Nose And Paranasal Air Sinuses Question And Answers

Nose

Question 1. What is the nose? List its functions.
Answer.

The nose is a pyramidal-shaped projection in the midface. It presents the tip (apex), alae, dorsum, root, and nostrils or nares. Its cavity is divided into two halves by a median nasal septum. Each cavity (also called the nasal cavity) communicates anteriorly to the exterior through the nostril (anterior nare) and posteriorly with the nasopharynx through the choana (posterior nare).

Nose Functions

• Is the organ of smell.
• Plays a significant role in respiration.
• Provides protection to the lower respiratory tract.
• Performs air conditioning of inspired air.
• Provides vocal resonance to voice.

Question 2. Enumerate the bones and cartilages forming the skeleton of external nose.
Answer.

Bones (four in number)

• Two nasal bones
• Frontal processes of maxillae

Cartilages (five in number)

• Two lateral nasal cartilages/superior nasal cartilages
• A single, median septal cartilage
• Two major alar cartilages/inferior nasal cartilages

Question 3. Describe the nasal septum under the following headings:

1. Formation,
2. Arterial supply,
3. Nerve supply and
4. Applied anatomy.
   

Answer.

Nasal Septum  Formation

The nasal septum is a median osseocartilaginous partition between two nasal cavities covered on each side by the mucous membrane.

• The bony part is formed by:
  • Vomer, below and behind
  • The perpendicular plate of the ethmoid, above
• The cartilaginous part is formed by:
  • Septal cartilage
  • Septal processes of major alar cartilages
• The particular part is formed by:
  • Fibrofatty tissue

Arterial supply

• Anterosuperior part, by anterior ethmoidal artery
• Posteroinferior part, by sphenopalatine artery
• Anteroinferior part, by superior labial and greater palatine arteries
• Posterosuperior part, by sphenopalatine artery

Nerve supply

General sensory:

• Anterosuperior part by internal nasal branches of the anterior ethmoidal nerve
• Anteroinferior part by anterior superior alveolar nerve
• Posterosuperior part by medial, posterior, and superior nasal branches of the pterygopalatine ganglion
• Posteroinferior part by nasopalatine nerve – a branch of the pterygopalatine ganglion

Special sensory By the olfactory nerve.

Nasal Septum  Applied anatomy

Deviated nasal septum (DNS): It may occur as a sequel to postnasal trauma (the most common cause) or due to congenital malformation. Excessive deviation of the nasal septum may cause nasal obstruction. It is treated by submucous resection (SMR) of the septum.

Epistaxis: It is nose bleeding that commonly occurs due to trauma of Kiesselbach’s plexus in the Little’s area.

 

Read And Learn More: Selective Anatomy Notes And Question And Answers

Question 4. What is Little’s area? Describe its clinical importance.
Answer.

It is an area in the anteroinferior part of the nasal septum where four arteries anastomose form an arterial plexus called Kiesselbach’s plexus.

The arteries forming this plexus are as follows:

• Septal branch of sphenopalatine
• Septal branch of the greater palatine
• Septal branch of anterior ethmoidal artery
• Septal branch of the superior labial artery – a branch of the facial artery

Kiesselbach’s Plexus Clinical importance The Little’s area is the most common site of nose bleeding (i.e. epistaxis) in young adults, usually due to fingernail trauma (nose picking)/small ulcer. The septal branch of the sphenopalatine artery is the largest, longest, and most tortuous. It is the main source of bleeding. Hence, it is also termed the artery of nose bleeding/rhinologist’s artery.

Question 5. Enumerate the characteristic features of the lateral wall of the nose.
Answer.

The lateral wall of the nose presents the following features:

Three conchae/turbinates

Superior concha:

It is a curved bony projection from the medial surface of the ethmoid bone. It is the smallest concha.

Middle concha:

It is a curved bony projection from the medial surface of the ethmoid bone.

Inferior concha:

It is an independent bone.

Three meatuses

Three meatuses are passages beneath the overhanging conchae.

Superior meatus:

Lies below the superior concha.

Middle meatus:

Lies underneath the middle concha. It presents:

• Ethmoidal bulla, a rounded elevation produced by underlying middle ethmoidal sinus.
• Hiatus semilunaris, a deep semicircular sulcus below the bulla.

Inferior meatus (largest):

Lies underneath the inferior concha.

Sphenoethmoidal recess

It is a triangular recess situated just above and behind the superior concha.

