 In this video, I will identify the muscles that move the humeral ulnar joint, commonly known as the elbow joint, and list the origin, insertion, and action of the major muscles that move the humeral ulnar joint. We'll start by taking a look at the large superficial muscles that move the humeral ulnar joint. The most familiar is the biceps brachii, commonly just referred to as the biceps muscle, but it's important to give the full name biceps brachii, distinguish biceps brachii from the biceps femoris. Biceps means two heads, so there are two muscle bellies or two origins for biceps brachii. The short head of biceps brachii is more medial as well as shorter than the long head, which is more lateral. The origin of the short head is the corcoid process of the scapula, whereas the origin of the long head is the supraglenoid cubicle. The action of biceps brachii is to flex the humeral ulnar joint, and also the biceps brachii performs the action of supination of the proximal radio ulnar joint. Deep to biceps brachii is the brachialis muscle, and the brachialis muscle performs the action of flexion at the humeral ulnar joint. On the posterior of the brachial region is the triceps brachii, commonly shortened to triceps. The triceps brachii has three origins, or three heads, and from this view we can see just the lateral head and the long head, but there is also a medial head, which is mostly deep to the long head, so it cannot be seen in this illustration. The triceps brachii has the action of extension at the humeral ulnar joint, so the long head of biceps brachii has its origin from the supraglenoid cubicle, and insertion onto the radius down here at the radial tuberosity. The actions of biceps brachii include flexion of the humeral ulnar joint, and supination of the proximal radio ulnar joint. The short head of biceps brachii has its origin from the coracoid process of the scapula, and inserts together with the long head onto the radial tuberosity to have those same actions of flexion and supination, flexion of the humeral ulnar joint, and supination of the proximal radio ulnar joint. The brachialis has its origin deep to the biceps brachii on the anterior diathesis of the humerus, and insertion on the ulna at the ulnar tuberosity and the coranoid process of the ulna. The action of brachialis is to flex the humeral ulnar joint. This illustration allows us to see all three heads of biceps brachii. In the yellow color we can see the lateral head of biceps brachii. In the red color we see the long head of biceps brachii. And then the green color shows us the medial head of biceps brachii. And so you can see that the medial head of the biceps brachii is visible on the medial surface of the alecranol region at the distal end of the brachial region. But the majority of the medial head of biceps brachii is deep to the long head of biceps brachii. The origin of the long head of biceps brachii is the infraglenoid tubercle of the scapula. The insertion of biceps brachii is the alecranon process of the ulna, and the action is to extend the humeral ulnar joint. The origin of the lateral head of biceps brachii is along the posterior diaphysis of the humerus, just superior to the radial groove. The insertion is the alecranon process of the ulna, and the action is extension of the humeral ulnar joint. The medial head of biceps brachii has its origin on the posterior diaphysis of the humerus, just inferior and medial to the origin of the lateral head. And then the insertion of all three heads for the triceps brachii is on to the alecranon process of the ulna, and the action of all three heads is the same extension of the humeral ulnar joint. Now we'll take a look at a couple muscles that move the humeral ulnar joint that are found in the antibrachial region. There's brachioradialis, a muscle found in the lateral antibrachial region that has the action of flexion at the humeral ulnar joint as a synergist to assist biceps brachii and brachialis. You can see brachioradialis from either an anterior or a posterior view, but on the right here in our posterior view there's another muscle that moves the humeral ulnar joint known as anconius. Anconius is a synergist with the triceps brachii to perform the action of extension of the humeral ulnar joint. So the origin of brachioradialis is the lateral supercondylar ridge of the humerus, and the insertion of brachioradialis is the styloid process of the radius way down at the distal end of the radius. And the action of brachioradialis is to flex the humeral ulnar joint.