Pressures under the Ischium Detected by a Pedobarograph *

Pressure between the ischium and the flat surface of a pressure sensitive device (pedobarograph) are reported. There are no consistent patterns of the pressures detected this way with age, weight, sex or gross anatomy. When sitting on a gel cushion or 3 in foam cushion, the centre of load moves anteriorly and the pressures between the under surface of the cushion and the flat surface of the pedobarograph appear to be both similar and considerably lower than those pressures detected between the ischium and the flat surface.

In spinal cord injured patients with pressure sores, the device indicated areas of high pressures (greater than 300 mm Hg) in the region of the pressure sores as well as a very much reduced contact area (usually less than a third) compared with normal subjects of similar weight.