Free multiple-choice quizzes on the muscular system of the human body, including the locations and actions of all the main muscles of the head and neck, the torso, and the upper and lower limbs. Plus there are links to lots of other great anatomy and physiology quizzes and other resources; all free! Jan 28, 2020 · Muscle anatomy reference charts. Last reviewed: January 28, 2020 If you’ve ever attempted to learn the origins, insertions, innervations, and functions of all 600+ muscles in the body… you’ll know what a soul-destroying task it can be. Just like the deltoid, two of the main muscles of the arms have their origins on the scapula. These are the biceps brachii and triceps brachii, or more commonly referred to as the biceps and triceps. However, unlike the deltoid, these two muscles insert on the bones of the forearm, the radius and ulna. The brachialis is a muscle in the upper arm that flexes the elbow joint. It lies deeper than the biceps brachii, and is a synergist that assists the biceps brachii in flexing at the elbow. It makes up part of the floor of the region known as the cubital fossa.