Neuroanatomy Practice Questions

Q: Which of the following statements regarding chorda tympani is false?

Contains motor nerves that supply facial muscles. ***Contains motor nerves that supplies facial muscles*** - The chorda tympani carries special visceral afferent fibers for **taste from the anterior two-thirds of the tongue** [1] and preganglionic parasympathetic fibers to the **submandibular and sublingual glands**. - It does not contain **motor nerves that supply facial muscles**; those are supplied directly by the main trunk of the facial nerve (CN VII) after it exits the stylomastoid foramen. *Contains secretomotor nerves that supply salivary gland* - The chorda tympani contains **preganglionic parasympathetic fibers** that synapse in the submandibular ganglion. - These postganglionic fibers then innervate the **submandibular and sublingual salivary glands**, promoting saliva production. *Passes through the petrotympanic fissure* - The chorda tympani nerve exits the temporal bone via the **petrotympanic fissure (Glaserian fissure)**. - This is its exit point from the middle ear cavity to join the **lingual nerve**. *Contains sensory neurons that supply anterior 2/3rd of tongue* - The chorda tympani carries **special visceral afferent (taste) fibers** from the taste buds on the anterior two-thirds of the tongue [1]. - These fibers are part of the **facial nerve (CN VII)** pathway for taste sensation [1].

Q: What is the primary function of the superior cervical ganglion?

Supplies sympathetic fibers to the dilator pupillae muscle. Supplies sympathetic fibers to the dilator pupillae muscle - The superior cervical ganglion is the primary source of postganglionic sympathetic fibers to the head and neck. - One of its key functions is providing sympathetic innervation to the dilator pupillae muscle [1] via the long ciliary nerves, causing mydriasis (pupil dilation) [2]. - This represents a clear physiological function of the ganglion in autonomic control of the eye. Is the largest cervical ganglion - While the superior cervical ganglion is indeed the largest of the three cervical sympathetic ganglia, this is an anatomical characteristic, not a function. - Size is a structural feature, not a physiological role. Left superior cervical cardiac branch goes to deep cardiac plexus - The superior cervical ganglion does contribute cardiac branches to the cardiac plexus for sympathetic innervation of the heart. - However, this describes an anatomical pathway rather than the primary function itself, and specifying "left" and "deep cardiac plexus" makes it overly specific rather than addressing overall function. Deep petrosal nerve of pterygopalatine ganglion is derived from plexus around internal carotid artery - The superior cervical ganglion does send postganglionic fibers forming a plexus around the internal carotid artery, which contributes to the deep petrosal nerve. - However, this is an anatomical derivation/pathway, not a functional description of what the ganglion does physiologically.

Q: Following a head injury, a man lost his tears from both eyes. Absence of lacrimation is due to injury to which structure?

Greater petrosal nerve. ***Greater petrosal nerve*** - The **greater petrosal nerve** carries **parasympathetic preganglionic fibers** from the facial nerve (CN VII) that are destined for the **lacrimal gland**. - Damage to this nerve before it synapses in the **pterygopalatine ganglion** would result in the loss of **lacrimation**. *Supraorbital nerve* - The **supraorbital nerve** is a branch of the **ophthalmic division of the trigeminal nerve (CN V1)** and provides **sensory innervation** to the forehead, upper eyelid, and scalp. - It does not carry fibers for lacrimal gland function. *Tympanic plexus* - The **tympanic plexus** is formed by branches of the **glossopharyngeal nerve (CN IX)** and provides **parasympathetic innervation to the parotid gland** for salivation. - It plays no role in lacrimal gland function. *Nasociliary nerve* - The **nasociliary nerve** is a branch of the **ophthalmic division of the trigeminal nerve (CN V1)** and provides **sensory innervation** to the eyeball, conjunctiva, and part of the nasal mucosa. - It does not carry fibers for lacrimal gland secretion.

Q: Which of the following cranial nerves does not have a parasympathetic component?

Abducens nerve. Abducens nerve - The abducens nerve (CN VI) is a purely motor nerve, primarily responsible for innervating the lateral rectus muscle of the eye. - Its function is to cause abduction (outward movement) of the eye, and it does not carry any parasympathetic fibers. Oculomotor nerve - The oculomotor nerve (CN III) contains parasympathetic fibers that control the pupillary constrictor muscles and the ciliary muscles [1]. - These fibers originate from the Edinger-Westphal nucleus and cause pupillary constriction (miosis) and accommodation [1]. Facial nerve - The facial nerve (CN VII) has parasympathetic components that innervate the submandibular and sublingual salivary glands, as well as the lacrimal glands. - These fibers are crucial for tear production and salivation. Vagus nerve - The vagus nerve (CN X) is a major parasympathetic nerve, carrying widespread innervation to the thoracic and abdominal viscera. - It regulates heart rate, digestion, respiration, and other autonomic functions in organs like the heart, lungs, and gastrointestinal tract.

