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.
Quick Answer. The thickest layer of the atmosphere is the troposphere, which averages 11 miles high at the equator and is thinner at the poles. All the weather occurs in this layer, and the troposphere contains nearly 80 percent of the air in the Earth's atmosphere. Above the troposphere, in ascending order, is the stratosphere, mesosphere, thermosphere and exosphere.