CPC — Medical Coding Concepts & Guidelines Study Guide (2026)

Medical coding begins with reading. Before you can assign a single code, you must be able to read an operative note, a pathology report, or an office chart and understand what the physician actually did and why. That comprehension rests on two foundations: medical terminology (the word-building system that lets one term carry a diagnosis, a location, and a procedure all at once) and anatomy (where in the body the work happened). On the CPC exam, medical terminology and anatomy questions are woven through nearly every section — a surgery question you cannot answer is often really a terminology question in disguise. This chapter builds the reading skill first, because every later chapter depends on it.

1.1 How medical words are built

Almost every medical term is assembled from a small set of interchangeable parts. Learn the parts and you can decode thousands of words you have never seen. A term has up to four kinds of pieces:

• Root — the core meaning, usually a body part or system. Cardi (heart), nephr (kidney), oste (bone), hepat (liver), gastr (stomach), derm (skin), pneum/pneumon (lung/air), my (muscle), neur (nerve), arthr (joint).
• Combining vowel — usually an o, inserted to make a root pronounceable before another part. The root plus its combining vowel is a combining form, written cardi/o, nephr/o, oste/o.
• Prefix — attaches to the front and typically modifies number, direction, time, or negation. Hyper- (excessive), hypo- (deficient), brady- (slow), tachy- (fast), peri- (around), endo- (within), sub- (under), a-/an- (without).
• Suffix — attaches to the end and usually names the condition, the procedure, or the part of speech. -itis (inflammation), -ectomy (surgical removal), -otomy (incision into), -ostomy (create an opening), -plasty (surgical repair), -oma (tumor), -megaly (enlargement), -scopy (visual exam with a scope), -graphy (process of recording), -pathy (disease).

Read a term from the suffix backward. Take gastroenteritis: the suffix -itis (inflammation), then the roots gastr (stomach) and enter (intestine) → inflammation of the stomach and intestine. Nephrolithotomy: -otomy (incision into) + nephr (kidney) + lith (stone) → an incision into the kidney to remove a stone. Decode from the end, then fill in front to back.

Combining-vowel rule. Keep the combining vowel when the next part starts with a consonant (gastr/o/scopy); usually drop it when the suffix starts with a vowel (gastr/itis, not gastroitis). The vowel is always kept between two roots, even before a vowel (gastr/o/enter/itis), so the word stays pronounceable.

1.2 The surgical suffixes coders confuse most

Three suffixes decide whether an operative note describes a diagnostic look, an opening, or a removal — and mixing them up sends you to the wrong CPT family. Fix these cold:

• -otomy — a cut into an organ (a temporary incision), e.g., tracheotomy, cutting into the trachea.
• -ostomy — surgically creating a new permanent (or semi-permanent) opening, often to the outside or between two structures, e.g., colostomy, an opening from the colon to the abdominal wall.
• -ectomy — removal of an organ or part, e.g., appendectomy, cholecystectomy (gallbladder removal).

Two more procedure suffixes matter constantly in surgery and radiology: -plasty (surgical repair/reshaping, e.g., rhinoplasty) and -pexy (surgical fixation, e.g., orchiopexy, fixing an undescended testis). And distinguish the imaging pair: -graphy is the process of recording (angiography), -gram is the record/image produced (angiogram), and -scopy is looking directly through a scope (colonoscopy).

1.3 Directional and positional terms

Anatomic descriptions assume the anatomical position: standing, facing forward, palms turned forward. Every direction is described relative to that position, which is why a surgeon's "the lateral aspect of the right arm" is unambiguous.

• Anterior (ventral) = front; posterior (dorsal) = back.
• Superior (cephalad) = toward the head; inferior (caudad) = toward the feet.
• Medial = toward the midline; lateral = away from the midline.
• Proximal = nearer the trunk/point of origin; distal = farther from it. (The wrist is distal to the elbow.)
• Superficial = nearer the surface; deep = farther in.
• Supine = lying face up; prone = lying face down.

The three body planes: sagittal divides left/right, coronal (frontal) divides front/back, and transverse (axial) divides top/bottom — the last is the plane most CT "slices" are named for.

1.4 A quick tour of the body systems

You do not need a medical degree, but you must recognize the organs and word roots of each system well enough to route a code to the right chapter.

