Scalp and Facial Muscles — MCQs

10 questions

In acoustic neuroma, cranial nerve to be involved earliest is

After an accident, a patient is unable to close her mouth completely due to certain facial injuries. Which muscle is paralyzed most commonly?

Which of the following is not a tributary of the cavernous sinus?

Hemostasis in scalp wound is best achieved by -

Which cranial nerve supplies the muscles of facial expression?

True about lower motor neuron palsy of VIIth nerve:

Bleeding as shown in the image is due to which of the following vessels?

Which of the following muscles has dual nerve supply:

A body is brought to you for autopsy. On examination, you find a bluish-purple lesion with well-defined margins. On incising the lesion, blood is present in the vessels. The lesion is confined to the dermis and is absent in areas under pressure. What is the lesion described in the scenario?

Q10

After a minor head injury a young patient was unable to close his left eye and had drooling of saliva from left angle of mouth. He is suffering from -

Scalp and Facial Muscles Indian Medical PG Practice Questions and MCQs

Question 1: In acoustic neuroma, cranial nerve to be involved earliest is

A. Cranial nerve VIII (Correct Answer)
B. Cranial nerve VII
C. Cranial nerve IX
D. Cranial nerve V

Explanation: ***Cranial nerve VIII*** - Acoustic neuromas (vestibular schwannomas) arise from the **Schwann cells** of the vestibular branch of the **eighth cranial nerve (vestibulocochlear nerve)** [1]. - Due to their origin, symptoms related to CN VIII, such as **unilateral hearing loss**, **tinnitus**, and **vertigo**, are typically the earliest to appear [1]. *Cranial nerve VII* - The **facial nerve (CN VII)** is anatomically close to the eighth nerve within the **internal auditory canal**, but its involvement usually occurs later as the tumor grows and compresses it [1]. - Early involvement of CN VII would primarily manifest as **facial weakness or paralysis** or taste disturbances [1]. *Cranial nerve IX* - The **glossopharyngeal nerve (CN IX)** is located more medially in the **cerebellopontine angle** and is typically affected only by larger tumors. - Symptoms would primarily include **dysphagia (difficulty swallowing)** or loss of taste on the posterior tongue. *Cranial nerve V* - The **trigeminal nerve (CN V)** is also situated in the cerebellopontine angle, further from the initial growth site of an acoustic neuroma. - Involvement of CN V would lead to **facial numbness**, pain, or weakness in the muscles of mastication, which are late manifestations.

Question 2: After an accident, a patient is unable to close her mouth completely due to certain facial injuries. Which muscle is paralyzed most commonly?

A. Orbicularis oris (Correct Answer)
B. Zygomaticus major
C. Levator anguli oris
D. Buccinators

Explanation: ***Orbicularis oris*** - The **orbicularis oris** muscle forms a ring around the mouth and is primarily responsible for **closing and protruding the lips**, as well as other facial expressions involving the mouth. - Injury leading to paralysis of this muscle would directly impair the ability to **close the mouth completely** and **seal the lips**. *Zygomaticus major* - The **zygomaticus major** muscle acts to pull the corners of the mouth **upward and laterally**, contributing to smiling. - Its paralysis would affect the ability to smile effectively, but not directly impede the ability to close the mouth. *Levator anguli oris* - The **levator anguli oris** muscle elevates the corner of the mouth (angle of the mouth). - Its dysfunction would impair the ability to raise the corner of the mouth, not the ability to completely close the mouth. *Buccinators* - The **buccinator** muscle is involved in pressing the cheek against the teeth, which helps in chewing, whistling, and sucking. - Paralysis of the buccinator would primarily affect these actions, potentially causing food to pocket in the cheeks, but would not directly prevent mouth closure.

Question 3: Which of the following is not a tributary of the cavernous sinus?

