Which of the following is NOT a content of the occipital triangle?
Which muscle plays a role in winking?
The roof of the olfactory region is formed by?
What is Galen's anastomosis?
All pass through jugular foramen except
Which of the following is a cerebellar nucleus?
What is the nerve supply of the larynx above the level of the vocal cords?
Which of the following structures pass through the superior orbital fissure?
Vertebral arteries of both sides unite to form
Which muscle is the deepest in the anterior neck region?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 21: Which of the following is NOT a content of the occipital triangle?
- A. Lesser occipital nerve
- B. Occipital artery
- C. Suprascapular nerve (Correct Answer)
- D. Great auricular nerve
Explanation: Suprascapular nerve - The **suprascapular nerve** originates from the brachial plexus and supplies the supraspinatus and infraspinatus muscles; it travels through the suprascapular notch and is not found within the occipital triangle. - Its primary course and innervation are associated with the shoulder, entirely separate from the neck region defining the occipital triangle. *Great auricular nerve* - The **great auricular nerve** emerges from the cervical plexus and supplies sensory innervation to the skin over the parotid gland, mastoid process, and auricle, courses superficially across the sternocleidomastoid in the region of the occipital triangle. - It is a recognized content of the posterior triangle of the neck, which encompasses the occipital triangle. *Lesser occipital nerve* - The **lesser occipital nerve** arises from the cervical plexus at C2 and C3, providing sensory innervation to the skin of the neck and scalp posterior to the auricle. - It ascends along the posterior border of the sternocleidomastoid muscle, placing it within the boundaries of the occipital triangle. *Occipital artery* - The **occipital artery** is a branch of the external carotid artery that supplies blood to the posterior scalp. - It traverses the apex of the posterior triangle (including the occipital triangle) as it ascends to the back of the head.
Question 22: Which muscle plays a role in winking?
- A. Levator labii superioris
- B. Orbicularis oculi (Correct Answer)
- C. Levator palpebrae
- D. Corrugator supercilii
Explanation: ***Orbicularis oculi*** - This muscle is responsible for **closing the eyelid** and is essential for actions like blinking, squinting, and winking. - Its fibers encircle the eye and facilitate the **controlled closure** required for winking. *Levator labii superioris* - This muscle primarily functions to **elevate the upper lip**, playing a role in facial expressions such as sneering or smiling. - It has no direct involvement in the movement of the eyelids or the act of winking. *Corrugator supercilii* - This muscle is located in the eyebrow region and is responsible for **drawing the eyebrows medially and inferiorly**, creating vertical wrinkles between the eyebrows. - It is associated with expressions of frowning or concern, not eyelid closure. *Levator palpebrae* - This muscle is responsible for **opening the upper eyelid**, thus counteracting the action of the orbicularis oculi. - While essential for eye movement, it is not involved in the closing action required for winking.
Question 23: The roof of the olfactory region is formed by?
- A. Nasal bone
- B. Sphenoid
- C. Temporal bone
- D. Cribriform plate of ethmoid (Correct Answer)
Explanation: ***Cribriform plate of ethmoid*** - The **cribriform plate** of the ethmoid bone forms the superior boundary, or roof, of the nasal cavity specifically in the olfactory region [1]. - It is perforated by numerous **olfactory foramina** through which the olfactory nerves pass from the nasal cavity to the olfactory bulb of the brain [2]. *Nasal bone* - The **nasal bones** form part of the bridge of the nose and contribute to the anterior part of the bony framework of the external nose. - They do not form the roof of the olfactory region within the nasal cavity. *Sphenoid* - The **sphenoid bone** is a complex bone at the base of the skull, contributing to the posterior wall of the nasal cavity and parts of the cranial floor. - It does not directly form the roof of the olfactory region. *Temporal bone* - The **temporal bones** are located on the sides and base of the skull, housing structures related to hearing and balance. - They are not involved in forming the roof of the nasal cavity or the olfactory region.
Question 24: What is Galen's anastomosis?
