Know the moving parts — bones, joints, and muscles in 3D.
⚠ DRAFT — readiness & anatomy that feeds a CAPTE associate program; the PTA works under a PT
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K
Coach Katie
Before you ever help someone move, you need a map of the body. Bones give you structure, joints give you motion, and muscles do the pulling. Let's get oriented — and then explore it in 3D so the words stick.
Explore in 3D
The 360° Human Explorer
Spin, zoom, and pull the body apart. Use the buttons to switch models as you read — see the skeleton that gives structure, the back muscles that pull, and a shoulder moving through its motions.
Now showing: Skeletal system — the bones that give the body structure and leverage.
The moving parts
Bones, joints, and muscles
The musculoskeletal (MSK) system is the body's framework and motor. Four players work together every time you move:
🦴 Bones
Give structure and act as levers for movement.
🔗 Joints
Where bones meet — they allow motion.
💪 Muscles
Cross joints and pull bones to create movement.
🎗️ Connective tissue
Tendons and ligaments hold it all together.
Muscles only pull, never push. To move a joint one way and back, muscles work in pairs — the agonist (prime mover) shortens to create the motion while its antagonist relaxes; to reverse the motion, they swap roles. Your biceps and triceps at the elbow are a classic pair.
Joints allow motion
Two joint types to know
Joints come in shapes that allow different amounts and directions of movement. Two are worth knowing cold:
🚪 Hinge joint
Moves mostly one way, like a door — bending and straightening. Examples: elbow and knee.
🍦 Ball-and-socket joint
A round head sits in a cup, moving in many directions and rotating. Examples: shoulder and hip.
Tendon vs. ligament — don't mix them up. A tendon attaches muscle to bone (it transmits the pull). A ligament attaches bone to bone (it stabilizes the joint). Memory hook: Ligament = Links two bones.
The shared language of movement
Anatomical position, planes & motion terms
Everyone on the rehab team describes the body from the same starting point — anatomical position: standing, facing forward, arms at the sides with palms forward. From there, movement gets named with a shared vocabulary:
Flexion / Extension — decreasing a joint angle (bending) vs. increasing it (straightening). Bending your elbow is flexion; straightening it is extension.
Abduction / Adduction — moving a limb away from the body's midline vs. back toward it. (Hook: abduct = moves away; adduct = adds back to the middle.)
Rotation — turning around a long axis, like rotating the arm at the shoulder (internal vs. external rotation).
Use the Shoulder movements model above to watch abduction and rotation happen in 3D.
Scope — read this
Where a PTA fits
A Physical Therapist Assistant (PTA) is a licensed role. It requires a CAPTE-accredited associate degree and passing the NPTE-PTA exam. This module is readiness and anatomy — it helps you get oriented and feeds a college partner's associate program; it is not the program itself.
The PTA works under the direction of a physical therapist (PT), carrying out the PT's plan of care. A PTA does not evaluate patients, diagnose, or write the plan of care. Knowing your anatomy makes you a stronger teammate — the clinical decisions stay with the PT.
K
Coach Katie
Two real moments in a rehab setting. Pick the answer that is clear, accurate, and stays in your lane — helpful anatomy, without stepping into the PT's clinical decisions.
K
Coach Katie
Five questions. 75% to pass, then make your pledge.
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Coach Katie
Learning sticks when you commit to a next step. Pick at least two pledges you'll actually do.
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