College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What structure "jams" into the anteroinferior surface of the acromion during the Neer Impingement Sign Test?

1. Greater Tuberosity

2. Humeral Head

3. Subscapularis

4. Coracoid Process

The correct answer is: Greater Tuberosity

The correct answer is related to the anatomy of the shoulder and the mechanics involved in the Neer Impingement Sign Test. During this test, the greater tuberosity of the humerus is assessed for potential impingement against the anteroinferior surface of the acromion as the arm is elevated. The greater tuberosity is a prominent bony feature on the humerus where the rotator cuff muscles attach. When the arm is lifted, particularly in a forward direction (flexion), if there is a restriction or narrowing of the subacromial space due to either anatomical variations or pathologies like rotator cuff injuries, the greater tuberosity can come into contact with the acromion. This contact is what leads to the "jamming" sensation or potential pain, which the test aims to provoke in order to assess for shoulder impingement syndrome. Understanding this mechanical interaction is crucial in diagnosing shoulder conditions, as well as recognizing the importance of the greater tuberosity in the context of shoulder mobility and stability. The other structures mentioned do not directly "jam" against the acromion in this context.