Figure 1-8. Nasal skeletal framework.
a. External Nose.
(1) The external nose projects from the face. The upper portion of the nose
is formed by the nasal bones and the frontal process of the maxillae. The lower portion
is formed by a group of nasal cartilages and connective tissue covered with skin. The
nostrils and the tip of the nose are shaped by the major alar cartilages. The nares are
separated by the columella, which is formed by the lower margin of the septal cartilage,
the medial parts of the major alar cartilages and the anterior nasal spine, all of which
are covered by skin.
(2) The nasal septum is composed of three structures: the nasal cartilage,
the vomer bone, and the perpendicular plate of the ethmoid bone. The septum is
covered by mucous membrane on either side. The deviated or fractured septum may
cartilage or bone.
b. Internal Nose.
(1) The internal nose or nasal cavity is divided into two parts at its midline
by the nasal septum. The nasal cavity communicates with the outside by its external
openings, called the anterior nares. The nares open into the nasopharynx behind
through the choanae. The nasal cavity is also associated with each ear by means of
the eustachian tube and with the paranasal air sinuses (see figure 1-9) (frontal,
maxillary, ethmoid, and sphenoid) via their respective orifices (meatuses). The nasal
cavity communicates with the conjunctive through the nasolacrimal duct as well.