Nasal Septum Anatomy and Vascularization

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Questions and Answers

What is the primary arterial source for the vascular plexus known as Kiesselbach's plexus?

Temporal artery

Carotid artery

Maxillary artery

Facial artery (correct)

Which lymphatic nodes drain the anterior part of the nasal septum?

Cervical lymph nodes

Retropharyngeal lymph nodes

Submandibular lymph nodes (correct)

Deep cervical lymph nodes

Which type of epithelium lines the paranasal air sinuses?

Stratified columnar epithelium

Pseudo-stratified ciliated columnar epithelium (correct)

Simple squamous epithelium

Cuboidal epithelium

What is the most likely complication of an infection from the mobile part of the nasal septum?

Cavernous sinus thrombosis Signup and view all the answers

Which of the following statements about the sympathetic fibers supplying the nasal cavity is correct?

They induce vasoconstriction. Signup and view all the answers

Which of the following describes Little's Area in the nasal septum?

A highly vascular area prone to epistaxis Signup and view all the answers

What is the function of the vibrissae located in the vestibule of the nasal cavity?

To trap large particles of dust from the air Signup and view all the answers

Which part of the nasal cavity is primarily responsible for communication with the nasopharynx?

Choanae Signup and view all the answers

What procedure involves inserting a mirror into the pharynx to examine the nasal cavity?

Posterior rhinoscopy Signup and view all the answers

Which sinus is most commonly infected due to viral rhinitis?

Maxillary sinus Signup and view all the answers

What is the primary method for surgically draining the maxillary air sinus?

Antrostomy Signup and view all the answers

Which symptom is NOT associated with the invasion of carcinoma in the maxillary air sinus?

Severe headache Signup and view all the answers

What structure forms the upper limit of the vestibule in the nasal cavity?

Limen nasi Signup and view all the answers

Which element primarily contributes to the mucosal lining of the maxillary air sinus?

Epithelial tissue Signup and view all the answers

What is the anatomical significance of the meatuses in the nasal cavity?

They serve as passages beneath the overhanging conchae. Signup and view all the answers

Which of the following sinus openings is associated with the hiatus semilunaris?

Maxillary air sinus Signup and view all the answers

What type of epithelium lines the olfactory region of the nasal cavity?

Olfactory epithelium composed of bipolar olfactory cells Signup and view all the answers

Which concha is an independent bone among the nasal conchae?

Inferior concha Signup and view all the answers

The bulla ethmoidalis contains which of the following?

Middle ethmoidal air cells Signup and view all the answers

Which area receives the opening of the sphenoidal air sinus?

Spheno-ethmoidal recess Signup and view all the answers

Which part of the nasal cavity slopes downwards and forwards?

Anterior part Signup and view all the answers

What forms the floor of the nasal cavity proper?

Hard palate Signup and view all the answers

Which component primarily forms the bony part of the nasal septum?

Perpendicular plate of ethmoid Signup and view all the answers

Which structure supports the posterior part of the nasal cavity?

Body of the sphenoid Signup and view all the answers

Which part of the nasal cavity is developed from the frontonasal process?

Nasal septum Signup and view all the answers

Which of the following is a minor contributor to the bony part of the nasal septum?

Nasal spine of frontal bone Signup and view all the answers

Which type of cartilage forms the major anterior part of the nasal septum?

Septal cartilage Signup and view all the answers

Which bone is part of the lateral wall of the nasal cavity?

Lacrimal bone Signup and view all the answers

What is the primary role of the vomero-nasal organ of Jacobson?

Facilitates olfactory perception Signup and view all the answers

What characterizes the anterior part of the lateral wall of the nasal cavity?

Vestibule Signup and view all the answers

Study Notes

Septal Branches of Superior Labial Artery

The septal branches of the superior labial artery supply the mobile portion of the nasal septum.

Little's Area

Found in the antero-inferior part of the nasal septum, above the vestibule.
Highly vascular due to the anastomosis of septal branches from the anterior ethmoidal, sphenopalatine, greater palatine, and superior labial arteries, forming Kiesselbach's plexus or Little's area.
A common site for epistaxis (nosebleeds) in children and young adults, often caused by fingernail trauma.

Venous Drainage of Nasal Septum

Antero-superior portion drains into the superior ophthalmic vein.
Postero-inferior portion drains into the pterygoid venous plexus.
Mobile part of the septum drains into the internal jugular vein via the facial vein.
Infection in the mobile part can spread to the cavernous sinus via the deep facial vein and the pterygoid venous plexus.

Lymphatic Drainage of Nasal Septum

Anterior part drains into submandibular lymph nodes.
Intermediate and posterior parts drain into the retropharyngeal lymph nodes.

Autonomic Nerves of Nasal Cavity

Both sympathetic and parasympathetic fibers are supplied by the Vidian nerve through the pterygopalatine ganglion.
Parasympathetic fibers supply nasal glands and control nasal secretion.
Sympathetic fibers, when stimulated, cause vasoconstriction.
Excessive rhinorrhea (runny nose) due to vasomotor and allergic rhinitis can be controlled by sectioning the Vidian nerve.

