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.
Hydrogen is the lightest and most abundant element in the universe. The hydrogen-helium abundance ratio is an important clue to the cosmological process. The nucleus of ordinary hydrogen consists of a single proton, but it also occurs as deuterium with a proton and a neutron.ydrogen burns in oxygen or air with an almost colorless flame and has potential as a fuel. Since it requires energy to separate hycrogen, its real potential is as a storage medium for energy; processes like electrolysis of water can produce hydrogen for storage as a fuel.