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.
metric (Noun). A measurement of the distance between two points in some metric space: it is a real-valued function d(x,y) between points x and y satisfying the following properties: (1) positive definiteness: and, (2) symmetry: , and (3) triangle inequality: . metric (Verb).