Sign of the Buttock Test

What is the "Sign of the Buttock Test" used for?

• Differentiate between pathology in the hip joint or pelvis and pathology in the lumbar spine or hamstring muscles. 
• This test helps determine whether limitation of hip flexion is due to: 
  • A musculoskeletal cause such as hamstring tightness or lumbar spine dysfunction, or 
  • A serious intra-pelvic or buttock lesion such as a bursitis, abscess, tumor, or other space-occupying pathology posterior to the hip joint.

How to perform the "Sign of the Buttock Test"?

• The patient lies supine on the examination table. 
• The examiner performs a passive unilateral straight leg raise (SLR) on the affected side. 
• If hip flexion is restricted and painful, the examiner notes the limitation. 
• The examiner then flexes the knee while maintaining hip flexion. 
• This movement relaxes the hamstring muscles and should allow greater hip flexion if the restriction originates from the lumbar spine or hamstrings.

What is the positive result?

Negative Sign of the Buttock: When the hip flexion increases after the knee is flexed. This indicates the limitation is due to hamstring tightness or lumbar spine involvement, not a problem in the hip or pelvis. 

Positive Sign of the Buttock: When the hip flexion does not increase even after flexing the knee. This suggests a pathology located posterior to the hip joint, such as:

• Ischial bursitis 
• Gluteal abscess 
• Neoplasm (tumor) 
• Septic arthritis of the hip 
• Fracture or infection involving the ischium or pelvis

A positive Sign of the Buttock is a red flag finding. It indicates the presence of a serious underlying pathology requiring immediate further investigation, such as imaging (MRI or CT) and appropriate medical referral.