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to the larger middle part of the meatus. Upon this observation is based the operation of anterior turbinectomy.

The middle turbinate varies from 30-40 mm. in length and is 15 mm. in height in its largest part. Arising from the lateral mass of the ethmoid it curves inwards, downwards, and finally outwards. Its line of attachment, as shown in Figs. 3 and 15, consists of an anterior hook-shaped part and a posterior nearly horizontal part. Under the anterior hook-shaped part, the middle meatus bulges upwards and forms a cavity known as the recessus meatus medii which approaches closely to the floor of the frontal sinus. The free border of the middle turbinate is often thickened,

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FIG. 4.-VERTICAL TRANSVERSE SECTION THROUGH THE NASAL FOSSA IN THE PLANE OF THE OPTIC NERVES AND THE THIRD MOLAR, VIEWED FROM THE FRONT. a. Optic nerve; b. superior turbinate; c. middle ethmoidal cell; d. septum; e. middle meatus; f. ostium of the maxillary antrum; g. middle turbinate showing a cell; h. maxillary antrum; i. inferior meatus; k. inferior turbinate.

especially at its anterior extremity, where a small air-cell may be found. Lothrop found this cell present in 18 per cent. of his specimens, but in 6 per cent. it was quite small. Harmer stated that the cell was commonly present and that it was lined with normal mucous membrane similar to that of other ethmoidal cells. In disease the cell may become greatly distended. The anterior border of the middle turbinate commonly runs vertically downwards and joins the horizontal border at a well-marked angle, thus forming the lobulus, or operculum meatus medii (see Fig. 2). Occasionally the middle turbinate is partially divided into two by a slight horizontal furrow which is most marked posteriorly.

The removal of the middle turbinate brings into view the uncinate process, the hiatus semilunaris, the bulla ethmoidalis and the openings of the infundibulum, of the maxillary antrum and of some of the anterior ethmoidal cells (Fig. 3).

The uncinate process is a narrow shelf on the outer wall of the nose, broadest in front, and gradually tapering behind. It arises in front from the anterior portion of the lateral mass of the ethmoid in close proximity to the upper part of the anterior border of the middle turbinate. It thence passes downwards and backwards parallel to the bulla ethmoidalis, ending just below and behind the maxillary ostium. It is slightly curved, with its concavity upwards. The inner convex surface looks downwards, inwards and forwards. The external concave surface looks outwards, upwards and backwards, and forms the lower border of the hiatus semilunaris (see Figs. 3 and 5).

The bulla ethmoidalis is a smooth rounded eminence lying just above the

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FIG. 5.-VERTICAL TRANSVERSE SECTION OF THE NOSE, IN THE PLANE OF THE EYEBALLS AND SECOND MOLARS, VIEWED FROM BEHIND. a. Inferior turbinate; b. middle fossa; c. uncinate process; d. nasal septum; e. superior turbinate; f. pupil; g. middle ethmoidal cell; . middle turbinate; i. infra-orbital vessels and nerve; k. cavity of the antrum; . inferior meatus; m. hard palate.

uncinate process, and extending upwards to the attached border of the middle turbinate. It is formed by the projection of one or more of the larger middle ethmoidal cells, and varies greatly in size, according to the degree, of development of these cells (see Fig. 3).

Between the bulla ethmoidalis and the uncinate process is a long, narrow, half-moon-shaped cleft, the hiatus semilunaris. It is 15-20 mm. long and about 3-4 mm. in width. Its anterior end, which is deepest, reaches up into the recessus meatus medii: its posterior part gradually shallows away. Into this cleft open the infundibulum in front, the ostium maxillare near its posterior end, and some of the anterior ethmoidal cells, usually near the anterior end. These openings are entirely concealed from view until the uncinate process has been removed. From this anatomical arrangement it will be seen how easily swelling of the mucous membrane,

which is very loosely attached in this region, will occlude the openings of the cavities: and further that it will be very difficult, or quite impossible in most instances, to catheterize the sinuses through the ostia. in the living subject.