Paranasal Air Sinuses

Air-filled cavities in the bones surrounding the nasal cavity.
Develop as mucosal diverticulae of the nasal cavity invading adjacent bones.
Lined by pseudo-stratified ciliated columnar epithelium.
Four pairs: Frontal, Ethmoidal, Maxillary, and Sphenoidal.

Ethmoidal Air Sinuses

Divided into three groups: Anterior, Middle, and Posterior.

Anatomy of Nasal Cavity, Larynx, Pharynx, and Trachea

Nasal septum divides the nasal cavity into right and left halves, often deviating to one side, leading to asymmetry.
Communicates with the exterior (anteriorly) through the nares (nostrils).
Communicates with the nasopharynx (posteriorly) through the posterior nasal aperture or choanae.

Division of Nasal Cavity

Two portions: A small antero-inferior vestibule lined by skin, and a large postero-superior nasal cavity proper lined by mucosa.

Examination of Nasal Cavity

Anterior rhinoscopy through the nostril.
Posterior rhinoscopy through the pharynx.

Anterior Rhinoscopy

Visualizes the middle and inferior conchae, superior, middle, and inferior meatuses, nasal septum, and floor of the nasal cavity.

Posterior Rhinoscopy

Visualizes the choanae, conchae, and posterior border of the nasal septum.

Maxillary Sinusitis

Most commonly infected due to viral rhinitis, caries in upper premolar and molar teeth, and infected frontal and anterior ethmoidal air sinuses.
The most dependent part, acting as a secondary reservoir for pus from the frontal air sinus through the frontonasal duct and hiatus semilunaris.
Diagnosed using radiological examinations, transillumination test, and proof puncture.
Surgically drained by antral puncture (antrostomy) using a trocar and canula or by fenestrating the antrum through the gingivo-labial sulcus (Caldwell-Luc operation).
Carcinoma of maxillary air sinus arises from the sinus's mucous lining.

Carcinoma of Maxillary Air Sinus

Invasion can lead to:
- Upward invasion displacing the eyeball, causing proptosis (protrusion) and diplopia (double vision).
- Involvement of the infraorbital nerve causing pain below the orbit.
- Medial invasion obstructing the nasal cavity and causing epistaxis.
- Lateral invasion causing facial swelling and palpable mass in the gingivo-labial fold.
- Backward invasion involving the palatine nerves leading to severe referred pain in the upper teeth.

Vestibule

The antero-inferior part of the nasal cavity.
Lined by skin containing sweat glands, sebaceous glands, and coarse hairs called vibrissae.
Vibrissae trap large dust particles as air passes through the nostrils.
Limen nasi forms the upper limit of the vestibule on the lateral wall of the nasal cavity.
Columella forms the medial wall of the vestibule.

Nasal Cavity Proper

Roof, floor, medial (septal) wall, and lateral wall.

Roof of Nasal Cavity Proper

Consists of three parts:
- Anterior or fronto-nasal part:
  - Slopes downward and forward.
  - Supported by nasal cartilages, nasal and frontal bones.
- Intermediate or ethmoidal part:
  - Horizontal in course.
  - Supported by cribriform plate of ethmoid, perforated by olfactory nerves and ethmoidal vessels.
- Posterior or sphenoidal part:
  - Continuous posteriorly with the roof of the nasopharynx.
  - Supported by the anterior and inferior surfaces of the body of the sphenoid.

Floor of Nasal Cavity Proper

Almost horizontal.
Formed by the upper surface of the hard palate.

Hard Palate

Anterior three-fourths formed by palatine processes of maxilla.
Posterior one-fourth formed by horizontal processes of palatine bone.

Medial Wall or Nasal Septum

Develops from the frontonasal process.
Osseo-cartilaginous partition between the two nasal cavities.
Seldom in the median plane.
Bulges to one side or the other, more often to the right.

Bony Part of Nasal Septum

Postero-superior part formed by the perpendicular plate of the ethmoid.
Postero-inferior part formed by the vomer.
Minor contributions from the nasal spine of the frontal bone, the crest formed by the nasal bones, and the sphenoidal crest.

Cartilaginous Part of Nasal Septum

Septal cartilage forming the major anterior part of the nasal septum.
Septal processes of lower nasal cartilages.

Vomero-Nasal Cartilage

Sometimes intervenes between the vomer and septal cartilage.
Contains a mucous pouch on each side, called the vomeronasal organ of Jacobson.
Pouch lined by olfactory epithelium and supplied by olfactory nerves.
Rudimentary in humans, well-developed in macrosmatic animals (rabbit, dog).

Lateral Wall of the Nasal Cavity

Formed by a number of bones and cartilages: Nasal bone, frontal process of maxilla, lacrimal bone, conchae and labyrinth of ethmoid, inferior nasal concha, perpendicular plate of palatine, and medial pterygoid plate of sphenoid.

Cartilages Forming the Lateral Wall

Lateral nasal cartilage.
Major alar cartilage.
3 or 4 tiny cartilages of the ala.

