Word Structure & the Decoding Method

This is Unit One of Medical Terminology, Part Two: what the decoding machine cannot do, and the older languages sitting underneath it. Part One built the machine — the four word parts, the combining vowel, the joining rules, and the three-step decode. This part draws its boundary. Some terms were never built from parts at all, and running a decode on them returns a meaning the term does not carry. Then the inheritance. Medical English took its roots from two languages, and many structures ended up with one Greek root and one Latin root, both still in use. Neither is more correct, and they are not interchangeable term by term. Spelling arrives next, and it does real work here. A silent first letter, a soft consonant, or one changed vowel separates terms that name unrelated parts of the body. Two pairs in this part differ by a single letter each. Then plurals. Most medical terms take Latin or Greek plurals rather than an English s, and the unit gives seven rules, one ending at a time, each naming its own exceptions. The unit then closes on six terms it has never covered, decoded cold using nothing but Unit One. By the end you will be able to do five things. One: name the two kinds of term the decode cannot touch. Two: say why one structure carries two roots. Three: keep the sound-alike pairs apart. Four: form the classical plural for any singular ending. Five: say what an English s on a Latin singular costs.

Part One established that an eponym is a name rather than an assembly, and carries no decodable meaning. Two entries here finish that thread. The first is a spelling convention this course declares rather than a correction it makes, and the second names a whole second class of term built from letters instead of word parts.

The possessive, dropped.

MedTerm 0024 Convention: Non-Possessive Eponyms

This course writes eponyms without the possessive: Parkinson disease, Down syndrome, Crohn disease. Alzheimer disease appears in this course; Alzheimer's disease does not. Both forms are in current use and charts will show either, so this is a declared convention rather than a correction of anyone's spelling.

Terms made of first letters.

MedTerm 0025 Acronyms and Initialisms

An acronym or initialism is a medical term formed from the first letters of a longer phrase. C A B G, spoken as cabbage, stands for coronary artery bypass graft. The same letters can stand for different phrases in different departments, so context decides which expansion is meant.

Three entries on where the vocabulary came from. Greek and Latin both supplied roots, and for many structures both survived, which produces a doubling that looks like an anatomy problem and is a history problem. The third entry covers terms that arrived as whole Latin words and never became English at all.

One kidney, two roots.

MedTerm 0026 Greek and Latin Roots for One Structure

Many body structures have two roots, one Greek and one Latin, and both are in current use. The kidney is ren slash o from Latin and nephr slash o from Greek. The two are not interchangeable term by term: renal failure and nephrology are standard, and the swapped versions are not.

The anatomy that is not there.

MedTerm 0027 Error: Treating Two Roots as Two Structures

Assuming a Greek root and a Latin root name different structures invents an anatomy that does not exist. Ren slash o and nephr slash o both name the kidney, and there is no second organ. Neither root is more correct; which one a term uses is fixed by convention, not by rule.

Latin, carried in whole.

MedTerm 0028 Latin Terms Borrowed Whole

Some medical terms are complete Latin words or phrases carried into English unchanged. In vitro means in a glass; placebo means I shall please. These keep Latin plurals and Latin word order, so English rules applied to them will mislead — which is the problem the plural run later in this part exists to handle.

Two rules about sound, and both concern what the written form does not tell you. A medical term can open with a letter nobody pronounces, and the same consonant can take two values depending on the vowel that follows it. Neither rule touches meaning, which is precisely why they are worth stating.

Letters that are not spoken.

MedTerm 0029 Silent Initial Letters

When a medical term begins with p n, p s, p t, g n, or m n, the first letter is silent in English. Pneumonia begins with a silent p, spoken as new MOH nee uh. The letter is silent, not optional: dropping it from the spelling makes the term unsearchable.

Soft and hard consonants.

MedTerm 0030 The Soft C and Soft G Rule

In medical terms, c and g are soft before e, i, and y, and hard before a, o, and u. Cephalic opens with a soft c; carcinoma opens with a hard c and then a soft one. The rule governs sound and not meaning, so two terms can sound close and mean nothing alike.

