The AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Fourth Edition, offers several categories to describe impairment in the shoulder, including shoulder amputation, abnormal shoulder motion, peripheral nerve disorders, subluxation/dislocation, and joint arthroplasty. This article clarifies appropriate methods for rating shoulder impairment in a specific patient, particularly with reference to the AMA Guides, Section 3.1j, Shoulder, Section 3.1k, Impairment of the Upper Extremity Due to Peripheral Nerve Disorders, and Section 3.1m, Impairment Due to Other Disorders of the Upper Extremity. A table shows shoulder motions and associated degrees of motion and can be used in assessing abnormal range of motion. Assessments of shoulder impairment due to peripheral nerve lesion also requires assessment of sensory loss (or presence of nerve pain) or motor deficits, and these may be categorized to the level of the spinal nerves (C5 to T1). Table 23 is useful regarding impairment from persistent joint subluxation or dislocation, and Table 27 can be helpful in assessing impairment of the upper extremity after arthroplasty of specific bones of joints. Although inter-rater reliability has been reasonably good, the validity of the upper extremity impairment rating has been questioned, and further research in industrial medicine and physical disability is required.