Neuroanatomy Practice Questions

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

Medial. 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**.

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

Caudate nuclei. 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].

Q: What is true about the spinal cord?

All of the above.. The spinal cord's termination level is a high-yield concept in anatomy, primarily governed by the differential growth rates between the vertebral column and the spinal cord (ascensus spinalis). **Explanation of Options:** * **Option A:** In adults, the spinal cord (conus medullaris) typically terminates at the **lower border of the L1 vertebra** or the L1-L2 intervertebral disc. This is the standard anatomical landmark used for clinical procedures. * **Option B:** In newborns, the spinal cord ends lower, typically at the **L3 vertebra**. As the child grows, the vertebral column lengthens faster than the spinal cord, causing the cord to "occupy" a higher relative position over time. * **Option C:** The **cauda equina** (horse's tail) is a bundle of spinal nerves (L2-Co1) that continues inferiorly from the conus medullaris. It occupies the subarachnoid space (the lumbar cisterna) and extends through the lumbar and sacral regions toward the coccyx to exit via their respective foramina. Since all statements are anatomically accurate, **Option D** is the correct answer. **Clinical Pearls for NEET-PG:** 1. **Lumbar Puncture (LP):** To avoid spinal cord injury, an LP is typically performed at the **L3-L4 or L4-L5** interspace in adults. In infants, it must be performed lower (below L3). 2. **Tethered Cord Syndrome:** A clinical condition where the conus medullaris is abnormally low (below L2 in adults), often associated with a thickened filum terminale. 3. **Filum Terminale:** An extension of the pia mater that anchors the spinal cord to the coccyx. 4. **Dural Sac:** While the cord ends at L1, the subarachnoid space (dural sac) ends at the **S2 level** in adults.

Q: Special visceral efferent innervation does NOT involve which of the following structures?

Dorsal nucleus of X cranial nerve. The concept of **Special Visceral Efferent (SVE)** fibers refers to the motor innervation of muscles derived from the **pharyngeal (branchial) arches**. These are distinct from General Somatic Efferent (GSE) fibers, which supply limb and trunk muscles, and General Visceral Efferent (GVE) fibers, which provide autonomic (parasympathetic) innervation [1]. **Why Option D is Correct:** The **Dorsal Nucleus of the Vagus (X)** is a **General Visceral Efferent (GVE)** nucleus [1]. It provides preganglionic parasympathetic innervation to the thoracic and abdominal viscera (heart, lungs, and GI tract). It does not supply branchiomeric muscles, making it the correct answer for "NOT" being an SVE nucleus. **Analysis of Incorrect Options:** * **A. Nucleus Ambiguus:** This is the SVE nucleus for CN IX, X, and XI. It supplies the muscles of the pharynx, larynx, and soft palate (derived from the 4th and 6th arches). * **B. Motor Nucleus of V:** This provides SVE fibers to the muscles of mastication, tensor tympani, and tensor veli palatini (derived from the 1st arch). * **C. Motor Nucleus of VII:** This provides SVE fibers to the muscles of facial expression, stapedius, and stylohyoid (derived from the 2nd arch). **High-Yield NEET-PG Pearls:** * **SVE Mnemonic:** Remember the "Branchial Motor" nuclei: **V, VII, IX, X, XI**. * **Nucleus Ambiguus** is a frequent exam favorite; it contributes SVE fibers to the Vagus nerve, while the **Dorsal Nucleus** contributes GVE fibers. * **Functional Components:** * **SVE:** Pharyngeal arch muscles. * **GVE:** Parasympathetic (Secretomotor/Smooth muscle). * **GSE:** Extraocular muscles and Tongue muscles (CN III, IV, VI, XII).

Q: General visceral fibres do not supply which of the following structures?

Skeletal muscles. **Explanation:** The classification of nerve fibers in neuroanatomy is based on the structures they innervate. The term **General Visceral Efferent (GVE)** refers to the autonomic nervous system fibers that provide motor supply to involuntary structures [2]. 1. **Why Skeletal Muscle is the correct answer:** Skeletal muscles are derived from somites (myotomes) and are under voluntary control. They are supplied by **General Somatic Efferent (GSE)** fibers (e.g., alpha motor neurons in the ventral horn of the spinal cord) [2]. Since GVE fibers only target involuntary "visceral" structures, they do not supply skeletal muscles. 2. **Analysis of Incorrect Options:** * **Smooth Muscles (A):** These are involuntary muscles found in the walls of blood vessels and hollow organs. They are a primary target of GVE (autonomic) fibers [1], [3]. * **Cardiac Muscles (C):** The specialized muscle of the heart is involuntary and regulated by the autonomic nervous system via GVE fibers. * **Glands (D):** Secretomotor supply to sweat glands, salivary glands, and lacrimal glands is provided by GVE fibers (Sympathetic and Parasympathetic). **High-Yield Clinical Pearls for NEET-PG:** * **GVE (General Visceral Efferent):** Think "Autonomic." These are the pre- and post-ganglionic fibers of the sympathetic and parasympathetic systems [4]. * **SVE (Special Visceral Efferent):** These fibers supply muscles derived from the **pharyngeal (branchial) arches**, such as the muscles of mastication and facial expression. Despite being skeletal muscles, they are classified as "visceral" due to their embryological origin. * **GSE (General Somatic Efferent):** Supplies all skeletal muscles *except* those derived from branchial arches (e.g., limb muscles, extraocular muscles, and tongue muscles).