One rule and two worked pairs, and this is the run where spelling stops being clerical. Terms differing by a single letter can name a section of intestine and a hip bone, or a substance and the tissue that produces it. The book is direct about the cause: dictation software and rushed handwriting both produce these errors.

Two letters, two organs.

MedTerm 0031 Sound-Alike Terms

Some medical terms differ by one or two letters, sound nearly identical, and name unrelated structures. Ileum and ilium differ by a single letter and name different body parts. Dictation software and rushed handwriting both produce these errors, and spelling is the only defense against them.

The end of the small intestine.

MedTerm 0032 Ileum

The ileum, spelled with an e in the second position, is the third and final section of the small intestine. An ileostomy creates an opening from the ileum through the abdominal wall. The ileum belongs to the digestive system; its sound-alike belongs to the skeleton.

The broad hip bone.

MedTerm 0033 Ilium

The ilium, spelled with an i in the second position, is the broad upper portion of the hip bone. The iliac crest, the ridge felt at the waist, is the upper edge of the ilium. The ilium belongs to the skeleton; its sound-alike belongs to the digestive system.

The substance itself.

MedTerm 0034 Mucus

Mucus, spelled with a u in the second syllable, is a noun naming the slippery secretion itself. A chart entry might record thick mucus in the airway. If the word is doing the work of a noun, it takes the u spelling.

The tissue that makes it.

MedTerm 0035 Mucous

Mucous, spelled with an o in the second syllable, is an adjective describing tissue that produces or contains mucus. The mucous membrane lines the respiratory tract. A membrane is mucous; what it secretes is mucus. The adjective never names the substance.

The plural run opens with the principle and then takes the endings one at a time. Each rule names its own exceptions, and the exceptions are not decoration — inside the first three endings sit two words that look like they follow a rule and do not.

Not an English s.

MedTerm 0036 Latin and Greek Plurals

Most medical terms form plurals by Latin or Greek rules rather than by adding s or e s. One vertebra becomes two vertebrae, not two vertebras. A few terms accept both forms in current use, and each of the seven rules that follows names its own exceptions rather than leaving them to be found.

a becomes ae.

MedTerm 0037 Plural Rule: a Becomes ae

A singular ending in a forms its plural by changing the a to a e. Vertebra becomes vertebrae; bursa becomes bursae. The ending is spoken as ee by some clinicians and as ay by others, and both are accepted, so hearing one of them is not evidence of an error.

us becomes i.

MedTerm 0038 Plural Rule: us Becomes i

A singular ending in u s forms its plural by changing the u s to i. Bronchus becomes bronchi; nucleus becomes nuclei; alveolus becomes alveoli. Virus and sinus are the exceptions: virus takes viruses, and sinus takes either sinuses or the unchanged sinus.

um becomes a.

MedTerm 0039 Plural Rule: um Becomes a

A singular ending in u m forms its plural by changing the u m to a. Ovum becomes ova; bacterium becomes bacteria; serum becomes sera. Bacteria is already plural — one organism is a bacterium, a distinction charts still get wrong.

Four more endings, and three of them change how the word sounds as well as how it is spelled. The last rule in the run is not a Latin rule at all. It is a place where clinical writing has moved toward the English plural, and the course follows current usage and says that it is doing so.

is becomes es.

MedTerm 0040 Plural Rule: is Becomes es

A singular ending in i s forms its plural by changing the i s to e s. Diagnosis becomes diagnoses; prosthesis becomes prostheses. The plural is spoken with a long e in the last syllable: dye ag NO sees. The change is audible, which is what keeps it from passing unnoticed in speech.

ex and ix become ices.

MedTerm 0041 Plural Rule: ex and ix Become ices

A singular ending in e x or i x forms its plural by changing that ending to i c e s. Apex becomes apices; appendix becomes appendices. Appendixes is standard for sections of a book, and appendices is the anatomical plural, so the two forms are not in competition.

nx becomes nges.

MedTerm 0042 Plural Rule: nx Becomes nges

A singular ending in n x forms its plural by changing the n x to n g e s. Phalanx becomes phalanges; larynx becomes larynges; meninx becomes meninges. The g goes soft in the plural: fa LAN jeez. That is the soft g rule from earlier in this part, doing work.

oma becomes omas.