A. Central vein of retina
B. Sphenoparietal sinus
C. Inferior cerebral vein (Correct Answer)
D. Superior ophthalmic vein

Explanation: Detailed anatomical knowledge of the dural venous sinuses is required to answer this question. Venous drainage from the brain by way of the deep veins and dural sinuses typically empties principally into the internal jugular veins, though blood also drains via the ophthalmic and pterygoid venous plexuses [1]. ***Inferior cerebral vein*** - The **inferior cerebral veins** drain the inferior surface of the cerebral hemispheres and typically empty into the **basal vein of Rosenthal**, **transverse sinus**, or other dural sinuses. - They do **not directly drain** into the cavernous sinus, making this the correct answer. - While some small inferior cerebral veins may occasionally communicate with the cavernous sinus, they are not considered standard tributaries. *Central vein of retina* - The **central vein of retina** drains the retina and exits the eye through the optic nerve. - It drains into the **superior ophthalmic vein**, which then empties into the cavernous sinus. - It is an **indirect tributary** via the superior ophthalmic vein, not a direct tributary itself. *Sphenoparietal sinus* - The **sphenoparietal sinus** is a dural venous sinus that runs along the posterior edge of the lesser wing of the sphenoid bone. - It is a **direct tributary** that drains anteriorly into the cavernous sinus. - This is one of the standard tributaries listed in anatomical texts. *Superior ophthalmic vein* - The **superior ophthalmic vein** is the **major tributary** draining orbital structures including the eyeball, extraocular muscles, and eyelids. - It passes posteriorly through the **superior orbital fissure** to drain directly into the cavernous sinus. - This is the most clinically significant tributary, as infections can spread from the face to the cavernous sinus via this route.

Question 4: Hemostasis in scalp wound is best achieved by -

A. Catching and crushing the bleeders by hemostats
B. Coagulation of bleeders
C. Eversion of galea aponeurotica
D. Direct pressure over the wound (Correct Answer)

Explanation: ***Direct pressure over the wound*** - Initial and most effective method for immediate **hemostasis** in scalp wounds due to the rich vascular supply and the ability to compress vessels against the underlying bone. - Applying **firm, sustained pressure** directly to the bleeding site helps to tamponade the vessels and promote clot formation. *Catching and crushing the bleeders by hemostats* - While hemostats can be used for individual vessels, it is often impractical and time-consuming for the numerous small vessels in a scalp wound and can cause **tissue damage**. - This method is typically reserved for **identified, larger arterial bleeders** once initial control has been achieved. *Coagulation of bleeders* - **Electrocautery** can be effective for smaller bleeders but risks **thermal injury** to surrounding tissues of the scalp, which has a relatively thin overlying skin. - It is often used after direct pressure has controlled the bulk of the bleeding and individual vessels need precise control. *Eversion of galea aponeurotica* - **Eversion of the galea** is a technique used during wound closure to ensure proper anatomical apposition, but it does not directly achieve hemostasis. - This step is for facilitating wound closure and preventing dead space rather than immediate bleeding control.

Question 5: Which cranial nerve supplies the muscles of facial expression?

A. Trigeminal nerve
B. Glossopharyngeal nerve
C. Facial nerve (Correct Answer)
D. Vagus nerve

Explanation: ***Facial nerve*** - The **facial nerve (cranial nerve VII)** is primarily responsible for innervating all the muscles of **facial expression**, allowing for actions like smiling, frowning, and closing the eyes. - It also carries **taste sensation** from the anterior two-thirds of the tongue and controls **salivary and lacrimal gland** secretions. *Trigeminal nerve* - The **trigeminal nerve (cranial nerve V)** is largely responsible for **sensory innervation** to the face, including touch, pain, and temperature. - It supplies the **muscles of mastication** (chewing), not facial expression. *Glossopharyngeal nerve* - The **glossopharyngeal nerve (cranial nerve IX)** provides **sensory innervation** to the posterior tongue, pharynx, and middle ear. - It controls certain **pharyngeal muscles** and plays a role in taste and **salivary secretion** from the parotid gland. *Vagus nerve* - The **vagus nerve (cranial nerve X)** has extensive innervation, controlling muscles of the **pharynx and larynx** (voice and swallowing) and carrying autonomic innervation to most **visceral organs**. - It has no role in the innervation of the muscles of facial expression.

