid organs** with **end-arterial circulation** (single blood supply). When an artery is occluded, there is no collateral flow to bypass the blockage. The tissue undergoes ischemic necrosis, and because the organ is solid/dense, it limits the amount of blood that can seep into the necrotic area from adjacent capillary beds. Over time, the area becomes pale and well-circumscribed. * **Kidney:** A classic site for white infarcts due to its end-arterial system (arcuate and interlobular arteries). These infarcts are typically wedge-shaped. * **Spleen:** Similar to the kidney, the splenic artery branches are end-arteries, making the spleen highly susceptible to pale, wedge-shaped infarcts (often seen in embolic events like infective endocarditis). * **Heart:** Myocardial infarction is a white infarct [2]. Although there are some anastomoses, the coronary arteries function as functional end-arteries [2]. **Why "All the above" is correct:** All three organs—Kidney, Spleen, and Heart—possess the structural density and limited collateral blood supply required to produce a pale/white infarct upon arterial occlusion. **Clinical Pearls for NEET-PG:** * **Red (Hemorrhagic) Infarcts:** Occur in loose tissues (Lungs), organs with dual blood supply (Liver, Lungs, Small Intestine), or when there is venous occlusion (Ovarian torsion). * **Morphology:** Most white infarcts are **wedge-shaped**, with the apex pointing toward the occluded vessel and the base at the organ periphery. * **Microscopy:** The hallmark of most infarcts (except the brain) is **Coagulative Necrosis**. Brain infarcts result in **Liquefactive Necrosis** [1].

Question 1540: The floor of the body of the lateral ventricle is formed by which structure?

A. Septum pellucidum
B. Rostrum of corpus callosum
C. Thalamostriate vein (Correct Answer)
D. Genu of corpus callosum

Explanation: ### Explanation The lateral ventricle is a C-shaped cavity within the cerebral hemisphere. To answer questions regarding its boundaries, it is essential to distinguish between its different parts (Anterior horn, Body, Posterior horn, and Inferior horn). **Why the Correct Answer is Right:** The **Body (Central part)** of the lateral ventricle extends from the interventricular foramen of Monro to the splenium of the corpus callosum. Its **floor** is formed by the following structures (from lateral to medial): 1. Caudate nucleus (body) [1] 2. **Thalamostriate vein** 3. Stria terminalis 4. Thalamus (superior surface) [3] 5. Choroid plexus 6. Fornix (body) The thalamostriate vein and stria terminalis lie in the groove between the caudate nucleus and the thalamus, making them key anatomical landmarks in the floor of the body. **Analysis of Incorrect Options:** * **A. Septum pellucidum:** This forms the **medial wall** of the body and the anterior horn, separating the two lateral ventricles. * **B. Rostrum of corpus callosum:** This forms the **floor of the anterior horn**, not the body. * **C. Genu of corpus callosum:** This forms the **anterior wall** of the anterior horn [2]. **High-Yield Facts for NEET-PG:** * **Roof of the Body:** Formed by the under surface of the **Corpus Callosum** (trunk). * **Medial Wall:** Formed by the **Septum Pellucidum** and the body of the **Fornix**. * **The "CS-T" Mnemonic for the Floor:** **C**audate nucleus, **S**tria terminalis, **T**halamostriate vein, and **T**halamus. * **Clinical Pearl:** The thalamostriate vein is a crucial radiological landmark on CT/MRI; it drains the basal ganglia and internal capsule into the internal cerebral vein [1].

Practice by Chapter

Organization of the Nervous System

Practice Questions

Spinal Cord Anatomy

Practice Questions

Brainstem Anatomy

Practice Questions

Cerebellum

Practice Questions

Diencephalon

Practice Questions

Cerebral Cortex

Practice Questions

Basal Ganglia

Practice Questions

Limbic System

Practice Questions

Cranial Nerves

Practice Questions

Autonomic Nervous System

Practice Questions

Neural Pathways and Tracts

Practice Questions

Neurovascular Anatomy

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free