MedTerm 0043 Plural Rule: oma Becomes omas

A singular ending in o m a forms its plural as o m a s in this course. Carcinoma becomes carcinomas. The older form o m a t a is also accepted and is not an error; the course declares o m a s as its convention, which makes this the one member of the run that is a choice.

The seven rules exist to prevent one error. This pair states the error, then gives the procedure that avoids it. The order inside the procedure is the whole of it: the singular ending is identified first, and the rule is chosen second, never the other way around.

The English s.

MedTerm 0044 Error: Adding an English s to a Latin Singular

Adding an English s to a Latin or Greek singular produces a form that is wrong in charts and returns nothing in a database search. Bronchuses, vertebras, and diagnosises are not terms. When the plural is uncertain, the singular is always safe — rewrite around it.

Seven singulars, then two that look like rules.

MedTerm 0045 Forming Plurals

Forming a medical plural means identifying the singular ending first, then applying the rule that governs that ending. Bursa ends in a, so bursae. Bronchus ends in u s, so bronchi. Ovum ends in u m, so ova. Prosthesis ends in i s, so prostheses. Appendix ends in i x, so appendices. Phalanx ends in n x, so phalanges. Carcinoma ends in o m a, so carcinomas. Then two that look like they follow a rule and do not: virus takes viruses, and sinus takes sinuses. Choosing the rule before the ending is what produces virus becoming viri.

Two entries close the unit. The first explains the notation this course uses for pronunciation everywhere it appears, and states the limit of that notation. The second takes six terms the course has not covered and decodes each of them using only what Unit One has supplied.

How the stress is marked.

MedTerm 0046 How Pronunciation Is Marked in This Course

This course marks pronunciation by capitalizing the stressed syllable and separating syllables with hyphens. Pericarditis is written per ih kar DYE tis. Pronunciation varies by region and by specialty, so the marked form is the common one rather than the only correct one.

The capstone. Six terms, decoded cold.

MedTerm 0047 Capstone: Decoding Six Unfamiliar Terms

Six terms not previously covered, decoded with only the parts, joining rules and method from Unit One. Osteoarthritis: inflammation of bone and joint, the o kept between the two roots. Nephrologist: one who studies the kidney, the o kept before a consonant suffix. Dysphagia: difficult swallowing, a prefix and a suffix with no separate root. Electroencephalogram: a record of the electrical activity of the brain. Pericardium: the structure surrounding the heart. Splenomegaly: enlargement of the spleen. Every one was decoded without a dictionary, and every one should still be confirmed against one.

Five things to carry out of Part Two. Two classes of term fall outside the machine. An eponym is a name and carries no decodable meaning, and this course writes eponyms without the possessive — a declared convention rather than a correction, since charts will show either form. An acronym or initialism is built from first letters rather than word parts, and the same letters can expand differently in different departments. One structure often carries two roots, one Greek and one Latin, and both are current. Ren slash o and nephr slash o both name the kidney, and there is no second organ. Neither root is more correct, and which one a given term takes is fixed by convention. Terms borrowed whole from Latin keep Latin plurals and Latin word order, so English rules applied to them mislead. Spelling carries meaning here. A term can open with a silent p, and c and g go soft before e, i and y. Ileum with an e is a section of intestine and ilium with an i is a hip bone; mucus with a u is the secretion and mucous with an o is the tissue that produces it. Spelling is the only defense against either pair. Seven endings take classical plurals: a to a e, u s to i, u m to a, i s to e s, e x and i x to i c e s, n x to n g e s, and o m a to o m a s in this course. Virus and sinus are the named exceptions to the second of those, and the ending is always identified before the rule is chosen. The error the whole run exists to prevent is an English s on a Latin singular, which is wrong in a chart and returns nothing in a database search. When the plural is uncertain, the singular is always safe. And the capstone's finding holds for the rest of the course: six unfamiliar terms yielded to the parts alone, and every one still wants confirming against a reference. Unit Two opens the universal suffixes, where the parts this unit described start getting numbers of their own.