NOSE ANATOMY

INTRODUCTION

the nose is the most prominent part of the face.

It is the opening for the respiratory pathway and it acts as an olfactory sensor in our body.

it contains various olfactory receptors and nasal sinus

the olfactory mucosa lines

the nose is divided into the following sections

• external Nose

• nasal cavity

• lateral wall of Nose

• conchae and meatuses

EXTERNAL NOSE the external nose is further divided into

• root

• dorsum

• tip

bones in the nose: - nasal bone - forms the nasal bridge cartilages in nose : - septa nasal cartilage - lateral nasal cartilage - major alar cartilage - minor alar cartilage - vomerovaginal cartilage muscles in the nose: - dilator naris - depressor septi - levator labi superiors alaeque nasi the skin over external nose is supplied external nasal, infratrochlear and infraorbital nerve. NASAL CAVITY the nasal cavity extends from nostrils to posterior nasal aperture. it is divided into right and left half each half has a floor, roof, medial wall and lateral wall roof:

• about 5 - 7 cm long

• has an anterior and posterior slope

• the anterior slope is formed by a nasal plate of the frontal bone

• posterior bone is formed by the inner surface of the sphenoid bone

floor:

• made by the palatine process of the maxilla and horizontal plate of palatine

• about 5 cm long

lateral wall:

• lateral walls contain concha

NASAL SEPTUM

it separates both nasal cavities it contains both boney and cartilaginous part boney part is formed by:

• vomer

• perpendicular part of the ethmoid

• frontal, sphenoid, palatine and maxillary bone contribute to the margins

cartilaginous part is formed by :

• septal process

• septal part of inferior nasal cartilage

cuticular part- fibrofatty tissue

the nasal septum is usually deflected ARTERIAL SUPPLY

anterosuperior - anterior and posterior ethmoidal artery anteroinferior - septal branch of superior labial artery posterosuperior - sphenopalatine artery ( also called the artery of epistaxis) the anteroinferior region has anastomoses of all the arteries that form a capillary network called kiesselbach's plexus

VENOUS DRAINAGE

anterior - facial vein posterior - sphenopalatine vein NERVE SUPPLY 1. General sensory nerves they arise from the trigeminal nerve

• anterosuperior part -

  • internal nasal branch of the ethmoid nerve

• posteroinferior part

  • nasopalatine branch of the pterygopalatine ganglion

2. special sensory nerves (olfactory nerves)

• olfactory nerves are confined to the upper part of the olfactory area

• the olfactory area contains olfactory mucosa

• the mucus protects the olfactory epithelium and allows diffusion of odor

LYMPHATIC DRAINAGE anterior half - submandibular nodes posterior half - reterophyrageal and deep cervical nodes LATERAL WALL OF NOSE it contains shelf-like boney projections called conchae. they increase the surface area of air conditioning the lateral wall separates the nose from - orbit - ethmoidal air sinus - maxillary air sinus - lacrimal sac - nasolacrimal duct it is divided into 3 parts

• vestibule - small depressed part in the anterior

• atrium - middle space

• conchae and conchae meatus

the lateral wall is partly cartilaginous and partly boney the boney parts are formed by

• nasal

• frontal process of the maxilla

• superior and middle nasal conchae (made from the labyrinth of ethmoid)

• inferior conchae formed by spongy bone

• palatine bone and their processes

cartilaginous part

• superior nasal cartilage

• inferior nasal cartilage

• cartilage of ala

the cuticular lower part is formed by fibrofatty tissue

CONCHAE nasal conchae are boney projections that are present in the lateral wall there are 3 concha's

• superior concha

  • smallest concha

  • situated above the posterior part of the middle concha

• middle concha

  • from the medial wall of the ethmoid labyrinth

• inferior concha

  • it is an independent bone

MEATUS meatus of the nose is the passage below the conchae 1. inferior meatus

• the largest meatus

• nasolacrimal duct opens in the middle

• the opening is guarded by lacrimal fold or hasners valve

2. middle meatus

• middle ethmoidal sinus opens at ethmoidal bulla

  • ethmoidal bulla is a rounded prominence

• the infundibulum is a short passage below the meatus

• hiatus semilunaris is a deep semicircular sulcus below bulla

  • frontal air sinus opens in the anterior part

  • ethmoidal air sinus opens behind frontal sinus

  • maxillary sinus opens in the posterior part

3. superior meatus

• below superior concha

• receives opening of posterior ethmoidal air sinus

4. sphenoethmoidal recess

• triangular fossa above superior concha

• opening of sphenoidal air sinus

5. Atrium of the middle meatus

• a shallow depression in front of the middle meatus

ARTERY SUPPLY anterosuperior quadrant - anterior ethmoidal artery anteroinferior quadrant - facial artery posterosuperior quadrant - sphenopalatine artery posteroinferior quadrant - great plalatine artery VENOUS DRAINAGE veins from plexus to drain into

• facial vein

• pharyngeal plexus

• pterygoid plexus

NERVE SUPPLY 1. general sensory nerves

• anterosuperior quadrant - anterior ethmoidal nerve

• anteroinferior quadrat - anterior superior alveolar nerve

• posterosuperior quadrant - posterior superior nasal branch from pterygopalatine ganglion
  

2. special sensory nerves - upper part of the lateral wall LYMPHATIC DRAINAGE - drained by submandibular, retropharyngeal and deep cervical node