Shoulder instability and rotator cuff tests

Special tests help identify which anatomical structure is likely contributing to a patient’s symptoms. Each test below follows the same basic pattern: a technique the examiner performs, and a positive finding that points to a specific structure or condition. As you read through each test, focus on three things: how it’s performed, what a positive result looks like, and what structure or condition it implicates.

PTA scope note: special tests are typically selected, performed, and interpreted by the supervising physical therapist as part of the initial evaluation. As a PTA, your role is to recognize and reproduce relevant signs during treatment sessions and to communicate any changes in a patient’s presentation to the supervising PT - not to diagnose or independently modify the plan of care based on these findings.

Shoulder special tests

Instability tests

Definitions

Glenohumeral instability

Occurs when the lining of the shoulder joint (the capsule), ligaments, or labrum become stretched, torn, or detached, allowing the ball of the shoulder joint (humeral head) to move either completely or partially out of the socket.

Below are tests to assess if this condition is present:

• Apprehension test (tests anterior instability)
  • Patient is supine, the shoulder is in 90 degrees of abduction; therapist attempts to externally rotate
    • Positive: patient seems apprehensive about performing movement and resists motion

• Sulcus sign (tests inferior instability; often seen with multidirectional instability)
  • Patient stands with arm relaxed at the side; therapist pulls the arm distally
    • Positive: presence of sulcus inferior to the acromion with symptom reproduction

Rotator cuff tests

Definitions

Rotator cuff pathologies

A range of conditions that affect the muscles and tendons of the shoulder joint.

Below are tests to assess if this condition is present:

• Drop arm test
  • Patient seated with the shoulder passively abducted to 90 degrees and externally rotated; patient instructed to slowly lower the arm back to the side
    • Positive: patient is unable to lower their arm down slowly and suddenly drops it to the side without control

• Infraspinatus/supraspinatus muscle test
  • Patient is seated or standing; therapist resists external rotation with the arm in the neutral position and adducted to the trunk
    • Positive: patient is unable to sustain external rotation

• External rotation lag sign
  • Patient is seated or standing with the shoulder passively abducted to 90 degrees and externally rotated
    • Positive: patient is unable to maintain external rotation

• Lift off test (Gerber’s test)
  • Patient is standing with the shoulder passively placed in internal rotation and the hand at waist level against the back
    • Positive: patient is unable to lift off the back

• Internal rotation lag sign
  • Patient is seated with arm held behind the back in internal rotation, passively
    • Positive: patient is unable to maintain internal rotation

• Empty can test
  • The patient stands or sits with their arms at their sides. The patient abducts their arm to 90 degrees, elbow extended, then internally rotates the shoulder so the thumb points toward the floor. The examiner applies downward pressure on the patient’s wrist or forearm.
    • Tests the supraspinatus muscle
    • Positive: pain in the shoulder, weakness in the arm, and the patient’s arm dropping involuntarily

Rotator cuff tests at a glance

Muscle	Tests that point to it
Supraspinatus	Empty can test, drop arm test
Infraspinatus	Infraspinatus/supraspinatus muscle test (resisted external rotation with the arm at the side), external rotation lag sign
Subscapularis	Lift off test (Gerber’s test), internal rotation lag sign