The alpha angle is a key measurement in the Graf method of neonatal hip ultrasound, used to evaluate whether an infant’s hip joint is developing normally. It measures the angle formed between the iliac bone and the bony acetabular roof, reflecting how deep and well-formed the bony socket is. A normal alpha angle is 60 degrees or greater, indicating a mature, well-developed hip joint. An alpha angle less than 60 degrees suggests varying degrees of hip dysplasia, meaning the socket is too shallow to properly hold the femoral head, and the infant may need treatment such as a harness or brace to encourage proper development.
Sonography Term