What does the term intrinsic refer to in regards to muscle?

Question

Quizplus · Accepted Answer

The origin is the attachment of a muscle to the bone or structure that does not move when the muscle contracts. Insertion is the attachment of a muscle to the bone or structure that does move when the muscle contracts. An intrinsic muscle is a muscle that has an origin and insertion located in the same body region. An extrinsic muscle is a muscle that has an origin located in a different body region than its insertion.

What Does the Term Intrinsic Refer to in Regards to Muscle