Neuroanatomy Practice Questions

Q: Which part of thalamus is related to motor control?

Ventrolateral thalamus. ***Ventrolateral thalamus*** - The **ventrolateral (VL) nucleus** of the thalamus is a key relay station for **motor control**, receiving input from the **basal ganglia** and **cerebellum** and projecting to the motor cortex [1]. - It plays a crucial role in the planning, initiation, and coordination of **voluntary movements**. *Ventral posteromedial* - The **ventral posteromedial (VPM) nucleus** is involved in processing **somatosensory information** from the face and taste sensations. - It does not primarily contribute to motor control pathways. *Ventral posterolateral* - The **ventral posterolateral (VPL) nucleus** relays **somatosensory information** from the body (limbs and trunk) to the primary somatosensory cortex. - Its main function is sensory perception, not motor control. *Lateral geniculate nucleus* - The **lateral geniculate nucleus (LGN)** is exclusively involved in the **visual pathway**, receiving input from the retina and projecting to the primary visual cortex. - It has no direct role in motor control.

Q: The cranial nerve passing through cavernous sinus is

Abducens. ***Abducens*** - The **abducens nerve (CN VI)** is the only cranial nerve that travels **through the substance of the cavernous sinus** itself, running alongside the internal carotid artery. - This unique intracavernous location makes it the most vulnerable cranial nerve to injury from cavernous sinus pathology (thrombosis, tumors, aneurysms). - Other nerves (CN III, IV, V1, V2) run in the **lateral wall** of the sinus, not through it. *Olfactory* - The **olfactory nerve (CN I)** runs from the nasal cavity through the cribriform plate to the olfactory bulb. - It does not traverse the cavernous sinus. *Facial* - The **facial nerve (CN VII)** exits the skull via the stylomastoid foramen and has a complex course through the temporal bone. - It does not pass through the cavernous sinus. *Optic* - The **optic nerve (CN II)** exits the orbit through the optic canal to reach the optic chiasm. - It does not travel through the cavernous sinus, though it is in close anatomical proximity to structures anterior to it.

Q: Ventricles are lined by?

Ependymal cells. Ependymal cells - Ependymal cells are a type of glial cell that form the epithelial lining of the ventricles of the brain and the central canal of the spinal cord [3]. - They possess cilia that help circulate the cerebrospinal fluid (CSF) and microvilli involved in CSF absorption. Schwann cells - Schwann cells are responsible for forming the myelin sheath around axons in the peripheral nervous system (PNS) [4]. - They do not line the ventricles, which are part of the central nervous system [2]. Oligodendrocytes - Oligodendrocytes are glial cells that form the myelin sheath around axons in the central nervous system (CNS) [1], [4]. - While they are CNS cells, their primary function is myelination, not lining the ventricular system [1]. Astrocytes - Astrocytes are the most abundant and diverse glial cells in the CNS, providing structural support, metabolic regulation, and forming the blood-brain barrier. - They are found throughout the brain parenchyma but do not directly line the ventricular cavities.

Q: Somatic efferent does not include:

Facial nerve. ***Facial nerve*** - The **facial nerve (CN VII)** is a **mixed nerve** that does **NOT** contain **general somatic efferent (GSE)** fibers - Its motor component consists of **special visceral efferent (SVE)** fibers that innervate **muscles of facial expression** derived from the **2nd pharyngeal arch**, not from somites - Also contains **general visceral efferent (GVE)** fibers (parasympathetic to lacrimal, submandibular, and sublingual glands) and sensory fibers - **This is the correct answer** because it lacks GSE fibers *Abducent nerve* - The **abducent nerve (CN VI)** is a **pure general somatic efferent (GSE) nerve** - Exclusively innervates the **lateral rectus muscle** of the eye, which is derived from **somites** - Its function is to cause **abduction** of the ipsilateral eye - This nerve DOES contain somatic efferent fibers, so it is incorrect *Trochlear nerve* - The **trochlear nerve (CN IV)** is also a **pure general somatic efferent (GSE) nerve** - Innervates the **superior oblique muscle** of the eye, derived from **somites** - Responsible for **depression**, **abduction**, and **internal rotation** of the eye - This nerve DOES contain somatic efferent fibers, so it is incorrect *Oculomotor nerve* - The **oculomotor nerve (CN III)** contains **general somatic efferent (GSE) fibers** that innervate most **extraocular muscles** (superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae superioris) - Also contains **general visceral efferent (GVE)** fibers (parasympathetic to pupillary sphincter and ciliary muscles) [1] - This nerve DOES contain somatic efferent fibers, so it is incorrect

Q: Which of the following cranial nerves passes through the internal auditory meatus?