Question 6: True about lower motor neuron palsy of VIIth nerve:

A. Forehead muscles are affected unlike upper motor neuron lesions
B. Melkersson's syndrome causes recurrent paralysis
C. Eye protection is done
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - All statements regarding **lower motor neuron (LMN) palsy of the VIIth cranial nerve** (facial nerve) are accurate. - This type of injury affects the entire ipsilateral side of the face, including the forehead and eye, which require specific protective measures [1]. *Melkersson's syndrome causes recurrent paralysis* - **Melkersson-Rosenthal syndrome** is characterized by the triad of **facial nerve palsy** (often recurrent), **orofacial swelling**, and **fissured tongue**. - The facial palsy in this syndrome is typically a **lower motor neuron lesion**. *Forehead muscles are affected unlike upper motor neuron lesions* - In a **lower motor neuron lesion**, all muscles of the ipsilateral face, including the **frontalis muscle** (which controls the forehead), are affected due to damage to the facial nerve nucleus or its peripheral branches. - In contrast, **upper motor neuron lesions** spare the forehead muscles because the upper face receives bilateral innervation from the cerebral cortex [1]. *Eye protection is done* - Due to paralysis of the **orbicularis oculi muscle**, patients cannot fully close their eye (lagophthalmos), leading to exposure keratitis and dryness. - **Eye protection** with artificial tears, lubricating ointments, and eyelid taping is crucial to prevent corneal damage [1].

Question 7: Bleeding as shown in the image is due to which of the following vessels?

A. Lenticulostriate artery
B. Vertebral artery
C. Bridging veins (Correct Answer)
D. Middle meningeal artery

Explanation: ***Bridging veins*** - The image depicts a **subdural hemorrhage (subdural hematoma)**, a collection of blood between the dura mater and the arachnoid mater, typically appearing as a **crescent-shaped** hyperdensity that conforms to the brain surface. - This type of hemorrhage is caused by the tearing of **bridging veins** that traverse the subdural space, connecting the cerebral cortex to the dural venous sinuses. - Tearing of these veins occurs due to rapid acceleration-deceleration forces causing the brain to move relative to the dura, stretching and rupturing the veins. This is common in **head trauma**, especially in the elderly (due to brain atrophy increasing vein vulnerability) or infants. *Lenticulostriate artery* - Rupture of the lenticulostriate arteries (perforating branches of the middle cerebral artery) typically leads to **intraparenchymal hemorrhage**, specifically in the basal ganglia or internal capsule. - This type of bleeding is confined within the brain parenchyma, rather than collecting in the subdural space as seen in the image. - Associated with hypertensive hemorrhage. *Vertebral artery* - The vertebral arteries supply the posterior circulation of the brain, and their rupture can lead to **subarachnoid hemorrhage** (if a posterior circulation aneurysm ruptures) or **intraparenchymal bleeding** in the brainstem or cerebellum. - Bleeding from the vertebral artery is not associated with the subdural collection pattern shown in the image. *Middle meningeal artery* - The middle meningeal artery runs in the epidural space, and its rupture (often due to temporal bone fracture) causes an **epidural hematoma**. - An epidural hematoma is characterized by a **biconvex (lentiform) shape** on imaging and is situated between the dura mater and the skull, which is distinct from the **crescent-shaped** subdural collection shown. - Does not cross suture lines, unlike subdural hematomas which can extend over multiple lobes.

