Presentation
Shoulder pain.
Patient Data

Hypoechoic area representing supraspinatus tear

Large hypoechoic region within the supraspinatus tendon. Deep to this there is a well-seen thin echogenic line known as the cartilage interface sign (arrow). This line is created by reflection of sound waves at the fluid-cartilage interface. This interface is only seen when there is a rotator cuff tear and can assist in making the diagnosis of such.
Case Discussion
This case demonstrates an excellent example of the cartilage interface sign which refers to the sonographic presence of a thin markedly hyperechoic line at the interface between the hyaline articular cartilage of the humeral head and an abnormally hypoechoic supraspinatus tendon. The sign indicates the presence of partial or complete supraspinatus tear and has been shown to be 100% specific. The sign however is not often present and therefore has a low sensitivity of around 30%.