Deep Gluteal Syndrome
Many tests have been described over the years with variations added to several of them. Only Martin et al have reported diagnostic accuracy from a well conducted cross-sectional study.
Tonic external rotation of hip at rest is a consequence of contracture of the piriformis muscle and therefore not expected to occur unless shortening has occurred. It has been described less often than other signs.
The other tests reproduce the patient’s pain by increasing pressure on the sciatic nerve by tensing the piriformis and related muscles. They do so either passively (forced stretching by the examiner) or actively (contraction of the muscle performed by the patient against resistance). See references for these tests