1. Chapter 4 Body Openings and
Plural Endings

2. Some Examples of Body Openings
Term
Definition or Usage
Aperture
An opening or orifice
Constriction
Making something narrow; to contract, to close (an opening)
Foramen
A natural opening or passage, especially one into or through a bone
Lumen
Opening within a hollow tube or organ

3. Some Examples of Body Openings
Term
Definition or Usage Os
Mouth opening; os uteri: mouth of the uterus or cervix
Patent
Adjective, meaning open or not plugged, as in “the tube is patent”
Stoma
Artificial opening established by colostomy, ileostomy, and tracheostomy

4. Regular Plural Endings
Some medical terms have plural endings that are formed the same as most English words. For example:
Add an “s” to a singular noun (i.e. abrasion, abrasions)
Singular nouns that end in “s” or “ch” are plural by adding “es” (i.e. abscess. Abscesses)
Singular nouns that end in “y” preceded by a consonant form are plural by changing the “y” to “i” and adding “es” (i.e. artery, arteries)

5. Special Plural Endings
Many medical terms have special plural forms. The following rules are common for forming the plural form. If the word:
Ends in “a” retain the “a” and add “e” (i.e. bursa, bursae)
Ends in “is”, drop the “is” and add “es” (i.e. crisis crises, diagnosis, diagnoses)
Ends in “ix” or “ex”, drop the “ix” or “ex” and add “ices” (i.e. appendix, appendices)
Ends in “on”, drop the “on “ and add “a” (i.e. ganglion, ganglia)

6. Special Plural Endings
The following rules are common for forming the plural form. If the word:
Ends in “um”, drop the “um” and add “a” (i.e. ovum, ova)
Ends in “us”, drop the “us” and add “i” (i.e. nucleus, nuclei)
There are exceptions to the rules. Some terms have more than one acceptable plural. Consult your medical dictionary if in doubt.

7. Confusing Medical Terminology
strata Versus striae
strata  = layers, plural of stratum, e.g., strata (strey-tuh) of tissues refers to layers of tissues
striae = striae [strahy-ee] refers to a slight or narrow furrow, ridge, stripe, or streak, especially one of a number in parallel arrangement, e.g., striae of muscle fiber, as in stretch marks

8. Confusing Medical Terminology
hidr/o Versus hydr/o
hidr/o = sweat, e.g., hidropoiesis (hid-roh-poi-ee-sis) refers to the production of sweat
hydr/o = water, relating to water, e.g., hydrencephalomeningocele (hi-dren-cef-al-o-men-in-jo-sel) refers to herniation of brain substance and meninges caused by a defect, with accumulation of cerebrospinal fluid along with brain substance in the sac

9. Confusing Medical Terminology
sarc/o Versus sacr/o
sarc/o = flesh (connective tissue), cancer of connective tissue, e.g., sarcocele (sar-ko-sel) refers to a fleshy tumor or sarcoma of the testis
sacr/o = sacrum, e.g., sacrum (sak-ruhm) refers to a bone resulting from the fusion of two or more vertebrae between the lumbar and the coccygeal regions, in humans being composed usually of five fused vertebrae and forming the posterior wall of the pelvis; it means the area of the tailbone