MAY 16 90? LIBRARY CHAPTER I. THE SURGICAL ANATOMY OF THE NOSE AND ITS THE nasal fossae are two irregularly-shaped cavities opening in front on to the face by the anterior nares, and behind into the pharynx by the posterior nares or choanae. Each cavity presents a floor, a roof, an inner and an outer wall. The floor is formed by the palatal processes of the superior maxilla and palate bones. It is concave from side to side and wider in the middle than at either extremity. It is The roof is long, narrow and concave from before backwards. formed in front by the nasal bone and fronto-nasal process of the superior maxilla, which slope downwards and forwards; in the middle by the cribriform plate of the ethmoid, which is practically horizontal; and behind by the anterior or under surface of the body of the sphenoid, which slopes downwards and backwards. The thinness of the cribriform plate, the narrowness of the nose in this region (about 2 millimetres), and the concavity of the roof as a whole are well shown in Figs. 1 and 5. The inner wall or septum nasi is formed by the thin perpendicular plate of the ethmoid above, by the vomer below, and by the triangular cartilage in front (see Fig. 1). Morell Mackenzie found that the bony septum presented more or less asymmetry in nearly 77 per cent. of over 2000 skulls which he examined with special reference to this point. The triangular cartilage is hardly ever in the median line and is often irregularly thickened. One of the more common irregularities of the septum is a ridge, which commences at the lower and posterior part of the triangular cartilage near the floor of the nose and runs obliquely upwards and backwards towards the sphenoid. It corresponds in position to, and represents an abnormal thickening of, the processus sphenoidalis of the triangular cartilage (see Fig. 1). Thickenings and deflections of the septum are almost limited to its anterior two-thirds and to its lower part: the posterior third is usually in the median line, and the posterior choanae are of equal size. Though some septal irregularities are A undoubtedly traumatic, the great majority are probably developmental. They may be found in quite young children (in 16 per cent. according to Anton1), and even in the embryo, but most often become marked at about the 10th-12th year or later, when the rapid development of the face and upper jaw is in progress. This subject will be fully discussed in Chapter VII, where additional statistics will be found. According to Zuckerkandl congenital apertures may occasionally be found in the bony septum, The outer wall of the nose is formed chiefly by the inner surface of 2 7 5 FIG. 1. THE NASAL SEPTUM. 1, Frontal sinus; 2, sphenoidal sinus; 3, perpendicular plate of the ethmoid; 4, processus sphenoidalis of the triangular cartilage; 5, triangular cartilage; 6, vomer; 7, hard palate. The thickened ridge at the junction of the vomer with the processus sphenoidalis is well shown. the body of the superior maxilla, the inferior turbinate, the lateral mass of the ethmoid, the vertical plate of the palate bone and the internal pterygoid plate of the sphenoid. This wall is most important from a surgical standpoint and merits detailed study. From it project three horizontal ridges, the inferior, middle and superior turbinates, which divide the nasal cavity into four passages, namely, the inferior meatus, lying between the inferior turbinate and the floor of the nose; the middle meatus, between the middle and inferior turbinates; the superior meatus, between the middle and superior turbinates; and the fourth or highest meatus, sometimes called the spheno-ethmoidal recess, between the superior 1Arch. für Ohrenheilk., 1893, xxxv. p. 305. turbinate and the roof of the nose (see Figs. 2, 4 and 5). In front of the turbinates the outer wall of the nose is smooth: its lowest and most anterior part is lined by skin continuous with that of the face, and forms the outer wall of the vestibule. Behind and above the vestibule and on a level with the entrance to the middle meatus of the nose is a smooth triangular area of mucous membrane known as the atrium of the middle meatus (see Fig. 2). Occasionally a slight elevation is found in the atrium near the anterior end of the middle turbinate. This is FIG. 2.-VERTICAL ANTERO-POSTERIOR SECTION OF THE HEAD PASSING THROUGH THE RIGHT NASAL FOSSA IMMEDIATELY TO THE OUTER SIDE OF THE SEPTUM. a. Lower jaw; b. hard palate; c. inferior meatus; d. inferior turbinate; e. middle meatus; f. middle turbinate; g. superior turbinate; h. superior meatus; i. frontal sinus; k. posterior ethmoidal cell; fourth or highest meatus; m. sphenoidal sinus; n. body of the sphenoid; o. Eustachian tube. known as the agger nasi, and constitutes the remains of the large nasal turbinate of the carnivora. The inferior turbinated body is about 40 to 50 mm. long, and 12 to 15 mm. in width near the centre, its widest part. It tapers rapidly towards both extremities: the anterior end is more rounded and larger than the posterior. On transverse section near its central part the inferior turbinate is seen to be markedly curved, and to consist of a horizontal and a vertical limb (Fig. 5). In the adult the lower edge lies 3-4 mm. above the floor of the nose; in the new-born it is almost in contact (Fig. 8). The inferior meatus of the nose is small in front, smaller still behind, and much more roomy in the centre, owing to the strong outward bend of the outer wall of the nose and the curved line of attachment of the inferior turbinate. The average length of the inferior meatus is 60-65 mm., though according to Thane, it may attain 73 mm. The width of the inferior meatus measured from the septum to the outer wall of the nose, near its central part, is 12-18 mm.; the height is about 20 mm. At the highest part of the meatus and under the inferior turbinate, about 25 mm. behind the entrance to the nose, is the orifice of the FIG. 3.-VERTICAL ANTERO-POSTERIOR SECTION THROUGH THE NASAL FOSSA SOMEWHAT TO THE LEFT OF THE MIDDLE LINE. The middle turbinate has been removed and a dissection made to expose the structures on the outer wall of the nose. a. Uvula; b. soft palate; c. Eustachian tube; d. sphenoidal sinus; e. ostium of the sphenoidal sinus; posterior ethmoidal cells; middle ethmoidal cell; h. frontal sinus; i. infundibulum; k. a window cut in the uncinate process to show the fossa on its outer side; . uncinate process; m. hiatus semilunaris; n. attachment of the middle turbinate; o. inferior turbinate; p. inferior meatus; 9. hard palate. nasal duct, which is often marked by a small crescentic fold of mucous membrane (Fig. 6). The shape of the inferior meatus is of some surgical importance, for the width of the air-way may be greatly increased by simply removing the anterior extremity of the inferior turbinate and thus allowing free access |