Q: Which of the following structures is not involved in the auditory pathway?

Lateral geniculate body. Lateral geniculate body - The lateral geniculate body (LGB) is a major relay nucleus in the thalamus that processes visual information from the retina before it reaches the cerebral cortex [2]. - It plays no direct role in the transmission or processing of auditory signals [1]. *Trapezoid body* - The trapezoid body is a collection of nerve fibers and nuclei located in the pons that is a crucial component of the auditory pathway. - It primarily functions in sound localization and relays auditory information from the cochlear nuclei to the superior olivary complex. *Inferior colliculus* - The inferior colliculus is a major midbrain nucleus and a key integrative center of the auditory pathway [1]. - It receives input from various lower auditory structures and projects to the medial geniculate body of the thalamus, playing a role in sound localization, frequency integration, and startle response [1]. *Superior olivary complex* - The superior olivary complex (SOC) is a group of nuclei in the pons that is critical for processing auditory information. - It receives input from the cochlear nuclei and is primarily involved in sound localization through interaural time and intensity differences.

Q: Which action of the extraocular muscle is spared in involvement of the oculomotor nerve?

Abduction. ***Abduction*** - The **oculomotor nerve (CN III)** innervates most extraocular muscles: superior rectus, inferior rectus, medial rectus, and inferior oblique [1]. - The **lateral rectus muscle**, responsible for **abduction** (moving the eye laterally away from the midline), is innervated by the **abducens nerve (CN VI)** [1]. - Therefore, abduction is **completely spared** in oculomotor nerve palsy, making this the correct answer. *Depression* - Depression of the eye involves two muscles: the **inferior rectus** (innervated by CN III) and the **superior oblique** (innervated by CN IV, the trochlear nerve) [1]. - In CN III palsy, the inferior rectus is paralyzed, but the superior oblique remains functional, allowing **partial depression** (especially when the eye is adducted). - Since depression is only partially affected (not completely spared), this is not the best answer. *Elevation* - **Elevation** is performed by the **superior rectus** and **inferior oblique muscles**, both innervated by the **oculomotor nerve (CN III)** [1]. - In oculomotor nerve palsy, elevation would be **severely impaired or lost**. *Adduction* - **Adduction** (moving the eye medially toward the midline) is performed by the **medial rectus muscle**, which is innervated by the **oculomotor nerve (CN III)** [1]. - In oculomotor nerve palsy, adduction would be **completely lost**.

Q: In a case of unilateral supranuclear lesion of the facial nerve, which part of the face is affected?

Only contralateral lower part of the face is affected. ***Only contralateral lower part of the face is affected*** [1] - The **upper part of the face** receives **bilateral innervation** from both cerebral hemispheres, meaning it is spared in a unilateral supranuclear lesion [1]. - The **lower part of the face** receives **contralateral innervation** only, leading to weakness on the opposite side of the lesion [1]. *No part of the face* - This is incorrect because a **supranuclear lesion** of the facial nerve definitively impacts motor control, specifically affecting the contralateral lower face. - Such lesions disrupt the corticobulbar tracts, leading to noticeable **motor deficits** [2]. *Only ipsilateral upper part of the face is affected* - This is incorrect because the **upper face** has **bilateral cortical innervation**, which means a unilateral supranuclear lesion typically spares it [1]. - Also, the weakness would be on the **contralateral side**, not the ipsilateral side, if any part of the face were affected. *Whole of the lower face is affected* - This is partially correct in that the lower face is affected, but it fails to specify that the involvement is **contralateral** to the lesion. - Specifying "whole of the lower face" lacks the anatomical precision regarding laterality and the sparing of the upper face due to bilateral innervation.

Q: Inferior cerebellar peduncle has all of the following tracts, except which one?

Pontocerebellar. ***Pontocerebellar*** - The **pontocerebellar tracts** originate from the **pontine nuclei** and project to the contralateral cerebellum exclusively through the **middle cerebellar peduncle** (NOT the inferior cerebellar peduncle). - These tracts are crucial for carrying information about voluntary movements initiated by the cerebral cortex to the cerebellum for motor coordination. - The middle cerebellar peduncle is the largest cerebellar peduncle and consists almost entirely of pontocerebellar fibers. *Olivocerebellar* - The **olivocerebellar tracts** originate from the **inferior olivary nucleus** and pass through the **inferior cerebellar peduncle** to reach the contralateral cerebellar cortex [1]. - These fibers are crucial for motor learning, coordination, and error correction [1]. *Spinocerebellar* - The **posterior spinocerebellar tract** is a major component of the **inferior cerebellar peduncle**, conveying **unconscious proprioception** from the lower limb and lower trunk [1]. - This information helps the cerebellum coordinate posture and movement [1]. *Vestibulocerebellar* - **Vestibulocerebellar tracts** transmit essential information from the **vestibular nuclei** and organs to the cerebellum through the **inferior cerebellar peduncle** [1]. - These fibers contribute to balance, posture, and vestibulo-ocular reflexes [1].

