public float getRetroversion (short joint11, short joint12) {
		float retroversionModifier = 1f;
		// Retroversion is angle of the axis-components in sagittal plane to negative body axis
		if ((joint11 == LEFT_ELBOW && joint12 == LEFT_SHOULDER) || 
			(joint11 == LEFT_KNEE && joint12 == LEFT_HIP) ||
			(joint11 == RIGHT_ELBOW && joint12 == RIGHT_SHOULDER) || 
			(joint11 == RIGHT_KNEE && joint12 == RIGHT_HIP)) {
			if (getOrientationInSagittalPlane(joint11,joint12) == ANTERIOR) {
				retroversionModifier *= -1f;
			}
		} else {
			return 0f;
		}
		
		PVector axis1 = PVector.sub(jointLCS[joint11],jointLCS[joint12]);
		axis1.x = 0f; // use component vector of axis1 in sagittal plane
		float angle = PVector.angleBetween(axis1,new PVector(0f,-1f,0f));
		
		return angle*=retroversionModifier;
	}