In 1951 Feneis took samples of the flexor muscle in the finger and he made cuts over a huge distance doing about 1900 slices. He traced single cells and what he found was that one cell starts and ends then another starts with gaps in-between. They are lined up but they are like a series of tiny "little worms" but they don't necessarily touch each other. They are all independent worms all scattered longitudinally through the muscle. See the photo below.
Muscle fibres (cells) are discontinuous; however, its collagen is continuous. In other words the muscle fibres don't run from one end of the muscle to the other. The below picture is misleading, and its also how most of us have been taught to think of a muscle. The muscle cells are long but are not more than a few millimetres at most, not centimetres. In other words one muscle cell of the sartorius muscle does not run the whole length of the muscle.
So each "little worm" muscle cell doesn't pull directly on the next cell. It does it by pulling on the collagen. The collagen is spread throughout like an unbroken fabric in the muscle, a molecular continuum from one end to the other that runs around twisting and making spirals connecting each of the muscle cells. The collagen holds the muscle together like a unit and transmits the force from one little worm to the next, to the next and so on until it reaches the tendon and then the bone.
A muscle like the drawing above (or in the top diagram of the below photo) that had each fibre running from tendon to tendon could not work. When the muscle contracted and hardened it would cut of its own blood supply and compress its own nerves and render the whole action useless. The interesting thing is Niels Stensen wrote this in 1667, and yet I wasn't exposed to this view until now.
The true architecture of a muscle is a parallelogram where the tendon plates are offset to each other and the muscle fibres run between them on an angle. Where the tendon plates are K, M, D, C and E, F, O, N and the muscle fibres are A, B, F, E and C, D, H, G in the below diagram.
On the below picture you can see the representation of the collagen fibres as a cross hatching that is molecularly continuous from one tendon plate to the other and around all the muscle fibres. As the muscle fibres (1 and 2) shorten and thicken (1' and 2') it preserves constant volume. One tendon is fixed (the top) and the other is free to move. The space between the fibres is not compromised, in fact there is a slight increase in the available space so that more blood can be drawn in, or lymph can flow and nerves aren't squashed. You can see a blood vessel between the fibres as a red dot. This is a simple representation in two dimensions, whereas real muscles are complex and have a spiral to them.
Here is a representation of the orientation of fibres in the deltoid muscle. It is aligned like a chevron. Somehow this type of explanation is missed in texts I have read. It certainly seems a very logical setup.
Unfortunately modern textbooks don't talk about this it would seem. Somehow science has overlooked this contribution from long ago. When we look at muscles in this way it does explain so much.
This material was taken from a lecture by Dr Brian Freeman PhD, Embryology from a Biodynamic perspective; in Bath, UK July 2010.
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