Hi, welcome back, start off the second lecture of section three. At the end of this lecture you know how the elbow can extend and flex and pronate and supinate and how the wrist can move. We start like before with an overview of the muscles that we will encounter in this lecture. The first movement will be flexion of the elbow there are three muscles active when you flex your elbow. The first is biceps break yeah we met biceps before, both long and short head of biceps are active inflection. biceps is supported by two muscles which we will get to know now.

We are talking about brachialis and brachial radialis. brachialis is a strong flexor with the origin on the humerus bone, the distal half and the insertion is right after the elbow joint at the owner. This spot is called the current process and is at the anterior side. The second new muscle for flexing the elbow is brachioradialis. It starts at the rich just proximal of the lateral condyle of humerus. From there, it has a muscle belly that becomes a tendon after two thirds of its full muscle length, and the tendon inserts at the distal silhouette process of the radius.

Extension of the elbow is mainly enabled by triceps break here alone. triceps has a little help from econia is a small muscle at the posterior side of the elbow joint. It starts from the posterior side of the lateral canal of the humerus. It crosses right over the joint to the electron in line with the insertion of triceps Now we arrive at the pronation and supination of the elbow joint. These two movements occur in the two radio only joints, the proximal and the distal one. pronation is enabled by two muscles who are named after their activity pronator terrorists and frenetic quadratus Panetta terrorists is the proximal muscle that starts from the medial conduct of humerus and the tip from the coronoid process, and it inserts at a small spot in the middle of the radial bone distally we find pronator quadratus which is a square muscle between the distal parts of both elna and radius when pronation requires a lot of strength brachioradialis helps along supination is also done by a muscle with a speaking name supinator.

This little muscle has two origins, one at the posterior side of the lateral condyle of humerus, and one at the ulna. The fibers wrap around the radius to insert at the frontal side at the same radius. biceps also has a supinating function, and when things get tough brachioradialis assists in supinating the elbow as it does when pronation gets tough. Now we will continue with the movements of the wrist, the muscles for dorsal and pharma flexion. Our first and after that we'll take a look at owner and radial deviation There are a lot of muscles that together enable dorsal flexion of the wrist. I will treat them as a group and explain details when necessary.

The same for the palm of flexion. The group of flexes can be seen as one with different accents in their specific actions due to where they insert. So about dorsal flexion. From the lateral come dial off the humerus arise several extensors. They insert at different places. The long and short radial extensors inserted metacarpals, two and three were the omo extensor ends at metacarpal five.

Then we have the extensor digitorum. That goes all the way down to the third phalanges or fingers 234 and five. We'll talk some more about this muscle in the next lecture. When we talk about fingers. flexing the wrist is also a good Action have several muscles. They arise from the medial kondal of the humerus and also from some proximal parts of the owner.

They do have different insertions for instance, radial flexor copy inserts at the basis of metacarpals, two and three and Erna flexor copy at the basis of metacarpal five. In between go the tendons of the flexor digitorum that go further down to the fingers, but assist in flexing the wrist. And so does Palmer's lumbus a muscle that ends at the palm Epona roses. Not everyone has this muscle and it is dispensable making it a good candidate for tendon surgery after hand injuries. Now for the radial and ulnar deviation, the extensors and flexors you just met have a second function depends On their insertion, inserting to the radial side of the midline through the wrist makes radial deviation possible when the muscles contract and insertion at the other side of this midline causes owner deviation. To summarize, radial deviation is done by extensive copy radiologists the long and the short head, together with flexor carpi radialis an honor deviation is possible through activity of both extensive copy on Iris and flexor copy on average.

This the end of lecture two about elbow and Bridgman. I think you are able to understand the arms quite a bit already. And in the next lecture, you will get a good idea of the movements of the fingers and thumb. I hope to see you again in the next lecture.