Thomas Test

Original Editor - Tyler Shultz, Aurelie Canas-Perez

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Definition/Description

Patient should be lied on his back and must then maximally flex both knees, using both arms. One limb is then lowered toward the table.   

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Clinically Relevant Anatomy

 Iliopsoas muscle group

M.iliopsoas: Main function → thigh flexion    
                   Additional feature→external rotation

M. Rectus Femoris: Main function → thigh flexion                          
                              Additional feature→knee extension                               
M. Tensor Fascia Latae: Main function → thigh flexion    
                                    Additional feature→internal rot., abduction  

M. Sartorius: Main function → thigh flexion    
                    Additional feature→knee flexion

Purpose

The Thomas Test or Iliacus Test or Iliopsoas Test is used to measure the flexibility of the iliopsoas muscle group, the M. Rectus Femoris, as well as the M. Tensor Fascia Latae and the M. Sartorius.Measuring the flexibility of this muscle is not useful, because we don’t have a  standard meeting length of muscle. The most important aspect of this test is that of the range of motion  of  the hip, as various diseases such as patellofemoral pain syndrome , lower back pain, osteoarthritis and rheumatoid arthritis, may be related to this impaired range of motion.

Technique

The patient should be supine, using the whole length of the table. The patient must then maximally flex both knees, using both arms. This ensures that the lumbar spine is flexed and flat on the table and avoids a posterior tilt of the pelvis. The patient then lowers the<span style="mso-spacerun:yes" /> tested limb toward the table. During the test the contralateral hip is held in maximal flexion. The length of the iliopsoas is measured by the angle of the hip flexion.

A modified version of the test is one in which the patient lies down on their back, at the very edge of the table, with both legs hanging freely. The patient must then flex their knee and pull it back to their chest as close as they can, using both arms while doing so. The other leg can hang down. The lumbar spine must remain flat and in contact with the table during the test^. The physiotherapist controls the opposite leg to ensure that it maintains full contact with the table. 

•  Negative result: The lower back and the sacrum should 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.

• Positive result: When the

patient is not able to maintain their lower back and sacrum against the table. Otherwise if the hip has a large posterior tilt or hip extension greater than 15°, or if the knee is not able to meet flexion of 80° or more.

Consequences: a reduced range of motion may be a sign of one of these diseases:  patellofemoral pain syndrome, lower back pain, osteoarthritis and rheumatoid arthritis

Reliability of the test: Investigation into the validity of tests are important to know whether our tests are reliable or not. Studies that test the reliability of the Thomas study are very limited. One^{<span style="mso-spacerun:yes" />} study has demonstrated that the modified Thomas test has a very good inter-rater reliability. Another has demonstrated that the modified Thomas test, has an average of only moderate levels of reliability. In order to prove or to refute the reliability of the Thomas test, further research is required. 

Resources

<span lang="EN" /> ↑ The “iliacus test”: New information for the evaluation Assessment of the flexibility of elite athletes using the modified Thomas test.

↑ Iliotibial band Friction Syndrome.

↑ Postural Screening using the Tomas Test- Part 1

Clinical Bottom Line

When examining patients with LBP, hip, and/or knee conditions, the Thomas test can be useful in determining associated impairments.

Recent Related Research (from Pubmed)

•  The influence of corrective exercises in a water environment on the shape of the antero-posterior curves of the spine and on the functional status of the locomotor system in children with Io scoliosis.

•  Normative and critical criteria for iliotibial band and iliopsoas muscle flexibility.