Nasal Septum Anatomy and Functions

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Questions and Answers

What is Little's Area and why is it clinically significant?

Little's Area is a vascular plexus located in the antero-inferior part of the nasal septum that is a common site for epistaxis in children and young adults.

Describe the venous drainage of the nasal septum.

The antero-superior part drains into the superior ophthalmic vein, while the postero-inferior part drains into the pterygoid venous plexus.

What are the lymphatic drainage patterns of the nasal septum?

The anterior part drains into the submandibular lymph nodes, while the intermediate and posterior parts drain into the retropharyngeal lymph node.

Explain the role of the Vidian nerve in nasal function.

The Vidian nerve carries both sympathetic and parasympathetic fibers that supply the nasal cavity, aiding in secretion and vasoconstriction. Signup and view all the answers

What are the four pairs of paranasal sinuses?

The four pairs of paranasal sinuses are the frontal, ethmoidal, maxillary, and sphenoidal sinuses. Signup and view all the answers

What is Kiesselbach’s plexus and where is it located?

Kiesselbach’s plexus is a vascular anastomosis located in Little's Area of the nasal septum, responsible for most nosebleeds. Signup and view all the answers

How can excessive rhinorrhea be managed surgically?

Excessive rhinorrhea can be managed by sectioning the Vidian nerve, which reduces parasympathetic stimulation. Signup and view all the answers

What epithelium lines the paranasal air sinuses?

The paranasal air sinuses are lined by pseudo-stratified ciliated columnar epithelium. Signup and view all the answers

What is the significance of the cavernous sinus in relation to nasal infections?

Infections from the mobile part of the nasal septum can extend into the cavernous sinus via the deep facial vein and pterygoid venous plexus. Signup and view all the answers

Describe the anatomical significance of the nasal septum in the nasal cavity.

The nasal septum divides the nasal cavity into right and left halves, which may be asymmetrical due to deviation. Signup and view all the answers

What are the two portions of each nasal cavity, and how do they differ in lining?

Each nasal cavity is divided into the vestibule, lined by skin, and the nasal cavity proper, which is lined by mucosa. Signup and view all the answers

Identify the procedure used for anterior rhinoscopy and its purpose.

Anterior rhinoscopy involves inserting a nasal speculum through the nostril to visualize internal nasal features. Signup and view all the answers

What are the common causes of maxillary sinusitis?

Maxillary sinusitis is commonly caused by infected nose (viral rhinitis) and dental issues like caries in upper teeth. Signup and view all the answers

How can infection of the maxillary air sinus be detected?

Infection can be detected through radiological examinations, transillumination tests, or proof puncture. Signup and view all the answers

What surgical techniques are used to drain the maxillary air sinus?

Antral puncture (antrostomy) and Caldwell-Luc operation for fenestration through the gingivo-labial sulcus are used. Signup and view all the answers

List the signs and symptoms associated with carcinoma of the maxillary air sinus invasion.

Signs include proptosis, diplopia, facial pain, nasal obstruction, epistaxis, and facial swelling. Signup and view all the answers

What is the role of vibrissae in the vestibule of the nasal cavity?

Vibrissae trap large particles of dust as air passes through the nostrils. Signup and view all the answers

Explain the boundaries of the nasal cavity proper.

The nasal cavity proper is bounded by the roof, floor, medial (septal) wall, and lateral wall. Signup and view all the answers

What is the limen nasi and its significance in the structure of the nasal cavity?

The limen nasi forms the upper limit of the vestibule, delineating its boundary with the nasal cavity proper. Signup and view all the answers

What is the primary structural support for the anterior part of the nasal cavity?

Nasal cartilages, nasal, and frontal bones. Signup and view all the answers

How is the medial wall of the nasal cavity primarily formed?

It is mainly formed by the perpendicular plate of the ethmoid and the vomer. Signup and view all the answers

What defines the horizontal course of the intermediate part of the nasal cavity?

It is supported by the cribriform plate of the ethmoid. Signup and view all the answers

What contributes to the formation of the hard palate?

The anterior three-fourths is formed by the palatine processes of the maxilla and the posterior one-fourth by the horizontal processes of the palatine bone. Signup and view all the answers

In which direction does the nasal septum commonly bulge?

More frequently to the right side. Signup and view all the answers

What are the primary functions of the air sinuses?

They lighten facial bones, add resonance to the voice, and condition inspired air. Signup and view all the answers

What is a unique feature of the vomero-nasal organ in humans compared to macrosmatic animals?

