Long Sitting Test (Supine to Sit): Checking SI Joint Rotation

The Long Sitting Test, also known as the Supine to Sit Test, is a functional SI joint test. It helps diagnose if the ilium is rotated anteriorly or posteriorly by observing changes in apparent leg length during movement.

1. Purpose

The primary purpose of the Long Sitting Test is to **differentiate** between an Anterior or Posterior rotation of the innominate (ilium) on the sacrum. It uses the functional leg length changes that occur when moving from lying down to sitting up to identify SI joint dysfunction.

2. How to Perform

1. The patient is positioned in supine (lying on their back).
2. The patient is asked to perform a bridge (lift hips up and place them down) to ensure the pelvis is in a neutral starting position.
3. The examiner passively extends the patient's legs and checks the level of the medial malleoli (inner ankle bones) to assess leg length in the supine position.
4. The patient is then asked to sit up (come into a long sitting position) while the examiner holds the feet and observes the level of the malleoli again.

3. Positive & Negative Sign

Positive Sign (Test is POSITIVE):
The diagnosis is based on how the leg length changes:

• Anterior Rotation (Ipsilateral Anterior Rotation): The leg appears LONGER in supine and becomes SHORTER in sitting (Long to Short).
• Posterior Rotation: The leg appears SHORTER in supine and becomes LONGER in sitting (Short to Long).

Negative Sign (Test is NEGATIVE):
A negative test is when there is no significant change in the leg length difference between the two positions.