Deepening your anatomical perspective refines your kinesthetic sense by helping you feel into your entire body—which is greater than the sum of its anatomical parts. The connective-tissue net, known popularly as fascia, weaves those parts into one integrated whole.
If I asked you what a heart is like, chances are you’d say it’s like a pump. The lungs are often described as “bellows,” the kidneys “a filter,” the brain “a computer.” We tend to view the body in mechanical terms because we live in an industrial age—and because the body has been described as a “soft machine” ever since the scientist René Descartes coined the term in the early 17th century.
So it comes as no surprise that most anatomy books show you body parts—this muscle, that ligament—as if we’re assembled part by part like a car or an iPhone. But instead of timing belts and motherboards, we have hamstrings and biceps. An anatomy atlas is a helpful tool for learning, but the error comes when we start thinking that humans are actually built that way. What is actually going on under your skin is so different from what’s in those pictures.
Your body is much more like a plant than a machine. We are grown from a tiny seed—a single cell, or fertilized ovum, about the size of a pin prick—not glued together in parts. This seed contains sufficient instructions (given the proper nourishment) to create a helpless, squalling baby, who turns into an energetic toddler, a feckless teenager, and then finally a mature adult.
By the time we’re adults, we consist of approximately 70 trillion cells, all surrounded by a fluid fascial network—a kind of sticky yet greasy fabric that both holds us firmly together, yet constantly and miraculously adjusts to accommodate our every movement.
The traditional biomechanical theory of the musculoskeletal system says that muscles attach to bones via tendons that cross the joints and pull bones toward each other, restricted by other “machine parts” called ligaments. But all these anatomical terms, and the separations they imply, are false. No ligaments exist on their own; instead they blend into the periosteum—vascular connective tissue that serves as cling-wrap around the bones—and the surrounding muscles and fascial sheets. What this means is that you weren’t assembled in different places and glued together—rather, all your parts grew up together within the glue.
For example, the triceps are wedded by fascial fabric to their neighboring muscles north, south, east, and west, as well as to the ligaments deep in both the shoulder and elbow. If you contract the triceps in Plank Pose, all these other structures will have an effect and be affected. Your whole body engages in the action—not just your triceps, pectoral, and abdominal muscles.
The takeaway for yoga? When you do poses, it is useful to put your attention anywhere and everywhere in your body—not just the obviously stretched and singing bits. A release in your foot can help your hip; a change of your hand position can ease your neck.
The fluid fascial network that lives between each cell in your body consists of bungee cord–like fibers made mostly from collagen, including reticulin, and elastin. These fibers run everywhere—denser in certain areas such as tendons and cartilage, and looser in others like breasts or the pancreas.
The other half of the fascial network is a gel-like web of variable mucopolysaccharides, or mucus. Basically, your cells are glued together with snot, which is everywhere, and is more or less watery (hydrated) depending on where it is in the body and what condition it’s in.
All the circulation in your body has to pass through these fibrous and mucousy webs. Generally speaking, the denser the fibers and the drier the mucous, the less the fascial web allows molecules to flow through it—nourishment in one direction and waste in the other. Yoga helps both stretch and ease the fiber webbing, as well as hydrate the gel, making it more permeable.
New research shows that this web of proteins runs down through the membranes of each cell and connects both aspects of the connective-tissue web through the cytoskeleton to the cell nucleus. This means that when you’re doing yoga stretches, you are actually pulling on your cells’ DNA and changing how it expresses itself. Thus, the mechanical environment around your cells can alter the way your genes function.
We’ve known for a while that the chemical environment (hormones, diet, stress catecholamines, and more) can do this, but these new connections explain some of the deeper changes we see when people start practicing regularly.
More on that mechanical environment: Cells are never more than four deep from your capillaries, which excrete food, oxygen, messenger molecules (neuropeptides like endorphins), and more. Tension in your body—slumping your shoulders forward, for example—prompts the fibroblasts (the most common cells found in connective tissue) to make more fibers that will arrange themselves along the line of stress. These bulked-up fascial fibers will form a barrier that will slow or stop capillary-sourced food from reaching your cells. You’ll get enough to survive, but function will slow down. In addition to a thicker barrier of fascial-tissue fibers, the mucus that completes your fluid fascial network will also become thicker and more turgid, which contributes to stopping the flow to your cells.
And because the exchange of goods from capillaries to cells is a two-way street, with cells delivering messenger molecules and CO2 and other waste products back into the bloodstream, a hardened fascial network can trap unprocessed cell products (toxins or metabolites) like a stream eddy traps leaves.
The fix: deep strengthening and stretching squeezes your fascial network the way you would squeeze a sponge. Those metabolites that were trapped in the mucousy bits rush in hoards to the capillaries and your bloodstream. Many of us may feel out of sorts after we release deeply held tension—that’s your liver dealing with the metabolites you squeezed from the tissues. Try an Epsom salts bath, or go back for more movement to keep the process going.
Over yoga time, fascial fibers will slowly thin out and unadhere over weeks, sometimes months, but the mucus can change to a more liquid state in as quickly as a minute, allowing more sliding, less pain, more feeling, and less resistance. Use your yoga—it’s a great tool to get fluids and information flowing to their maximum sensitivity and adaptability.