- A. Recurrent laryngeal nerve and external laryngeal nerve
- B. Internal laryngeal nerve and recurrent laryngeal nerve (Correct Answer)
- C. None of the options
- D. Recurrent laryngeal nerve and sympathetic trunk
Explanation: ***Internal laryngeal nerve and recurrent laryngeal nerve*** - **Galen's anastomosis** (also known as **ansa Galeni**) is the connection between the **internal laryngeal nerve** (a sensory branch of the superior laryngeal nerve) and the **recurrent laryngeal nerve** (motor branch of the vagus nerve). - This anastomosis occurs in the **laryngeal mucosa** and allows for communication between these two important nerves. - The **internal laryngeal nerve** provides **sensory innervation** to the larynx above the vocal cords, while the **recurrent laryngeal nerve** provides **motor innervation** to most intrinsic laryngeal muscles (except cricothyroid). - This anastomosis is clinically significant in understanding the complex innervation patterns of the larynx. *Recurrent laryngeal nerve and external laryngeal nerve* - While both nerves are branches of the vagus nerve and innervate laryngeal structures, this connection does not constitute **Galen's anastomosis**. - The recurrent laryngeal nerve innervates intrinsic laryngeal muscles (except cricothyroid), while the external laryngeal nerve innervates the **cricothyroid muscle** and is motor in nature. *None of the options* - This option is incorrect because the correct definition of **Galen's anastomosis** is provided in the first option. *Recurrent laryngeal nerve and sympathetic trunk* - While there may be sympathetic contributions to laryngeal innervation, this does not represent **Galen's anastomosis**. - The sympathetic trunk provides autonomic innervation but the specific named anastomosis refers to the connection between the internal laryngeal and recurrent laryngeal nerves.
Question 25: All pass through jugular foramen except
- A. Mandibular nerve (Correct Answer)
- B. Vagus nerve
- C. Internal jugular vein
- D. Glossopharyngeal nerve
Explanation: ***Mandibular nerve*** - The **mandibular nerve** (CN V3) exits the skull through the **foramen ovale**, not the jugular foramen. - It is a branch of the **trigeminal nerve** and is responsible for motor innervation to muscles of mastication and sensory innervation to the lower face and mouth. *Glossopharyngeal nerve* - The **glossopharyngeal nerve** (CN IX) is one of the three cranial nerves that exit through the **jugular foramen**. - It provides motor, sensory, and parasympathetic innervation including taste from posterior third of tongue and motor to stylopharyngeus muscle. *Vagus nerve* - The **vagus nerve** (CN X) is one of the major cranial nerves that exits the skull through the **jugular foramen**. - It provides extensive motor, sensory, and parasympathetic innervation to the head, neck, thorax, and abdomen. *Internal jugular vein* - The **internal jugular vein** is formed at the jugular foramen by the continuation of the **sigmoid sinus**, and it exits the skull through this foramen. - It is one of the primary venous drainage pathways for the brain.
Question 26: Which of the following is a cerebellar nucleus?
- A. Putamen
- B. Caudate nucleus
- C. Subthalamic nucleus
- D. Fastigial nucleus (Correct Answer)
Explanation: ***Fastigial nucleus*** - The **fastigial nucleus** is one of the four principal deep cerebellar nuclei, involved in regulating **balance** and **posture** [2]. - The deep cerebellar nuclei are crucial for the cerebellum's output, relaying processed information to other brain regions [2]. *Caudate nucleus* - The **caudate nucleus** is part of the **basal ganglia**, a group of subcortical nuclei in the forebrain [1]. - It plays a significant role in **motor control**, learning, memory, and reward processing. *Subthalamic nucleus* - The **subthalamic nucleus** is a small nucleus located in the **diencephalon**, below the thalamus and above the substantia nigra [1]. - It is also part of the **basal ganglia system** and is critical for modulating motor control [1]. *Putamen* - The **putamen** is another structure belonging to the **basal ganglia**, located in the forebrain [1]. - It is primarily involved in regulating various types of **motor behavior** and learning.
Question 27: What is the nerve supply of the larynx above the level of the vocal cords?
