Myringotomy and tympanostomy, in parallel with the general distinction between an -otomy (cutting) and an -ostomy (creating a stoma with some degree of permanence or semipermanence). In this distinction, only a tympanostomy involves tympanostomy tubes and creates a semipermanent stoma. This distinction in usage is not always made. The word "tympanocentesis" specifies that centesis (aspiration for sampling) is being done. Etymologically, "myringotomy" ("myringo-", from Latin "myringa" "eardrum", + "-tomy") and "tympanotomy" ("tympano-" + "-tomy") both mean "eardrum cutting", and "tympanostomy" ("tympano-" + "-stomy" means "making an eardrum stoma". In 1649, Jean Riolan the Younger accidentally pierced a patient's ear drum while
Composition of the human body viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal