The cartilage interface sign refers to the sonographic presence of a thin markedly hyperechoic line at the interface between the normally hypoechoic hyaline articular cartilage of the humeral head and an abnormally hypoechoic supraspinatus tendon, due to the marked difference in acoustic impedances of the two tissues at the interface 1.The sign indicates the presence of partial or complete supraspinatus tear with fluid replacing the fibers and has been shown to be 100% specific 2. The sign however is not often present and has a low sensitivity for supraspinatus tear of around 30% 2.
- 1. Jacobson JA. Fundamentals of musculoskeletal ultrasound. W B Saunders Co. (2007) ISBN:1416035931. Read it at Google Books - Find it at Amazon
- 2. Jacobson JA, Lancaster S, Prasad A et-al. Full-thickness and partial-thickness supraspinatus tendon tears: value of US signs in diagnosis. Radiology. 2004;230 (1): 234-42. doi:10.1148/radiol.2301020418 - Pubmed citation