Yergason test is primarily designed to check the ability of the transverse humeral ligament to hold the biceps tendon in the bicipital groove.
The patient sits or stands, and the upper arm is positioned with the elbow at 90 degrees of flexion and the forearm pronated. The patient is asked to supinate his or her forearm against the manual resistance of the clinician.
The patient will exhibit a pain response, snapping or both in the bicipital groove. Pain with no associated popping might indicate bicipital tendinopathy. A snapping indicates a tear or laxity of the transverse humeral ligament, which would prevent the ligament from securing the tendon in the groove.
Relevant anatomy of the Biceps Brachii Muscle
The biceps brachii is a long muscle extending the length of the humerus. It arises in two places. It arises in two places; medially, the short head arises from the coracoid process of the scapula and laterally, the long head arises as a slender tendon from the supraglenoid tubercle inside the capsule of the shoulder joint. The tendon passes over the head of the humerus into a groove called the intertubercular sulcus. At this point the muscle has two bellies which fuse and then form a single tendon at the bottom. The tendon inserts on the tuberosity of the radius.
The biceps brachii muscle, familiarly known as the biceps, moves the arm forward and assists in turning the hand outward, a movement called supination.