Q angle

Last revised by Daniel J Bell on 7 Apr 2021

Citation, DOI, disclosures and article data

Citation:

Knipe H, Bell D, Q angle. Reference article, Radiopaedia.org (Accessed on 24 Apr 2024) https://doi.org/10.53347/rID-71043

DOI:

https://doi.org/10.53347/rID-71043

Permalink:

https://radiopaedia.org/articles/71043

rID:

71043

Article created:

16 Sep 2019, Henry Knipe ◉ ◈

Disclosures:

At the time the article was created Henry Knipe had no recorded disclosures.

View Henry Knipe's current disclosures

Last revised:

7 Apr 2021, Daniel J Bell ◉

Disclosures:

At the time the article was last revised Daniel J Bell had no recorded disclosures.

View Daniel J Bell's current disclosures

Revisions:

2 times, by 2 contributors - see full revision history and disclosures

Systems:

Musculoskeletal

Tags:

cases

Synonyms:

Q-angle
Quadriceps angle

The Q angle (quadriceps angle) is measured between two intersecting lines with the knee in 25° of flexion ¹:

anterior superior iliac spine to center of the patella
central of the patella to the tibial tuberosity

A Q angle of <15° is considered normal, and >20-25° abnormal ^2,4 and as the Q angle increases there is increasing lateral force on the patella from the quadriceps muscles contributing to lateral patellar translation ². However, TT-TG distance (which is the linear equivalent of the Q angle) has been shown to be a more reliable measure of patellofemoral instability ^2,3.