What is O'Brien's Test
O'Brien's Test, also known as the O’Brien’s active compression test, is a clinical evaluation used to identify labral tears in the shoulder (O’Brien et al., 1998). While it can also be used to detect acromioclavicular (AC) joint abnormalities, the test is particularly useful for diagnosing superior labrum anterior to posterior (SLAP) lesions, a type of tear that occurs at the upper part of the shoulder’s labrum. The glenoid labrum is a ring of cartilage around the shoulder socket (glenoid) that helps stabilize the shoulder joint. A SLAP tear typically affects the labrum, where it attaches to the shoulder blade.
Here's how O'Brien's Test is typically performed:
- With the patient standing, ask them to flex their shoulders to 90 degrees.
- Move the patient’s arms so that the shoulders are horizontally adducted 10 to 15 degrees.
- Ask the patient to internally rotate their arms to the maximum range (thumbs pointing downward). This is Position 1.
- Apply downward force on the arms while the patient resists.
- Next, ask the patient to externally rotate their arms (palms facing upward). This is Position 2.
- Again, apply downward force and ask the patient to resist.
O'Brien's Test stresses the superior labrum to identify symptoms of a SLAP tear. However, doing other assessments is crucial for an accurate diagnosis and to gain a broader clinical context.