7th cranial nerve. ***7th cranial nerve*** - The **facial nerve (CN VII)** passes through the internal auditory meatus along with the vestibulocochlear nerve (CN VIII). - This nerve is responsible for **facial expression**, taste from the anterior two-thirds of the tongue, and parasympathetic innervation of some glands. *9th cranial nerve* - The **glossopharyngeal nerve (CN IX)** exits the skull through the **jugular foramen**, not the internal auditory meatus. - It is involved in taste, swallowing, and sensation from the posterior tongue and pharynx. *11th cranial nerve* - The **accessory nerve (CN XI)** exits the skull through the **jugular foramen**, supplying the sternocleidomastoid and trapezius muscles. - Its spinal root ascends into the skull through the foramen magnum and then joins the cranial root before exiting. *10th cranial nerve* - The **vagus nerve (CN X)** also exits the skull through the **jugular foramen**, alongside CN IX and CN XI. - It has extensive innervation to the heart, lungs, and digestive tract.

Q: Dissociated sensory loss in a case of tumor of central Spinal cord is due to lesion of-

Decussating fibres of lateral spinothalamic tract. ***Decussating fibres of lateral spinothalamic tract*** - A tumor in the central spinal cord, such as a **syringomyelia**, primarily affects the decussating fibers of the **lateral spinothalamic tract**. - This typically results in a **dissociated sensory loss**, meaning loss of **pain and temperature sensation** while preserving light touch, proprioception, and vibration. *Dorsal column fibres* - Lesions here would typically cause loss of **proprioception**, **vibration**, and **fine touch**, not primarily dissociated sensory loss involving pain and temperature [1]. - These fibers ascend ipsilaterally and do not decussate in the spinal cord, so they would be less likely to be affected by a central lesion in a dissociated pattern [1]. *Anterior Spinothalamic tract* - This tract primarily mediates **crude touch** and **pressure** and is less commonly the sole cause of dissociated sensory loss as described [1]. - While it does decussate, isolated damage to this tract alone would not typically explain the classic dissociated pain and temperature loss pattern. *Central spinal center of spinal cord* - This is a broad and less specific term; the specific fibers affected within the central spinal cord, leading to dissociated sensory loss, are the **decussating fibers of the lateral spinothalamic tract**. - While a central lesion is the cause, specifying "central spinal center" doesn't precisely identify the neural pathway responsible for the characteristic sensory deficit.

Q: Which structure carries axons from the nucleus gracilis to the thalamus?

Medial lemniscus. ***Medial lemniscus*** - The **medial lemniscus** is formed by the decussation of internal arcuate fibers, which originate from the **nucleus gracilis** and nucleus cuneatus [1]. - These fibers carry **fine touch**, **vibration**, and **proprioception** from the body to the thalamus [1]. *Fasciculus gracilis* - The **fasciculus gracilis** is part of the **dorsal column** in the spinal cord, ascending ipsilaterally [1]. - It carries sensory information from the **lower body** to the nucleus gracilis in the medulla, not directly to the thalamus [1]. *Fasciculus lemniscus* - This is an **incorrect anatomical term**; there is no recognized neurological structure called the fasciculus lemniscus. - The term "lemniscus" refers to ascending sensory tracts, but it does not combine with "fasciculus" in this manner. *Lateral spinothalamic tract* - The **lateral spinothalamic tract** carries information about **pain** and **temperature** from the body to the thalamus [1]. - It originates from the dorsal horn of the spinal cord and decussates at the spinal cord level, distinct from the dorsal column-medial lemniscus pathway [1].

Q: Neurologic examination reveals bilateral medial rectus paresis on attempted lateral gaze, monocular horizontal nystagmus in the abducting eye, and unimpaired convergence. The lesion is in the:

Midpontine tegmentum, dorsomedial zones, bilateral.. ***Midpontine tegmentum, dorsomedial zones, bilateral.*** - The combination of **bilateral medial rectus paresis** on attempted lateral gaze, **monocular horizontal nystagmus** in the abducting eye, and **unimpaired convergence** is the classic presentation of **bilateral internuclear ophthalmoplegia (INO)**. - Bilateral INO is caused by lesions in the **medial longitudinal fasciculus (MLF)**, which is located in the **dorsomedial tegmentum** of the midpons and is crucial for coordinating horizontal eye movements. *Rostral midbrain, bases pedunculorum.* - Lesions in the **rostral midbrain** are more likely to affect vertically oriented eye movements or cause disorders like **Parinaud's syndrome**, not bilateral INO. - The **bases pedunculorum** primarily contain motor tracts and would cause motor deficits, not isolated eye movement disorders like INO. *Caudal midbrain tectum.* - The **caudal midbrain tectum** contains the superior and inferior colliculi, which are involved in visual and auditory reflexes respectively, not direct control of conjugate horizontal gaze. - Lesions here are unlikely to cause the specific pattern of bilateral medial rectus paresis and abducting nystagmus seen in INO. *Caudal pontine base.* - The **caudal pontine base** contains the abducens nucleus and the paramedian pontine reticular formation (PPRF), lesions of which cause different oculomotor deficits such as **gaze palsies** or **abducens nerve palsies**, not bilateral INO with preserved convergence. - A lesion here would typically affect the generation of horizontal gaze, leading to an inability to look in one direction, rather than dysconjugate eye movements.

