Paranasal Sinuses — MCQs
Sphenoid sinus drains into what?
Which paranasal sinuses are present at birth?
Which of the following is not a tributary of the cavernous sinus?
All of the following arteries are branches of ECA that supply nasal septum except:
Which of the following parts of the nasal septum is the most common site for epistaxis?
Which of the following sinus grows till early adulthood?
Commonest cause for acute sinusitis is:
Most prominent and largest air cell of ethmoidal sinus?
A pregnant woman presents with fever, retroorbital pain, headache, pulsatile proptosis of the right eye, and tinnitus. BP and fundus were normal. Which of the following structures are involved?
Which of the following drains into the middle meatus except?
Paranasal Sinuses Indian Medical PG Practice Questions and MCQs
Question 1: Sphenoid sinus drains into what?
- A. Sphenoethmoidal recess (Correct Answer)
- B. Middle meatus
- C. Superior meatus
- D. Inferior meatus
Explanation: ***Sphenoethmoidal recess*** - The **sphenoid sinus** consistently drains into the **sphenoethmoidal recess**, a small area located superior and posterior to the superior concha. - This drainage pathway is distinct from other paranasal sinuses and is a key anatomical landmark for sinus drainage. *Middle Meatus* - The **middle meatus** serves as the drainage site for the **frontal sinus**, **maxillary sinus**, and the **anterior ethmoidal air cells**. - Its complex anatomy includes the hiatus semilunaris and ethmoidal bulla, which are not involved in sphenoid sinus drainage. *Superior meatus* - The **superior meatus** typically receives drainage from the **posterior ethmoidal air cells**. - It is located inferior to the superior nasal concha and is distinct from the superior-most sphenoethmoidal recess. *Inferior meatus* - The **inferior meatus** is the drainage site for the **nasolacrimal duct**, which carries tears from the eye into the nasal cavity. - It does not receive drainage from any of the paranasal sinuses.
Question 2: Which paranasal sinuses are present at birth?
- A. Frontal and maxillary sinuses
- B. Frontal and ethmoid sinuses
- C. Sphenoid and ethmoid sinuses
- D. Ethmoid and maxillary sinuses (Correct Answer)
Explanation: ***Ethmoid and maxillary sinuses*** - The **ethmoid sinuses** are present as rudimentary air cells at birth. - The **maxillary sinuses** are also present but very small, developing further throughout childhood. *Frontal and maxillary sinuses* - While **maxillary sinuses** are present at birth, the **frontal sinuses** typically begin to develop around age 2 and continue to grow into adolescence. - Therefore, the frontal sinuses are not present at birth. *Frontal and ethmoid sinuses* - The **ethmoid sinuses** are present at birth, but the **frontal sinuses** are not. - **Frontal sinus** development is a postnatal event. *Sphenoid and ethmoid sinuses* - The **ethmoid sinuses** are present at birth. - The **sphenoid sinuses** are usually not fully developed until around 2-3 years of age, though a small indentation may be present at birth.
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: All of the following arteries are branches of ECA that supply nasal septum except:
- A. Facial artery
- B. Superior labial artery
- C. Anterior ethmoidal artery (Correct Answer)
- D. Sphenopalatine artery
Explanation: ***Anterior ethmoidal artery*** - The **anterior ethmoidal artery** is a branch of the **ophthalmic artery**, which itself is a branch of the **internal carotid artery (ICA)**, not the external carotid artery (ECA). - It supplies the **upper anterior nasal septum** and lateral wall of the nasal cavity. *Facial artery* - The **facial artery** is a direct branch of the **external carotid artery (ECA)**. - It contributes to the blood supply of the nasal septum through its septal branches. *Superior labial artery* - The **superior labial artery** is a branch of the **facial artery**, meaning it indirectly originates from the **external carotid artery (ECA)**. - It sends a septal branch to supply the **anterior inferior part of the nasal septum**. *Sphenopalatine artery* - The **sphenopalatine artery** is a direct terminal branch of the **maxillary artery**, which is one of the terminal branches of the **external carotid artery (ECA)**. - It is the major blood supply to the **posterior nasal septum** and lateral wall, forming part of Kesselbach's plexus.
Question 5: Which of the following parts of the nasal septum is the most common site for epistaxis?
