Knee Bugs
There is a pain behind the knee that is called 'knee bugs'. This condition causes a very unpleasant feeling in the knee, and it leaves the injured, feeling like having something crawling on their leg. This is caused by a trigger point in the rectus femoris.
Lower back pain?
The rectus femoris can cause lower back pain. If this muscle is tight, because it attaches to the AIIS, it can pull on the pelvis and pull it forward, and then cause pain in the lower back.
Did you know that the rectus femoris is not attached to the femur? Although it may seem as if it should be attached because it is located on the anterior middle of the femur it is attached to the hip! It's the only quadricep muscle that isn't attached to the femur!