Fascia is strong connective tissue which performs a number of functions, including enveloping and isolating the muscles of the body, providing structural support and protection. It is a product of mesenchyme, a type of connective tissue which develops in embryos before differentiating into numerous other structures in the body. Mesechyme also forms the foundation for bone, cartilage, and important components of the circulatory and lymphatic systems. Fascia is a very important part of the body, and it has three layers, starting with the superficial directly under the skin and ending with subserous, deep inside the body.
Fascia is thin, but very fibrous and strong. Anyone who has skinned chicken breasts or trimmed meat has encountered it, the whitish colored thin sheets of tissue between the skin and muscle of the meat. This tissue forms directly under the skin and serves as a strong layer of connective tissue between the skin and muscles underneath it.
The top layer is superficial fascia, which may be mixed with varying amounts of fat, depending on where it is on the body. The skull and hands have a particularly noticeable superficial layer that connects the skin to the tissues and bone underneath it. By wriggling your scalp, you can see that superficial fascia is strong but flexible, keeping the skin firmly anchored while allowing its owner to move freely.
Underneath lies deep fascia, a much more densely packed and strong layer. Deep fascia covers the muscles in connective tissue aggregations which help to keep the muscles divided and protected. On occasion, it can create tight knots or connective adhesions which act as trigger points which can cause pain. A variety of treatments including myofascial release and stretching are used to treat this condition, which can be debilitating and extremely painful. If a patient is diagnosed with a condition like myofascial pain syndrome, it may be useful to know that the term means “fascia related to the muscles,” and that these conditions do not necessarily involve the superficial and subserous fascia.
The subserous fascia lies between the deep layer and major organs of the body. It is more flexible than deep fascia, and the body leaves space around it so that the organs can move freely. Like that layer, the subserous tissue can also form fibrous knots and adhesions which can be painful unless they are addressed.