Concept:
Neer's test is a specific physical examination maneuver used to assess shoulder pathology, specifically targeting the structures passing through the subacromial space.
Explanation:
• Rotator cuff impingement syndrome (Subacromial Impingement) occurs when the tendons of the rotator cuff (particularly the supraspinatus) and the subacromial bursa are compressed against the anteroinferior aspect of the acromion and the coracoacromial ligament during arm elevation.
• Neer's Impingement Test: The examiner stabilizes the patient's scapula with one hand and forcibly forward elevates the patient's internally rotated arm to the maximum limit. This maneuver mechanically traps the greater tuberosity of the humerus against the acromion. Pain reproduced by this maneuver is a positive test, indicating subacromial impingement.
• Option (C), Tear of the supraspinatus, is typically evaluated using strength tests like the "Empty Can" (Jobe's) test or the Drop Arm test. While an impinged tendon might also be torn, Neer's test specifically isolates the impingement mechanism, not the structural integrity of the tendon.
• Option (A), Glenohumeral arthritis, restricts global range of motion (frozen shoulder pattern) and is not isolated by Neer's test.
• Option (D), AC joint osteoarthritis, is best provoked by the Cross-Body Adduction test.
Final answer:
Neer's test is a provocation test designed to reproduce the mechanical compression characteristic of rotator cuff (subacromial) impingement syndrome.