human anatomy

Superficial Fascia: somewhat technical contemplation from the lab

Posted on by Juno Üjiié

As a manual therapist, this layer holds additional significance. When I work on a specific “muscle,” I am actually working through this layer, in addition to the skin. Unlike the skin, the subcutaneous adipose layer is more uneven in thickness and depth. Generally the adipose tissue is firmly attached to the skin and moves along with it, but its relationship with muscles is more complex. 

Subcutaneous adipose tissue is loose, areolar connective tissue with collagen fibers that provide structure. If you were to remove all the lipids from this tissue, a scaffolding-like matrix made of collagen fibers would be revealed. In Integral Anatomy, this is referred to as superficial fascia. In the human body, adipocytes—commonly know as fat cells—are embedded in this collagen matrix and cannot be separated from it. A typical fat cell has a diameter of about 0.1mm, making it too small to be seen with the naked eye. The lobules you observe at a gross level are not individual fat cells but rather clusters of them, encapsulated within the matrix. Each fat cell is enclosed by a cell membrane, with lipid stored inside. Under normal conditions, body fat doesn’t melt and can’t be sucked out like melted butter—unless it’s in a state of putrefaction.

In meditation, I imagine fat cells dissipating like dew on a spider web touched by the first summer sun, leaving a soft, white, flexible, three-dimensional lace-like structure. The cosy beeswax-yellow fleece onesie transforms into a milky-white dress, gently covering my body like summer clouds in the sky. Though it appears ephemeral, the fabric is deceivingly strong. It holds the weight of skin—the epidermis, dermis, and hypodermis—in places. The skin, after all, is the largest and heaviest organ, weighing between 5 and 10 kilogram.  Gil Hedley, Ph.D., demonstrated the strength of superficial fascia with and without adipose.  He could lift 22 kilograms with a piece of superficial fascia that had adipose intact, and 14.5 kilograms with it removed. I personally participated in this experiment, and the tactile sensation of handling the piece of superficial fascia without adipose has stayed with me ever since. In a tub of warm water, it floated and danced like a mystical creature.

Subcutaneous Adipose Tissue Removal

I’m not talking about liposuction, which I consider a form of amputation, given the destruction of structural, vascular, lymphatic, and nervous elements.  Subcutaneous adipose tissue has structural integrity. 

On dissection tables, human forms lie without the boundary that usually blocks observers from entering the inner space. I’ve never sensed hesitation to cut from workshop participants at this stage. They are usually eager to cut into the tissue and reveal the familiar, anatomy-book-defined muscles hidden beneath the shapeless yellow. I used to feel the same.

Without the dermis, human forms become transparent in a way. The dermis layer is relatively uniform in depth, while the subcutaneous adipose layer varies considerably from one area to another. When manual therapists manipulate soft tissue, they typically aim to target specific muscles. However, this work is done through the dermis and the subcutaneous adipose tissue. I need to be mindful of the variability in adipose layers. For example, the glutes are covered with thick adipose tissue, while the adipose tissue covering forearm is generally thin.

The process to remove subcutaneous adipose tissue is a significant learning opportunity. When you carefully incise the tissue with the tip of scalpel, it opens up with relative ease. Most of the time, you still see the yellow tissue, and you have no idea how deep it goes. You cut again until you finally reveal the familiar brown muscular tissue, covered with a transparent sheen. The energy around the table shifts from weariness to excitement and expectation. Suddenly energized, you eagerly remove the yellow, wet substance. However, if you become too hasty and task-oriented, you risk missing the wealth of information this process can reveal. 

This is where tactile learners, like myself, have an advantage. Unlike the removal of skin (dermis), subcutaneous adipose tissue allows blunt dissection by fingers. The relationship with the underlying structure can be loose, and tissue planes can be easily separated. A scalpel cuts through the connecting structure between tissue planes with little effort. It almost feels as if the subcutaneous adipose layer slide over the muscular structure beneath it. 

When you grasp your forearm and twist it without moving the forearm itself, your skin (all three layers) slides over the muscle. There is a massage technique called skin rolling, where a therapist pull the skin away from muscle tissue and “rolls” it forward. This is possible because the bond between the skin and underlying muscular structure has some play, allowing for movement. In some areas, subcutaneous adipose tissue is firmly anchored to the structure beneath, preventing the skin from slipping. In other areas, the plane where two layers meet is so intimately bonded that the only way to separate them is to carve the adipose tissue away.  

