Neuroanatomy — MCQs
On this page
Nerve supply of stapedius is:
Which of the following structures is seen in the cavernous sinus?
From which structure is the greater petrosal nerve formed?
The nerve which has the longest intracranial course is:
Hilton's law primarily relates to which of the following?
Oculomotor nucleus is located in -
Largest cranial nerve is:
Which artery is the major supply of the medial surface of the cerebral hemisphere?
Which are the second order neurons in the optic pathway?
Which muscles are responsible for the elevation of the eye?
Neuroanatomy Indian Medical PG Practice Questions and MCQs
Question 1731: Nerve supply of stapedius is:
- A. Facial nerve (7th nerve) (Correct Answer)
- B. Oculomotor nerve (3rd nerve)
- C. Trigeminal nerve (5th nerve)
- D. Glossopharyngeal nerve (9th nerve)
Explanation: ***Facial nerve (7th nerve)*** - The **facial nerve** is responsible for innervating the **stapedius muscle**, which helps to dampen loud sounds by pulling the stapes away from the oval window. - A lesion in the facial nerve can lead to **hyperacusis** due to the paralysis of the stapedius muscle. *Oculomotor nerve (3rd nerve)* - The **oculomotor nerve** primarily controls **eye movements** and **pupil constriction**. - It does not have any direct involvement in the innervation of middle ear muscles. *Trigeminal nerve (5th nerve)* - The **trigeminal nerve** is responsible for **sensation of the face** and innervates the **muscles of mastication**. - It provides motor supply to the **tensor tympani muscle**, not the stapedius. *Glossopharyngeal nerve (9th nerve)* - The **glossopharyngeal nerve** is primarily involved in **taste sensation** from the posterior tongue, **swallowing**, and mediating the **gag reflex**. - It does not innervate any muscles of the middle ear.
Question 1732: Which of the following structures is seen in the cavernous sinus?
- A. Internal carotid artery (Correct Answer)
- B. Facial nerve
- C. Mandibular division of the trigeminal nerve (V3)
- D. Optic nerve (CN II)
Explanation: ***Internal carotid artery*** - The **internal carotid artery** passes directly through the body of the **cavernous sinus**, making it highly vulnerable to injury or compression in this region. - This artery is surrounded by venous blood within the sinus and is a common site for **carotid-cavernous fistulas** if damaged. *Mandibular division of the trigeminal nerve (V3)* - The **mandibular division (V3)** of the trigeminal nerve does not pass through the cavernous sinus itself; it exits the skull via the **foramen ovale**. - Only the **ophthalmic (V1)** and **maxillary (V2)** divisions are found in the lateral wall of the cavernous sinus. *Facial nerve* - The **facial nerve (CN VII)** has a long and complex course but does not pass through the cavernous sinus. - It travels through the **internal auditory meatus** and then exits the skull via the **stylomastoid foramen**. *Optic nerve (CN II)* - The **optic nerve (CN II)** enters the skull via the **optic canal** and is surrounded by meninges, but it does not traverse the cavernous sinus. - It is located superior and medial to the cavernous sinus, passing into the **middle cranial fossa** to join the optic chiasm.
Question 1733: From which structure is the greater petrosal nerve formed?
- A. Geniculate ganglion (Correct Answer)
- B. Plexus around ICA
- C. Plexus around middle meningeal artery
- D. None of the options
Explanation: ***Geniculate ganglion*** - The **greater petrosal nerve** arises directly from the **geniculate ganglion** of the **facial nerve (cranial nerve VII)**. - This nerve carries **preganglionic parasympathetic fibers** destined for the lacrimal gland and mucous glands of the nose, palate, and pharynx, as well as **taste fibers** from the palate. *Plexus around ICA* - The **plexus around the internal carotid artery (ICA)** typically carries **postganglionic sympathetic fibers**, primarily for structures in the head, including the dilator pupillae muscle. - It does not give rise to the greater petrosal nerve, which is predominantly parasympathetic and sensory. *Plexus around middle meningeal artery* - The **plexus around the middle meningeal artery** consists mainly of **sympathetic fibers** that supply the artery itself and surrounding structures. - It has no direct connection or contribution to the formation of the greater petrosal nerve. *None of the options* - This option is incorrect because the **greater petrosal nerve** does indeed arise from the **geniculate ganglion**.
