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.
The outer wall has on it the three turbinated bones - superior, middle, and inferior. The inferior is a separate bone, but the middle and superior are parts of the ethmoid bone (Figs. 121 and 122).
The inferior meatus is between the inferior turbinated bone and the floor of the nose. The lachrymonasal duct enters this meatus just below the anterior end of the inferior turbinated bone. It pierces the mucous membrane obliquely, being guarded by a fold called the valve of Hasner. The opening is not visible from the anterior nares and usually it is impossible to introduce a probe into it from them.
The middle meatus is between the middle and inferior turbinated bones. The mucous membrane covering the middle turbinated bone lies closer to it than does that of the inferior turbinated bone, so that it is comparatively rare that treatment is necessary to reduce it.
Polypi usually have their origin in this meatus. Beneath the middle turbinated bone on the outer wall of the nose and only to be seen after removal of the bone, there is, just anterior to its middle, a rounded eminence, the bulla ethmoidalis. In it is an opening for the middle ethmoidal cells. Immediately in front is a slit, the hiatus semilunaris, into which open the maxillary sinus (antrum of Highmore) and the anterior ethmoidal cells. The hiatus is continued above as the infundibulum, which enters the frontal sinus. The relation between the hiatus and the opening into the maxillary sinus is such, in some cases, that it is possible for pus originating in the frontal sinus to discharge into the maxillary sinus. A knowledge of the relation of these parts is essential to those desirous of treating nasal diseases.
Fig. 120. - View of anterior and posterior hypertrophies of the inferior turbinate.
The superior meatus is comparatively small and lies above the middle turbinated bone. At the anterior edge of the superior turbinated bone is the opening for the posterior ethmoidal cells. Sometimes there are two or three superior turbinals.
The sphenoethmoidal recess is the cleft above the superior turbinated bone; into it opens the sphenoidal sinus. In order to examine and reach the openings of any of these sinuses, it is practically necessary to take away a part or all of the middle turbinated bone before they can be exposed to view. When this is done, they can be probed, washed out, drained, etc. (see Fig. 125).
The frontal sinuses begin to develop about puberty. They occupy the lower anterior portion of the frontal bone. Their size and extent vary considerably. The usual size is from the nasion below to the upper edge of the superciliary ridges above and laterally from the median line to the supra-orbital notch. These limits may be exceeded considerably. They may go as far out as the middle of the upper edge of the orbit or even nearly to the temporal ridge. The anterior and posterior walls are separated a distance of 0.5 to 1 cm. The distance which they extend back over the orbit and upward also varies. The two sinuses are separated by a partition which is often to one side of the median line, so that it is apt to be encountered in opening the sinus through the forehead. The two cells often differ greatly in size and may be divided into various recesses by incomplete septa. They have the infundib-ulum as their lower extremity, which passes into the hiatus semilunaris beneath the middle turbinated bone and empties into the middle meatus. The frontal sinuses are frequently the seat of suppurative inflammation. This gives rise to pain and tenderness in the supra-orbital region and to a discharge from the corresponding nostril. This discharge can be seen coming from beneath the anterior extremity of the middle turbinated bone. Owing to the proximity of the opening into the maxillary sinus, pus, coming down the hiatus from the frontal sinus, may pass into the maxillary sinus, thus simulating disease of that cavity. In order to wash out the sinus, cocaine may be first applied to shrink the nasal membrane; then sometimes one is able to pass a probe or irrigating tube into the hiatus semilunaris and thence up into the sinus. By removing the anterior extremity of the middle turbinated bone access to the hiatus semilunaris is more readily obtained. In certain cases the frontal sinus is opened either through the supra-orbital region or entered through the roof of the orbit at its inner upper corner. The glabella is the depression in the median line separating the superciliary ridges. In operating on the sinus from in front, the opening is to be made just to the outer side of the glabella in order to avoid the septum between the sinuses. In curetting the sinus, the thinness of the upper and posterior wall separating it from the brain, and of the lower wall or roof of the orbit, should be borne in mind, otherwise they are apt to be perforated. The sinus may be divided into recesses by partial septa projecting from the sides. Drainage into the nose is obtained by passing an instrument from above downward through the anterior ethmoidal cells. In entering the sinus from below from the outside, the opening is made at the extreme anterior upper edge of the orbit, perforating the bone in a direction upward and inward. The opening into the sinus may be enlarged from within the nose by first inserting a probe to protect the brain and posterior wall and then chiselling or gnawing away the bone in front so that easy access is obtained through the nose for drainage, packing, etc.
Fig. 121. - Outer wall of nose, showing the superior, middle, and inferior turbinate bones.