The vomero-nasal organs are rudimentary in humans but well-developed in animals like rabbits and dogs. Signup and view all the answers

Describe the development timeline of the frontal air sinus.

The frontal air sinus develops 2-3 years after birth and exhibits further growth spurts around 7-8 years and at puberty. Signup and view all the answers

Which structures comprise the lateral wall of the nasal cavity?

Nasal bone, frontal process of maxilla, lacrimal bone, and the conchae of the ethmoid. Signup and view all the answers

Explain the significance of the maxillary sinus opening's position related to drainage.

The maxillary sinus opening is positioned high above the floor, creating challenges for natural drainage. Signup and view all the answers

What role does the septal cartilage play in the nasal septum?

It forms the major anterior part of the nasal septum. Signup and view all the answers

Identify a feature that limits the middle part of the nasal cavity above.

The agger nasi, a faint ridge of mucous membrane. Signup and view all the answers

What differentiates the right and left frontal air sinuses?

The right frontal air sinus is larger than the left and they are separated by a septum. Signup and view all the answers

What is the primary function of the olfactory epithelium within the vomero-nasal organ?

It is responsible for the sensory perception of smell. Signup and view all the answers

What structures create boundaries for the base of the maxillary sinus?

The uncinate process of the ethmoid, inferior nasal concha, descending process of the lacrimal, and perpendicular plate of the palatine. Signup and view all the answers

Identify the nerve supplies for the maxillary sinus.

The nerve supply comes from the anterior, middle, and posterior superior alveolar nerves of the maxillary nerve as well as infraorbital nerves. Signup and view all the answers

What is the primary function of the conchae and meatuses within the nasal cavity?

They help in filtering, moistening, and humidifying the air entering the respiratory tract. Signup and view all the answers

Identify the independent bone among the nasal conchae.

The inferior concha. Signup and view all the answers

What structure opens into the inferior meatus of the nasal cavity?

The nasolacrimal duct. Signup and view all the answers

Describe the location and significance of the bulla ethmoidalis.

It is a bony bulging in the middle meatus containing middle ethmoidal air cells. Signup and view all the answers

What is the role of the hiatus semilunaris in the nasal cavity?

It serves as a passage where several sinuses open into the middle meatus. Signup and view all the answers

Where does the posterior ethmoidal air sinus open?

Into the superior meatus. Signup and view all the answers

What characterizes the olfactory region of the nasal cavity?

It is lined by olfactory epithelium and occupies the roof and adjoining walls above the superior concha. Signup and view all the answers

What does the spheno-ethmoidal recess receive, and where is it located?

It receives the opening of the sphenoidal air sinus and is located above and behind the superior concha. Signup and view all the answers

Explain the epithelial lining of the respiratory region in the nasal cavity.

It is lined by pseudo stratified ciliated columnar epithelium. Signup and view all the answers

What is the highest concha or supreme concha, and where is it located?

It is an additional concha that sometimes appears above the superior concha. Signup and view all the answers

Study Notes

Nasal Septum

Mobile part of the septum receives blood supply from septal branches of the superior labial artery and is part of Kiesselbach's plexus (Little's area).
Kiesselbach's plexus is a highly vascular area, a common site for epistaxis (nosebleeds), especially in children and young adults. Anterior ethmoidal, sphenopalatine, greater palatine, and superior labial arteries contribute to this plexus.
Venous drainage of the anterosuperior septum is via the superior ophthalmic vein; the posteroinferior part drains into the pterygoid venous plexus. The mobile part drains into the internal jugular vein via the facial vein. Infection can spread to the cavernous sinus.
Lymphatic drainage of the anterior septum is to the submandibular lymph nodes, while the intermediate and posterior parts drain to retropharyngeal lymph nodes.
Autonomic innervation is derived from the Vidian nerve via the pterygopalatine ganglion, with parasympathetic fibers controlling nasal secretion and sympathetic fibers causing vasoconstriction. Sectioning the Vidian nerve can treat excessive rhinorrhea.

Paranasal Air Sinuses

Air-filled cavities in bones around the nasal cavity, developing as mucosal diverticulae. Lined with pseudostratified ciliated columnar epithelium.
Four pairs: frontal, ethmoidal, maxillary, and sphenoidal sinuses.
Ethmoidal sinuses are divided into anterior, middle, and posterior groups.

