Dance Anatomy & Kinesiology

260 Dance Anatomy and Kinesiology

measure for promoting sound patellar mechanics

and preventing patellofemoral injuries.

Patellofemoral Compression Forces

Another important consideration in patellar mechan-

ics is patellofemoral compression forces. Patello-

femoral compression force is the force pressing the

kneecap back against the underlying femur. This

force can become quite large, and an understanding

of its genesis is important for preventing and alleviat-

ing patellofemoral problems.

The two most important determinants of patel-

lofemoral compression forces are the magnitude

Patellofemoral Alignment: The Q Angle and Patellar Tracking

Perform the following procedures to measure your Q angle, and note the movements of the patella

and presence of lateral patellar tracking.

1. Sit with your legs extended to the front and your quadriceps relaxed. Grasp the sides of your patella
   between your thumb and index finger, and move the patella from side to side. Note how mobile it
   is with the quadriceps relaxed. Passive movement of the patella up to half of its width medially
   and up to half of its width laterally is considered normal (Magee, 1997). Now, draw an “x” in ink
   on your tibial tuberosity and another “x” on the midpoint of your patella as shown in A. Then, draw
   one line connecting the tibial tuberosity and the midpoint of the patella and extending about 3
   inches (7.6 centimeters) past the patella. Draw a second line from the midpoint of the patella
   upward, in line with the anterior superior iliac spine of the pelvis. The angle that is described with
   its apex at the midpoint of the patella is the Q angle. Use a protractor or goniometer to measure
   it and note if it is above “normal” values for your gender.


2. Now slowly tighten your quadriceps, focusing on “pulling” the kneecap up toward your waist without
   letting the knee move backward into hyperextension. While keeping the quadriceps contracted,
   draw another “x” on the midpoint of the patella, and note any lateral excursion of the patella
   (“lateral patellar tracking”) that has occurred as shown in B. Also, with the quadriceps firmly con-
   tracted, grasp the sides of the patella between your thumb and index finger and carefully attempt
   to move the patella from side to side. Note how limited passive movement of the patella is when
   the quadriceps is contracted and how important the quadriceps is for stabilizing and directing
   movement of the patella.

TESTS AND MEASUREMENTS 5.3