Posterior Drawer Test of the Shoulder

Posterior Drawer test of the shoulder is used to assess the posterior instability of the shoulder joint. It was first described by C.Gerber and R.Ganz in 1984.

How do you perform the Posterior Drawer Test of the Shoulder?

• The patient lies supine.
• The examiner stands at the level of the shoulder and grasps the patient’s proximal forearm with one hand, flexing the patient’s elbow to 120° and the shoulder to between 80° and 120° of abduction and between 20° and 30° of forward flexion.
• With the other hand, the examiner stabilizes the scapula by placing the index and middle fingers on the spine of the scapula and the thumb on the coracoid process. (The examining table partially stabilizes the scapula as well.)
• The examiner then rotates the upper arm medially and forward flexes the shoulder to between 60° and 80° while taking the thumb of the other hand off the coracoid process and pushing the head of the humerus posteriorly.
• The head of the humerus can be felt by the index finger of the same hand.
• The posterior drawer test of the shoulder is similar to the Norwood Stress test without the horizontal adduction.

What does a positive Posterior Drawer Test of the shoulder mean?

Where there is sufficient laxity in the capsular ligaments, this test will provoke a posterior drawer (subluxation or dislocation of the humeral head). The posterior drawer test of the shoulder is usually not painful, but the patient may exhibit apprehension.

Horizontal extension, slight external rotation of the arm , and additional posteroanterior pressure applied by the finger to the posterior aspect of the humeral head will suffice to reduce the humeral head. The snap that accompanies reduction must be carefully distinguished from anterior subluxation.

The important thing is to assess the motion of the humeral head relative to the glenoid fossa by placing the index finger posteriorly around the glenoid and pressing the humeral head in an anteroposterior direction with the thumb.

Notes

The posterior drawer test of the shoulder may also be performed with the patient seated. With the patient in a relaxed posture bending slightly forward with the arm hanging alongside the trunk, the examiner places his or her thumb on the patient’s scapular spine or posterior glenoid and grasps the humeral head anteriorly. Applying rotation and pressure with the fingers will provoke posterior subluxation of the head where there is sufficient laxity in the capsular ligaments.

In posterior instability, the humeral head can be posteriorly displaced by one-half its diameter.

Posterior Instability

Posterior instabilities, which are rare and only comprise approximately 2% of all shoulder dislocations, are often associated with seizure, electric shock, diving into a shallow pool, or motor vehicle accidents.

Patients who have a posterior instability pattern typically report symptoms with the arm in a forward flexed, adducted position, such as when pushing open heavy doors.

Posterior dislocations are classified as:

1. Subacromial (posterior and inferior to the acromion process, the most common),
2. Subglenoid (posterior and inferior to the glenoid rim),
3. Subspinous (medial to the acromion and inferior to the scapular spine).

The most characteristic sign for a posterior dislocation is a loud clunk as the shoulder is moved from a forward flexed position into abduction and external rotation, a positive finding that is often misdiagnosed as an anterior dislocation.

The findings for a posterior dislocation are usually severe pain, limited ER, often to less than 0 degree, and limited elevation to less than 90 degrees. There is usually a posterior prominence and rounding of the shoulder as compared to the opposite side, and a flattening of the anterior aspects of the shoulder. Looking down at the patient’s shoulders from behind can best assess these asymmetries

Reference

1. C Gerber, R Ganz. Clinical assessment of instability of the shoulder. With special reference to anterior and posterior drawer tests. J Bone Joint Surg Br. 1984 Aug;66(4):551-6. doi: 10.1302/0301-620X.66B4.6746691. PMID: 6746691. Pubmed
2. Matsen FA 3rd, Harryman DT 2nd, Sidles JA. Mechanics of glenohumeral instability. Clin Sports Med. 1991 Oct;10(4):783-8. PMID: 1934096. Pubmed
3. Brody LT: Shoulder. In: Wadsworth C, ed. Current Concepts of Orthopedic Physical Therapy—Home Study Course. La Crosse, WI: Orthopaedic Section, APTA, 2001.
4. Clinical Tests for the Musculoskeletal System 3rd Edition.
5. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
6. Millers Review of Orthopaedics, 7th Edition
7. Campbel’s Operative Orthopaedics 13th Book