A medical rehabilitation device includes an inflatable body which is formed of a resiliently deformable, slightly elastic material, the exact configuration and construction of the body, however, being greatly variable. The body may be spherical, or elliptical, ovoid or even hemispherical in shape. A pressure monitoring unit is linked to the device and monitors changes in the internal pressure in the inflatable body in response to deformation of the body as a result of external pressure exerted on the body.