The Architecture of Action: A New Way to Map Human Movement
In the world of fitness and rehabilitation, the prevailing assumption is that human movement can be neatly reduced to the "7 primal movements" (the squat, lunge, push, pull, hinge, twist, and gait). While this model is a useful shorthand for the gym, it is a superficial way of looking at a biological masterpiece. To understand how we truly move, we must look deeper than these external categories and adopt an Inside-Out taxonomy. This is a hierarchy that starts with the autonomic functions that keep you alive and ends with the big, powerful movements used to interact with the world.
This guide is a reference for the muscular system, organised by what the muscles actually do for you.
Level 1: Biological Sustainment (The Survival Base)
The foundation of the hierarchy is all about keeping you alive and taking in information from your surroundings. These muscles are "always-on" systems that allow you to breathe, see, and eat before you even think about moving a limb.
Breathing & Lung Function
Diaphragm: The main muscle for breathing; it flattens to pull air into the lungs.
External Intercostals: Lift the ribs to help you breathe in.
Internal Intercostals & Membranes: Pull the ribs down to help you breathe out forcefully.
Innermost Intercostals: Help the internal intercostals squeeze the ribs.
Levatores Costarum: Help lift the ribs.
Subcostales: Pull the ribs down to help you breathe out.
Transversus Thoracis: Squeezes the chest to help with breathing out.
Eyes & Ears (Sensory Tracking)
Orbitalis: Keeps the eye in position.
Superior Rectus: Moves the eye up and slightly inwards.
Inferior Rectus: Moves the eye down and slightly inwards.
Medial Rectus: Moves the eye towards the nose.
Lateral Rectus: Moves the eye towards the ear.
Superior Oblique: Moves the eye down and outwards.
Inferior Oblique: Moves the eye up and outwards.
Levator Palpebrae Superioris: Lifts the upper eyelid.
Tensor Tympani: Tightens the eardrum to protect against loud noise.
Stapedius: Dampens vibrations in the ear to protect your hearing.
Facial Expression & Mouth
Occipitofrontalis: Lifts the eyebrows and wrinkles the forehead.
Procerus: Pulls the skin between the eyebrows down (for frowning).
Nasalis: Opens and closes the nostrils.
Depressor Septi Nasi: Pulls the nose downwards.
Orbicularis Oculi: Squeezes the eyes shut.
Corrugator Supercilii: Pulls the eyebrows together.
Depressor Supercilii: Lowers the eyebrows.
Auricularis (Ant/Sup/Post): Move the ears forward, up, or back.
Orbicularis Oris: Purses and closes the lips.
Depressor Anguli Oris: Pulls the corners of the mouth down (a sad face).
Transversus Menti: Helps pull the mouth down.
Risorius: Pulls the mouth sideways.
Zygomaticus Major/Minor: Lift the mouth and upper lip (smiling).
Levator Labii Superioris: Lifts the upper lip.
Depressor Labii Inferioris: Pulls the lower lip down.
Levator Anguli Oris: Lifts the corner of the mouth.
Buccinator: Flattens the cheeks (essential for chewing and blowing).
Mentalis: Wrinkles the chin and pushes the bottom lip out.
Masseter: Closes the jaw with high force.
Temporalis: Closes and pulls the jaw back.
Lateral Pterygoid: Pushes the jaw forward and helps it grind side-to-side.
Medial Pterygoid: Closes the jaw and helps it grind.
Tongue & Throat
Genioglossus: Sticks the tongue out and pulls it down.
Hyoglossus: Pulls the tongue down and back.
Styloglossus: Lifts and pulls the tongue back.
Tongue Muscles (Longitudinal/Transverse/Vertical): Change the shape of the tongue for speech and eating.
Palatoglossus: Lifts the back of the tongue.
Levator Veli Palatini: Lifts the soft palate when you swallow.
Tensor Veli Palatini: Makes the soft palate firm.
Musculus Uvulae: Shortens and lifts the uvula.
Palatopharyngeus: Tightens the throat and pulls it up.
Throat Constrictors (Sup/Mid/Inf): Squeeze food down towards the stomach.
Stylopharyngeus & Salpingopharyngeus: Lift and widen the throat.
Cricothyroid: Tightens the vocal cords to make your voice higher.
Posterior Crico-arytenoid: Opens the vocal cords so you can breathe.
Lateral Crico-arytenoid: Closes the vocal cords so you can speak.
Vocalis & Thyro-arytenoid: Adjust the tension of your voice.
Arytenoid Muscles: Close the back of the airway.
Summary: Level 1 is all about keeping you alive and aware. These muscles handle the basics: breathing, seeing, hearing, and eating. If these systems aren't working smoothly, your brain stays in "survival mode”.
Level 2: Structural Integrity (The Chassis)
This level is about your "chassis", keeping your head straight and your spine steady. These muscles provide a stable base so your arms and legs have something solid to push from.
Neck & Head Positioning
Platysma: Tightens the neck skin and pulls the jaw down.
Longus Colli & Capitis: Bend the neck and head forward.
Scalenes (Ant/Mid/Post): Tilt the neck and help with deep breathing.
Sternocleidomastoid: Turns the head and bends the neck forward.
Rectus Capitis Group: Small muscles that tilt and turn the head precisely.
Obliquus Capitis Group: Rotate and tilt the head at the top of the neck.
