Which part of the muscle is attached to the skeleton and typically does not move?

The part of the muscle that is attached to the skeleton and typically does not move is known as the origin. The origin serves as the fixed attachment point where the muscle begins and remains stationary during muscle contraction. This feature is crucial because it provides a stable base from which the muscle can exert force on the bony structures it is associated with.

Understanding the role of the origin helps in comprehending how muscles function in coordinated movement. When the muscle contracts, it pulls on the insertion point, causing movement at the joint, while the origin remains fixed. This distinction is fundamental in anatomy and kinesiology, as it informs various practices in fields such as physical therapy, sports science, and anatomy education.

The other parts mentioned, such as the insertion, muscle belly, and fascia, have different roles and characteristics, making the origin a unique and essential concept in muscle anatomy.