The phrase "knee cap" refers to the round bone at the front of your knee joint that protects it and helps you to walk, run, or bend your leg. Full definition
This requires a professional to execute; if done incorrectly, there is a risk of hip injuries, loose knee caps, and muscle strains. (petsmagazine.com.sg)
Firm your thighs and turn your left thigh outward so that the center of the left knee cap is in line with the center of the left ankle. (yogajournal.com)
Firm your thighs and turn your right thigh outward, so that the center of the right knee cap is in line with the center of the right ankle. (yogajournal.com)