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.
Source: Oxygen is the most abundant element in the Earthâs crust, accounting for almost half of it by mass. More than half of the atoms in the Earthâs crust are oxygen atoms. About 86 percent of the mass of Earthâs oceans is oxygen â mainly in the form of water. Oxygen is the third most common element in the Universe, behind hydrogen and helium. It is obtained commercially from liquefied air separation plants. It can be prepared in the laboratory by electrolysis of water. Isotopes: 13 whose half-lives are known, with mass numbers 12 to 24.