Origin

The anatomical origin is a concept used when describing muscles, tendons, ligaments, nerves, and blood and lymph vessels. While it often has a slightly different meaning depending on which kind of origin is referred to,^[1] it is generally used to explain the relative location of the anatomical structure in question. It is not to be understood in a temporal/ontogenetical sense.

Muscles

The origin of a muscle is a point at which it attaches to a bone (muscles do not attach to other muscles).

The structure that the origin is attached to does not tend to be moved by the contraction of the muscle.^[2] The site of the origin tends to be more proximal and have greater mass than what the other end attaches to.

The opposite end of the muscle is called the insertion. The point of insertion tends to be more distal, and have less mass than the site of origin. It is the end that tends to move while the body part of the origin is stabilized.

These definitions means that there are functional aspects to the definition of a muscle's origin and insertion. Both origin and insertion are important for understanding the physiological function of the muscle.

Example

With the latissimus dorsii muscle, the origin site is the torso, and the insertion is the arm. Normally the distal (arm) moves, due to having less mass. This is the case when grabbing objects lighter than the body (like someone beginning on a lat pulldown machine). This can be reversed however, such as a gymnast doing a front lever, whose arms is stabilized by holding onto a chin up bar and whose torso moves up to meet the arm.

Tendons, ligaments, nerves, and blood and lymph vessels

This section requires expansion.

The origin of an artery is the (usually bigger) artery that the former artery branches off of.

Footnotes and references

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