At the level of the iliac tubercle, a bony prominence on the lateral aspect of the crest 5 cm posterior to the anterior superior iliac spine, the FL is preferentially thickened and this represents the origin of the ITB.
The highest layer of earths atmosphere is the exosphere. The inner core has the most or highest amount of density (iron/nickel). I think its the core of the Earth with highest temperature with  6000 degree Celsius. The crust is the layer of the Earth that has the the lowest density. It depends a bit on what you consider being a part.
Earth's mantle is the thickest part of the planet and consists of very hot and plastic like solid rock. The mantle is divided into the lower and upper mantle, with the upper mantle making up 15.3 percent of the mantle crust mass and 10.3 percent of Earth's total mass. Learn more about Layers of the Earth