- The the temple and the tip of the chin are two primary targets if you use your elbows. Also from the clinched position you can easily go for the nape with a crushing elbow strike.
- The top of the head is very vulnerable also.
- Ears are nice targets for palm strikes.
- The nose obviously, but thats not much of a pain factor. Just break it quick to have a permanent distacting injury.
- The mandible. It connects only with 2 joints and an array of muscles to the skull, dislocating it with your elbow is a piece of cake. The pain is intense and hurts like f***.
The knee? Thats an entirely different story.

Just clinch up and 2-3 powerful kicks to anywhere but the forehead will be devastating. For maximum efficiency go for the throat or the temple.