Understanding the Posterior Sag Sign (Gravity Drawer Test) Assessment
To detect a rupture of the **Posterior Cruciate Ligament (PCL)** by observing the effect of gravity.
Watch How It's Done
How do I start?
Patient is supine. Hips and knees are flexed to **90°**. Feet are flat on the table, unsupported.
What happens?
The examiner observes the contour of the knee joint from the side.
In Plain English
What Does a Positive Result Mean?
The **tibia on the affected side sags or drops posteriorly** relative to the femur (The step-off created by the tibial plateau is lost), indicating a PCL tear.
Helpful Tip:
This is often the first and most obvious sign of a PCL injury.
Safety First
This guide is to help you understand what happens in a clinic. Do not try to diagnose yourself. If you have severe pain, swelling, or cannot put weight on your leg, please visit an urgent care center or your doctor immediately.
Other Knee Tests
Pivot Shift Test
To dynamically assess for **anterolateral rotatory instability** of the knee, which is highly indicative of a **complete ACL tear**.
Posterior Drawer Test of the Knee
To assess the integrity of the **Posterior Cruciate Ligament (PCL)**.
Slocum Test (Anterolateral Rotatory Instability)
To assess for **anterolateral rotatory instability** and the function of the **Anterolateral Ligament** (a dynamic variant of the Anterior Drawer).
Thessaly Test
To assess for **meniscal tears** by dynamically loading the meniscus in a weight-bearing, rotational manner.