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 introducing the Eustachian catheter, the tip of the nose is to be tilted upward until the anterior nares are raised to the level of the floor of the nose. The tip of the catheter is then passed first upward (Fig. 152), then along the floor until it is felt to pass beyond the soft palate and strike the posterior wall of the pharynx (Fig. 153). It is usually advised to enter the catheter in a vertical position and then change to a horizontal one as soon as the beak passes over the elevation which marks the separation of the vestibule of the nose from the interior. If this method is used, care should be taken to keep the tip of the catheter on the floor of the nose and not pass it up in the region of the middle turbinate bone.
There are three ways of introducing the beak of the catheter into the mouth of the tube after it is felt touching the posterior pharyngeal wall. The first is to withdraw the beak about 2 cm. away from the wall of the pharynx and then turn it upward and outward, pushing it a trifle onward. The second way is to turn the beak directly outward and draw it forward, when it can be felt passing over the cartilaginous opening of the tube. The third way is to turn the beak inward and draw it forward until it catches behind the septum. This is opposite the anterior edge of the mouth of the tube. The beak is then rotated downward and then upward and outward into the tube.
Liquids and sprays are sometimes injected into the ear through the catheter; bougies are also passed into the tube in the same manner as the catheter or, if flexible bougies are used, they are passed through the catheter. As the tip of the bougie passes into the bony portion of the canal, the constriction of the isthmus can be felt 2.5 cm. up from its mouth. The bougie should not be passed farther than 3 cm. into the tube, otherwise, if the tympanum is entered, the ossicles are apt to be injured.
The opening of the mouth into the pharynx is sometimes narrowed from cicatricial contractions, resulting from ulcerative processes due to syphilis, caustics, etc. I here is rarely obstruction downward, so that these patients can usually swallow, but the cicatrices contract the opening upward, and the soft palate, its arches, and the walls of the pharynx may be all bound together in one cicatricial mass, preventing, as I have seen, all respiration through the nose. This condition is an exceedingly difficult one to remedy, as the contraction tends to recur even after the most radical operations.
FlG. 152. - Introducing the Eustachian catheter, first step.
Fig. 153. - Introducing the Eustachian catheter, second step.
Fig. 154. - Introducing the Eustachian catheter, third step.
The opening into the larynx is more accessible than is often supposed. On drawing the tongue well forward, the tip of the epiglottis can be seen. If a long straight tongue depressor is used, Kirstein has shown that in many patients the arytenoid cartilages and even a portion of the vocal cords can be seen. The opening into the larynx can readily be felt by a finger introduced into the mouth. In cases of suffocation from a foreign body, as a piece of meat, it is usually lodged at this point, part of the foreign body being in the larynx and part in the pharynx. It can readily be dislodged by the finger, as I have done in impaction of meat, the result of vomiting in ether narcosis. The forefinger should be thrust its full length into the mouth and throat and swept from side to side. The obstructing body can usually be brushed aside and brought up in front of the finger into the mouth.
The opening of the oesophagus is in a line with the long axis of the pharynx; it is at its lower end. The opening of the larynx, on the contrary, is more on its anterior wall. It is for this reason that when an oesophageal tube is introduced, either through the mouth or through the nose, it goes down into the oesophagus and does not enter the larynx. The oesophagus is narrowest at this point.
The pharyngeal tonsil stretches across the posterior wall and roof of the pharynx from the opening of one Eustachian tube to that of the other. It is also known as Luschka's tonsil. It is composed of lymphoid tissue, and when enlarged constitutes the disease known as adenoids. It is not true secreting gland tissue, though it contains some mucous glands. It hangs from the vault of the pharynx in a more or less lobulated mass and when large, in children, obstructs nasal respiration. Mouth-breathing results, the child is apt to snore and make queer sounds when sleeping, and the habit of keeping the mouth open causes a peculiar expression of the face almost pathognomonic of the affection. The blood supply at times is abundant. When adenoids are present, their removal is usually undertaken. This is done by introducing an instrument either through the nose or through the mouth and scraping them off. A curette is used for this purpose. That known as Gottstein's consists of an oval-shaped ring set at right angles to a long shaft. It is introduced through the mouth and up behind the soft palate. It is then pushed against the vault of the pharynx and posterior wall and drawn downward cutting and scraping the adenoid tissue away. A much smaller ring curette set on a long, delicate, but stiff handle may be used through the nose for the same purpose. In using the latter instrument, it is common to use an anaesthetic and operate with the head in a hanging position. Free bleeding may occur from this operation. To control it, injections of ice water or a strong alum solution may be tried or gauze may be packed behind the soft palate or pushed in from the anterior nares. A folded pad of gauze may be attached to the thread of a Bellocq cannula and the pad introduced as is done in plugging the posterior nares. A curved forceps with cutting blades is also used to remove this growth.
Fig. 155. - Lateral view of the pharyngeal region.