Generally, an external fixator is mounted quite securely to the bone, and can withstand mild contact, any positioning of the body, and oftentimes even weightbearing immediately after surgery. In fact, it is often more comfortable to pick up the leg by grabbing the fixator, rather than holding the leg itself.he fixator is composed or one or more metal bars and rings, which in turn connect to a child via metal pins and wires. By gradually manipulating the fixator on the outside, we can carefully control the position of the bones and joints on the inside.
Habitat and Distribution. Pin this Image. Green sea urchins used to live in cold waters of the sub Polar Regions. They live in Northern cooler part of the Pacific and Atlantic Ocean. Some also live in the Arctic too. The sea animal can be found in rocky sea beds. They often live in the low depth tidal zones.
The purple sea urchins are equipped with a test which is made up of calcium carbonate and then covered with skin which protects the sea urchins internal organs. The calcite which is used to keep the plates of the endoskeleton together is rich in magnesium, therefore allowing the endoskeleton to strengthen.abitat: The purple sea urchins are found in shallow areas of water usually along a coast with strong waves. They are mainly found along the coast line of Alaska all the way down the Pacific Coast to Mexico.