Features in the Lateral Wall

Divided into three parts:
- Anterior part: Vestibule.
- Middle part: Atrium of the middle meatus.
- Posterior part: Presents scroll-like projections called conchae.

Conchae and Meatuses

Conchae and meatuses are the main features of the lateral wall.

Nasal Conchae

Three in number: Superior, middle, and inferior.
Superior and middle conchae are projections from the medial surface of the labyrinth of ethmoid bone.
Inferior concha is an independent bone.
Sometimes a highest concha, or supreme concha, lies above the superior concha.

Meatuses

Passages beneath the overhanging conchae.
Recesses or passages beneath the overhanging conchae.

Inferior Meatus

Largest and lies beneath the inferior nasal concha.
Nasolacrimal duct opens in its anterior part.

Middle Meatus

Lies beneath the middle concha.
Presents the bulla ethmoidalis and hiatus semilunaris.

Bulla Ethmoidalis

Bony bulging containing middle ethmoidal air cells.
Middle ethmoidal air cells open into the middle meatus, on or above the bulla.

Hiatus Semilunaris

Crescentic space below the bulla.
Anterior end called the infundibulum.
Maxillary air sinus opens into the hiatus below the bulla.
Anterior ethmoidal air sinus opens into the hiatus in front of the bulla.
Frontal air sinus opens into the infundibulum through the frontonasal duct.

Superior Meatus

Smallest meatus.
Lies below the superior concha.
Posterior ethmoidal air sinus opens into it.

Supreme Meatus

Intervenes between the nasal roof and the superior concha.
Sometimes traversed by the highest concha or supreme concha.

Spheno-Ethmoidal Recess

Above and behind the superior concha.
Receives the opening of the sphenoidal air sinus.

Lining of Nasal Cavity

Vestibule: Lined by skin.
Olfactory Region:
- Occupies the roof and adjoining septal and lateral walls of the nasal cavity above the superior concha.
- Lined by olfactory epithelium (bipolar olfactory cells, tall columnar supporting cells, and basal cells).

Respiratory Region

Lined by pseudostratified ciliated columnar epithelium.
Cilia and secretions from serous and mucous glands in the nasal cavity moisten and humidify air, protecting the lower respiratory tract.

Development

Air sinuses are present in rudimentary form at birth except the frontal air sinus, which starts developing 2-3 years after birth.
Two spurts of growth:
- First around 7-8 years during eruption of teeth.
- Second at puberty.

Functions of Paranasal Air Sinuses

Lighten facial bones and establish the adult contour of the face.
Add resonance to the voice.
Condition inspired air by adding humidity and temperature.

Frontal Air Sinus

Two in number.
Lie between the inner and outer tables of the frontal bone, deep to the medial end of the superciliary arch.
Left and right sinuses are usually unequal in size and rarely symmetrical.
Right is larger than the left and separated by a septum.
Each drains into the anterior part of the hiatus semilunaris (infundibulum) of the middle meatus.
Supplied by supra-orbital nerves and vessels.
Lymphatics drain into the submandibular group of lymph nodes.

Relations of Frontal Air Sinus

Anterior Wall: Superciliary Arch.
Posterior Wall: Meninges and frontal lobe of the brain.
Inferior Wall: Roof of the nose, roof of the orbit, and ethmoidal air cells.

Maxillary Sinus (Antrum of Highmore)

Largest of the paranasal air sinuses.
Present in the body of the maxilla.
Drains into the posterior part of the hiatus semilunaris.
First sinus to develop, appearing at about the 4th month of intrauterine life.
Rudimentary at birth, enlarges rapidly during 6-7 years, becoming fully developed at puberty.
Pyramidal in shape, with the base directed medially towards the lateral wall of the nose, and apex laterally towards the zygomatic bone.

Base of Maxillary Sinus

Presents a large opening, the maxillary hiatus, reduced in size by:
- Uncinate process of ethmoid above.
- Inferior nasal concha below.
- Descend process of lacrimal in front.
- Perpendicular plate of palatine behind.

Maxillary Sinus Opening

Opens into the hiatus semilunaris of the middle meatus.
The opening is located much higher than the floor of the sinus, hindering natural drainage.

Maxillary Sinus Blood Supply

Anterior, middle, and posterior superior alveolar vessels of the maxillary.

Maxillary Sinus Lymphatics

Drain into the submandibular group of lymph nodes.

Maxillary Sinus Nerve Supply

From anterior, middle, and posterior superior alveolar nerves of the maxillary nerve, and infraorbital nerves.

Ethmoidal Sinus

Made up of a number of air cells.
Present within the labyrinth of the ethmoid bone.
Ethmoidal air sinus is divided into three groups:
- Anterior, Middle, and Posterior.

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Description

This quiz covers the anatomy and vascular supply of the nasal septum, including the role of the superior labial artery and the function of Little's area in nasal health. It explores the venous and lymphatic drainage patterns relevant to the nasal septum and implications for clinical conditions like epistaxis.