System used to describe pediatric condylar fractures of humerus. Type 1, fracture runs from trochlear sulcus to medial superior eminence or from trochlear sulcus to lateral superior eminence (usually due to compression; type 2, fracture runs from trochlear sulcus to lateral superior eminence or trochlear groove to medial superior eminence (usually due to compression or dislocation.)