The subtalar joint contributes to 10% of dorsiflexion of the ankle. There are three articulating facets between the talus and the calcaneus, delineated as the anterior, middle and posterior facets. The sustentaculum tali forms the floor of middle facet, and the anterior facet articulates with the head of the talus, and sits lateral and congruent to the middle facet.
The most abundant element on Earth is oxygen, but the most abundant element in the entire universe is hydrogen. On Earth, oxygen makes up approximately 47 percent of the Earth's mass and is found both in Earth's atmosphere and crust. Continue Reading.
The earth is not made mostly of hydrogen because the earth is small (less gravity) and hydrogen is light, so the hydrogen that was here, has mostly escaped the gravitational pull of Earth. On Earth, hydrogen can be found in many places. Hydrogen combines with oxygen to form water, which is essential for life on earth. Water makes up three quarters of the earth s surface (See Fig. 4). Three quarters of our bodies are made of water. Fossil fuels are made of hydrocarbons, a combination of hydrogen and carbon.