THE CLEVELAND MEDICAL JOURNAL COMPANY
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No. 12

Entered as second-class matter March 7, 1902, at the post-office at Cleveland, Ohio, under the Act of
Congress of March 3, 1879.

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JAN15 1918

TheRY
BRARY

Cleveland Medical Journal

Vol. XVI

JANUARY, 1917

No. 1

THE INTERPRETATION OF STEREO-ROENTGENOGRAMS OF THE MASTOID*

J. M. INGERSOLL, A. M., M. D.

Professor of Oto-Laryngoloy in the Medical Department of Western Reserve University, Cleveland, Ohio

The practical value of stereo-Roentgenograms of the head depends upon the correct interpretation of the stereoscopic picture. The only way to acquire skill in interpreting the picture is by practice and study. Fortunately it does not require the expenditure of much time or study to gain a reasonable amount of skill in interpreting the stereoscopic plates.

In order to identify positively in the stereoscopic pictures some of the landmarks in the bones of the skull, we took a macerated and cleaned skull, sawed off the top of the skull, uncovered the semicircular canals in one mastoid and inserted copper wires in the canals. Then we took stereo-Roentgenograms of both mastoids of this skull, using the same technique that we use in the living subject. These plates gave us beautiful stereoscopic pictures of the mastoids and the copper wires located absolutely the position of the semicircular canals. By studying these pictures and the skull alternately, the following structures can be definitely located: the external and internal auditory canals, all of the mastoid cells, the mastoid. antrum, the semicircular canals, the groove of the lateral sinus and the jugular bulb, forming the floor of the tympanic cavity, the foramen lacerum posterior or jugular foramen, the foramen ovale, just anterior to the petrous portion of the temporal bone, the foramen lacerum medium showing dimly through the extreme anterior part of the petrous bone, the groove of the superior petrosal sinus on the posterior superior surface of the petrous bone, the foramen. magnum, the grooves of the middle meningeal arteries, and the floor of the middle fossa of the brain.

*This paper was read before the Academy of Oto-Laryngology, at Memphis, Tenn., December 20, 1916.