A set of flashcards below contains medical prefixes that are used to describe the position of or direction of a medical term.
#1 ab-
The medical prefix term ab- means "away".
Example Word: ab/duct/ion
Word Breakdown: ab- is a prefix that means "away", duct is is a word root that means "to lead or to carry" and -ion is a suffix that means "action or process".
Definition: Abduction is a movement in which a limb or structure is pulled away from the body's median plane.
#2 ad-
The medical prefix term ad- means "toward".
Example Word: ad/duct/ion
Word Breakdown: ad- means "toward", duct is a word root that means "to lead or to carry" and -ion is a suffix that means "action or process".
Definition: Adduction is the motion of pulling something toward the midline of the body or towards the midline of a limb.
#3 ambi-
#4 ante-, anter(o)-
The medical prefix term ante- or anter(o)- means "anterior or front".
Example Word: anter(o)/sept/al
Word Breakdown: Anter(o)- means "front", sept is a word root for "septum", -al is a suffix that means to "pertaining to".
Definition: The term anteroseptal refers to the area in front of a septum, most notably the interventricular septum.
#5 circum-
#6 dextr(o)-
The medical prefix term dextr(o)- means "right".
Example Word: dextr(o)/cardi/a
Word Breakdown: Dextr(o)- means "right",  cardi is a word root for "heart", -a is a noun ending suffix with no specific meaning.
Definition: Dextrocardia is a congenital condition characterized by the abnormal position of the heart on the right side of the chest.
#7 dia-
The medical prefix term dia- means "through".
Example Word:Â dia/lysis
Word Breakdown:Â Dia- is a prefix term that pertains to "through", and -lysis denotes "separating" or "dissolution".
Definition: When the kidneys stop working, dialysis removes and separates wastes and excess fluids from the blood through a machine to be cleaned.
#8 dors(o)-, dors(i)-
The medical prefix term dors(o)- or dors(i)- means "back" or "posterior".
Example Word: dors(i)/flex/ion
Word Breakdown: Dors(i)- means "back", flex is a word root for "bend", -ion is a suffix that refers to "process".
Definition: Dorsiflexion can be described as the backward bending or contracting of your hands or feet.
#9 ect(o)-
The medical prefix term ect(o)- means "out" or "outside".
Example Word: ect(o)/derm
Word Breakdown: Ect(o)- means "outside", derm is a word root that refers to the "skin".
Definition: Following the formation of the three primary germ layers, the ectoderm is the outermost layer of cells of an embryo.
#10 endo-, end-
The medical prefix term end(o)- means "inside".
Example Word:Â end(o)/metr/i/um
Word Breakdown: End(o)- means "inside",  metr/i is a combining form that refers to the "uterus", -um is a noun ending suffix with no specific meaning.
Definition:Â Endometrium is the innermost lining layer of the uterus.
More Examples of Medical Terms Starting in Endo-
Endocardium: endo- ("inner" or "within") + cardi ("heart") + -um ("pertaining to").
Definition: The inner layer of the heart, consisting of a thin membrane lining the chambers of the heart and surrounding the heart valves.
Endocrinology: endo- ("inner" or "within") + crin/o ("to secrete") + -logy ("the study of").
Definition: The study of the glands that produce hormones to regulate the body's functions.
Endodontics: endo- ("inner" or "within") + odont ("tooth") + -ics ("pertaining to").
Definition: Branch of dentistry concerned with diagnosis and treatment of diseases and injuries of pulp and root of tooth.
Endometriosis: endo- ("inner" or "within") + metr ("uterus") + -osis ("abnormal condition").
Definition: Condition in which tissue similar to lining of uterus grows outside of uterus, often causing pain and fertility issues.
Endomyocardium: endo- ("inner" or "within") + my/o ("muscle") + cardi (meaning "heart") + -um (suffix indicating "pertaining to").
Definition: The inner layer of the heart muscle.
Endonuclease: endo- ("inner" or "within") + nucle (meaning "nucleus") + -ase ("enzyme").
Definition: An enzyme that breaks down the bonds within nucleic acids, such as DNA and RNA.
Endophthalmitis: endo- ("inner" or "within") + ophthalm (meaning "eye") + -itis (indicating "inflammation").
Definition: Inflammation of the inner structures of the eye, including the vitreous humor and the retina.
Endoplasm: endo-" ("inner" or "within") + -plasm ("living substance" or "tissue").
Definition: The inner, more granular portion of the cytoplasm in some cells, containing organelles such as ribosomes, mitochondria, and lysosomes.
Endorphin: end- ("inner" or "within") + -orphine (meaning "morphine").
Definition: A hormone produced by the pituitary gland that acts as a natural painkiller.
Endoskeleton: endo- ("inner" or "within") + skeleton ("skeleton").