- A. Anterosuperior part of nasal septum
- B. Posterosuperior part of nasal septum
- C. Anteroinferior part of nasal septum (Correct Answer)
- D. Posteroinferior part of nasal septum
Explanation: ***Anteroinferior part of nasal septum*** - This region contains **Kiesselbach's plexus** (also known as Little's area), a highly vascularized area located in the anteroinferior nasal septum where four major arteries anastomose (anterior ethmoidal, sphenopalatine, greater palatine, and superior labial arteries). - Due to its **superficial location** and **rich blood supply**, Kiesselbach's plexus is the most common site for **epistaxis** (nosebleeds), accounting for approximately 90% of anterior nosebleeds. - This area is easily accessible and prone to trauma from nose picking, dry air, and minor injuries. *Anterosuperior part of nasal septum* - While part of the anterior septum, this region does not contain the dense vascular network of Kiesselbach's plexus. - It is less commonly associated with epistaxis compared to the anteroinferior region. *Posterosuperior part of nasal septum* - This area is supplied by branches of the **sphenopalatine artery** (Woodruff's plexus) and is associated with **posterior epistaxis**, which is less common but potentially more severe. - Posterior nosebleeds account for only about 10% of all epistaxis cases and typically occur in elderly patients or those with hypertension. *Posteroinferior part of nasal septum* - This region has a relatively less dense vascular supply compared to the anteroinferior or posterosuperior parts. - It is not a primary site for epistaxis and is less clinically significant for nasal bleeding.
Question 6: Which of the following sinus grows till early adulthood?
- A. Ethmoidal
- B. Frontal
- C. Sphenoid
- D. Maxillary (Correct Answer)
Explanation: ***Maxillary*** - The **maxillary sinuses** are the largest paranasal sinuses and continue to grow and expand until **early adulthood**, typically reaching their full size around 18-20 years of age. - This **post-pubertal growth** contributes to the shaping of the facial skeleton. *Ethmoidal* - The **ethmoidal sinuses** are present at birth and continue to develop, but their major growth spurt occurs in **early childhood**. - They reach close to adult size by around 7-10 years of age, not early adulthood. *Frontal* - The **frontal sinuses** begin to develop around age 6-7, starting as extensions of the ethmoid air cells. - While they continue to pneumatize, their significant growth largely finishes by **late adolescence**, earlier than the maxillary sinuses. *Sphenoid* - The **sphenoid sinuses** are rudimentary at birth and begin to pneumatize the sphenoid bone during childhood. - Their significant growth and expansion are usually complete by **late adolescence**, around 12-15 years of age.
Question 7: Commonest cause for acute sinusitis is:
- A. Swimming/Diving
- B. Acute rhinitis (Correct Answer)
- C. Nasal tumours
- D. Deviated nasal septum
Explanation: **Acute rhinitis** - **Acute rhinitis**, commonly known as the common cold, is the most frequent precursor to acute sinusitis due to inflammation and obstruction of the ostia. - The **inflammation** and **edema** of the nasal passages in rhinitis can block the sinus drainage pathways, leading to fluid accumulation and secondary bacterial infection within the sinuses. *Swimming/Diving* - While **swimming** and **diving** can introduce water and pathogens into the sinuses, leading to sinusitis, they are not the most common cause overall. - **Pressure changes** and chemical irritants like chlorine can also contribute, but usually as an exacerbating factor rather than the primary etiology. *Nasal tumours* - **Nasal tumors** can cause chronic sinusitis by physically obstructing sinus drainage, but they are relatively rare and not the most common cause of acute sinusitis. - Symptoms typically develop **gradually** and may include unilateral nasal obstruction, epistaxis, or facial pain, which are distinct from acute inflammatory onset. *Deviated nasal septum* - A **deviated nasal septum** can predispose individuals to sinusitis by impairing mucociliary clearance and ventilation of the sinuses, but it is a predisposing factor rather than the direct cause of acute sinusitis itself. - Often contributes to **recurrent** or **chronic sinusitis** by creating anatomical blockages, but an acute infectious trigger is usually necessary for an acute episode.
Question 8: Most prominent and largest air cell of ethmoidal sinus?