Q: Gustatory pathway involves which nerve(s)?

Facial and Glossopharyngeal. ***Facial and Glossopharyngeal*** - The **facial nerve (cranial nerve VII)** innervates the taste buds on the **anterior two-thirds of the tongue** via the **chorda tympani** branch [1]. - The **glossopharyngeal nerve (cranial nerve IX)** innervates the taste buds on the **posterior one-third of the tongue** and the circumvallate papillae [1]. *Glossopharyngeal* - While the **glossopharyngeal nerve** is involved in taste sensation for the posterior tongue, it does not cover the entire taste pathway. - It specifically transmits taste from the **posterior one-third of the tongue** and **circumvallate papillae** [1]. *Vagus* - The **vagus nerve (cranial nerve X)** plays a minor role in taste sensation, primarily innervating taste buds on the **epiglottis and pharynx** [1]. - Its contribution to the overall gustatory pathway is not as significant as the facial and glossopharyngeal nerves. *Facial* - The **facial nerve** is crucial for taste sensation, specifically transmitting taste from the **anterior two-thirds of the tongue** [1]. - However, it does not innervate the posterior portion of the tongue, making it an incomplete answer for the entire gustatory pathway.

Q: Spinal nerve roots are supplied by -

Radicular arteries. ***Radicular arteries*** - The **radicular arteries** are branches of the segmental arteries (e.g., intercostal, lumbar, lateral sacral arteries) that supply the **spinal nerve roots** and their coverings. - They provide crucial blood supply to the peripheral parts of the spinal cord and the nerve roots as they exit the vertebral canal. *Posterior spinal artery* - The **posterior spinal artery** supplies the posterior one-third of the spinal cord, primarily the **posterior columns** and posterior horns. - It does not directly supply the spinal nerve roots themselves as they emerge from the cord. *Anterior spinal artery* - The **anterior spinal artery** supplies the anterior two-thirds of the spinal cord, including the **anterior horns** and lateral funiculi. - While it's a major supplier to the spinal cord, it does not directly vascularize the spinal nerve roots. *Vertebral artery* - The **vertebral arteries** form the **basilar artery** and primarily supply the brainstem, cerebellum, and posterior cerebrum. - They give off the anterior and posterior spinal arteries, but they do not directly supply the spinal nerve roots.

Question 1

Which part of thalamus is related to motor control?

Accepted Answer

Ventrolateral thalamus

Answer

Ventral posteromedial

Answer

Ventral posterolateral

Answer

Lateral geniculate nucleus

Question 2

The cranial nerve passing through cavernous sinus is

Accepted Answer

Abducens

Answer

Olfactory

Answer

Facial

Answer

Optic

Question 3

Ventricles are lined by?

Accepted Answer

Ependymal cells

Answer

Schwann cells

Answer

Oligodendrocytes

Answer

Astrocytes

Question 4

Somatic efferent does not include:

Accepted Answer

Facial nerve

Answer

Abducent nerve

Answer

Trochlear nerve

Answer

Oculomotor nerve

Question 5

Which of the following cranial nerves passes through the internal auditory meatus?

Accepted Answer

7th cranial nerve

Answer

9th cranial nerve

Answer

11th cranial nerve

Answer

10th cranial nerve

Question 6

Dissociated sensory loss in a case of tumor of central Spinal cord is due to lesion of-

Accepted Answer

Decussating fibres of lateral spinothalamic tract

Answer

Dorsal column fibres

Answer

Anterior Spinothalamic tract

Answer

Central spinal centre of spinal cord

Question 7

Which structure carries axons from the nucleus gracilis to the thalamus?

Accepted Answer

Medial lemniscus

Answer

Fasciculus gracilis

Answer

Fasciculus lemniscus

Answer

Lateral spinothalamic tract

Question 8

Neurologic examination reveals bilateral medial rectus paresis on attempted lateral gaze, monocular horizontal nystagmus in the abducting eye, and unimpaired convergence. The lesion is in the:

Accepted Answer

Midpontine tegmentum, dorsomedial zones, bilateral.

Answer

Rostral midbrain, bases pedunculorum.

Answer

Caudal midbrain tectum.

Answer

Caudal pontine base.

Question 9

Gustatory pathway involves which nerve(s)?

Accepted Answer

Facial and Glossopharyngeal

Answer

Glossopharyngeal

Answer

Vagus

Answer

Facial

Question 10

Spinal nerve roots are supplied by -

Accepted Answer

Radicular arteries

Answer

Posterior spinal artery

Answer

Anterior spinal artery

Answer

Vertebral artery

Neuroanatomy — MCQs

Neuroanatomy — MCQs

On this page

Practice by Chapter

Want unlimited practice?