Q: Which of the following cell types is absent in the cerebellar cortex?

Bipolar. ***Bipolar*** - Bipolar cells are primarily found in the **retina** [2] and as **sensory neurons** in the olfactory epithelium, not in the cerebellar cortex [1]. - They function in transmitting visual and olfactory signals, respectively, and are not a component of cerebellar circuitry [3]. *Purkinje* - **Purkinje cells** are a defining feature of the cerebellar cortex, forming the middle layer and serving as the sole output neurons [1]. - They are large, flask-shaped neurons with extensive dendritic trees that integrate information from many thousands of other neurons [1]. *Granule* - **Granule cells** are the most numerous neurons in the brain and are abundant in the cerebellar cortex, forming the innermost layer [1]. - They receive input from mossy fibers and send parallel fibers to activate Purkinje cells [1]. *Golgi* - **Golgi cells** are interneurons found in the granular layer of the cerebellar cortex [1]. - They play a crucial role in regulating the activity of granule cells by providing inhibitory feedback [1].

Q: Which of the following is not true about the Trochlear nerve?

Supplies the ipsilateral superior oblique muscle. ***Supplies the ipsilateral superior oblique muscle*** - The trochlear nerve (CN IV) is unique in that it **decussates** (crosses over) before innervation. - This means that the trochlear nerve arising from one side of the brainstem actually supplies the **contralateral superior oblique muscle**. *Has the longest intracranial course* - The trochlear nerve indeed has the **longest intracranial course** of all cranial nerves. - It emerges dorsally from the midbrain, courses anteriorly around the brainstem, and then travels a significant distance to reach the superior orbital fissure. *Enters orbit through the superior orbital fissure outside the annulus of Zinn* - The trochlear nerve passes through the **superior orbital fissure** but specifically **outside the annulus of Zinn**. - This anatomical detail is important for understanding its vulnerability and involvement in certain orbital syndromes. *Only cranial nerve that arises from the dorsal aspect of the brainstem* - The trochlear nerve is unique among cranial nerves for its **dorsal emergence** from the brainstem [1]. - All other cranial nerves emerge from the ventral or ventrolateral aspects of the brainstem.

Question 1

Which of the following statements regarding chorda tympani is false?

Accepted Answer

Contains motor nerves that supply facial muscles

Answer

Contains secretomotor nerves that supply salivary gland

Answer

Passes through the petrotympanic fissure

Answer

Contains sensory neurons that supply anterior 2/3rd of tongue

Question 2

What is the primary function of the superior cervical ganglion?

Accepted Answer

Supplies sympathetic fibers to the dilator pupillae muscle

Answer

Is the largest cervical ganglion

Answer

Deep petrosal nerve of pterygopalatine ganglion is derived from plexus around internal carotid artery

Answer

Left superior cervical cardiac branch goes to deep cardiac plexus

Question 3

Following a head injury, a man lost his tears from both eyes. Absence of lacrimation is due to injury to which structure?

Accepted Answer

Greater petrosal nerve

Answer

Supraorbital nerve

Answer

Tympanic plexus

Answer

Nasociliary nerve

Question 4

Which of the following cranial nerves does not have a parasympathetic component?

Accepted Answer

Abducens nerve

Answer

Oculomotor nerve

Answer

Facial nerve

Answer

Vagus nerve

Question 5

Which of the following structures is not involved in the auditory pathway?

Accepted Answer

Lateral geniculate body

Answer

Trapezoid body

Answer

Inferior colliculus

Answer

Superior olivary complex

Question 6

Which action of the extraocular muscle is spared in involvement of the oculomotor nerve?

Accepted Answer

Abduction

Answer

Depression

Answer

Elevation

Answer

Adduction

Question 7

In a case of unilateral supranuclear lesion of the facial nerve, which part of the face is affected?

Accepted Answer

Only contralateral lower part of the face is affected

Answer

No part of the face

Answer

Only ipsilateral upper part of the face is affected

Answer

Whole of the lower face is affected

Question 8

Inferior cerebellar peduncle has all of the following tracts, except which one?

Accepted Answer

Pontocerebellar

Answer

Olivocerebellar

Answer

Spinocerebellar

Answer

Vestibulocerebellar

Question 9

Which of the following cell types is absent in the cerebellar cortex?

Accepted Answer

Bipolar

Answer

Purkinje

Answer

Granule

Answer

Golgi

Question 10

Which of the following is not true about the Trochlear nerve?

Accepted Answer

Supplies the ipsilateral superior oblique muscle

Answer

Enters orbit through the superior orbital fissure outside the annulus of Zinn

Answer

Has the longest intracranial course

Answer

Only cranial nerve that arises from the dorsal aspect of the brainstem

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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