The anatomical origin is a concept used when describing muscles, tendons, ligaments, nerves, blood, and lymph vessels. Although it can have a slightly different meaning depending on which kind of origin is referred to, 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.
The origin is the bone, typically proximal, which has greater mass and is more stable during a contraction than its counterpart called the insertion. The insertion is a bone which tends to be distal, has less mass, and has greater motion than the origin during a contraction.
A muscle's origin and insertion have functional aspects that are important in understanding the physiological function of a muscle.
With the latissimus dorsi 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 are stabilized by holding onto a chin up bar as the torso moves up to meet the arm.
Tendons, ligaments, nerves, and blood and lymph vessels