Posterior instability of the shoulder joint, although less common than its anterior counterpart, presents a significant challenge in diagnosis and management. This article delves into the anatomy, epidemiology, pathophysiology, examination techniques, imaging diagnosis, and treatment modalities associated with this condition. Understanding the shoulder’s intricate structure, which involves both static and dynamic stabilizers, is crucial for comprehending the mechanisms leading to instability. Clinical evaluation, encompassing visual inspection, palpation, and specialized tests like the Kim and Jerk tests, aids in identifying posterior instability. Imaging techniques, including radiographs, CT scans, and MRIs, play a pivotal role in visualizing dislocations, bone defects, and soft tissue pathologies, thereby facilitating precise treatment planning. The treatment approach typically involves conservative measures, with surgical intervention reserved for severe cases or persistent instability. Awareness of the condition’s rarity, coupled with a comprehensive diagnostic and treatment approach, ensures optimal outcomes and prevents progression to advanced stages.