. Manual of operative surgery. penetrating the bone is a bur rapidly rotated EXPOSURE OF MASTOID ANTRUM 35 by a surgical engine. One may conveniently use a bur operated by the braceshown in Fig. 13. Apply the bur to the bone at a point inside and beside thebase of the suprameatal triangle. Penetrate the outer shell of hard bone. Insome cases the whole mastoid is thickened and sclerosed by disease. With thebur, slowly and cautiously advance through the bone in a direction inwards anda little forwards, parallel to the posterior wall of the external auditory not use the bur as if it wer
. Manual of operative surgery. penetrating the bone is a bur rapidly rotated EXPOSURE OF MASTOID ANTRUM 35 by a surgical engine. One may conveniently use a bur operated by the braceshown in Fig. 13. Apply the bur to the bone at a point inside and beside thebase of the suprameatal triangle. Penetrate the outer shell of hard bone. Insome cases the whole mastoid is thickened and sclerosed by disease. With thebur, slowly and cautiously advance through the bone in a direction inwards anda little forwards, parallel to the posterior wall of the external auditory not use the bur as if it were a drill, making a uniform cylindrical perforationthe same size as the instrument; this would be dangerous and nearly it to make a hole in the mastoid very much larger than the instrument—large enough to permit of the continuance of the work under the guidance of theeye as well as of touch. The external opening may safely be made the wholesize of the suprameatal triangle. Whenever a dark spot is seen on the cut. Fig. 32.—C, F, E (X^ Suprameatal or Alacewen s triangle. A. B. Upper two-thirds of this line overlies the sigmoid sinus. C, D. Overlies sigmoid sinusfrom knee to commencement. surface of bone, examine it at once with a fine probe or searcher (a dental probeis good). The dark spot is probably an opening into one of the mastoid cellsor even the antrum; if the latter, the probe will find a large cavity communicat-ing with the middle ear. The depth of the antrum from the surface varies from/i to ^ inch. A small opening having been made in the antrum and itscavity explored with a probe, bur away all its external wall, remove all pus,granulation tissue, or other disease products. II. Observe the position of the opening between the antrum and the middleear, the position of the facial nerve traversing the inner half of the floor of theantral passage obliquely from without inwards, as it passes into the inner walland roof of the tympanum above the foramen ovale.
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherphila, bookyear1921