Fig. 122. - View of outer wall of the nose and accessory cavities.
Figs. 123 and 124. - Two views of the frontal sinus, showing variation in size in different individuals. The anterior wall has been cut away to expose the interior of the sinus.
The ethmoidal sinuses or cells, three in number on each side, anterior, middle, and posterior, lie between the sphenoidal sinus posteriorly, and the lower extremity of the frontal sinus anteriorly. The anterior cells lie in front of or just above the hiatus and open into it. The middle lie just posterior to the hiatus and open into the outer wall of the middle meatus, perforating the bulla ethmoidalis, which is a rounded projection on the outer wall beneath the middle turbinated bone. The posterior cells open still farther back beneath the superior turbinated bone in the superior meatus. In disease of these cells, pus from the middle and anterior ones will show in the middle meatus; from the posterior cells in the superior meatus. In this latter case it is to be detected posteriorly by means of the rhinoscopic mirror. Access to the cells is obtained by removing the middle turbinated bone. This is done by dividing it into two pieces by a transverse cut with forceps or scissors and then removing the two halves with a snare. By means of probes, curettes, and forceps, the openings into the cells may be discovered and enlarged as thought necessary. The region of the ethmoidal cells is that from which mucous polypi of the nose take their origin. They are a common accompaniment of suppuration of the accessory nasal cavities. They are usually removed by snares introduced through the anterior nares or more rarely by forceps. Caries affecting the anterior cells may extend into the orbit and the pus may form a fluctuating tumor above the inner canthus of the eye. Care should be taken not to mistake a meningocele for such a tumor.
Fig. 125. - Probes introduced into the frontal, maxillary, and sphenoidal sinuses. The anterior portion of the middle turbinate has been removed.
The sphenoidal sinuses are the most posterior, lying still farther back than the ethmoidal. They open into the spheno-ethmoidal recess above and posterior to the superior turbinated bone. Discharge from them goes into the pharynx and is to be seen with the rhinoscopic mirror. They can be reached by first removing the middle turbinated bone and then introducing a probe upward and backward from the anterior nares for a distance of 7.5 cm. (3 in.) in women and 8 cm. in men. They can be drained by cutting away their anterior wall with punch forceps introduced through the anterior nares.
The maxillary sinus lies beneath the orbit and to the outer side of the nasal fossae. It is the seat of tumors, often malignant, and inflammation; the latter accompanied by an accumulation of mucus or pus. The walls of the sinus are thin, so we find tumors bulging forward, causing a protrusion of the cheek. They press inward and obstruct the breathing through that side of the nose, or they push upward and cause protrusion of the eye by encroaching on the orbit. In operating on these tumors, the superior maxilla is usually removed; the lines of the cuts through the bones being shown in Fig. 64. In prying the bone down posteriorly, it may not be torn entirely away from the pterygoid processes and some plates of bone may be left attached. This should be borne in mind in operating for malignant growths. The sphenoidal cells are behind the upper posterior portion of the maxillary sinus, therefore in operating on Meckel's ganglion, if too much force is used in breaking through the posterior wall of the antrum, the instrument may pass across the sphenomaxillary fossa, a distance of about 3 mm., and open the sphenoidal sinus.
The infra-orbital nerve is usually separated from the cavity of the sinus by a thin shell of bone. At the upper anterior portion of the sinus there may be a small cell between the bony canal in which the nerve runs and the bony floor of the orbit. The superior dental nerves reach the upper teeth usually by going through minute canals in the bone, but sometimes, particularly the middle set supplying the bicuspid teeth, may run directly beneath the mucous membrane, and thus be irritated by troubles originating within the sinus.
The inflammatory and infectious diseases of the sinus originate either by extension from the nose or the teeth. The sinus opens into the nose by a slit-like opening into the middle meatus about its middle,posterior to the hiatus semilunaris and 2.5 cm. above the floor of the nose. When the opening is close to the hiatus, liquids may run into it from the hiatus. The bone beneath the hiatus and opening almost down to the floor of the nose is quite thin, so that the sinus can readily be drained by thrusting a trocar and cannula through the outer wall of the nose into the sinus just below the hiatus semilunaris. The sinus is also opened from the front through the canine fossa to the outer side of the canine tooth. This opening affords direct access to the cavity, but is some distance above the floor, thus it does not drain the cavity completely. The roots of the upper teeth project into the antrum forming elevations, usually covered by a thin plate of bone. This is particularly the case of the first and second molars. Disease of the roots of these teeth frequently infects the antrum and drainage is often made through their sockets.
Fig. 126. - Side view of the maxillary and frontal sinuses.