Final answer:
A skeletal muscle's insertion is the moveable end of the muscle that attaches to the bone being pulled. It is crucial for the muscle's function and influences the muscle's action, force of contraction, name, and the load capacity. Muscle names reflect their insertion and origin, as well as their actions.
Step-by-step explanation:
A skeletal muscle's insertion is defined by most texts as the moveable end of the muscle that attaches to the bone being pulled. This is distinct from the muscle's origin, which refers to the end of the muscle attached to a fixed or stabilized bone. Tension created by muscle contraction is transferred to the tendons, which are strong bands of dense, regular connective tissue that connect muscles to bones. This connection facilitates the movement of the skeleton, such as during forearm flexion when the brachioradialis muscle assists the brachialis by acting as a synergist.
The location of a muscle's insertion can play a role in determining the muscle's action, the force of contraction, its name, and the load it can carry. Furthermore, the names of muscles often reflect the location of their insertion and origin. For example, the sternocleidomastoid muscle has its origin on the sternum and clavicle, and inserts on the mastoid process, which is reflected in its name. Additionally, muscles are also named based on their action, such as flexors, extensors, abductors, or adductors.