• Integumentary (skin): derm/o, dermat/o (skin), onych/o (nail), trich/o (hair). Lesions, biopsies, repairs, and grafts live here.
• Musculoskeletal: oste/o (bone), arthr/o (joint), my/o, myos/o (muscle), ten/o, tendin/o (tendon), chondr/o (cartilage). Fractures, dislocations, and casting cluster here.
• Cardiovascular: cardi/o (heart), angi/o, vas/o (vessel), ven/o, phleb/o (vein), arteri/o (artery). Know the four chambers (right/left atrium and ventricle) and the difference between arteries (away from the heart) and veins (toward it).
• Respiratory: pulmon/o, pneum/o (lung), bronch/o (bronchus), rhin/o, nas/o (nose), laryng/o (voice box), pharyng/o (throat).
• Digestive: gastr/o (stomach), enter/o (small intestine), col/o (colon), hepat/o (liver), chol/e (bile/gall), cholecyst/o (gallbladder), proct/o (rectum/anus).
• Urinary: nephr/o, ren/o (kidney), cyst/o (bladder), ureter/o (ureter), urethr/o (urethra). Do not confuse ureter (kidney→bladder) with urethra (bladder→outside).
• Reproductive: hyster/o, metr/o (uterus), oophor/o (ovary), salping/o (fallopian tube), orchi/o, orchid/o (testis), prostat/o (prostate).
• Nervous: neur/o (nerve), encephal/o (brain), myel/o (spinal cord or bone marrow — context decides), mening/o (meninges).
• Endocrine: thyr/o (thyroid), adren/o (adrenal), pancreat/o (pancreas). These glands drive many diagnosis codes for hormone disorders.

Two roots deserve a warning flag because they collide: myel/o means spinal cord in a neurology note but bone marrow in a hematology note, and -emia (blood condition) is not the same as -penia (deficiency) — leukopenia is too few white cells, leukemia is a malignant proliferation of them.

Key facts

• Decode a term from the suffix first, then read the roots front to back.
• Keep the combining vowel before a consonant and between two roots; drop it before a suffix that starts with a vowel.
• -otomy = cut into; -ostomy = create an opening; -ectomy = remove. Confusing these routes you to the wrong CPT family.
• -graphy = the process of recording; -gram = the image; -scopy = direct visual exam.
• Directions assume the anatomical position. Proximal/distal are relative to the trunk; the wrist is distal to the elbow.
• Planes: sagittal (L/R), coronal (front/back), transverse/axial (top/bottom).
• Watch collisions: myel/o (cord vs. marrow), ureter vs. urethra, -emia vs. -penia.

Worked example — decoding an operative title

Scenario. An operative report is titled "Laparoscopic salpingo-oophorectomy, left." The coder has never seen this exact phrase. What was done, and to what?

Work the parts. Start at the suffix: -ectomy = removal. Roots: salping/o = fallopian tube, oophor/o = ovary. Prefix/qualifier: laparo- = abdomen and -scopic = done through a scope; "left" is laterality. So the surgeon removed the left fallopian tube and left ovary through a laparoscope (minimally invasive), on the left side.

Why it matters for coding. That single decoded title tells you three coding-critical facts before you ever open a manual: the approach (laparoscopic, which selects a different CPT family than an open removal), the structures (tube + ovary, so you need a combined-procedure code, not two separate ones if a combined descriptor exists), and the laterality (left — which for ICD-10-CM diagnosis coding will require a left-sided code). Nothing here required memorizing a code number; it required reading.

Exam traps

• Reading a term front to back. Students see gastroenteritis and start with "stomach" as the main idea. The main idea is always the suffix (inflammation). Decode the suffix first or you will misjudge what the term describes.
• -otomy vs. -ostomy vs. -ectomy. One letter changes an incision into a new opening or a removal. Exam writers put all three in the answer choices on purpose.
• Ureter vs. urethra. Nearly identical spelling, different organs. A "ureter" code on a "urethra" procedure is an automatic miss.
• Proximal/distal reversed. "Proximal" is toward the trunk, not toward the fingertips. On extremity questions the exam rewards getting this right.
• Myel/o context. In a spine case it is the cord; in a leukemia/marrow case it is bone marrow. Let the surrounding terms decide, not a memorized single meaning.
• Combining-vowel spelling distractors. Options may offer gastroitis vs. gastritis. The vowel drops before a vowel-initial suffix; the correctly spelled term is gastritis.