Breathing is then done through the tube, bypassing the mouth, nose, and throat. A tracheostomy is commonly referred to as a stoma. This is the name for the hole in the neck that the tube passes through.
A millimeter (mm) is the smallest. In order from smallest to largest they rank millimeter, centimeter (cm), decimeter (dm), and meter (m). These are all common units of length in the metric system.
The metric unit system is easy to handle because everything is a multiple or a fraction of ten. There is a base unit for each type of measurement, such as meter (abbreviation m) for length, gramm (abbreviation g or gr) for weight or liter (abbreviation l or lt) for volume. Ten base units have the prefix deka (which is however rarely used), for example 1 dekameter (Dm) equals to 10 meters.