Describe location, planes and movement

Where you are

You can distinguish the anatomy named in a term from the action or condition described. Now learn where structures are in relation to one another. These words let a short clinical phrase carry precise information about side, depth, and location.

Sketch a simple standing figure in your notebook. Label the figure's right and left. If you draw the person facing you, the person's right appears on your left side of the page. Keep the patient's perspective throughout the exercise.

Start from a standard position

Anatomical descriptions use a standard reference: the body upright, facing forward, with palms forward. The relationship does not change merely because a person lies down or turns a hand during an examination. Supine means lying on the back; prone means lying on the front. Those actual positions are different from the anatomical reference used to describe structures. [anatomy-position, section 2.6]

Imagine a note describing a mark on the palm side of the wrist. Turning the hand over does not move that mark to a different anatomical surface. The reference frame lets readers understand the same location even when they did not observe the examination.

Learn direction in pairs

Superior points toward the head; inferior toward the lower end. Anterior indicates the front, and posterior the back. Medial is toward the body's midline; lateral is away from it. Proximal is closer to a limb's attachment or origin; distal is farther away. [anatomy-direction, Directional Terms]

Use a comparison every time you practice. “Distal” by itself leaves a relationship unstated. “The wrist is distal to the elbow” names both structures and the direction between them. Reverse the sentence and the relationship reverses: the elbow is proximal to the wrist.

On your sketch, draw a line from the shoulder through the elbow to the wrist. Trace toward the shoulder while saying proximal, then toward the wrist while saying distal. Do not substitute upper and lower; the relationship is based on attachment, even when an arm is raised.

Side and depth answer different questions

Unilateral means one side, and bilateral both sides. Ipsilateral structures are on the same side; contralateral structures are on opposite sides. Superficial means closer to the surface; deep means farther from it. None of these terms alone names a diagnosis. [anatomy-position, section 2.6]

A description can use several relationships at once. A fictional note might identify a superficial mark on the lateral aspect of the left forearm. Left supplies laterality, lateral describes the aspect, and superficial describes depth. Preserve each detail instead of reducing the phrase to “arm problem.”

Do not confuse lateral with left. Lateral can describe a location on either side of the body. Similarly, bilateral does not mean that two separate services are automatically reportable. The relevant code instructions decide how the documented sides are represented. [icd-guidelines, I.B.13]

Planes describe a division

A sagittal plane divides right from left; a midsagittal plane passes through the midline. A coronal, or frontal, plane divides front from back. A transverse, or axial, plane divides upper from lower portions. These are imaginary divisions used to describe sections, not extra organs. [anatomy-direction, Planes of the Body]

Practice with a plain rectangular box on paper. Draw one division and label the two portions it creates. The question is not which way your pencil travels; it is which portions the plane separates. This distinction helps when an image or report is displayed in an unfamiliar orientation.

Before interpreting an image label, read the orientation supplied with it. Do not infer the patient's side from the viewer's left edge of a screen. This course teaches reading concepts and documented interpretations; it does not train you to diagnose from an image.

Movement uses its own vocabulary

Flexion reduces the angle at a joint; extension increases it. Abduction moves a limb away from the midline, and adduction brings it toward the midline. Rotation turns around an axis. For the forearm, supination turns the palm upward and pronation turns it downward. [anatomy-movement, Table 14.5]

Use imagined movement to distinguish the words, but keep the chart's documented movement separate from your demonstration. A note saying that a movement is painful does not establish the cause of the pain. A limitation described in an examination is also not permission to invent an injury diagnosis.

Connect movement to a named structure. “Limited extension” needs context. Extension at the elbow and extension at another joint involve different anatomy. The body-system lessons will build those connections.

Worked example: three location details

Original fictional office excerpt, August 21, 2026: the clinician documents pain at the lateral aspect of the left elbow during extension. No definitive cause is established in the available assessment.

First, identify the structure: elbow. Next, retain the side: left. Then explain lateral as the aspect and extension as the movement associated with the documented pain. Those details help you understand the note; they do not establish a specific tendon or bone disease.

For an outpatient diagnosis exercise, code to the certainty documented and verify the complete candidate in the Tabular List. Do not replace the symptom with a suspected condition because the location sounds familiar. [icd-guidelines, IV.F–H; I.B.1]

Now change the note so the assessment and examination disagree about right and left. The correct response is not to use whichever word occurs more often. Conflicting laterality needs clarification under the official guidance. [icd-guidelines, I.B.13]

Book drill

Locate a left-sided joint symptom in the ICD-10-CM index and verify the candidate in the Tabular List. Identify which part of the entry represents side. Then compare the nearby right-sided or unspecified-side alternatives without assuming that proximity makes them appropriate.

In your notebook, write the documented structure, side, and movement as separate fields. Add one sentence explaining which facts support the lookup and which do not establish a diagnosis.

Common traps

Lateral does not mean left. Distal does not simply mean below. Turning a patient does not rename an anatomical surface. A movement term does not diagnose the reason for a limitation. Conflicting sides require resolution rather than a majority vote.

Practice

1. Is the elbow proximal or distal to the wrist?

2. Which plane separates anterior and posterior portions?

3. Does a description of left-sided pain establish the cause of that pain?

Compare your reasoning

1. Proximal: the elbow is closer to the limb's attachment. 2. The coronal or frontal plane. 3. No; the assessment must establish the cause. Preserve the documented side while applying the outpatient certainty rule.

Checkpoint

Describe one location using structure, laterality, aspect and depth. Explain a movement without naming an unsupported diagnosis. Finally, draw and label the three principal planes from memory.

Sources

1. NIH/NCI SEER — Anatomical Terminology. accessed 2026. Accessed 2026-09-10.
2. Open RN / Chippewa Valley Technical College — Medical Terminology, 2nd edition — Chapter 2. 2024. Accessed 2026-09-10.
3. Open RN / Chippewa Valley Technical College — Medical Terminology, 2nd edition — Table 14.5 Muscle Actions. 2024. Accessed 2026-09-10.
4. CDC/NCHS and CMS — ICD-10-CM April 1 2026 Guidelines. FY2026 April. Accessed 2026-09-10.