Why anatomy vocabulary matters
Every cue you give a client — every form correction, every program — relies on a shared vocabulary. If you can't say 'bring your scapula into posterior tilt' and have your colleague know exactly what you mean, you're guessing. This lesson gives you the coordinate system.
Anatomical position
Anatomical position is the universal reference point: standing upright, feet shoulder-width apart, arms at the sides, palms facing forward. Every directional term you'll learn assumes the body is in this position. So when you read 'the bicep is anterior to the triceps,' it means anterior in anatomical position, even if the person is upside down in a handstand.
The three primary planes
Sagittal plane — Divides the body into left and right halves. Movement in this plane is forward and backward. Squats, bicep curls, deadlifts, running — all sagittal. This is the plane most exercises live in. Frontal (coronal) plane — Divides the body into front and back halves. Movement here is side-to-side. Lateral raises, side lunges, jumping jacks, side bends. Transverse plane — Divides the body into top and bottom halves. Movement here is rotational. Russian twists, cable woodchops, throwing a punch, looking left or right. Rule of thumb: programming only sagittal-plane work creates fragile athletes. Every program should hit all three planes.Directional terms (the ones you'll actually use)
- Anterior — toward the front. The quads are anterior.
- Posterior — toward the back. The hamstrings are posterior.
- Medial — toward the midline. Adductors are medial thigh muscles.
- Lateral — away from midline. Abductors work lateral hips.
- Proximal — closer to the trunk/origin. The shoulder is proximal to the elbow.
- Distal — further from the trunk. The hand is distal to the elbow.
- Superior — above. The head is superior to the chest.
- Inferior — below. The feet are inferior to the knees.
- Superficial — closer to skin. The lats are superficial; the rhomboids underneath are deep.
- Deep — further from skin.
Movement terms
- Flexion — decreasing the angle of a joint (bicep curl flexes the elbow)
- Extension — increasing the angle (tricep pushdown extends the elbow)
- Abduction — moving away from midline (lateral raise)
- Adduction — moving toward midline (cable adduction)
- Rotation — turning around an axis (internal/external rotation of the shoulder)
Putting it together — practical example
A proper squat involves: hip flexion, knee flexion, ankle dorsiflexion. The motion happens in the sagittal plane. The hips travel posteriorly and inferiorly. As you stand, the hips extend, knees extend, ankles plantarflex. You just described a squat in language any practitioner will understand.
What to memorize
You don't need to memorize every bone. You DO need: the three planes, the eight directional pairs (anterior/posterior, medial/lateral, proximal/distal, superior/inferior), and the six movement terms (flexion/extension, abduction/adduction, rotation). These come up in every other lesson.