What does the Q angle refer to?

The Q angle, or quadriceps angle, refers specifically to the angle formed between the line of pull of the quadriceps muscle and the patellar tendon as it connects to the knee. More technically, it is the angle between the line drawn from the anterior superior iliac spine (ASIS) to the midpoint of the patella and the line from the midpoint of the patella to the tibial tuberosity. This angle is vital in understanding biomechanics, particularly regarding knee alignment and function.

A larger Q angle can indicate a greater risk for certain knee injuries and conditions, such as patellofemoral pain syndrome. It is an important measure in sports medicine and physical therapy, allowing practitioners to assess a person's risk for injury or necessary interventions for rehabilitation.

The other options describe different anatomical aspects but do not relate to the established definition of the Q angle. For instance, the angle between the upper and lower leg bones is more related to knee joint mechanics but does not represent the specific measurement that defines the Q angle. The shoulder joint and spine angles pertain to upper body biomechanics, while the angle created by the foot and ground focuses on the lower extremity but not specifically on knee mechanics.