- A. Onodi cell
- B. Bulla ethmoidalis (Correct Answer)
- C. Haller cell
- D. Agger nasi cell
Explanation: ***Bulla ethmoidalis*** - The **bulla ethmoidalis** is universally present and is consistently described as the **largest and most prominent** of the anterior ethmoid air cells. - It forms an anatomical landmark that is consistently superior and posterior to the **hiatus semilunaris**. *Onodi cell* - The **Onodi cell** is a posterior ethmoid air cell that pneumatizes laterally and superiorly into the sphenoid bone, in close proximity to the optic nerve. - While clinically significant due to its relationship with the optic nerve, it is not the largest or most prominent ethmoidal air cell. *Haller cell* - A **Haller cell** is an infraorbital ethmoid cell located along the floor of the orbit, extending into the maxillary sinus. - These cells can contribute to **ostial obstruction** of the maxillary sinus but are typically small compared to the bulla ethmoidalis. *Agger nasi cell* - The **agger nasi cell** is the most anterior ethmoid air cell, located in the lacrimal bone anterior to the frontal recess. - It is often one of the first ethmoid cells to pneumatize but is generally small and not considered the most prominent.
Question 9: A pregnant woman presents with fever, retroorbital pain, headache, pulsatile proptosis of the right eye, and tinnitus. BP and fundus were normal. Which of the following structures are involved?
- A. Oculomotor nerve, Internal carotid artery, Cavernous sinus
- B. Abducens nerve, Internal carotid artery, Cavernous sinus
- C. Abducens nerve, Oculomotor nerve, Internal carotid artery
- D. Abducens nerve, Oculomotor nerve, Internal carotid artery, Cavernous sinus (Correct Answer)
Explanation: Abducens nerve, Oculomotor nerve, Internal carotid artery, Cavernous sinus - The combination of retroorbital pain, pulsatile proptosis, and tinnitus in a pregnant woman (indicating a potential hypercoagulable state) strongly suggests a carotid-cavernous fistula. - A carotid-cavernous fistula directly connects the high-pressure internal carotid artery to the low-pressure cavernous sinus, causing engorgement of the sinus and venous backflow. This can directly impact structures passing through or adjacent to the cavernous sinus, explaining the range of symptoms. - The oculomotor nerve (CN III) and abducens nerve (CN VI) both traverse the cavernous sinus and are commonly affected, leading to ophthalmoplegia and cranial nerve palsies. Abducens nerve, Oculomotor nerve, Internal carotid artery - This option incorrectly omits the cavernous sinus, which is central to the pathophysiology of the symptoms presented. - The cavernous sinus is the anatomical location where the internal carotid artery and multiple cranial nerves (including abducens and oculomotor) are in close proximity, making its involvement crucial for the observed signs. Oculomotor nerve, Internal carotid artery, Cavernous sinus - This option incorrectly omits the abducens nerve. While not explicitly stated as palsy, this nerve is often affected alongside the oculomotor nerve due to its passage through the cavernous sinus. - Involvement of the cavernous sinus often leads to dysfunction of cranial nerves III, IV, V1, V2, and VI, making abducens nerve involvement highly probable in such cases. Abducens nerve, Internal carotid artery, Cavernous sinus - This option incorrectly omits the oculomotor nerve. Pulsatile proptosis and retroorbital pain are strong indicators of cavernous sinus pathology, which frequently involves the oculomotor nerve (CN III), leading to ophthalmoplegia or partial palsies. - The oculomotor nerve is particularly vulnerable due to its course within the lateral wall of the cavernous sinus, making its involvement a common finding in cavernous sinus disorders.
Question 10: Which of the following drains into the middle meatus except?
- A. Lacrimal duct (Correct Answer)
- B. Maxillary sinus
- C. Frontal sinus
- D. Ethmoidal sinus
Explanation: ***Lacrimal duct*** - The **nasolacrimal duct**, also known as the lacrimal duct, drains tears from the eye into the **inferior meatus** of the nasal cavity. - It is not associated with the drainage of the paranasal sinuses into the middle meatus. *Maxillary sinus* - The **maxillary sinus** drains into the **middle meatus** via the **semilunar hiatus**, an opening located on the lateral wall of the meatus. - Obstruction of this drainage can lead to **maxillary sinusitis**. *Frontal sinus* - The **frontal sinus** drains into the **middle meatus** via the **frontonasal duct**, which opens into the anterior part of the meatus, often into the ethmoidal infundibulum. - Its drainage is crucial for preventing the accumulation of mucus and infection in the forehead. *Ethmoidal sinus* - The **anterior ethmoidal cells** and **middle ethmoidal cells** drain into the **middle meatus**, typically into the ethmoidal infundibulum or onto the **ethmoidal bulla**. - Note: The **posterior ethmoidal cells** drain into the **superior meatus**, not the middle meatus.
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