Final answer:
Anesthesia administration does not help in improving the visibility of a subscapularis tear during surgery. Proper lighting, patient positioning, and the use of surgical instruments are all critical in aiding exposure. The rotator cuff muscles provide primary support to the glenohumeral joint.
Step-by-step explanation:
During a case, all of the following can help improve exposure of a subscapularis tear, except: Anesthesia administration. Proper lighting, patient positioning, and surgical instruments are all direct aids in improving the visibility and access to the surgical site. Anesthesia does play a crucial role in patient comfort and immobility, but it does not directly enhance the visual exposure of a tear in the subscapularis or any other operative site.
As for the primary support for the glenohumeral joint, it is provided by the rotator cuff muscles. The other options, such as the coracohumeral ligament, the glenoid labrum, and the subacromial bursa, also support the joint, but the prime movers and stabilizers are indeed the rotator cuff muscles.