Sonography of full-thickness supraspinatus tears: comparison of patient positioning technique with surgical correlation.

Objective: Sonography has become a popular technique for the assessment of musculoskeletal disorders. Patient positioning is crucial to a thorough and accurate assessment of rotator cuff tendons. Two positions, the Crass and modified Crass, have been routinely used in the research and clinical settings to examine the supraspinatus tendon.