In the Thomas test protocol, where should the patient be positioned?

In the Thomas test protocol, where should the patient be positioned?

• A. Patient lies supine at the edge of the plinth; flex one knee to chest, keep lumbar spine flat, ensure posterior pelvic tilt.
• B. Patient stands with hips flexed.
• C. Patient sits with legs extended.
• D. Patient prone with knees flexed.

Answer: (A)

The test is designed to isolate hip flexor length by preventing compensations from the spine and opposite leg. Positioning the patient supine at the edge of the plinth, bringing one knee to the chest while keeping the lumbar spine flat through posterior pelvic tilt, and letting the other leg rest extended on the plinth, creates the proper setup. This arrangement allows the examiner to assess true hip flexion without the pelvis tilting forward and without trunk movement masking tight hip flexors. The edge of the plinth and the posterior tilt help the pelvis stay neutral, so any limitation reflects the hip flexors rather than the spine or pelvis. Other positions—standing, sitting, or lying prone with knees flexed—do not isolate hip flexor length and would introduce compensations that obscure the measurement.

The test is designed to isolate hip flexor length by preventing compensations from the spine and opposite leg. Positioning the patient supine at the edge of the plinth, bringing one knee to the chest while keeping the lumbar spine flat through posterior pelvic tilt, and letting the other leg rest extended on the plinth, creates the proper setup. This arrangement allows the examiner to assess true hip flexion without the pelvis tilting forward and without trunk movement masking tight hip flexors. The edge of the plinth and the posterior tilt help the pelvis stay neutral, so any limitation reflects the hip flexors rather than the spine or pelvis. Other positions—standing, sitting, or lying prone with knees flexed—do not isolate hip flexor length and would introduce compensations that obscure the measurement.