Shoulder Lock Test

The Shoulder Lock test is used to help differentiate the cause of symptoms when the patient complains of localized catching shoulder pain, and pain or restricted movement, when attempting to place the hand behind the back.

The lock position compresses the subacromial space and reproduces pain with shoulder impingement syndrome.

This test is done along with quadrant position of shoulder.

How do you perform the lock test of the shoulder?

It is assumed that the techniques are performed on the patient’s right side:

• The patient lies in the supine position with the right shoulder at the edge of the table, and the elbow positioned 10 degrees posterior to the frontal plane.
• The clinician places his or her left hand under the scapula.
• The clinician’s right hand is placed near the patient’s right elbow.
• After assessing the resting symptoms, the clinician slowly glides the patient’s elbow anteriorly, noting the location of onset of resistance and/or pain in the available range.
• The end position for the test is achieved when the patient’s right shoulder is in maximal humeral flexion with overpressure, and neither the patient nor the clinician can externally rotate the arm further while at this end range.
• In the locking position, the greater tuberosity and its rotator cuff attachments are caught within the subacromial space.
• Further motion into external rotation, flexion, or abduction is not possible, unless the arm is allowed to move into less flexion.

What is a positive lock test?

Positive findings for this test include reproduction of the patient’s symptoms and a decrease in ROM compared with the uninvolved shoulder.

Sensitivity & Specificity

Since the clinician controls the motion, this test can be a very sensitive test to help confirm the presence of an impingement of the supraspinatus tendon.

Quadrant Position of Shoulder

The quadrant position of shoulder stresses the anterior and inferior part of the shoulder capsule and indicates capsular tightening.

To test quadrant position of shoulder the examiner stabilizes the scapula and clavicle by placing the forearm under the patient’s scapula on the side to be tested and extending the hand over the shoulder to hold the trapezius muscle and prevent shoulder shrugging. To test the position, the upper limb is elevated to rest alongside the patient’s head with the shoulder rotated laterally. The patient’s shoulder is then adducted. Because adduction occurs on the coronal plane, a point (the quadrant position) is reached at which the arm moves forward slightly from the coronal plane.

At approximately 60° of adduction (from the arm beside the head), this position of maximum forward movement occurs (i.e., at about 120° of abduction) even if a backward pressure is applied. As the shoulder is further adducted, the arm falls back to the previous coronal plane. The quadrant position indicates the position at which the arm has medially rotated during its descent to the patient’s side.

The quadrant position of shoulder also may be found by abducting the medially rotated shoulder while maintaining extension. In this case, the quadrant position is reached (at about 120° of abduction) when the shoulder no longer abducts, because it is prevented from laterally rotating by the catching of the greater tuberosity in the subacromial space. This position is referred to as the locked quadrant position of shoulder. If the arm is allowed to move forward, lateral rotation occurs and full abduction can be achieved. Both the quadrant and locked quadrant simply indicate where the rotation normally occurs during shoulder abduction/ adduction.

Notes

• The two tests refer to the position of the greater tuberosity related to acromial arch and glenoid.
• locking position occurs when the greater tuberosity approximates a combination of the coracoacromial arch and coracoid process,
• The quadrant position occurs when the greater tuberosity lies under the acromion.
• Each test should be assessed for pain and end-feel, and should be compared with the uninjured side.

The results of this a study suggest that a number of pain sensitive structures may be involved, namely:

During ‘locking test’:

1. the supraspinatus tendon,
2. coracoacromial ligament
3. glenoid labrum,
4. acromioclavicula joint,
5. subacromial bursa.

Where there is anteroinferior capsular tightness, movement may be restricted.

During ‘quadrant position’:

The supraspinatus tendon, coracoacromial ligament, glenoid labrum, acromioclavicular joint and subacromial bursa are implicated.

The tendon of long head of biceps, the superior, anterior and inferior fibres of the capsule, and, to a lesser extent, tendons of infraspinatus and subscapularis may also be involved.

References

1. Mullen F, Slade S, Briggs C. Bony and capsular determinants of glenohumeral ‘locking’ and ‘quadrant’ positions. Aust J Physiother. 1989;35(4):202-8. doi: 10.1016/S0004-9514(14)60508-0. PMID: 25025618.
2. Maitland G: Peripheral Manipulation, 3rd ed. London: Butterworth, 1991.
3. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.