Nose Anatomy And Nose Reconstruction

The nose is made of three layers. From outside inwards:

Using the analogy of a house we will explain the layered structure of the nose.

Skin

The skin envelope has various thicknesses over the nose. It is thin over the bridge, but thicker over the lower third of the nose. Some patients have thin skin others have thick skin. The skin can be viewed as the cladding or paint that covers the house. If the cladding is thick the underlying structures (cartilages and bone) will be less pronounced. If the cladding is thin the underlying structures will be very visible and small irregularities will be visible to the eye.

Cartilage and Bone Framework

Green arrow bones of the maxilla (cheek bone) and nasal bones
Blue arrow septum attached to the upper lateral cartilages
Red arrow lower lateral cartilages

The nose is supported by it bone and cartilage framework. The upper portion of the nose is supported by the bones of the maxilla (cheek bone and nasal bones).

The middle third of the nose is supported by the septum attached to the upper lateral cartilages. These cartilages support the middle portion of the nose. Loss of support here will lead to a saddle nose deformity or in some cases a septal perforation (hole in the septum).

The lower third of the nose is supported by the lower lateral cartilages. These cartilages are curved and angulated outwards to give the characteristic shape to the tip and part of the sides of the nostrils (alar) and help support the tip and the nostrils (alar) of the nose.

The septum attached to the upper lateral cartilages, the lower lateral cartilages and the nasal bones give the shape of the nose (modified to a degree by the thickness of the skin). 

Inner Lining

The inner lining of the nose is made up of skin and mucosa. It is a vital layer of the nose and can be viewed as the foundation of the house. Any deficiencies (tears or gaps) allow bacteria normally carried in the nose to infect the middle framework layer of the nose and can cause damage to the cartilage of the nose and weaken the support structure. In addition when these gaps heal, they heal with scarring and contraction that causes the nose which is mobile to become twisted with the nostrils becoming narrowed, which can impair breathing and produce an external nose deformity. This is analogous to faulty foundation in a house leading to subsidence.