The aim of this study was to find a descriptive rationale to quantify articular-sided supraspinatus tendon tears in the transverse and coronal planes, leading to a 2-dimensional description of the tear pattern. Fifty-six consecutive patients with articular-sided, symptomatic supraspinatus tendon tears diagnosed clinically and by magnetic resonance imaging underwent standardized diagnostic arthroscopy. Intra-articular findings of the rotator cuff were classified according to Ellman and Snyder. In addition, the longitudinal tear was assessed according to the length of the peeled-off bony footprint in the coronal plane. The sagittal tear extension was defined as a tear of the lateral reflection pulley on the medial border of the supraspinatus tendon and/or a tear in the area of the crescent zone. Statistically, we found a high correlation (r = 0.920, P < .0001) between the classifications of Ellman and Snyder, and we found only a slight correlation between the classifications of Snyder and Ellman with this new classification. Neither the classification of Snyder nor that of Ellman reproduced the extension of the partial-thickness rotator cuff tear in the transverse and coronal planes related to its etiologic pathomorphology.