Because of sudden weight loss, I have an abundance of extra skin, which is somewhat loose. It’s relatively easy for me to pull up and “roll” the skin. For some people with tighter skin and/or firmer fat, it’s not as easy. However, there is a limit how much the skin can “slip.” There’s always a connection at the interface. No part of my body wants to be a separate entity. 

We shouldn’t overlook the perforating nervous and vascular structure that travel continuously through the layers. Nerves exit from muscular structures and extend into the subcutaneous adipose tissue, then continue to the dermis like a branching tree. Remember, the nerve endings are the furthest end of your brain, constantly searching for proof of life throughout the body. When I use a scalpel to separate subcutaneous adipose layer, I feel a consistent rhythm of bumps. This resistance occurs when the scalpel encounters something firmer than collagen fibers. Even though the nerves are very fine at the ending, they are strong enough to be part of the structure that physically hold your body in place.

I imagine my brain reaching out, through adipose tissue which cocoons me. How would it feel? The moist, warm, soft beeswax-yellow tissue moves, changes shapes, slides, and dances, conducting heat, sound, and energy. Don’t you feel the love in this layer?

Storage of Emotional Energy

Posted on by Juno Üjiié

The subcutaneous/hypodermis tissue is the deepest layer of your skin, usually dissected away along with the skin to reveal the underlying muscular structure. In Integral Anatomy, this layer is known as the superficial fascia, clearly distinguished from the skin layer. When I slid the scalpel deep enough, the distinctive yellow tissue broke through the pale edge of dermis. Its texture was strikingly different from that of the skin—it was wet, soft, vibrant in color, and greasy. This subcutaneous adipose, commonly known as fat, which everybody seems to dislike.

The true skin or dermis is tightly connected to the subcutaneous layer. They don’t want to be separated. Subcutaneous tissue is a connective tissue, anchoring the skin throughout the body. When I cut through this connection, I felt the resistance through the scalpel. The blade dulled quickly from hitting strong fibers in between. In my first dissection workshop, we spent a week dissecting away the skin layer as one continuous piece to reveal the yellow layer underneath. Every day, every minutes, we were faced with this yellow, bubble -wrap-like tissue. It was an assault on my nervous system. Most novice dissectors hated it. After class, when I closed my eyes, I saw yellow everywhere. Eventually, my nervous system seemed to adjust to the stimuli, and at a certain point, I began to appreciate and cherish this layer. 

Due to my stress-management diet of ice cream and cheesecake, I use to have an abundance of adipose tissue around my midsection, which I jokingly referred to as an “emergency energy reserve” for a potential zombie apocalypse. When I experienced a Meniere’s flare-up and couldn’t eat much, I lost about 20 pounds in three months, and my skin looked like that of a Shar Pei dog. I lost a substantial amount of “fat” along with some muscle mass. I didn’t feel unhappy about losing my energy reserve. Fat is something everybody dislikes having beneath the skin.

We are all covered with subcutaneous adipose tissue. Its distribution varies from one individual to another, though common patterns can be observed. For example, the surface of shin or tibia has very sparse, almost negligible adipose tissue beneath the skin, while the buttocks are primarily shaped by adipose tissue. Female breasts are mostly shaped by fat. When I lost weight, my breasts lost their shape, and the skin appeared looked loose and saggy.

Hate it or love it, a human being can’t live without subcutaneous adipose tissue. This loose connective tissue is embedded with adipocytes, those teeny tiny bags of fat. Currently about 23% of my body weight is subcutaneous fat, which is within the normal range for a woman. Sure, I wish I had abs like young Britney Spears or Miley Cyrus, but it’s my vanity talking. 

What happens if we lose too much of fat?  I once saw a cadaver without any adipose tissue. She was an elderly, petite woman who was so emaciated that she virtually had no fat. Once  the skin was removed, her body was almost translucent, revealing a white matrix of connective tissue without the familiar yellow. The mammary glands were visible on her breasts. She was beautiful but otherworldly. It still makes me sad to imagine her last days, with no soft layer hugging her body, keeping her warm, and cushioning her from pressure and occasional bumps and falls. It’s a cruel state of being.

