Laryngomalacia is the most common cause of chronic stridor in children younger than two years. It has a male-to-female ratio of approximately 2:1.1 The condition is due to an intrinsic defect or delayed maturation of supporting structures of the larynx.
Volcano Rocks Igneous Rocks. Introduction Volcano rocks are igneous rocks that form during a volcanic eruption. They were all once magma which is molten rock beneath the Earth's surface. There are four major groups of the igneous rocks: basalt, andesite, dacite and rhyolite. Each of these different rock groups form different types of volcanoes. Volcanic rocks forming during eruption of Kilauea, USGS Rhyolite rocks Rhyolite magma cooling underground forms granite.
Igneous rocks are called fire rocks and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth b â¦ ecomes trapped in pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rock.hen magma appears above the earth, it is called lava. Igneous rocks are formed as the lava cools above ground.     Metamorphic rocks are rocks that have morphed into another kind of rock. These rocks were once igneous or sedimentary rocks.