This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
In looking into the nose from in front, if the speculum is directed downward, the floor of the nose and the inferior meatus can be seen. On the inner side is the septum, on the outer the anterior end of the inferior turbinated bone. Still higher is the middle meatus and the anterior end of the middle turbinated bone. The superior turbinated bone is not visible from the front, being in the upper posterior corner and hidden from sight by the middle turbinated. Sometimes in the upper portion of the nose, beneath the outer surface of the anterior extremity of the middle turbinated bone, is seen a small cleft, the hiatus semilunaris, leading through the infundibulum into the frontal sinus. If the inferior turbinated has been shrunk with cocaine, and if the inferior meatus is roomy, one can see the posterior wall of the pharynx. This can be seen moving if the patient swallows, pronounces the letter "k," etc., (Fig. 116).
The nasal fossa are separated from each other by the septum. This septum is formed (see Fig. 117) by the triangular cartilage in front, forming the cartilaginous septum, and the perpendicular plate of the ethmoid and vomer behind, forming the bony septum. The posterior edge of the septum is formed solely by the edge of the vomer; it can readily be seen with the rhinoscopic mirror. The affections of the septum are haematoma, ulcer and abscess, deviation to one side, spurs or outgrowths, and it may be the site of nasal hemorrhages. Haematomas affect the cartilage of the septum and resemble those of the ear. They are usually due to traumatism and may become infected, forming a pus-like detritus or abscess. They can readily be recognized as a fluctuating swelling on the septum, one or both sides being affected.
Deviations of' the septum are bend-ings toward one side, and cause serious obstruction to breathing. They are probably traumatic in origin and involve the cartilaginous portion. In operating for their correction, incisions are made through the cartilage and the projecting part pushed toward the median line. In some operations care is taken not to cut through the mucous membrane on both sides, as well as through the cartilage. This is done to avoid the formation of a permanent perforation of the septum, the presence of which may cause a very objectionable whistling sound when the patient breathes. As the mucous membrane covering the cartilage is thin, great care is necessary in dividing the cartilage to avoid wounding the side which it is desired to leave intact. The triangular cartilage is thin at its centre and thick at its edges. Spurs are usually outgrowths of bone or cartilage occurring in the line of juncture of the cartilage and vomer. On the floor of the nose the nasal crest may project quite perceptibly to one side; a cartilaginous projection may likewise occupy this site. As these spurs are found on the anterior edge of the vomer, they sometimes form a distinct ridge of bone running upward and backward. If the spur is short in extent, the farther posterior it is situated, the higher up it is on the septum. If marked, it is often accompanied by deviation of the septum and it may impinge on the lower turbinated bone opposite to it. These spurs are usually removed by sawing. A narrow-bladed saw is introduced with its back on the floor of the nose and the spur removed by sawing upward (Fig. 118).
Fig. 115. - Lateral view of the interior of the nose.
Fig. 116. - Examining the anterior nares. Middle and inferior turbinates exposed to view.
Epistaxis or bleeding from the nose is said to occur in a large percentage of the cases from the septal branch of the sphenopalatine artery. This comes from the internal maxillary artery through the sphenopalatine foramen and passes downward and forward as the nasopalatine or artery of the septum. It anastomoses below with the anterior palatine branch of the descending palatine artery as it comes up from the roof of the mouth through the foramen of Stenson (incisor foramen). It also anastomoses with the inferior artery of the septum, a branch of the superior coronary. The bleeding point is to be sought for low down on the anterior portion of the cartilaginous septum near the anterior nares. Hemorrhage can be stopped by packing only the anterior or both the anterior and posterior nares.
Fig. 117. - Septum of the nose.
The arteries supplying the nasal cavities (Fig. 119; come from three directions: superior - the anterior and posterior ethmoidal, supplying the ethmoidal cells, the upper portion of the septum, the roof, and the outer wall anteriorly; inferior - the septal branch of the superior coronary artery and a branch of the descending palatine artery coming up through the incisor foramen; posterior - the sphenopalatine, giving its nasopalatine branch to the septum and also supplying branches to the ethmoidal cells, frontal and maxillary sinuses, and outer wall of nose, the Vidian and pterygopalatine going to the posterior portion of the roof, and the descending palatine giving branches to the posterior portion of the inferior meatus and posterior end of the inferior turbinated bone.
The veins, like the arteries, are in three sets: the superior are formed by the anterior and posterior ethmoidal and some smaller veins passing upward through the foramen in the cribriform plate, or foramen caecum, to the longitudinal sinus; the inferior communicate with the facial veins through the anterior nares; the posterior drain upward and backward through the sphenopalatine foramen into the pterygoid plexus.
The lymphatics drain either anteriorly on the face or posteriorly through the deep lymphatics of the neck. Therefore, acrid secretions causing ulcerations of the anterior nares are liable to be accompanied by swelling of the submaxillary lymphatic nodes; while enlargement of the deep cervical lymphatics follows disease of the deeper nasal cavities.
Nasal hypertrophies are enlargements of the nasal mucous membrane. The mucous membrane of the nose or Schneiderian membrane has columnar ciliated cells on its surface and mucous cells beneath. It is prolonged into the various sinuses and cavities in connection with the nasal fossae. The membrane on the upper third of the septum, the upper portion of the middle turbinated, and the superior turbinated bone, contains the terminal filaments of the olfactory nerve. The membrane over the lower portion of the septum, over the lower edge of the middle, and the greater part of the inferior turbinated bones, contains a venous plexus which renders it erectile. On the slightest irritation this portion of the membrane will swell and obstruct the passage of air through the nostrils. Repeated swelling of the membrane of the septum produces thickenings of the septum, which if anterior may be seen through the nostrils, and if posterior by the rhinoscopic mirror. The membrane over the inferior turbinated bones also becomes swollen and enlarged, constituting, if at the forward end, anterior hypertrophy; and if at the posterior extremity, posterior hypertrophy (Fig. 120). They can be readily seen through the nasal speculum anteriorly and by the rhinoscopic mirror posteriorly. They are treated by applications of acids, as chromic and trichloracetic, by the electrocautery, or are snared off with the cold snare. Snaring is more often employed in reducing posterior hypertrophies, but both the anterior and posterior can be reached by an electrocautery point or a knife introduced through a speculum in the anterior nares.
Fig. 118. - Nasal crest and septal spurs.