Healthy babies come with a generous layer of fat, essential for their survival. Their softness and warmth, which make them so cuddle-worthy, are thanks to the subcutaneous fat. This fat layer is what makes a mother’s hug feel so soothing to the baby. (So I hear from parents.)  Subcutaneous fat tissue acts as both a cushion and insulation. You really appreciate its cushioning function when you bump your shin against something hard or land on your rear end without breaking your sit bones.

Even though I have my fair share of fat, as a petite Asian woman, it is relatively thin compared to someone larger. I used to do scuba diving, and even in warm water, I needed a long-sleeved wetsuit to avoid loosing body heat quickly. Larger folks with more subcutaneous fat were fine with just a thin half-suit or even a swimsuit. Even as a cadaver, someone with a thick layer of adipose looked warmer compared to the translucent cadaver of the elderly woman. Adipose tissue is also known as the largest endocrine organ, producing hormones like leptin and estrogen. It’s vascular, innervated, and has lymphatic vessels running through it. Your midsection fat isn’t just a mere blob that can be cut away without consequences.

So, If fat beneath the skin isn’t just a lump of lipids, what is it? It is not a lump that you can simply suck out like a melted butter. It’s connective tissue anchoring the skin and holding the fat lobules in place. It firmly grips the skin and moves with it. Even though the textures are different, the skin and subcutaneous adipose tissue are indivisible. Think of an orange: the peel has a thin outer layer and a fibrous white inner layer. They aren’t separate layers but part of an integral “skin.” To separate them into two layers, you need to carve away the zest.

After you reflect the outer skin layer to reveal the yellow tissue beneath, you get a rare perspective of the dermis from underside. You see a cantaloupe-rind-like reticulate pattern, drawn in white all over. The density and size of this mesh vary depending on location and individual. It looks like a reflection of the adipose lobules in the subcutaneous layer. I imagine it as a mesh framework for sculpting, holding the plaster in shape. 

With the skin removed, a cadaver looks different, yet still retains the distinct shape of the individual. They are mostly covered with sometimes glistening, sometime muted yellow soft, wet substance. It is a human form most of us have never seen or imagined. The tone and saturation can vary within a single cadaver. You might see dark reddish areas, likely caused by subcutaneous bleeding after death. When a person dies, their body lies on its back. Without a beating heart, blood succumbs to gravity, pooling and coagulating in the tissues where it contacts the ground or a hard surface, staining the adipose tissue reddish-brown. In the abdominal area, you might even see an unusual green color, a sign of decay within the human form.

Female cadavers usually have more abundant adipose. Their breasts, shaped almost entirely by adipose, droop toward the sides of the body when the skin is removed, as gravity takes hold. Male cadavers also have substantial adipose tissue, but its distribution differs somewhat. After spending many hours in the dissection lab, I’ve come to appreciate this layer. The human form shrouded in yellow looks content to me. Freed from the skin, that once bounded and contained their shape, they seem relaxed. There is no longer a hard boundary between what’s inside and what’s outside. The body’s water content begins to leak and dissipate. 

More naked than actual nakedness, a body covered in adipose tissue can evoke strong emotional reactions: aversion, vulnerability, discomfort, shame, confusion, sadness—or even relief, strength, joy. I observed cadavers with all kinds of fat: thin, thick, compact, or loose. The first time I saw one — actually, we had six in the lab — I felt confusion and aversion. It wasn’t something I wanted to have in my body. For the first time, I confronted the usually hated fat, and the meaning of the word shifted from an abstract idea to the actual substance, as integral part of human beings. Just seeing and touching that ubiquitous yellow tissue exhausted me.  It’s this tissue that formed the physical image of the individual. And it’s the very substance I’m molded from at this moment. Throughout my life, I’ve gained, retained, and lost fat, and my present physical and energetic shape is represented by this layer. 

I sense that this layer holds a lot of energy—not just in a caloric way, but in a non-physical sense too. It demands that the beholder confront their emotional reaction, which actually reflects my own relationship with body fat. I’ve accumulated some around my midsection thanks to stress eating. Were those fats generated to protect me from the stresses I encountered too often?  Who knows? I heard one dissector started crying, recalling her relationship with fat. You just never know.  I realized I didn’t have any deep trauma stored in this layer. Eventually, I started to love this comfy, snuggly onesie made of soft beeswax pellets. 

I sometime chant Heart Sutra for meditation.  When I chant, I feel the sound wave and vibration travel through my body, and I often end up breaking into a sweat. I wonder if adipose tissue is acting as an energy conductor.