Question 1734: The nerve which has the longest intracranial course is:
- A. Trochlear nerve (Fourth cranial nerve) (Correct Answer)
- B. Oculomotor nerve (Third cranial nerve)
- C. Abducens nerve (Sixth cranial nerve)
- D. Trigeminal nerve (Fifth cranial nerve)
Explanation: The nerve which has the longest intracranial course is: ***Trochlear nerve (Fourth cranial nerve)*** - This nerve has the **longest intracranial course** of all the cranial nerves, emerging from the dorsal aspect of the midbrain. - Its long path makes it particularly susceptible to **injury** from head trauma or increased intracranial pressure. *Oculomotor nerve (Third cranial nerve)* - While significant in length, the **oculomotor nerve** does not have the longest intracranial course; it emerges from the ventral midbrain. [1] - It controls most of the **extraocular muscles**, but its intracranial path is shorter than that of the trochlear nerve. *Abducens nerve (Sixth cranial nerve)* - The **abducens nerve** has a relatively long course within the pons and across the clivus but is not the longest. - It is often impacted in conditions causing **elevated intracranial pressure** or skull base fractures due to its path. *Trigeminal nerve (Fifth cranial nerve)* - The **trigeminal nerve** has a large sensory ganglion and extensive peripheral branches but its intracranial course is comparatively short, emerging from the pons. - It is primarily responsible for **facial sensation** and mastication.
Question 1735: Hilton's law primarily relates to which of the following?
- A. Nerve innervation only
- B. Nerve supply of joints, muscles moving them, and overlying skin (Correct Answer)
- C. Blood supply to joints
- D. None of the above
Explanation: ***Nerve supply of joints, muscles moving them, and overlying skin*** - **Hilton's law** states that the nerve supplying a joint also supplies the muscles that move the joint and the skin overlying the insertions of those muscles - This anatomical principle is clinically significant as it explains **referred pain patterns** from joints to surrounding structures - The law demonstrates the **functional integration** between joint innervation, muscle control, and cutaneous sensation *Nerve innervation only* - While Hilton's law involves nerve innervation, this option is too vague and incomplete - The law specifically describes the **relationship between three components**: joint nerves, muscle nerves, and cutaneous nerves - Simply stating "nerve innervation only" misses the **clinical significance** of the anatomical pattern *Blood supply to joints* - This refers to the vascular supply of joints (articular arteries), which is important for joint nutrition - However, **Hilton's law** specifically addresses **nerve supply patterns**, not vascular anatomy - Blood supply to joints follows different anatomical principles *None of the above* - This is incorrect because Hilton's law clearly relates to the integrated nerve supply pattern described in the correct option - The law is a fundamental principle in anatomy explaining the **functional relationship** between joint, muscle, and skin innervation
Question 1736: Oculomotor nucleus is located in -
- A. Forebrain
- B. Midbrain (Correct Answer)
- C. Pons
- D. Medulla
Explanation: ***Midbrain*** - The **oculomotor nucleus** (cranial nerve III) and the Edinger-Westphal nucleus (parasympathetic component) are both located in the **ventral gray matter** near the cerebral aqueduct in the **midbrain** [1]. - This position allows the oculomotor nerve to exit from the interpeduncular fossa of the midbrain [1]. *Forebrain* - The **forebrain** primarily contains structures like the cerebral hemispheres, thalamus, and hypothalamus, which are involved in higher cognitive functions and sensory processing. - No cranial nerve nuclei are located within the forebrain itself; they are largely concentrated in the brainstem. *Pons* - The **pons** contains nuclei for cranial nerves V (trigeminal), VI (abducens), VII (facial), and VIII (vestibulocochlear), but not the oculomotor nucleus. - It is located inferior to the midbrain and superior to the medulla. *Medulla* - The **medulla oblongata** houses nuclei for cranial nerves IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal). - It is the most caudal part of the brainstem, inferior to the pons, and is not where the oculomotor nucleus is found.
