What does the prefix exo- indicate in medical terminology?

What does the prefix exo- indicate in medical terminology?

• A. Within
• B. Above normal or excessive
• C. Behind
• D. Outside

Answer: (D)

The prefix exo- means outside or external. It is used when describing something that lies on the outside of another structure or originates from outside the body. For example, exoskeleton refers to an outer skeleton, exocrine glands release substances onto surfaces outside or into ducts, and extracellular fluid is the fluid outside cells. This differs from endo- or intra- for inside or within, and from retro- or posterior for behind, or hyper- for above normal or excessive. So outside is the best interpretation of exo-.

The prefix exo- means outside or external. It is used when describing something that lies on the outside of another structure or originates from outside the body. For example, exoskeleton refers to an outer skeleton, exocrine glands release substances onto surfaces outside or into ducts, and extracellular fluid is the fluid outside cells. This differs from endo- or intra- for inside or within, and from retro- or posterior for behind, or hyper- for above normal or excessive. So outside is the best interpretation of exo-.