Muscle attachment points can be different for each main muscle group. Let's break it down:

1. Origin: This is the point where the muscle attaches and stays stable. It usually is closer to the center of your body. Here are some examples:

   • Pectoralis major: This muscle attaches to the clavicle and sternum. In about 60% of people, these are the main spots it connects.
   • Biceps brachii: This muscle attaches at the scapula (the shoulder area).

2. Insertion: This is the point where the muscle connects and can move. It is usually farther from the center of your body. Here are some examples:

   • Pectoralis major: This muscle connects to the humerus (the upper arm bone).
   • Biceps brachii: This muscle connects to the radius (one of the bones in your forearm).

Interestingly, about 40% of muscles have different attachment points in different people. This can change how the muscles work in your body.