A person is able to abduct his arm, internally rotate it, place the back of hand on the lumbosacral joint, but is not able to lift it from back. What is the etiology?
Ans. a. Subscapularis tendon tear (Ref: Apley's 9/e, p345-346; Campbell's 11/e p2605-2608)In cases of subscapularis tendon tear, the person is able to abduct his arm, internally rotate it, place the back of hand on the lumbosacral joint, but is not able to lift it from back."Failure to perform maximum internal rotation (as tested in belly press and lift off test) or inability to maintain position of maximal internal rotation (internal rotation lag sign) indicate tear of subscapularis tendon. Lift off test is done to assess the strength of subscapularis muscle and detect an isolated rupture of subscapularis tendon in a rotator cuff tear."Lift-Off TestThe Lift-off test was originally described by Gerber and Krushell (1991) and is sometimes referred to as 'Gerber's Test'.Method:The patient is examined in standing and is asked to place their hand behind their back with the dorsum of the hand resting in the region of the mid-lumbar spine.The dorsum of the hand is raised off the back by maintaining or increasing internal rotation of the humerus and extension at the shoulder.To perform this test the patient must have full passive internal rotation so that it is physically possible to place the arm in the desired position and pain cannot be a limiting factor during the maneuver.Result of Lift-Off TestThe ability to actively lift the dorsum of the hand off the back constitutes a normal lift-off test.Inability to move the dorsum off the back constitutes an abnormal lift-off test and indicates subscapularis rupture or dysfunction.Tests to assess rotator cuff integrityTestDetectMethodLift off testIsolated rupture of subscapularis tendonQ* With the patient seated or standing, the arm is internally rotated, and the dorsum of hand is placed against the lower back.* If the patient is unable to lift the dorsum of hand off the back the test is positive i.e. subscapularis is tomInternal rotation lag signIntegrity of subscapularis tendon* The arm is held by examiner in maximal internal rotation.* The elbow is flexed to 90deg and dorsum of hand is passively lifted away from the lumbar region until almost full infernal rotation is reached.* The patient is asked to maintain this position of maximal internal rotation (function of subscapularis) actively as the examiner releases the wrist while maintaining support at elbow.* The sign is positive when lag (i.e. failure to maintain occurs)Belly press testIntegrity of subscapularis tendon* Patient presses the abdomen with flat of hand and attempt to keep the arm in maximal internal rotation (i.e. elbow remains in front of trunk).* If the subscapularis is weak (tom), maximal internal rotation cannot be maintained and the elbow drops back behind the trunk and patient exerts pressure on abdomen by extending the shoulder and flexing the wrist rather than by internally rotating.Drop signIntegrity of infraspinatus* Arm is held at 90deg of elevation in scapular plane and almost at full external rotation with elbow flexed at 90deg.* The patient is asked to maintain this position and the sign is positive if a lag or drop occurs.External Rotation stress testIntegrity of external rotators of shoulder especially infraspinatus and teres minor* With the patients arm by his side in neutral flexion and abduction, the shoulders are externally rotated to 45-60deg.* The examiner applies force against dorsum of hands, attempting to rotate the shoulders internally back to neutral while the patient is asked to resist.* Pain and weakness suggest inflammation or tear.External rotation lag sign testIntegrity of supraspinatus and infraspinatus* Patient is asked to maintain the position of near maximal external rotation (i.e. maximum-50) with elbow flexed to 90deg and shoulder held at 20deg elevation. Sign is positive when lag or angular drop occurs
Subscapularis tendon tear
Teres major tendon tear
Long head of biceps tendon tear
Acromioclavicular joint dislocation
Injuries Around Shoulder