[HELP] proper knee strike.

[Kick of death]

Hi guys!I'm new here!and new to muay thai too! Tell me,which part of knee is used to make contact.....google is not worth for this question.Tell me,patella or lower end of Femur bone!!! Please help me. Also,add proper way to strike.I don't have any muay thai gym nearer,so your help will be appreciated.thank you.

[Kick of death]

Please i'm waiting guys.

[tenzen]

Strike with all surfaces of the body. Complete striker. Lol