The superior turbinate is a small thin projection situated far back and high up in the nose. It is usually 5-6 mm. long, but may attain the

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FIG. 6.-VERTICAL SECTION OF THE NOSE BEGINNING IN THE BODY OF THE SPHENOID, NEAR THE MIDDLE LINE, AND PASSING OBLIQUELY FORWARDS THROUGH THE OUTER WALL OF THE NOSE AND THE ORBIT. Viewed from the outer side. Part of the inner wall of the orbit and of the inner wall of the antrum have been subsequently cut away to show the infundibulum, the ethmoidal cells, and the large concavities under the middle and inferior turbinates. a. Post-pharyngeal wall; b. posterior margin of the nasal septum; c. outer surface of the middle turbinate; d. sphenoidal sinus showing a probe inserted into its ostium; e. posterior ethmoidal cells; f. middle ethmoidal cells; g. inner wall of the orbit; h. position of ostium of frontal sinus surrounded by anterior ethmoidal cells; i. probe passed down the infundibulum into the middle meatus; k. inner wall of the orbit; . lachrymal duct; m. ostium of maxillary antrum; . and o. parts of inner wall of antrum; p. large external surface of inferior turbinate; 9. hard palate; r. socket of first molar tooth showing its proximity to floor of antrum.

length of 15 mm. Under normal conditions it can be seen by posterior, but not by anterior, rhinoscopy.

The superior meatus is a mere short slit into which the posterior ethmoidal cells open, generally by one or two roundish ostia.

The fourth or highest meatus, sometimes called the spheno-ethmoidal recess, is the space above and behind the superior turbinate and below

the sphenoidal-the highest of the turbinate processes. Into it open the sphenoidal sinus and, occasionally, one of the posterior ethmoidal cells.

Above and behind the superior turbinate, and below the sphenoidal turbinate, may occasionally be seen a small ridge, the rudimentary remains of a fourth turbinate. According to Zuckerkandl a trace of this may be

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FIG. 7.-HORIZONTAL SECTION OF THE NOSE ABOUT HALF AN INCH ABOVE ITS FLOOR, VIEWED FROM ABOVE. On the left side the inferior turbinate has been entirely removed to show the antro-meatal septum. a. Large spur on the septum; . inferior turbinate; c. cavity of the antrum; d. floor of nose; e. septum.

seen in 8 per cent. of adults' skulls, whilst in infantile and foetal life it is almost constantly present.

The dimensions of the nasal cavity are largest near its centre. The height in this region is about 44 mm. (Thane), the width near floor 12-18 mm., and the width of the roof 2-3 mm. The length of the nose along the inferior meatus varies from 60-70 mm. The posterior choanae vary somewhat in size, averaging 20-25 mm. in height by 16 mm. in breadth. Zuckerkandl stated that the choanae were always equal in size, but Bergeat, who examined 1200 skulls with special reference to this point found slight asymmetry in 10 per cent. He concluded that this

1 Bergeat, Archiv für Laryngol., 1896, iv. p. 409.

was developmental, as it was never found at birth. Citelli, from an examination of 1,025 skulls, concluded that the average height was 24 mm., average width 12 mm., and that slight asymmetry was frequent.

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FIG. 8.-VERTICAL SECTION THROUGH THE NOSE OF AN INFANT. (Natural Size.) 1, The antrum; 2, inferior meatus; 3, inferior turbinate; 4, orbit; 5, unerupted teeth. The mucous membrane is shrunken, making the nasal passages appear unusually roomy.

Development of the Nose. The nose may be divided into two regions, an ethmoidal and a maxillary, and great differences exist in the relative size of these parts at various stages of development. In

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FIG. 9.-VERTICAL SECTION THROUGH THE NOSE OF A SIX YEAR OLD CHILD. (Natural Size.) To show the Development of the Antrum. 1, Orbit; 2, antrum; 3, middle meatus; 4, inferior turbinate; 5, temporary molar; 6, permanent tooth; 7, junction of the septum and hard palate.

infancy, corresponding to the small development of the face as compared to that of the skull, the ethmoidal portion of the nose is.

1 Citelli, Journal of Laryngol., 1903, xviii. p. 219.

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