Question 8: Which of the following muscles has dual nerve supply:

A. Lateral pterygoid
B. Masseter
C. Temporalis
D. Digastric (Correct Answer)

Explanation: ***Digastric*** - The digastric muscle has **dual nerve supply**; its **anterior belly** is innervated by the **trigeminal nerve** (via the mylohyoid nerve), and its **posterior belly** is innervated by the **facial nerve**. - This unique innervation pattern makes it distinct among the given options. *Lateral pterygoid* - The lateral pterygoid muscle receives its innervation solely from the **mandibular division of the trigeminal nerve** (cranial nerve V3). - It does not have dual nerve supply from two different cranial nerves. *Masseter* - The masseter muscle is innervated exclusively by the **mandibular division of the trigeminal nerve** (cranial nerve V3). - Its motor function is entirely dependent on this single nerve. *Temporalis* - The temporalis muscle is also innervated solely by the **deep temporal nerves**, which are branches of the **mandibular division of the trigeminal nerve** (cranial nerve V3). - It does not receive innervation from any other cranial nerve.

Question 9: A body is brought to you for autopsy. On examination, you find a bluish-purple lesion with well-defined margins. On incising the lesion, blood is present in the vessels. The lesion is confined to the dermis and is absent in areas under pressure. What is the lesion described in the scenario?

A. Hematoma
B. Hypostasis (Correct Answer)
C. Bruise
D. Burn

Explanation: ***Hypostasis*** - **Hypostasis**, also known as **livor mortis**, is the pooling of blood in the capillaries and venules of the skin due to gravity after cessation of circulation. - The description of a **bluish-purple lesion** with **well-defined margins**, blood remaining in vessels upon incision, confinement to the dermis, and absence in pressure areas (indicating relocation under pressure from a surface) are all classic characteristics of **post-mortem hypostasis**. *Hematoma* - A **hematoma** is a localized collection of blood outside blood vessels, usually from hemorrhage, forming a mass due to trauma. - Unlike hypostasis, a hematoma would typically involve extravasated blood forming a distinct mass within tissues, not just pooling within intact vessels in the dermis, and would not be absent in pressure areas after death. *Bruise* - A **bruise** (contusion) is caused by trauma that damages capillaries and venules, leading to leakage of blood into the surrounding interstitial tissue. - While a bruise can be bluish-purple, the key differentiating factor is that a bruise involves **extravasated blood** into the tissue, whereas hypostasis involves blood remaining within the vessels, which can be seen upon incision as blood flowing out. *Burn* - A **burn** is tissue damage caused by heat, chemicals, electricity, or radiation, leading to characteristic skin changes like redness, blistering, or charring. - The described lesion—a bluish-purple discoloration with blood in vessels and absence in pressure areas—is entirely inconsistent with the pathology of a burn injury.

Question 10: After a minor head injury a young patient was unable to close his left eye and had drooling of saliva from left angle of mouth. He is suffering from -

A. VIIth nerve injury (Correct Answer)
B. Combined VIIth and IIIrd nerve injury
C. Vth nerve injury
D. IIIrd nerve injury

Explanation: ***VIIth nerve injury*** - Inability to close the left eye and drooling of saliva from the left angle of the mouth are classic signs of **facial nerve (VIIth cranial nerve) palsy**. [1] - The facial nerve innervates the muscles of **facial expression**, including the **orbicularis oculi** (responsible for eye closure) and muscles that prevent drooling. *Combined VIIth and IIIrd nerve injury* - A combined injury would also present with signs of **oculomotor nerve (IIIrd cranial nerve)** dysfunction, such as **ptosis** (drooping eyelid), **mydriasis** (dilated pupil), and **ophthalmoplegia** (eye movement paralysis). [2], [3] - These additional symptoms are not mentioned in the patient's presentation. *Vth nerve injury* - **Trigeminal nerve (Vth cranial nerve)** dysfunction would typically involve sensory deficits of the face or weakness in the muscles of **mastication** (chewing). - It does not cause an inability to close the eye or drooling of saliva. *IIIrd nerve injury* - **Oculomotor nerve (IIIrd cranial nerve) injury** primarily affects eye movements, pupil constriction, and eyelid elevation. [3] - Symptoms would include **ptosis**, **dilated pupil**, and the eye being **down and out**, which are not described. [2]

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