Anatomy, Physiology, Terminology and Disease Recognition · 4 min read
Organization of the Body, Directions and Regions
NCMA questions rarely ask you to recite a definition alone. They describe a patient and ask which body system is involved, what a term means, which abbreviation is unsafe, or which symptom must be reported to the provider right away. Remember the scope rule throughout: the medical assistant (MA) recognizes and reports signs and symptoms; the provider diagnoses.
This chapter covers how the body is organized from cells to systems, the anatomical position, directional terms, body planes, body cavities, and the quadrants and regions used to describe the abdomen. These words appear in charting, exam instructions and patient complaints every day.
Levels of Organization
The body is built in levels, each made from the one below it.
Homeostasis is the body's ability to keep a stable internal environment, such as a steady temperature, blood sugar and blood pressure.
Anatomical Position and Directional Terms
Anatomical position is the reference posture used for every directional term: standing upright, facing forward, arms at the sides, palms facing forward, feet flat and slightly apart. "Right" and "left" always mean the patient's right and left, not yours.
| Term | Meaning | Clinic Example |
|---|---|---|
| Superior / inferior | Toward the head / toward the feet | The nose is superior to the mouth |
| Anterior (ventral) / posterior (dorsal) | Front / back | The sternum is anterior to the heart |
| Medial / lateral | Toward the midline / away from the midline | The big toe is medial to the little toe |
| Proximal / distal | Closer to / farther from the point of attachment of a limb | The elbow is proximal to the wrist |
| Superficial / deep | Toward the surface / away from the surface | Skin is superficial to muscle |
Body Planes
A plane is an imaginary flat surface that divides the body, used for imaging and anatomy descriptions.
Body Cavities
| Cavity | Subdivision | Main Contents |
|---|---|---|
| Dorsal | Cranial | Brain |
| Dorsal | Spinal (vertebral) | Spinal cord |
| Ventral | Thoracic | Heart, lungs, esophagus, great vessels |
| Ventral | Abdominal | Stomach, liver, gallbladder, spleen, pancreas, intestines, kidneys (behind the peritoneum) |
| Ventral | Pelvic | Urinary bladder, rectum, reproductive organs |
The diaphragm, a dome-shaped muscle, separates the thoracic cavity from the abdominopelvic cavity.
Abdominal Quadrants and Nine Regions
The abdomen is described in two ways. Four quadrants are made by crossing a vertical and a horizontal line at the umbilicus (navel). Clinicians use quadrants most in charting.
| Quadrant | Key Organs | Symptom Link |
|---|---|---|
| Right upper (RUQ) | Liver, gallbladder, part of pancreas | Gallbladder pain after fatty meals |
| Left upper (LUQ) | Stomach, spleen, part of pancreas | Gastric pain, spleen injury |
| Right lower (RLQ) | Appendix, cecum, right ovary | Appendicitis |
| Left lower (LLQ) | Sigmoid colon, left ovary | Diverticulitis |
The nine regions give a finer map, made by two vertical and two horizontal lines, like a tic-tac-toe grid.
| Left Column (Patient's Right) | Middle Column | Right Column (Patient's Left) |
|---|---|---|
| Right hypochondriac | Epigastric | Left hypochondriac |
| Right lumbar | Umbilical | Left lumbar |
| Right iliac (inguinal) | Hypogastric (suprapubic) | Left iliac (inguinal) |
Word parts explain the names: hypochondriac means below (hypo-) the rib cartilage (chondr/o), and epigastric means above (epi-) the stomach (gastr/o).
Key Takeaways
- Organization runs chemical, cellular, tissue, organ, system, organism; the four tissue types are epithelial, connective, muscle and nervous.
- All directional terms assume anatomical position and the patient's right and left.
- Sagittal divides right and left, frontal (coronal) divides front and back, transverse divides top and bottom.
- The dorsal cavity holds the brain and spinal cord; the ventral cavity holds thoracic and abdominopelvic organs, separated by the diaphragm.
- Know which organs lie in each quadrant: the appendix is RLQ, the liver and gallbladder RUQ, the stomach and spleen LUQ.
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