HumanTrait.RequiredBone
static function RequiredBone(i: int): bool;
Parameters

i Index of the bone to test.
Description

Is the bone a member of the minimal set of bones that Mecanim requires for a human model?

The indexing order of the bones is the same as that used for the BoneName array.
function Start() {
	var boneName: String[] = HumanTrait.BoneName;
	
	for (var i = 0; i < HumanTrait.BoneCount; i++) {
		if(HumanTrait.RequiredBone(i))
			Debug.Log(boneName[i]);
	}
}