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.
- 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.