Thomas Test (or as it called Hugh Owen Thomas well leg raising test) is used to measure the flexibility of the hip flexor muscles, which includes:
The iliopsoas muscle group (It’s made up of 3 muscles, the Psoas Major, Psoas Minor and Iliacus muscle).
The rectus femoris muscle.
Tensor fascia latae muscle.
It’s used to test for hip flexion contracture and psoas syndrome, which is more common in runners, dancers, and gymnasts with symptoms of hip “stiffness” and “clicking” feeling when flexing at the waist.
Thomas test first described by Dr. Hugh Owen Thomas, a British orthopaedic surgeon (1834–1891).
The patient should be supine on the examination table, maximally flex both knees, using both arms to ensure that the lumbar spine is flexed and flat on the table and avoids a posterior tilt of the pelvis.
The patient then lowers the tested limb toward the table, whilst the contralateral hip and knee is still held in maximal flexion to stabilize the pelvis and flatten out the lumbar lordosis.
What does a positive Thomas Test mean?
The Thomas test is negativewhen the subject’s lower back and the sacrum is able to remain on the table.
The hip can make a 10° posterior tilt or a 10° hip extension. The knee must be able to make a 90° flexion.
The Thomas test is positivewhen:
Subject is unable to maintain their lower back and sacrum against the table.
Hip has a large posterior tilt or hip extension greater than 15°.
Knee unable to meet more than 80° flexion.
Sensitivity & Specificity
Sensitivity: 31 %
Specificity: 57 %
In a flexion contracture, the hip being examined does not continue to lie extended on the examining table.
Instead it moves along with the increasing hip flexion or pelvic tilt, taking on a position of increasing flexion.
The flexion contracture can be quantified by measuring the angle that the flexed, affected leg forms with the examining table.
Contractures of the hip occur in osteoarthritis, in inflammation, and articular deformities of the hips. They can also cause spinal disorders.
The modified Thomas test is not a valid measure of hip extension unless pelvic tilt is controlled Andrew D. Vigotsky, Gregory J. Lehman, Chris Beardsley, Bret Contreras, Bryan Chung, Erin H. Feser PeerJ. 2016; 4: e2325. Published online 2016 Aug 11. doi: 10.7717/peerj.2325 PMCID: PMC4991856