With a positive Sulcus Sign, what type of glenohumeral instability is suspected?

A positive Sulcus Sign indicates inferior glenohumeral instability. This test is performed by pulling the arm downward while the patient is seated or standing, and a noticeable sulcus or indentation below the acromion indicates that the humeral head is translating inferiorly relative to the glenoid. In cases of inferior instability, the humeral head has a tendency to move down and create space between the acromion and the humeral head, resulting in the distinct sulcus.

This examination finding suggests that the ligaments and stabilizing structures around the shoulder may be compromised, leading to this specific type of instability. It is important to note that while other types of instability can exist, the Sulcus Sign specifically highlights issues related to the inferior aspect of the shoulder joint, making it a key indicator for diagnosing inferior glenohumeral instability.