Final answer:
During a frontal plane view postural assessment, the most appropriate corrective exercise for a client with an elevated or shrugged left shoulder would be scapular depression exercises.
Step-by-step explanation:
During a frontal plane view postural assessment, if you notice that your client's left shoulder appears to be elevated or shrugged at rest, the most appropriate corrective exercise would be scapular depression exercises. Scapular depression is the downward movement of the scapula, which can help bring the elevated shoulder back into a more neutral position. This exercise would focus on strengthening the muscles responsible for depressing the scapula, such as the lower trapezius and lats.