Alive-Cat
is full of epic win
purple

I don't have a knot.

UZERNOT.

You're a good man, Levian. A man of vast knowledge.

That was exactly what he was looking for. Trust me, I know.

The best way to scratch a knee is, at best, a controversial way. Anything you might hear outside this room may or may not lead you to doubt my sanity. This is to be expected, as they all did in the end. They forced me out, into the darkness, in which I have stayed. Until someone, someone like YOU, Psychotic Paul, asked me this question again.
So, I will tell you, and tell you I will. This is the best way to scratch your knee.

Disclaimer - this information is for Psychotic Paul, to do with whatever he sees fit. No one else should follow this advice, for dreadful consequences will be met.

There are basically three types of limb joint in animals and humans. These are the ball and socket joint (e.g. hip and shoulder), the pivot joint (e.g. elbow) and the condylar joint (e.g. knee). The knee joint is the largest and most complex joint in the human body. The knee is called a condylar joint because of the articulation between the femur and the tibia, as shown in Figures 1 and 2.[10] The femur has two protrusions called condyles. These have a convex curvature in order to roll and slide against the tibia. The tibia has two concave grooves that match the condyles of the femur. The two central ligaments that connect the tibia to the femur are called cruciate ligaments because of the way they form a cross. These cruciate ligaments fit neatly inside the space between the two condyles.

The knee joint is an irreducible joint because each of its four complex parts needs to exist simultaneously and in a complex assembly to be able to perform its basic function. The two bones are essential because they perform the rolling and sliding motion. The two cruciate ligaments are essential because they act as mechanical linkages and perform a vital guiding function in the joint, as shown in Figure 2. If just one ligament is removed, then the joint cannot function as a hinge, and the joint can have no useful function.

The irreducibility of the knee joint is most clearly demonstrated by identifying the critical geometrical characteristics that must be defined in the genetic code. The knee has many critical geometrical characteristics because the two cruciate ligaments and the two leg bones form a very sophisticated and precise mechanism, called a four-bar hinge.[11]

The four-bar hinge mechanism of the knee is shown at various stages of rotation in Figure 2. These stages of rotation are schematically presented in Figure 3 to show clearly how the four-bar hinge works. The cruciate ligaments form the two crossed bars (b & c) whilst the upper and lower bones effectively form the other two bars (a & d). The cruciate ligaments are able to pivot where they are attached to the bones (points 1, 2, 3 & 4) because they are made of a non-rigid material. In a four-bar hinge, the length of each of the four bars remains constant, but the angle between each bar can change so the lower leg can rotate. One important feature of the four-bar hinge is that the instantaneous centre of rotation approximately coincides with the cross-over point of the cruciate ligaments. This cross-over point moves as the joint opens and closes so that the knee does not have a fixed point of rotation, as does a simple pivot joint. The knee joint is a particularly sophisticated kind of four-bar hinge, because the cruciate ligaments are not rigid and have to be kept taut by the rolling action of the bones.

I hope THIS was what you were looking for, Psychotic Paul.

keep on rockin'

Is Alive-man still a MAN?

:chef:

No thanks, it may cause controversy over the actual shape of the planet Earth...

Define the word 'Phatt'.