Head Practice Questions

Q: Protrusion of mandible is due to which of the following muscles?

Lateral pterygoid. ***Lateral pterygoid*** - The **lateral pterygoid muscle** is the primary muscle responsible for **protrusion of the mandible**. - Its bilateral contraction pulls the condyle of the mandible and the articular disc anteriorly, causing the lower jaw to move forward. *Medial pterygoid* - The **medial pterygoid muscle** primarily functions in **elevation** and **side-to-side movements** of the mandible. - While it assists in some mandibular movements, its main role is not protrusion. *Masseter* - The **masseter muscle** is a strong muscle involved in **elevating the mandible** and is crucial for **closing the jaw** (biting and chewing). - It does not contribute significantly to the forward movement or protrusion of the mandible. *Temporalis* - The **temporalis muscle** is a major muscle of mastication, responsible for **elevating the mandible** and **retracting** it. - Its fibers, particularly the posterior ones, pull the mandible backward, directly opposing protrusion.

Q: Which branch of facial nerve supplies muscles of lower lip

Marginal mandibular. ***Marginal mandibular*** - The **marginal mandibular branch** of the facial nerve innervates muscles of the lower lip and chin, including the **depressor labii inferioris**, **depressor anguli oris**, and **mentalis**. - Damage to this nerve causes an inability to depress the lower lip, leading to an **asymmetric smile**. *Buccal* - The **buccal branch** primarily innervates the **buccinator muscle** and the muscles of the upper lip. - It is crucial for **cheek compression** (e.g., blowing or sucking) and expression around the mouth. *Cervical* - The **cervical branch** supplies the **platysma muscle**, a broad sheet of muscle in the neck that helps depress the mandible and draw down the corners of the mouth. - It does not directly innervate the muscles of the lower lip. *Temporal* - The **temporal branch** provides motor innervation to the muscles of the forehead and around the eye, including the **frontalis** and **orbicularis oculi**. - It is responsible for actions like raising the eyebrows and closing the eyelids.

Q: Trismus is due to spasm of which of the following muscles

Medial pterygoid. ***Medial pterygoid*** - **Trismus** is characterized by persistent spasm of the **muscles of mastication**, leading to difficulty opening the mouth. - The **medial pterygoid** is a strong jaw **closer** muscle, and its spasm contributes significantly to trismus along with other masticatory muscles (masseter and temporalis). - Among the given options, medial pterygoid is the muscle of mastication that causes trismus when in spasm. *Mentalis* - The **mentalis muscle** is primarily involved in **pouting** and elevating the lower lip. - While it affects the lower face, it does not directly control jaw opening or closing to cause trismus. - It is **not a muscle of mastication**. *Lateral pterygoid* - The **lateral pterygoid muscle** is primarily responsible for **depressing** (opening) the jaw and is also involved in protrusion and side-to-side movements. - While it is a muscle of mastication, in the context of trismus (jaw closure spasm), the **medial pterygoid** (jaw closer) is more directly implicated than the lateral pterygoid. *Buccinator* - The **buccinator muscle** forms the muscular wall of the cheek and is involved in **chewing**, whistling, and keeping food between the teeth. - It does not directly control jaw opening or closing, and its spasm would not be the primary cause of trismus. - It is **not a muscle of mastication**.

Q: Orbital blow-out fracture involves:

Medial wall and floor of orbit. Medial wall and floor of orbit - An orbital blow-out fracture typically involves the **medial wall** (lamina papyracea of the ethmoid bone) and the **floor** (maxillary bone) of the orbit because these are the weakest bony structures. - The force of impact on the globe is transmitted to the orbital walls, causing them to fracture outwards into the adjacent sinuses. *Lateral wall and roof of orbit* - The **lateral wall** (zygomatic bone) and **roof** (frontal bone) of the orbit are structurally strong and less commonly involved in isolated blow-out fractures. - Fractures in these areas typically result from high-impact trauma and are often associated with other facial bone injuries. *Medial wall and roof of orbit* - While the **medial wall** is frequently involved, the **roof** of the orbit is a thick, sturdy bone and is less susceptible to blow-out forces. - Fractures of the orbital roof usually occur due to direct impact or high-energy trauma to the forehead. *Lateral wall and floor of orbit* - Although the **floor** is commonly fractured, the **lateral wall** is a robust structure and is not typically involved in isolated blow-out fractures. - Combined fractures of the lateral wall and floor would indicate a more extensive orbital impact, often with other mid-facial trauma.