Question 1737: Largest cranial nerve is:
- A. Trochlear
- B. Trigeminal (Correct Answer)
- C. Oculomotor
- D. Vagus
Explanation: ***Trigeminal*** - The **trigeminal nerve (CN V)** is the largest cranial nerve, both in terms of its overall diameter and the number of fibers it contains. - It has three major divisions: **ophthalmic, maxillary, and mandibular**, providing extensive sensory innervation to the face and motor innervation to the muscles of mastication. *Trochlear* - The **trochlear nerve (CN IV)** is the smallest cranial nerve in terms of diameter and number of axons. - It primarily innervates a single muscle, the **superior oblique muscle** of the eye. *Oculomotor* - The **oculomotor nerve (CN III)** is responsible for innervating several extrinsic eye muscles and plays a role in pupil constriction. - While significant, it is not the largest cranial nerve. *Vagus* - The **vagus nerve (CN X)** has the longest anatomical course among all cranial nerves, extending into the abdomen, but it is not the largest in terms of overall size or fiber count. - It carries extensive **parasympathetic fibers** and has broad effects on visceral organs.
Question 1738: Which artery is the major supply of the medial surface of the cerebral hemisphere?
- A. Anterior cerebral artery (Correct Answer)
- B. Posterior cerebral artery
- C. Middle cerebral artery
- D. Posterior inferior cerebellar artery
Explanation: ***Anterior cerebral artery*** - The **anterior cerebral artery (ACA)** is a primary branch of the internal carotid artery and is responsible for supplying blood to the **medial surface** of the frontal and parietal lobes of the cerebral hemispheres [1]. - It also supplies the **corpus callosum**, the superior aspect of the frontal and parietal lobes, and parts of the basal ganglia [1]. *Posterior cerebral artery* - The **posterior cerebral artery (PCA)** primarily supplies the **occipital lobe** and the inferior part of the **temporal lobe** [1]. - It also provides blood to parts of the midbrain and the **thalamus** [1]. *Middle cerebral artery* - The **middle cerebral artery (MCA)** is the largest cerebral artery and supplies most of the **lateral surface** of the cerebral hemispheres [1]. - It is crucial for the blood supply to the **motor and sensory cortices** for the face and upper limb, as well as language areas (Broca's and Wernicke's). *Posterior inferior cerebellar artery* - The **posterior inferior cerebellar artery (PICA)** is a branch of the **vertebral artery** and exclusively supplies the **cerebellum** and the lateral medulla. - It is not involved in the blood supply to the cerebral hemispheres.
Question 1739: Which are the second order neurons in the optic pathway?
- A. Bipolar cells (Correct Answer)
- B. Ganglionic cells
- C. Cells of lateral geniculate body
- D. Astrocytes
Explanation: ***Bipolar cells*** - **Photoreceptors** (rods and cones) are first-order neurons, sensing light. [1] - **Bipolar cells** receive input from photoreceptors and transmit signals to retinal ganglion cells, acting as second-order neurons. [1] *Ganglionic cells* - **Ganglion cells** are third-order neurons in the visual pathway. [1] - Their axons form the **optic nerve**, which carries visual information to the brain. [2] *Cells of lateral geniculate body* - The **lateral geniculate nucleus (LGN)** of the thalamus contains fourth-order neurons. [1] - These cells project to the primary visual cortex. [2] *Astrocytes* - **Astrocytes** are a type of glial cell that provides support and protection to neurons in the central nervous system. - They are **not directly involved** in the transmission of visual information in the optic pathway.
Question 1740: Which muscles are responsible for the elevation of the eye?
- A. SR and IO (Correct Answer)
- B. IO and SO
- C. IR and SR
- D. SO and IR
Explanation: ***SR and IO*** - The **superior rectus (SR)** muscle primarily elevates the eye, especially when the eye is **abducted** [1]. - The **inferior oblique (IO)** muscle also contributes to elevation, particularly when the eye is **adducted** [1]. *IO and SO* - While the **inferior oblique (IO)** elevates the eye, the **superior oblique (SO)** muscle is responsible for **depression** and **intorsion**, not elevation [1]. - Therefore, this combination does not exclusively perform elevation. *IR and SR* - The **superior rectus (SR)** muscle elevates the eye, but the **inferior rectus (IR)** muscle is responsible for **depression** of the eye, not elevation [1]. - This pair has opposing primary actions in vertical movement. *SO and IR* - Both the **superior oblique (SO)** and **inferior rectus (IR)** muscles are primarily involved in **depression** of the eye [1]. - The superior oblique also causes **intorsion**, and the inferior rectus causes **extorsion** [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