Q: Which of the following is NOT a branch of the intracranial part of the Internal carotid artery?

Anterior communicating artery. ### Explanation The **Internal Carotid Artery (ICA)** enters the cranial cavity and terminates by dividing into its major branches. To answer this question, one must distinguish between the direct branches of the ICA and the components of the **Circle of Willis**. **1. Why "Anterior communicating artery" is the correct answer:** The **Anterior communicating artery** is a short vessel that connects the two Anterior Cerebral Arteries (ACA). While it is a vital part of the Circle of Willis, it is **not** a direct branch of the ICA itself [1]. It arises from the ACAs to complete the anterior portion of the arterial circle. **2. Analysis of Incorrect Options:** * **Anterior cerebral artery (ACA):** This is one of the two terminal branches of the ICA. It supplies the medial surface of the cerebral hemispheres. * **Middle cerebral artery (MCA):** This is the larger terminal branch of the ICA and is often considered its direct continuation. It supplies the majority of the lateral convexity of the brain. * **Posterior communicating artery (PCoA):** This is a pre-terminal branch of the intracranial (cerebral) part of the ICA. It connects the ICA system to the Vertebro-basilar system (specifically the Posterior Cerebral Artery) [1]. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Mnemonic for ICA branches (Cerebral part):** **"O P A M"** — **O**phthalmic, **P**osterior communicating, **A**nterior choroidal, and the terminal branches: **A**nterior cerebral and **M**iddle cerebral arteries. * **Berry Aneurysms:** The most common site for a Berry aneurysm is the junction of the **Anterior communicating artery** and the ACA. * **Stroke Correlation:** The MCA is the most common artery involved in ischemic strokes; the ICA provides roughly 80% of the brain's blood supply [1].

Q: Identify the structure indicated by the arrow in the corpus callosum.

Splenium. ***Splenium*** - The **splenium** is the **posterior thickened rounded end** of the corpus callosum, connecting the **occipital and temporal lobes** of both hemispheres. - It contains **visual association fibers** and is the **most posterior** and **thickest** part of the corpus callosum, making it easily identifiable on sagittal sections. *Rostrum* - The **rostrum** is the **anterior-most thin portion** of the corpus callosum, located **below the genu**. - It connects the **orbital surfaces** of the frontal lobes and is the **smallest** and **thinnest** part of the corpus callosum. *Genu* - The **genu** is the **anterior curved portion** that forms the **knee-shaped bend** of the corpus callosum. - It connects the **prefrontal cortices** and is located **anterior** to the body, not posterior like the structure in question. *Body* - The **body** forms the **main central portion** of the corpus callosum, extending between the genu and splenium. - It has **uniform thickness** and connects the **motor and sensory cortices**, lacking the characteristic **posterior thickening** seen in the splenium.

Question 1

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

Accepted Answer

Medial

Answer

Answer

Lateral

Answer

Posterior

Question 2

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

Accepted Answer

Purkinje cells

Answer

Golgi cells

Answer

Basket cells

Answer

Oligodendrocytes

Question 3

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

Accepted Answer

Caudate nuclei

Answer

Dentate nuclei

Answer

Emboliform nuclei

Answer

Fastigial nuclei

Question 4

What is true about the spinal cord?

Accepted Answer

All of the above.

Answer

In adults, the spinal cord ends at the lower border of the L1 vertebra.

Answer

In newborns, the spinal cord may extend up to L3.

Answer

The cauda equina extends from the lumbar vertebrae to the coccyx.

Question 5

In Bogorad syndrome, where does damage to the parasympathetic fibres of the facial nerve occur?

Accepted Answer

Before entering the stylomastoid foramen

Answer

At the parotid gland

Answer

Just before the geniculate ganglion

Answer

Before entering the internal auditory meatus

Question 6

Special visceral efferent innervation does NOT involve which of the following structures?

Accepted Answer

Dorsal nucleus of X cranial nerve

Answer

Nucleus ambiguus

Answer

Motor nucleus of V cranial nerve

Answer

Motor nucleus of VII cranial nerve

Question 7

A young woman presents with neurological deficits following an explosion. She has no movement in her right lower extremity with hyperreflexia, loss of proprioception and fine touch in this extremity, but pain and temperature sensation are intact. Pain and temperature sensation are absent in the left lower limb. Movement and reflexes are normal in the left lower extremity and upper extremities. A lesion in which of the following locations can explain her neurological examination?

Accepted Answer

Hemisection of the right side of the spinal cord at the level of the first lumbar segment

Answer

Hemisection of the left side of the spinal cord at the level of the first lumbar segment

Answer

Hemisection of the left side of the spinal cord at the level of the fourth sacral segment

Answer

Hemisection of the right side of the spinal cord at the level of the fourth sacral segment

Question 8

General visceral fibres do not supply which of the following structures?

Accepted Answer

Skeletal muscles

Answer

Smooth muscles

Answer

Cardiac muscles

Answer

Glands

Question 9

Which of the following is NOT a branch of the intracranial part of the Internal carotid artery?

Accepted Answer

Anterior communicating artery

Answer

Anterior cerebral artery

Answer

Middle cerebral artery

Answer

Posterior communicating artery

Question 10

Identify the structure indicated by the arrow in the corpus callosum.

Accepted Answer

Splenium

Answer

Rostrum

Answer

Genu

Answer

Body

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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