INTRODUCTION:

The lateral wall of the nose is an irregular surface due to the pressure of three shelf-like bony projections called Conchae, which increases the surface area of the nose for effective air conditioning of the inspired air.

FEATURES:

The lateral wall can be sub- divided into three parts as:
  • VESTIBULE: A small depressed area in the anterior part. It is lined by modified skin.
  • The middle part is known as ARTIUM OF THE MIDDLE MEATUS.
  • The Posterior part contains the Conchae.

FORMATION:

The skeleton of the lateral the wall is partly bony, partly cartilaginous and partly made up only of soft tissue.
A. The Bony Part is formed from before backward by -
  • Nasal Bone.
  • Frontal process of the maxilla.
  • Lacrimal.
  • Labyrinth of ethmoid with superior and middle conchae.
  • Inferior nasal concha.
  • Perpendicular plate of Palatine bone together with it's orbital and sphenoidal processes.
  • Medial pterygoid plate.

B. The Cartilaginous Part:
  • Superior Nasal Cartilage.
  • Inferior Nasal Cartilage.
  • Alar Cartilage.

C. The cuticular lower part is formed by fibrofatty tissue covered with skin.

CHONCHAE:

  • The nasal conchae are curved bony projections. 
  • Usually, three conchae are formed. 
  • The INFERIOR CHONCHAE is an independent bone. 
  • The MIDDLE & SUPERIOR CHONCHAE is a projection from the medial surface of the Ethmoidal labyrinth.

MEATUS:

The Meatus of the nose are passages beneath the overhanging conchae.
Each communicates with the nasal cavity proper.
1. INFERIOR MEATUS: 
  • It lies underneath the Inferior Chonchae.
  • The nasolacrimal ducts open here.
  • The opening is guarded by the lacrimal fold or Hasner's value.

2. MIDDLE MEATUS:
  • It lies underneath the middle conchae.
  • The anterior Ethmoidal air sinus opens here.
3. SUPERIOR MEATUS:
  • It lies underneath the superior conchae. 
  • It receives the openings of Posterior Ethmoidal air sinuses.

ARTERIAL SUPPLY:

  • ANTEROSUPERIOR quadrant is supplied by the anterior Ethmoidal and Posterior ethmoidal Artery.
  • ANTEROSUPERIOR quadrant is supplied by the branches of the facial artery.
  • The POSTEROSUPERIOR quadrant is supplied by the sphenopalatine artery.
  • The POSTEROINFERIOR quadrant is supplied by the branches of the greater Palatine artery.

VENOUS DRAINAGE:

The veins form a plexus which drains -
  • Anteriorly to the facial vein.
  • Posteriorly to pharyngeal plexus of veins.
  • Middle part to pterygoid plexus of veins.

NERVE SUPPLY:

General Sensory Nerve:

Arises from branches of trigeminal nerves.
  • ANTEROSUPERIOR quadrant is supplied by the anterior Ethmoidal Nerve.
  • ANTEROINFERIOR quadrant is supplied by the anterior superior alevolar nerve.
  • POSTEROINFERIOR quadrant is supplied by the lateral posterior superior nasal branches from the pterygopalatine ganglion.
  • POSTEROINFERIOR quadrant is supplied by the anterior Palatine branch from the pterygopalatine ganglion.

Special sensory nerves:

They are distributed to the upper part of the lateral wall.

LYMPHATIC DRAINAGE:

  • Anterior half drain into submandibular nodes.
  • Posterior half into retropharyngeal and upper deep cervical nodes.

APPLIED ANATOMY:

  • The common cold is the commonest infection of the nose.
  • Hypertrophy of mucosa of inferior nasal conchae is common feature of allergic rhinitis, characterized by sneezing blockage and excessive watery discharge from the nose.