The human nose is comprised of an underlying structure of bone and cartilage overlaid with skin and soft tissue. In the vast majority of aesthetic rhinoplasty procedures the underlying bony / cartilaginous framework is altered while the skin itself remains unchanged as it tends to conform to the remodelled underlying framework.
The most common reason for undertaking aesthetic or cosmetic rhinoplasty is to make a nose look smaller. This usually involves reducing the bridge (or dorsum) of the nose which may be humped or adjusting the extent to which the tip of the nose projects from the face.
However, there are many other aspects to rhinoplasty and cosmetic adjustment such as changing the angulations of the nose, the shape of the nasal tip, the shape of the nostrils, the width of the nose and the straightness or symmetry of the nose.