Nose

Nose. The outer part of the nose consists of a framework of bone and cartilage with certain muscles lying beneath the integument. The two orifices are termed the anterior nares. On tracing backwards the spaces into which these orifices lead, they are found to pass into what are known as the nasalfossce. These two fossae are separated one from another by a median partition, the septum of the nose, while their outer walls are formed by three bones which are called the turbinate, spongy bones. These bones project from without inwards, arching over, and, though they do not extend to the middle line, they practically divide each nasal fossa into three parts, which are known as the superior, middle, and inferior meatuses. Posteriorly, each nasal fossa communicates with the pharynx by an aperture, these apertures being known as the posterior nares. The bony framework of the nasal fossae is lined by a mucous membrane, the pituitary or Schneiderian membrane. The epithelial lining of this membrane presents different; characters in different parts. In the lower part the epithelial cells are ciliated, and, as it is through this part that the currents of air mainly pass in ordinary breathing, it is termed the respiratory region. The upper portion of the Schneiderian membrane is known as the olfactory portion. The epithelium here is non-ciliated, and there are in this situation peculiar cells, presumably connected with the terminal fibrils of the olfactory nerve. The ultimate filaments of this nerve are distributed over the upper third of the septum, over the roof of the nasal fossa, and extend on to the surface of the superior turbinated bone, and in part on to the middle turbinated bone.