Anatomy and Physiology of the Nose
What is the nose?
The nose is the organ involved in smell and breathing. It is located in the middle of the face. The internal part of the nose lies above the roof of the mouth.
The nose consists of:
- External nose - triangular-shaped projection in the center of the face.
- Nostrils - The two openings into the nasal passages.
- Nasal passages - passages that are lined with mucous membranes and tiny hairs (cilia) that help to filter the air and move nasal and sinus mucous to the back of the throat. Nasal passages are separated by the nasal septum.
- Septum - made up of cartilage and bone and covered by mucous membranes. The cartilage also gives support to the lower part of the nose and divides the nasal passages into right and left sides.
- Sinuses - four-paired, air-filled cavities.
What are sinuses?
The sinuses are cavities, or air-filled pockets inside the face, near the nasal passages. As in the nasal passages, the sinuses are lined with mucous membranes. There are four sinuses:
- Ethmoid sinus - located around the area of the bridge of the nose. This sinus is present at birth, and continues to grow until puberty.
- Maxillary sinus - located around the area of the cheeks. This sinus is also present at birth, and continues to grow until puberty.
- Frontal sinus - located in the area of the forehead. This sinus does not develop until around 7 years of age.
- Sphenoid sinus - located deep in the face, behind the nose. This sinus does not fully develop until adolescence.
Reviewed by: Steven D. Handler, MD, MBE
Date: April 2009