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Anatomy Of The Nose And Paranasal Sinus

  1. External Nose
    1. Osteocartilaginous Framework
      1. 2 nasal bones+2 nasal processes of frontal bones+2 frontal processes of maxilla
      2. Upper 1/3 : Bony
      3. Lower 2/3 : Cartilaginous
    2. Nasal bones
      The nasal bones unite with each other in the midline, with the frontal bone superiorly at the nasofrontal suture and laterally with the frontal process of the maxilla at the nasomaxillary suture
    3.  Cartilaginous part
      1. Upper lateral cartilages: (hyaline cartilage)
        They lie inferior to the nasal bones, the frontal processes of maxilla and the lower lateral cartilages
        P. S limen nasi  
        Or Is the junction between the upper and lower lateral cartilage
        Nasal valve (SITE for: intercartilaginous incision)
        Limen vestibuli
      2. Lower lateral cartilages (Alar Cartilages)
        Two parts
        1. Lateral : nasal ala
        2. Medial crura: columella
      3. Lower Alar (Sesamoid) Cartilages
      4. Septal Cartilage
    4. Nerve supply of the external nose: Receives its sensory supply from the opthalmic and the maxillary division of trigeminal nerve

MCQ . Rhinophyma is due to hypertrophy of sebaceous glands of nasal tip. It is associated with acne rosacea.


  1. Nasal cavity
    1. Nasal cavity proper : lateral wall, medial wall, roof, floor
    2. Vestibule
      Lined by skin
      Contains sebaceous glands and hair follicles (vibrissae)
    3. Muscles of the nose;
      1. Procerus                                                                      
      2. Nasalis
      3. Levator labii superioris alaque nasi                      
      4. Anterior dilator nares
      5. Posterior dilator nares                                                      
      6. Depressor septi

MCQ. Kallmann syndrome is anosmia and congenital hypogonadism.
MCQ. Schneiderian membrane (mucosa). It is another name for respiratory mucosa of nose and consists of pseudo­stratified ciliated columnar cells & therefore tumor of this mucosa in called : Schneiderans tumor commonly called inverted papilloma.

  1. Lateral Nasal Wall
    1. Inferior meatus          
      1. largest meatus, runs along the entire wall
      2. Highest point : junction of anterior and middle 1/3rd
      3. Nasolacrimal duct: opens just anterior to its highest point (it is closed by mucosal flap Called valve of hasner
Fig: (A) Coronal section through middle meatus. Uncinate process forms the medial wall and floor of the infundibulum. (B) Coronal section showing relationships of uncinate process, bulla ethmoidalis, middle turbinate, maxillary sinus, orbit and cribriform plate.

  1. Inferior turbinate
    1. Is a separate bone
    2. Has its own ossification → centre 5th i.u. month
    3. Has large submucosal cavernous plexus with large sinusoids contributes majorly to nasal resistance
  2. Middle meatus occupies posterior 1/2 of the wall
    1. Lies lateral to the middle turbinate
    2. Structures of importance
    3. Hiatus semilunaris: Is a 2-d semi-lunar groove which leads anteriorly to the ethmoidal
    4. infundibulum. It view below and in front of the bulla ethmoidalis-
    5. Ethmoidal infundibulum: 3-D structure in deep part of hiatus semilunaris, frontal sinus,
    6. maxillary and the anterior ethmoids drain into it
    7. Anterior/ Posterior fontanelles: Are membranous areas between the inferior turbinate and the uncinate process. Accessory ostia are found mostly in the posterior fontanelle
    8. Uncinate process : Thin, bony structure. Rims antero-superiorly to postero inferiorly antero-
    9. superior attachment: postero-medial to the nasolacrimal crest. Postero-inferior to inferior turbinate.
    10. Bulla ethmoidalis: due to middle ethmoidal cells. It is the most constant
    11. Agger nasi - a ridge, may have air cells, runs vertically downwards
    12. Natural incidence of accessory ostia = 4.5 %
      in chronic rhinosinusitis                 = 25 %
    13. These are the most anterior ethmoidal air cells.
  3. Osteomeatal complex (Piccardi’s circle)
    1. Is a site for the common drainage pathway of the anterior group of sinuses (frontal /anterior / maxillary)
    2. Structures contributing to its formation are
      1. Maxillary sinus ostium                                
      2. Hiatus semilunaris
      3. Ethmoidal infundibulum                            
      4. Middle meatus
      5. Frontal recess                                              
      6. Ethmoidal bulla              
      7. ​Uncinate process
  4. Middle turbinate : is a part of the Ethmoid bone.
    3 parts
    1. Vertical                            
    2. Oblique                          
    3. ​Horizontal
      Concha Bullosa : Pneumatized middle turbinate
  5. Superior meatus
    Posterior ethmoidal cells open into it
  6.  Superior turbinate
    1. The superior turbinates are the smallest of the three. The openings to the posterior ethmoidal sinuses exist under the superior turbinates.
    2. They completely cover and protect the nerve axons piercing through the cribriform plate (a porous bone plate that separates the nose from the brain) into the nose.
  1. Onodi Cells: Are the most posterior ethmoidal air cells extending laterally to the sphenoid 1.5 cm posterior to the anterior wall of the sphenoid. They may be close to optic nerve near the orbital apex.
  2. Haller Cells: ethmoidal air ceils present in the orbital floor
    P. S. Ethmoid sinus is present at birth
    Radiologically it is appreciable by I year of age
  3. Concha bullosa – Pneumatized middle turbinate
  1. Supreme Turbinate: may be present in some
  2. Nerve Supply of Nasal Cavity:
    1. Olfactory Nerves
    2. Autonomic nerves (secretomotor) vidian nerve (of pterygoid canal)
    3. Nerves of common Sensation: ant Ethmoidal, sphenopalatine ganglion brs., infraorbital nerve brs.
  3. Lining membrane of Nose:
    1. Vestibule - Skin
    2. Olfactory area (2-5 sq- cm.) - upper 1/3rd of lat wall + opp. Septal area + roof- Olfactory mucosa
    3. Rest - Respiratory epithelium (pseudostratified ciliated columnar epith with lots of goblet cells)
Nasal Septum

Fig.: Anatomy of nasal septum
  1. Columellar Septum - medial crura of the alar cartilage (freely mobile)
  2. Membranous septum - double layer of skin with no bony/cartilaginous support (freely mobile)
  3. Septum Proper -  septal cartilage (quad-cartilage), perpendicular plate of ethmoid, vomer Septal cartilage lies in a groove in the ant. edge of Vomer
  1. Blood supply of the nasal septum
  1. Sphenopalatine artery: Postero-inferior part
  2. Greater palatine
  3. Superior labial branch of facial artery
  4. Anterior ethmoidal & posterior ethmoidal: Superior end except post ethmoidal, rest form an anastomosis called Kiesselbach plexus
  1. Nerve Supply of the Nasal Septum
  1. Nasopalatine : Majority of the septal area
  2. Anterior ethmoidal nerve  : Antero - superior part
  3. Anterior superior alveolar Nerve : Antero - inferior portion
  4. Olfactory area : Upper part of the septum

Blood Supply of nasal septum

Blood supply of lateral wall of nose

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