Nasal Cavity

Divided into right and left halves by the nasal septum, which is often deviated.
Communicates anteriorly with the exterior via the nares (nostrils) and posteriorly with the nasopharynx via the choanae (posterior nasal apertures).
Divided into a smaller anteroinferior vestibule (lined by skin) and a larger posterosuperior nasal cavity proper (lined by mucosa).
Examination can occur via anterior rhinoscopy (through the nostril) or posterior rhinoscopy (through the pharynx).

Maxillary Sinusitis

Most commonly infected sinus due to factors such as viral rhinitis, dental caries, or infection from frontal and anterior ethmoidal sinuses.
Diagnosis involves radiological examinations, transillumination, and proof puncture.
Drainage may be surgical via antral puncture or Caldwell-Luc operation.
Carcinoma can arise from the mucous lining, with potential invasion affecting the orbit (proptosis, diplopia), infraorbital nerve (facial pain), nasal cavity (obstruction, epistaxis), and palate (referred tooth pain).

Vestibule and Nasal Cavity Proper

Vestibule: anteroinferior part, lined by skin with sweat glands, sebaceous glands, and vibrissae (coarse hairs). Limited superiorly by the limen nasi and medially by the columella.
Nasal Cavity Proper: Boundaries include the roof (fronto-nasal, ethmoidal, sphenoidal parts), floor (hard palate), medial wall (nasal septum), and lateral wall (various bones and cartilages).
- Hard Palate: Anterior ¾ from palatine processes of the maxilla, posterior ¼ from horizontal processes of the palatine bone.
- Nasal Septum: Develops from the frontonasal process, consists of bony (perpendicular plate of ethmoid, vomer, contributions from other bones) and cartilaginous (septal cartilage, septal processes of lower nasal cartilages, sometimes vomeronasal cartilage) parts. Vomeronasal organ (Jacobson's organ) may be present.
- Lateral Wall: Formedd by nasal bone, frontal process of maxilla, lacrimal bone, conchae, ethmoid labyrinth, inferior nasal concha, palatine bone, and medial pterygoid plate of sphenoid, plus various cartilages (lateral nasal, major alar, and minor alar cartilages).
- Conchae (Superior, Middle, Inferior, sometimes Supreme) and Meatuses (Inferior, Middle, Superior, Supreme) are key features of the lateral wall.
  - Inferior Meatus: receives the nasolacrimal duct
  - Middle Meatus: contains the bulla ethmoidalis and hiatus semilunaris, receiving drainage from the maxillary, anterior ethmoidal, and frontal sinuses.
  - Superior Meatus: receives drainage from posterior ethmoidal air sinuses
  - Supreme Meatus: may contain supreme concha, receives opening of sphenoidal sinus
- Sphenoethmoidal recess: receives opening of sphenoidal sinus.
Lining of the Nasal Cavity: Vestibule – skin; Olfactory region – olfactory epithelium; Respiratory region – pseudostratified ciliated columnar epithelium.

Frontal Air Sinus

Two sinuses between the inner and outer tables of the frontal bone. Sizes are usually unequal, the right generally larger.
Drains into the anterior part of the hiatus semilunaris (infundibulum).
Supplied by supraorbital nerves and vessels, with lymphatic drainage to the submandibular lymph nodes.
Relations: Anterior wall – superciliary arch; Posterior wall – meninges and frontal lobe; Inferior wall – roof of the nose, roof of the orbit and ethmoidal air cells.

Maxillary Sinus (Antrum of Highmore)

Largest paranasal sinus located in the body of the maxilla.
Drains into the posterior part of the hiatus semilunaris.
First sinus to develop (4th month of intrauterine life), enlarging during childhood and puberty.
Pyramidal shape with base medially toward the lateral wall of the nose and apex laterally towards the zygomatic bone.
Maxillary hiatus is the large opening in the base, partially reduced in size by surrounding structures (Uncinate process of ethmoid, Inferior nasal concha, Descend process of lacrimal, Perpendicular plate of palatine).
Opening is high in sinus causing drainage issues.
Blood Supply: anterior, middle and posterior superior alveolar vessels of maxillary artery.
Lymphatic Drainage: submandibular lymph nodes.
Nerve Supply: anterior, middle, and posterior superior alveolar nerves of maxillary nerve, and infraorbital nerves.

Ethmoidal Sinus

Collection of air cells within the ethmoid bone, divided into anterior, middle and posterior groups.

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Explore the intricate details of the nasal septum's anatomy, including its blood supply, venous drainage, and lymphatic connections. This quiz delves into the clinical significance of Kiesselbach's plexus and its role in common nasal conditions such as epistaxis. Test your knowledge and understanding of the nasal septum's structure and function.