Numerous articles dealing with the use of Pantopaque in myelography have appeared in the medical literature in the past three years. While the more typical myelographic pictures due to rupture of the nucleus pulposus are easily recognizable, one occasionally encounters bizarre patterns whose interpretation is difficult. We wish to present some of these unusual patterns, to discuss common sources of error in diagnosis, and to review 215 Pantopaque myelograms. Of the 215 cases examined, 69 came to operation, and the myelographic findings will be compared with the preoperative diagnosis. Technic Site of Injection: In myelography for detection of a protruded disk in the lumbar region, the needle should not be introduced at the level of the suspected protrusion, since removal of the oil may be more difficult and defects due to the needle may resemble those due to a protruded disk. If we encounter a defect at the site of introduction of the needle, it is our practice to remove it, continue the fluoroscopic and radiographic examination, and then re-insert the needle for withdrawal of the oil. (See Figs. 9 and 10.) Fluoroscopic Study: Careful fluoroscopic observation is just as essential in Pantopaque myelography as in examination of the gastro-intestinal tract. Slowing of the oil column, its passage over an apparent partial obstruction or hump, and study of the side on which the narrowed column of oil ascends or descends are all valuable in forming final conclusions (Fig. 5, B). All studies are carried out jointly by members of the neurosurgical and roentgenologic staffs. Spot films are made as indicated; it is our usual practice to make two exposures of each level where the oil is observed, to check the constancy of defects. Equipment: The ideal table for fluoroscopic use is one which permits at least a 40° tilt in the reverse Trendelenburg position and full upright tilt. A limited range of excursion maybe remedied by removing the curved head from the bottom of the table, substituting protective side panels, and installing a shock-proof fluoroscopic tube with cables. This will usually permit from 20 to 30° additional tilt toward the head. The gears on the average table are not constructed to permit this. Additional spacings may be cut in the ones already supplied. Spot-Film Device: While any spot-film device permitting rapid exposures may be used, we prefer to use one which provides two exposures on one 8 × 10-in. film. Our device embodies a quick change switch from fluoroscopic to radiographic current and was locally constructed. Any such device must be provided with a protective brace which will prevent the screen and spot-film device from falling on the spinal puncture needle. Figure 13 shows such a device with a protective support. This support is readily adjustable for patients of varying thickness. Amount of Oil Used: The amount of Pantopaque customarily employed is 3 c.c. Recently, we have used 5 and 6 c.c. in several instances.