Opening of paranasal air sinuses and nasolacrimal ducts

The features of the lateral wall of the nose.

Question 6. Enumerate the openings into the lateral wall of the nose.
Answer.

The following structures open in the lateral wall of the nose:

• Sphenoidal air sinus: Opens into the sphenoethmoidal recess.
• Posterior ethmoidal air sinuses: Open into the superior meatus.
• Middle ethmoidal air sinuses: Open on the bulla ethmoidal in the middle meatus.
• Maxillary air sinus: Opens into the posterior part of hiatus semilunaris at its posterior end in the middle meatus.
• Anterior ethmoidal air sinuses: Open into the anterior part of the hiatus semilunaris in the middle meatus.
• Frontal air sinus: Opens into the infundibulum at the anterior end of the hiatus semilunaris in the middle meatus.
• Nasolacrimal duct: Opens into the anterior part of the inferior meatus.

Question 7. Enumerate the structures opening in the middle meatus of the nose.
Answer.

These are as follows:

• Middle ethmoid air sinus
• Frontal sir sinus
• Anterior ethmoidal air sinus
• Maxillary air sinus

Paranasal air sinuses

Question 1. What are the paranasal air sinuses? Name them and enumerate their functions.
Answer.

The paranasal air sinuses are air-filled cavities in the paranasal bones, such as the frontal, ethmoid, sphenoid, and maxilla.

They are named according to the bones in which they are present, i.e.:

• Frontal air sinuses are present in the frontal bone.
• Ethmoidal air sinuses are present in the ethmoid bones.
• Sphenoidal air sinuses are present in the body of the sphenoid bone.
• Maxillary air sinuses (largest air sinuses) are present in the body of maxillae.

Paranasal Air Sinuses Functions The functions of air sinuses are as follows:

• Make the skull lighter.
• Add resonance to the voice.
• Humidify the air during inspiration.
• Provide an adult shape to the facial skeleton.

Question 2. Describe the maxillary air sinus under the following headings:

1. Location,
2. Boundaries,
3. Drainage,
4. Development and
5. Applied anatomy.
   

Answer.

Maxillary Air Sinus Location

The maxillary air sinus is the largest paranasal air sinus located in the body of the maxilla.

Maxillary Air Sinus Boundaries

It is a pyramidal-shaped cavity in the body of the maxilla. Its boundaries are as follows:

Maxillary Air Sinus Apex:

It is directed towards the zygoma and often extends into the zygomatic bone.

Maxillary Air Sinus Base:

It is formed by the lateral wall of the nasal cavity.

Maxillary Air Sinus Roof:

It is formed by the floor of the orbit.

Maxillary Air Sinus Floor:

It is narrow and formed by the alveolar process of the maxilla. It lies about 1 cm below the level of the floor of the nose.

Maxillary Air Sinus Drainage

It drains in the middle meatus of the nose in the posterior part of the hiatus semilunaris.

Note: The ostium for the maxillary air sinus is located near its roof – a disadvantageous location for natural drainage.

Maxillary Air Sinus Development

It is the 1st paranasal air sinus to develop. It develops in the 4th month of IUL. It grows rapidly during 6–7 years of life and reaches adult size after the eruption of permanent teeth.

Maxillary Air Sinus Applied anatomy

Maxillary Sinusitis (most common):

The maxillary sinus is most commonly infected because its ostium is located near the roof, which hampers its drainage. The infection may reach the sinus either from the nasal cavity or from caries of the upper molar teeth.

Maxillary Sinusitis Referred pain:

The pain of the maxillary sinus may be referred to the upper teeth due to the same nerve supply.

Question 3. Write briefly about frontal air sinuses.
Answer.

• These are located in the frontal bone between its outer and inner tables behind superciliary arches. The right and left frontal air sinuses are rarely of equal size, and the septum separating them is rarely situated in the median plane.
• The frontal sinus drains through the frontonasal duct inferiorly into a funnel-shaped infundibulum at the anterior end of the hiatus semilunaris of the middle meatus.
• The infection of the frontal sinus (frontal sinusitis) usually causes severe and localized pain in the forehead (frontal headache). The frontal headache shows characteristic periodicity, i.e. it increases as the sun rises and decreases as the sun sets.
• The pain of the frontal air sinus may extend up to the vertex through the supraorbital nerves that supply it. The frontal sinusitis can lead to brain abscess in the frontal lobe.