Anterolateral thigh (vastus lateralis) injection site

The hip and knee should be flexed to relax the vastus lateralis. Identify the following landmarks: anterior superior iliac spine (ASIS), pubic tubercle, upper part of the patella. Draw an imaginary line between the ASIS and the pubic tubercle. Draw a second imaginary line between the midpoint of the first line and the upper part of the patella. The correct injection site, depicted by the X above, is lateral to the second imaginary line in the vastus lateralis.