Southwick method for determining slipped capital femoral epiphysis (SCFE) severity using a frog-leg lateral radiograph. The first line (a) is drawn from the anterior to the posterior epiphyseal edges. Next, a line (b) is drawn perpendicular to the first line. A third line (c) is drawn down the middle of the femoral diaphysis. The angle formed by lines b and c is the lateral epiphyseal-shaft angle (LESA). The actual slip angle is the difference between the LESA of the SCFE hip and that of the uninvolved hip. | Peck, D. (2010). Slipped capital femoral epiphysis: diagnosis and management. American Family Physician, 82(3), 258–262.