- A. Superior laryngeal (Correct Answer)
- B. Recurrent laryngeal
- C. Glossopharyngeal
- D. External laryngeal nerve
Explanation: ***Superior laryngeal*** - The **superior laryngeal nerve** branches into the internal and external laryngeal nerves. The **internal laryngeal nerve** (a branch of the superior laryngeal nerve) provides all sensory innervation to the larynx **above the vocal cords**. - It also carries **parasympathetic fibers** to the laryngeal glands in this region. *Recurrent laryngeal* - The **recurrent laryngeal nerve** provides sensory innervation to the larynx **below the vocal cords** [1]. - It also innervates all of the intrinsic muscles of the larynx except for the cricothyroid muscle [1]. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** primarily provides sensory innervation to the **posterior one-third of the tongue**, tonsils, pharynx, and middle ear. - It does not directly provide sensory innervation to the larynx. *External laryngeal nerve* - The **external laryngeal nerve**, a branch of the superior laryngeal nerve, is primarily **motor** and innervates the **cricothyroid muscle**. - It provides **no sensory innervation** to any part of the larynx.
Question 28: Which of the following structures pass through the superior orbital fissure?
- A. Oculomotor nerve
- B. Trochlear nerve
- C. Superior ophthalmic vein
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - The **superior orbital fissure** is a key opening in the skull that allows passage of several important cranial nerves and vessels into the orbit. - The **oculomotor nerve**, **trochlear nerve**, and **superior ophthalmic vein** are all established structures that pass through this fissure. *Oculomotor nerve* - The **oculomotor nerve (CN III)** passes through the superior orbital fissure to innervate most of the extrinsic eye muscles. - It controls movements such as **adduction**, **elevation**, and **depression** of the eyeball, and also innervates the **levator palpebrae superioris** muscle for eyelid elevation [1]. *Trochlear nerve* - The **trochlear nerve (CN IV)**, which innervates the **superior oblique muscle**, also passes through the superior orbital fissure. - The superior oblique muscle is responsible for **intorsion** and **depression** of the eye, particularly when the eye is adducted [1]. *Superior ophthalmic vein* - The **superior ophthalmic vein** drains blood from structures within the orbit and passes through the superior orbital fissure to drain into the **cavernous sinus**. - This vein provides a connection between the facial veins and the cavernous sinus, which can be clinically relevant in cases of infection spread.
Question 29: Vertebral arteries of both sides unite to form
- A. Anterior spinal artery
- B. Posterior spinal artery
- C. Medullary artery
- D. Basilar artery (Correct Answer)
Explanation: Basilar artery - The paired vertebral arteries ascend through the neck via the transverse foramina of cervical vertebrae and enter the skull through the foramen magnum. - At the level of the pontomedullary junction, the two vertebral arteries merge to form a single basilar artery. Anterior spinal artery - The anterior spinal artery is formed by the union of two small branches derived from each vertebral artery near their intracranial origin. - It supplies the anterior two-thirds of the spinal cord, running along the anterior median fissure. Posterior spinal artery - The posterior spinal arteries are typically two vessels, one arising from each vertebral artery (or less commonly from the posterior inferior cerebellar artery). - They supply the posterior one-third of the spinal cord and do not form a single major merged vessel in the brainstem. Medullary artery - There is no single major artery termed the "medullary artery" formed by the union of the vertebral arteries. - The medulla oblongata is supplied by branches directly from the vertebral arteries and the basilar artery, such as the posterior inferior cerebellar artery (PICA) and direct medullary branches.
Question 30: Which muscle is the deepest in the anterior neck region?
- A. Sternocleidomastoid
- B. Platysma
- C. Longus colli (Correct Answer)
- D. Trapezius
Explanation: ***Longus colli*** - The **longus colli** muscle is the **deepest muscle** located in the anterior neck region, running along the front of the cervical vertebral column from C1 to T3. - It lies in the **prevertebral layer**, deep to all other anterior neck structures including the carotid sheath, visceral compartment, and superficial muscles. - Its position directly anterior to the vertebral bodies makes it the deepest anterior neck muscle. *Platysma* - The platysma is the **most superficial muscle** of the neck, located just beneath the skin in the superficial fascia. - It is not a deep muscle and lies superficial to all other neck muscles. *Sternocleidomastoid* - The sternocleidomastoid is enclosed within the **investing layer of deep cervical fascia**, making it relatively superficial. - While prominent in the anterior and lateral neck, it is not the deepest anterior neck muscle. *Trapezius* - The trapezius is a large, **superficial muscle of the back and posterior neck**. - It is not located in the anterior neck and is a superficial, not deep, muscle.