Bracing the Spine
Erector Spinae: The big muscles that keep you standing up straight.
Transverso-spinales & Spino-transversales: Deep muscles that twist and straighten the spine.
Inter-spinales & Inter-transversarii: Tiny muscles that bridge and steady the vertebrae.
Rectus Abdominis: Bends the body forward (the "six-pack").
Pyramidalis: Tightens the middle of the stomach.
Transversus Abdominis: Acts like a natural corset to squeeze and steady your middle.
Quadratus Lumborum: Steady the pelvis and bend the spine sideways.
Pelvic Diaphragm: Supports your internal organs from below.
Summary: Level 2 provides a steady base. These muscles protect your spine and keep your head in the right position. Think of this as the body's scaffolding; before you can throw a ball or lift a box, these muscles have to "lock in" to make sure your frame is secure.
Level 3: Integrated Locomotion & Force Projection (Power)
These are the big muscles that move your whole body through space (like running) or let you put a lot of power into something (like pushing or pulling).
Moving the Whole Body
Gluteus Maximus: The main engine for running, jumping, and standing up.
Quadriceps: Straighten the knee and provide power for walking and jumping.
Hamstrings: Bend the knee and pull the hip back.
Iliopsoas: The main muscles for lifting your knee up.
Gluteus Medius & Minimus: Steady the hips so you don't wobble when you walk.
Calf Muscles (Gastrocnemius & Soleus): Push you off the ground when you step or jump.
Tibialis Anterior: Lifts your toes so you don't trip.
Pushing, Pulling, & Hitting
Pectoralis Major: The main muscle for pushing or punching forward.
Latissimus Dorsi: The main muscle for pulling things toward you.
Serratus Anterior: Pushes the shoulder blade forward (essential for a long reach).
Deltoid: Lifts the arm and gives the shoulder its power.
Biceps & Brachialis: Bend the elbow for pulling.
Triceps: Straighten the elbow for pushing.
Obliques: Twist the torso to create power for throwing or hitting.
Adductors: Pull the legs together for stability and strength.
Wrist Flexors & Extensors: Steady the wrist so you can transfer power into your hands.
Summary: Level 4 is where you find the power. These big muscles move your body from A to B and let you push, pull, and strike with force. They are the "engines" of the body, but they rely entirely on the steady base and the survival systems in the levels below to work properly.
Level 4: Appendicular Interaction (Using Your Limbs)
This level is about reaching out and handling things. It focuses on how your arms and legs sit in their sockets and how your hands and feet handle objects.
Shoulders & Hips (The Sockets)
Trapezius: Shrugs, rotates, and pulls the shoulder blades back.
Rhomboids: Pull the shoulder blades together.
Levator Scapulae: Lifts the shoulder blade.
Pectoralis Minor: Pulls the shoulder forward and down.
Subclavius: Steadies the collarbone.
Rotator Cuff (Supraspinatus, Infraspinatus, Teres Minor, Subscapularis): These four muscles hold the arm in its socket and let it rotate.
Coracobrachialis: Pulls the arm in and forward.
Piriformis & Hip Rotators: Rotate the hip outwards and steady the leg.
Fine Tuning & Precision
Articularis Muscles: Small muscles that pull joint linings out of the way so they don't get pinched.
Anconeus: Helps straighten the elbow.
Supinator: Turns the palm upwards.
Pronators: Turn the palm downwards.
Hand & Finger Muscles (Thenar/Hypothenar): Allow the thumb and little finger to move across the palm for a strong grip.
Lumbricals & Interossei: Precision muscles in the hands and feet that let you spread your fingers/toes or grip small objects.
Foot Muscles: Support the arches and move the toes to help you balance.
Summary: Level 4 is about reaching and handling. These muscles manage the joints where your limbs meet your body and give you the "fine touch" in your hands and feet. They allow you to handle tools, grab onto things, and keep your balance on uneven ground.
Human Movement: A Philosophical Reflection
When we map the human body in this way, a deeper question emerges: What does this architecture suggest about our purpose?
If you look at the sheer quantity of muscles we possess, the vast majority are not dedicated to raw power. Instead, they are built for precise observation, emotional expression, verbal communication, and creative action. We have dozens of tiny muscles just to move our eyes, shape our tongues, steady our vertebrae, and articulate our fingers. We have more machinery for nuance and stability than we do for brute strength.
This taxonomy suggests that human movement is not merely a tool for getting from A to B. We are built to be collaborators in change. Our upright posture is a precarious way to stand, but it does three things no other design can: it places our sensors at the highest possible vantage point, it frees our breath to be modulated into complex speech, and it frees our upper limbs to interact with the environment.
While a predator’s movement is a short burst of high-intensity focus, the human body seems designed for the long view, the shared story, and the intervention. We have shock absorbers in our necks and stabilisers in our inner ears specifically so we can maintain a steady gaze over miles of terrain; we have a tongue and larynx capable of describing that terrain to our tribe; and we have fingers and thumbs for developing the tools to reshape it.
Does this mean our true function is to collectively change the world? Are we the species built to track the horizon, tell our story, and coordinate a new future? Every time you move, you are using a system that prioritises awareness, articulation, and action. Perhaps we should evaluate our movement not by how much weight we can shift, but by how well we can change our environment while maintaining our integrity. Are we moving with the purpose we are uniquely capable of?