Q: Middle meningeal artery is a branch of which artery?

Maxillary artery. ***Maxillary artery*** - The **middle meningeal artery** is a major branch of the **maxillary artery**, which itself is a terminal branch of the **external carotid artery**. - It supplies blood to the **dura mater** and cranial bones and is notably vulnerable to injury in temporal bone fractures. *Superficial temporal artery* - The **superficial temporal artery** is the other terminal branch of the **external carotid artery** (alongside the maxillary artery). - It supplies the scalp and superficial temporal region but does not give rise to the middle meningeal artery. *Facial artery* - The **facial artery** is a branch of the **external carotid artery** but primarily supplies structures of the face, such as muscles of facial expression and superficial facial tissues. - It does not give rise to the middle meningeal artery, which has an intracranial course. *Ophthalmic artery* - The **ophthalmic artery** is a branch of the **internal carotid artery** and supplies structures within the orbit, including the eye. - It does not contribute to the blood supply of the dura mater in the area supplied by the middle meningeal artery.

Q: CSF Otorrhea is due to trauma of:

Petrous temporal bone. ***Petrous temporal bone*** - **CSF otorrhea** (leakage of cerebrospinal fluid from the ear) most commonly results from a fracture of the **petrous portion of the temporal bone**. - This bone forms part of the skull base and houses structures of the inner and middle ear, a fracture here can create a direct communication between the **subarachnoid space** and the external ear canal. *Tympanic membrane* - A rupture of the **tympanic membrane** alone would lead to **otorrhea** (ear discharge), but it would primarily involve blood or middle ear fluid, not CSF. - While a ruptured tympanic membrane is necessary for CSF to exit the ear canal, the source of the CSF leak itself is proximal to the middle ear. *Cribriform plate* - A fracture of the **cribriform plate** typically results in **CSF rhinorrhea** (CSF leakage from the nose), as it is located structurally above the nasal cavity. - It is not directly involved in CSF leakage from the ear. *Parietal bone* - Fractures of the **parietal bone** are typically associated with epidural or subdural hematomas or brain injury, depending on the extent of the trauma. - They are not a usual cause of CSF leakage from the ear since this bone does not contain CSF pathways that directly communicate with the ear.

Q: Which artery lies deep to the pterion?

Middle meningeal artery. ***Middle meningeal artery*** - The **pterion** is a weak area of the skull where four bones meet: the frontal, parietal, temporal, and sphenoid bones. The **middle meningeal artery** runs deep to this point. - A blow to the pterion can cause a rupture of the middle meningeal artery, leading to an **epidural hematoma**. *Temporal artery* - The **superficial temporal artery** is located more superficially, anterior to the ear, and is not deep to the pterion. - It is a branch of the **external carotid artery** and supplies the scalp. *Frontal artery* - The **frontal branch of the superficial temporal artery** supplies the forehead, but it does not run deep to the pterion. - The main frontal artery (part of the ophthalmic artery) is located within the orbit. *Parietal artery* - This term is non-specific; there isn't a single major artery referred to solely as the "parietal artery" in this context. - The **parietal branch of the superficial temporal artery** supplies the parietal region of the scalp but is superficial rather than deep to the pterion.

Q: Muscle in the lid attached to posterior tarsal margin is:

Muller's muscle. Muller's muscle - Also known as the **superior tarsal muscle**, it is a **smooth muscle** that originates from the underside of the levator palpebrae superioris and inserts directly onto the **superior tarsal plate (posterior tarsal margin)**. - Its sympathetic innervation helps maintain the **upper eyelid position** and contributes to eyelid elevation, with damage leading to **ptosis (Horner's syndrome)**. *Superior rectus* - This is an **extrinsic ocular muscle** responsible for **elevating the eyeball** and also contributes to adduction and intorsion [1]. - It does not insert on the tarsal margin but rather on the **sclera** of the eyeball. *Superior oblique* - This is another **extrinsic ocular muscle** primarily responsible for **intorsion** (medial rotation) of the eyeball and also contributes to depression and abduction [1]. - Its tendon passes through the **trochlea** and inserts on the **posterolateral superior aspect of the sclera**, not the eyelid. *Levator palpebrae superioris* - This **striated skeletal muscle** is the **primary elevator of the upper eyelid**, innervated by the oculomotor nerve (CN III). - While it is the main elevator, its fibrous aponeurosis inserts onto the anterior surface of the tarsal plate and the skin, and **Muller's muscle** arises from its undersurface and inserts directly into the posterior tarsal margin.

