Navigating the complexities of frozen shoulder requires a thorough understanding of its clinical presentation and differential diagnosis. This condition, formally known as adhesive capsulitis, is defined by a significant loss of glenohumeral range of motion, particularly in external rotation, accompanied by a history of pain and stiffness. Accurate assessment is paramount. Observe both glenohumeral and scapulothoracic movement patterns, being mindful of compensatory "shrug" signs. Differentiate true joint stiffness from muscle guarding by assessing both active and passive range of motion. A key indicator of true frozen shoulder is equally limited active and passive movement. Consider pertinent risk factors during assessment, including age (40-50+), female gender, obesity, and a fivefold increased prevalence in individuals with diabetes. Differentiating frozen shoulder from other causes of shoulder stiffness, such as osteoarthritis, post-operative stiffness, or rotator cuff pathology,...