Thomas Test

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Original Editor - Tyler Shultz

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<div class="noeditbox">Welcome to  [[Arkansas Colleges of Health Education School of Physical Therapy Musculoskeletal 1 Project]].  This space was created by and for the students at Arkansas Colleges of Health Education School in the United States. Please do not edit unless you are involved in this project, but please come back in the near future to check out new information!!</div>

Purpose

The Thomas Test measures hip flexor length and distinguishes tightness between one joint and two joint muscles.

1. Impaired range of motion of the hip may be an underlying cause to other conditions such as: psoas syndrome; patellofemoral pain syndrome; lower back pain, osteoarthritis; rheumatoid arthritis.
2. Often associated with runners, dancers, and gymnasts who complain of hip "stiffness" and reported "snapping" feeling when flexing at the waist.

Image: Overview of the hip and thigh - anterior and posterior views

Relevant Anatomy

There are various muscles making up the hip flexor group being tested in the Thomas Test:

Hip Flexor Muscle	Picture (Muscle in green)	Number of Joints Crossed	Main Function	Additional Movement
Iliopsoas: Composed of iliacus and psoas major		One joint: Hip	Hip flexion	Hip external rotation
Pectineus		One joint: hip	Hip flexion	Hip abduction
Adductor Longus & Brevis		One joint: hip	Hip adduction	Hip flexion and external rotation
Adductor Magnus		One joint: hip	Adductor part: Hip flexion, adduction, external rotation	Hamstring part: Hip extension and internal rotation.
Rectus femoris		Two joints: Hip and knee	Hip flexion	Knee extension
Tensor fascia lata		Two joints: Hip and knee	Hip abduction, flexion, internal rotation	Knee extension
Sartorius		Two joints: Hip and knee	Hip flexion, abduction, external rotation	Knee flexion

"The copyright holder has given special permission to use these images in Physiopedia"

This 16 minute video is a good summary of the lower extremity muscles.

How to Remember Every Muscle of the Lower Limb and Leg | Corporis

Equipment

• Stable/firm table.
• Goniometer.
• Chart for recording findings.

Technique

• Starting Position: Patient is seated at the end of a table with half of their thigh off the edge. Examiner places one hand behind the patient’s knee and another behind their back before helping them to lay back onto the table with their knee flexed. Patient keeps the unaffected leg flexed, and slowly lowers the affected leg and lets it extend as far as it can.
  • Avoid bringing both knees into flexion as it allows for excessive posterior tilt of the pelvis. Correct Testing:
  • Examiner helps to lay patient back onto the table
  • Low back and sacrum are flat on the table
  • Flexed leg is in 90 degrees of hip flexion (perpendicular to the table)
    • Helps to improve accuracy across across tests/retests Errors in Testing:
  • Patient lays back on their own- unless doing the modified test
  • Patient pulls leg into too much flexion- pulling thigh off table
  • Low back and sacrum are not flat on the table Modified Version- Patient positioned in sitting at the end of an examination table. Patient is then asked to lie down while bringing both knees to their chest. They should then perform a posterior pelvic tilt- flat back. One limb should then be lowered towards the table while keeping the opposite tucked towards their chest.

Interpretation

The table below describes various presentations of a positive Thomas test and the muscles affected.

Presentation	Muscle(s) Affected	Signs
Typical length of hip flexors. (negative test)	Psoas major and iliacus, rectus femoris, tensor fasciae latae, sartorius, pectineus, adductor longus/brevis/magnus	Posterior thigh touches the table, knee flexes ~ 80°
Shortness of both one-joint and two-joint hip flexors. (positive test)	Psoas major and iliacus, rectus femoris, tensor fasciae latae, sartorius, pectineus, adductor longus/brevis/magnus	Posterior thigh does not touch the table, the knee extends.
Shortness of two-joint hip flexors. (positive test)	Rectus femoris, tensor fasciae latae, sartorius	Posterior thigh touches the table, knee extends
Shortness of one-joint hip flexors. (positive test)	Iliopsoas, pectineus, adductor longus/brevis/magnus	Posterior thigh does not touch table, knee flexes >80°
Shortness of tensor fasciae latae. (positive test)	Tensor fasciae latae	Abduction of the thigh as hip joint extends, lateral deviation of the patella. Knee extension if abduction/adduction is prevented with hip extension. Internal rotation of the thigh and external rotation of the leg on the femur.
Shortness of sartorius. (positive test)	Sartorius	Abduction, flexion, external rotation of the hip and flexion of the knee. Combination of three or more indicates tightness.

A muscle's strength and available length directly correlate to the range of motion at a joint. Two principles exist that describe the relationship between muscle strength and length and joint range of motion:

Active insufficiency: Occurs when a two joint muscle, produces movement at both joints simultaneously, and reaches a shortened length at which it can no longer generate force. [O'Connell and Gardner] [Kendall et al.] Active insufficiency refers to a lack of muscle strength. [black book]

Passive insufficiency: Occurs when a two-joint muscle is in such a lengthened position that it cannot sufficiently permit motion at both joints. [Kendall et al.] [O'Connell and Gardner] Passive insufficiency refers to a lack of muscle length, the muscle is tight. [black book]

Active and passive insufficiency principles describe potential reasons for decreased range of motion at a joint.

Goniometer: Goniometer measurements can also assist the clinician in determining the available range of motion at a joint. Goniometer measurements are unique to each individual person, therefore they should be compared bilaterally.

The following are considered to be typical goniometer measurements for the hip and knee:

*A- axis, SA- stationary arm, MA- movement arm

Action	Typical Degrees of Motion	Technique	Picture
Hip Flexion	125° [Black book]	Supine with knee flexed A: Greater trochanter SA: Aligned with midline of pelvis MA: Aligned with femur (lateral epicondyle)
Hip Extension	10° [Black book]	Prone with pelvis stabilized A: Greater trochanter SA: Aligned with midline of pelvis MA: Aligned with femur (lateral epicondyle)
Hip Internal Rotation	32° [Roach/Miles]	Seated on table with knee flexed A: Center of patella SA: Aligned vertically MA: Aligned with leg (crest of tibia)
Hip External Rotation	32° [Roach/Miles]	Seated on table with knee flexed A: Center of patella SA: Aligned vertically MA: Aligned with leg (crest of tibia)
Knee flexion	140° [Black book]	Supine A: Lateral epicondyle SA: Greater trochanter MA: Lateral malleolus
Knee extension	0° [Black book]	Supine with prop under heel A: Lateral epicondyle SA: Greater trochanter MA: Lateral malleolus

Viewing

This 40 second video shows the modified test.

Reliability

Studies that test the reliability of the Thomas study are very limited.

1. One 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. Further research is required to prove or to refute the reliability of the Thomas test.
2. Peeler & Anderson conducted a study in 2006 examining the reliability of the Thomas test for assessing hip range. Their study calls into question the reliability of the technique when used to score range of motion and iliopsoas muscle flexibility about the hip joint using both goniometer and pass/fail scoring methods.

Resources

This 17 minute video is a good summary of the muscles of the hip and thigh.