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 most abundant element, comprising about three quarters of the mass in the universe. Hydrogen is found in the water that covers 70% of the earth's surface and in all organic matter. Hydrogen is the simplest element in the universe. It is made up of one proton and one electron. Hydrogen is the lightest of all elements and gases, and is 14 times lighter than air. A gaseous hydrogen spill diffuses immediately into the air, and does not pollute the ground or groundwater.