1.6 Prefixes

The prefix dia- (“complete”) is frequently used in medical terms; for example, the term diagnosis, which most people are familiar with. Diagnosis means “pertaining to knowledge” (gnos/o -is) that is “complete” (dia-), or “complete knowledge.” Once a doctor has all the necessary information to provide a client with a proper diagnosis, they will often tell the client the prognosis of their animal. Prognosis literally means “knowledge before,” and in this situation, it refers to the veterinarian’s prediction of a patient’s outcome.

There are several other medical terms that use the prefix dia-. The list below provides some examples, but you may hear others, especially in specialty clinics:

• diaphragm: The muscle separating the abdominal and thoracic cavities
• diameter: To measure completely
• diarrhea: To flow completely

Simply changing the prefix can change the meaning of a medical term entirely.

The prefixes hyper- and hypo- are used in many medical terms and usually mean the opposite of each other. See the examples below:

• hypertension (high blood pressure) and hypotension (low blood pressure)
• hyperthyroidism (condition of overactive thyroid) and hypothyroidism (condition of underactive thyroid)
• hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar)

These terms can also describe movement. For example: hyperflexion.

The prefix pre-, meaning “before,” is used in a number of medical terms:

• precancerous: “pertaining to before cancer”; for example, a precancerous colonic polyp, shown in Figure 1.11
• prenatal: “pertaining to before birth”; for example, prenatal care
  

  

Numbers are often used in medical terminology, especially in the form of prefixes. For example, the terms unilateral and bilateral make it clear whether one side of the body or both sides are being discussed.

When examining a patient, we look for symmetry bilaterally, meaning we look at both sides of the body for similar shape and size of parts like ears or eyes. In Figure 1.12, looking at a rabbit head-on, you can see that both the ears and eyes are comparable in size.

We also use number prefixes to describe an amount on or in the body. A cat with more toes than usual, as in Figure 1.13, is called polydactyl: poly- means “many,” and dactyl/o means “digits.” This congenital anomaly may or may not cause issues with wellness, health, or development. It is a genetically inherited trait that is commonly found in North America.