A Southwick angle is a radiographic

Radiography

Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....

 angle used to measure the severity of a slipped capital femoral epiphysis

Slipped capital femoral epiphysis

Slipped capital femoral epiphysis is a medical term referring to a fracture through the physis , which results in slippage of the overlying epiphysis....

 (SCFE) on a radiograph. It was named after Wayne O. Southwick, a famous surgeon.

The angle is measured on a frog lateral view of the bilateral hips. It is measured by drawing a line perpendicular to a line connecting two points at the posterior and anterior tips of the epiphysis at the physis. A third line is drawn down the axis of femur

Femur

The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

. The angle between the perpendicular line and the femoral shaft line is the angle. The angle is measured bilaterally. The slipped side is then subtracted from the normal side. The number calculated determines the severity. Mild is classified by < 30^o. Moderate is 30^o-50^o. Severe is >50^o. 12^o is the normal control value and can be used in the case of bilateral involvement.