The quadriceps angle (Q angle) is measured as the angle between two lines drawn from the midpoint of the patella. What are these two reference points, and what is the approximate normal value?
- A Anterior superior iliac spine and tibial tuberosity; about 13 degrees in males ✓
- B Anterior inferior iliac spine and fibular head; about 20 degrees
- C Anterior superior iliac spine and Gerdy tubercle; about 5 degrees in females
- D Greater trochanter and tibial tuberosity; about 25 degrees
Correct answer: A. Anterior superior iliac spine and tibial tuberosity; about 13 degrees in males
Explanation
The Q angle is formed between a line from the anterior superior iliac spine to the centre of the patella and a line from the centre of the patella to the tibial tuberosity, representing the obliquity of the quadriceps pull. Normal values are approximately 13 to 14 degrees in males and 16 to 17 degrees in females because of a wider female pelvis. An increased Q angle predisposes to lateral patellar subluxation and patellofemoral pain.
Reference: Moore's Clinically Oriented Anatomy, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.