Q: The volume of the orbit is about:

30 cc. ***30 cc*** - The average **volume of the orbit** in adults is approximately **30 cubic centimeters (cc)** or 30 mL. - This volume accommodates the **eyeball** (approximately 7 cc), extraocular muscles, orbital fat, nerves (optic nerve), blood vessels, and lacrimal gland. - This is a standard anatomical measurement taught in medical education and used clinically for orbital imaging assessment. *40 cc* - This value **exceeds** the normal orbital volume by approximately 33%. - The actual orbital volume is closer to **30 cc**, not 40 cc. - This measurement does not represent the standard anatomical dimension. *50 cc* - This volume is significantly **larger** than the average orbital capacity. - It represents nearly **67% more** than the actual orbital volume. - This is not consistent with normal orbital anatomy. *60 cc* - This is **double** the actual average orbital volume. - Such a measurement far exceeds the normal anatomical dimensions of the human orbit. - The correct value is 30 cc, making this option clearly incorrect.

Q: Frankfort horizontal is a reference plane constructed by joining which of the following landmarks?

Porion and Orbitale. Frankfort horizontal is a reference plane constructed by joining which of the following landmarks? ***Porion and Orbitale*** - The **Frankfort horizontal plane** is a standard anatomical reference plane used in craniometry and orthodontics. - It is constructed by connecting the **uppermost point of the external auditory meatus (porion)** with the **lowest point on the inferior margin of the bony orbit (orbitale)**. *Porion and Nasion* - The **nasion** is the point where the frontal and nasal bones meet, and its connection to the porion does not define the Frankfort horizontal plane. - This line would represent a different cranial orientation, not the internationally recognized Frankfort plane. *Porion and Sella* - The **sella** (sella turcica) is a saddle-shaped depression in the sphenoid bone housing the pituitary gland, which is an internal landmark. - Connecting the porion to the sella would create an internal reference line, not a surface-based horizontal plane typically used for facial analysis. *Nasion and Sella* - The line connecting the **nasion** and **sella** is known as the **Sella-Nasion line**, a common reference line in cephalometric analysis. - This line represents the anterior cranial base and is used to assess jaw relationships and growth patterns, separate from the Frankfort horizontal plane.

Question 1

Protrusion of mandible is due to which of the following muscles?

Accepted Answer

Lateral pterygoid

Answer

Medial pterygoid

Answer

Masseter

Answer

Temporalis

Question 2

Which branch of facial nerve supplies muscles of lower lip

Accepted Answer

Marginal mandibular

Answer

Buccal

Answer

Cervical

Answer

Temporal

Question 3

Trismus is due to spasm of which of the following muscles

Accepted Answer

Medial pterygoid

Answer

Mentalis

Answer

Lateral pterygoid

Answer

Buccinator

Question 4

Orbital blow-out fracture involves:

Accepted Answer

Medial wall and floor of orbit

Answer

Lateral wall and roof of orbit

Answer

Medial wall and roof of orbit

Answer

Lateral wall and floor of orbit

Question 5

Middle meningeal artery is a branch of which artery?

Accepted Answer

Maxillary artery

Answer

Superficial temporal artery

Answer

Facial artery

Answer

Ophthalmic artery

Question 6

CSF Otorrhea is due to trauma of:

Accepted Answer

Petrous temporal bone

Answer

Tympanic membrane

Answer

Cribriform plate

Answer

Parietal bone

Question 7

Which artery lies deep to the pterion?

Accepted Answer

Middle meningeal artery

Answer

Temporal artery

Answer

Frontal artery

Answer

Parietal artery

Question 8

Muscle in the lid attached to posterior tarsal margin is:

Accepted Answer

Muller's muscle

Answer

Superior rectus

Answer

Superior oblique

Answer

Levator palpebrae superioris

Question 9

The volume of the orbit is about:

Accepted Answer

30 cc

Answer

40 cc

Answer

60 cc

Answer

50 cc

Question 10

Frankfort horizontal is a reference plane constructed by joining which of the following landmarks?

Accepted Answer

Porion and Orbitale

Answer

Porion and Nasion

Answer

Porion and Sella

Answer

Nasion and Sella

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