Definition: An internal skeleton, as found in many invertebrates such as insects and crustaceans.
Endothelium: endo- ("inner" or "within") + theli (meaning "lining") + -um ("pertaining to").
Definition: The inner lining of certain body cavities, such as the blood vessels, lymphatic vessels, and heart.
#11 epi-, ep-
The medical prefix term ep(i)- means "above".
Example Word: ep(i)/derm/is
Word Breakdown: Ep(i)- means "above", derm is a word root that refers to the "skin", -is is noun ending suffix with no specific meaning.
Definition: A layer of tissue that forms the outermost layer of skin is referred to as the epidermis.
More Examples of Medical Terms Starting in Epi-
Epidemic: epi- ("upon" or "on") + demos ("people") + -ic ("pertaining to").
Definition: A widespread occurrence of an infectious disease in a community at a particular time.
Epididymis: epi- ("upon" or "on") + didym ("testicle") + -is ("pertaining to").
Definition: A tube in the male reproductive system that stores and transports sperm.
Epiglottis: epi- ("upon" or "on") + glott ("tongue") + -is ("pertaining to").
Definition: A flap of cartilage in the throat that covers the opening to the larynx during swallowing.
Epilepsy: epi- ("upon" or "on") + lepsy ("seizure").
Definition: A neurological disorder characterized by recurrent seizures.
Epinephrine: epi- ("upon" or "on") + nephr/o ("kidney") + -ine ("related to").
Definition: A hormone produced by the adrenal gland that increases heart rate and blood pressure.
Epistaxis: epi- ("upon" or "on") + -staxis ("a dropping or falling").
Definition: Nosebleed.
Epithelium: epi- ("upon" or "on") + thel ("nipple") + -ium ("pertaining to").
Definition: A layer of cells that lines the surfaces and organs of the body.
#12 ex(o)-
The medical prefix term ex(o)- means "out" or "outside".
Example Word:Â ex(o)/therm/ic
Word Breakdown: Ex(o)- means "outside",  therm is a word root that refers to the "heat", -ic is a suffix that means "pertaining to".
Definition: In an exothermic process, heat is released into the environment.
#13 extr(a)-, extr(o)-
#14 infra-
The medical prefix term infra- means "below" or "under".
Example Word: infra/clavicul/ar
Word Breakdown: Infra- means "below", clavicul is a word root that pertains to the "clavicle" or "collar bone", -ar is a suffix that means "pertaining to".
Definition: The infraclavicular fossa is located below the clavicle.
#15 inter-
#16 intra-, intro-
The medical prefix term intra- or intro- means "inside" or "within".
Example Word: intra/muscul/ar
Word Breakdown: Intra- means "inside",  muscul is a word root that refers to the "muscle", -ar is a suffix that means "pertaining to".
Definition: The intramuscular refers to the inside of the muscle.
More Examples of Medical Terms Starting with Intra- or Intro-
Intravenous: intra- ( "inside" or "within") + ven ( "veins") + -ous ( "related to")
Definition: Inside or within a vein, typically referring to the administration of medication or fluids through a vein.
Intracellular: intra- ( "inside" or "within") + cellular ( "related to cells")
Definition: Inside or within a cell, typically referring to processes or substances that occur within a cell.
Intraoral: intra- ( "inside" or "within") + oral ( "pertaining to the mouth")
Definition: Inside or within the mouth, typically referring to dental procedures or devices.
Intrathecal: intra- ( "inside" or "within") + thec ( "related to a sheath or covering") + -al ( "related to")
Definition: Inside or within a protective sheath or covering, typically referring to the injection of medication into the spinal cord.
Intrauterine: intra- ( "inside" or "within") + uter/o ( "uterus")
Definition: Inside or within the uterus, typically referring to the location of a pregnancy or a device used in birth control.
Intracranial: intra- ( "inside" or "within") + crani ("skull" or "cranium") + -al ( "pertaining to")
Definition: Inside or within the skull, typically referring to conditions, injuries or pressure inside the skull.
Intratubular: intra- ( "inside" or "within") + tubul ( "tubules") + -ar ( "related to")
Definition: Inside or within a tubule, typically referring to a cell structure or organelles inside the tubule.
Introspection: intro- ( "inside" or "within") + spection ( "to look")
Definition: The act of looking inside oneself, typically referring to self-reflection and self-awareness.
Introvert: intro- ( "inside" or "within") + vert ( "to turn")
Definition: A person who tends to focus on their own thoughts and feelings rather than on external things.
#17 juxta-
#18 later(o)-
The medical prefix term later(o)- means "lateral" or "side".
Example Word: later(o)/crani/al
Word Breakdown: Later(o)- means "lateral" or "side", crani is a word root for "cranium" or "skull", -al is a suffix that means "pertaining to".
Definition: Laterocranial is the term for the side of the cranium.
#19 levo-
The medical prefix term levo- means "left".
Example Word: levo/scoli/o/sis
Word Breakdown: Levo- means "left", scoli/o is a combining form that pertains to "curved", -sis is a suffix that means "condition".
Definition: The term 'levoscoliosis' refers to a type of scoliosis where the spine curves on the left side.
#20 medi(a)-, medi(o)-
The medical prefix term medi(a)- or medi(o)- means "middle".
Example Word: medi(o)/tars/al
Word Breakdown: Medi(o)- pertains to "middle", tars is a word root that refers to "ankle", and -al is a suffix term that means "pertaining to".
Definition: Mediotarsal is in the middle of the tarsal (ankle) region.
#21 mes(o)-
#22 para-
The medical prefix term para- means "near", "apart from" or "abnormal" .
Example Word: para/thyr/oid
Word Breakdown: Para- in the term parathyroid means "beside" or "near", thyr is a word root for "thyroid gland", -oid is a suffix that means "resembling".
Definition: Parathyroid glands are four endocrine glands located near the thyroid gland, which secrete parathyroid hormone.
#23 per-
The medical prefix term per- means "through".
Example Word: per/cutane/ous
Word Breakdown: Per- means "through", cutane is a word root for "skin", -ous is a suffix that means "pertaining to".
Definition: Percutaneous refers to a form of administration or procedure that passes through the skin, either as an injection or as a topical injection.
#24 peri-
The medical prefix term peri- means "around" or "surrounding".
Example Word:Â peri/cost/al
Word Breakdown: Peri- means "around", cost is a word root for "rib", -al is a suffix that means "pertaining to".
Definition: Pericostal refers to the area surrounding a rib.
More Examples of Medical Terms Starting in Peri-
Periosteum: peri- (around, surrounding) + oste (bone) + -um (pertaining to)
Definition: A thin layer of connective tissue that covers the outer surface of bones.
Peritoneum: peri- (around, surrounding) + ton (stretch) + -eum (pertaining to)
Definition: Membrane covering the abdominal organs and lining the abdominal cavity.
Pericardium: peri- (around, surrounding) + cardi (heart) + -um (pertaining to)
Definition: The sac-like membrane surrounding the heart.
Periocular: peri- (around, surrounding) + ocul (eye) + -ar (pertaining to)
Definition: Located near or around the eye.
Perianal: peri- (around, surrounding) + an (anus) + -al (pertaining to)
Definition: Located near or around the anus.
Perioperative: peri- (around, surrounding) + operative (related to surgery)
Definition: Relating to the time period surrounding a surgical procedure.
Percutaneous: peri- (around, surrounding) + cutane/o (skin) + -us (pertaining to)
Definition: Performed through or on the skin.
Perioral: peri- (around, surrounding) + or (mouth) + -al (pertaining to)
Definition: Located near or around the mouth.
Perinatal: peri- (around, surrounding) + nat (birth) + -al (pertaining to)
Definition: Relating to the time period surrounding birth.
#25 poster(o)-
#26 sinistr(o)-
The medical prefix term sinistr(o)- means "left".
Example Word: sinistr(o)/ocul/ar
Word Breakdown: Sinistr(o)- means "left", ocul is a word root for "eye", -ar is a suffix that means "pertaining to".
Definition: A sinistrocular error occurs when the left eye is favored by habit or for effective vision over the right eye.
#27 sub-
#28 super-
#29 supra-
The medical prefix term supra- means "above".
Example Word: supra/ren/al
Word Breakdown: Supra- means "above", ren is a word root that refers to the "kidney", -al is a suffix that means "pertaining to".
Definition: The suprarenal glands, also known as the adrenal glands, are small glands on top of the kidneys.
#30 tele-, telo-
The medical prefix term tele- or telo- means "distant".
Example Word: tele/canthus
Word Breakdown: Tele- means "distant", canthus refers to the corner of the eye where the upper and lower lids meet.
Definition: Telecanthus means that the distance between the medial canthi of the eyes increased, whereas the interpupillary distance remains normal.
#31 trans-
The medical prefix term trans- means "through".
Example Word: trans/derm/al
Word Breakdown: Trans- means "through", derm is a word root for "skin", -al is a suffix that means "pertaining to".
Definition: Transdermal is a form of medication administration in which ingredients are absorbed through the skin into the bloodstream.
#32 ventr(o)-, ventr(i)
The medical prefix term ventr(o)- or ventr(i)- means "anterior or front".
Example Word: ventr(o)/crani/al
Word Breakdown: Ventr(o)- means "front", crani is a word root for "cranium or skull", -al is a suffix that means to "pertaining to".
Definition: A ventrocranial is a term used to refer to the front of the skull.