Hi, and welcome back to this third and last lecture of section three. We are going to explore the hand as promised. movements of the hand are always a combination of actions in the wrist fingers and some will start with a movement of the fingers, digits 234 and five, you can flex and extend your fingers and spread and cleanse them. When you extend your fingers, they use extensor digitorum. This muscle was mentioned earlier because it assists in extension of the wrist. But it's insertions go all the way to the third phalanges of the fingers.

And when it contracts, all three finger joints extend. The insertion is an ingenious network where part of the tendon attaches on one phalanx and the rest of the tendon moves on to the next failings, and then again on to the third failings. So all phalanges have an insertion of their own and still are part of one Extension System, the dorsal upon neuroses of the fingers and for some reason, there is an extra extensor just for the index finger vellum that arises separately from the distal third of the ulna and the membrane in between the forearm wounds. It inserts at the third phalanx together with extensor digitorum. flexing the fingers happens when flexor digitorum contracts there are two flexes the superficial and the profoundness superficial is arises from here and profound us from here. The superficial inserts at the second phalanges of the fingers and can flex on The MCP and PIP fundus.

However, inserts at the third phalanges and is the only muscle to enable flexion in the D. Another flexor other lumbar calls. They are called intrinsic hand muscles because they have their origin and insertion within the hand so they don't start at the forearm. There are four of them. They start here from the tendons of the deep flexor and these are the insertions. The function is flexing the MCP, but only was extended fingers like this. Now let's take a look at spreading and closing of the fingers.

The midline in these movements is always digit three. The dorsal interesti rise from the metacarpals as you can see here They all insert at the proximal phalanges. You can see that digit three has one insertion at the medial side and one at the lateral side. When all interest a are active, digit three is not moving to either side. But when using them separately, digit three can abduct and adapt through means of the interest 82 and three. On the power side, there are the Palmer interval say they arise from the metacarpals as well and they to insert at the proximal phalanges, but when active, they close the fingers towards digit three.

Now we have reached to some very important digit is able to make a lot Have movements that make it possible to grab and hold on to things. Try imagining having a cup of coffee without the use of your thumb. We could distinguish all movements in the finest details. But in daily life, we see that extension and abduction go together and flexion and adduction are combined. I will discuss them as such. First extension and abduction.

There are long and the short extensor and the long and short abductor that regulate the arm movements. You see them here. Three of them arise from halfway the forearm both owner radius and the membrane in between. At the dorsal side. They insert at different places namely extensor pollicis longus, inserts at the distal phalanx, enabling extension in the IP joint. Extensive policies brave is at proximal phalanx, enabling extension in MCP one and the abductor policies longest inserts at the basis of metacarpal.

One, enabling abduction in CMC one. In life, you can see all three tendons under the skin in a row. The fourth muscle here is the short abductor that is one of the center muscles. The center is the ball off the hand at the thumb side. You see it here and it enables abduction in CMC one. flexion happens mostly in combination with adduction.

We are going to explore the muscles that regulate this movement. Again, there is a long and a short flexor and one adductor flexor pollicis longus has its origin here, a large surface in the middle of the forearm at the Palmer side, and inserts at the distal phalanx, causing flexion in all joints of the thumb, both CMC MCP and IP. The other two are part of the center, flexor pollicis, bravest and adaptive policies flexure policies brief is inserts at the basis of failings one, thus flexing the MCP one and Dr policies has two parts. The transfers part starts at metacarpal. Three and inserts at the basis of feelings one and the oblique part inserts right next to the transfers part at failings one. Together these transfers and oblique parts adopted the thumb.

You can see that the short flexure and the adductor are close neighbors. So you will understand the combination effective tivity we have one movement left opposition. A small muscle in the center is leading, but the center muscles abductor and flexes are assisting. Opponents policies start at the carpal bone called scaphoid. And inserts in the middle of metacarpal. One.

Opposition is a movement of the CMC one joint. We're almost done. There are two things left to mention. Center and hyper center. Center is the radial ball of the hand, where the short intrinsic muscles are. They arise of the polymer, upper neuroses and all kinds of spots on carpal bones, too much to discuss and unnecessary for understanding their function.

But there is hypothermia as well. This is the owner ball of the hand. It has Little muscles that helped moving the fifth digit. I will present them to you and then we're done. First we see a small flexor ending at the basis of metacarpal five, flexing the MCP. Then we see the abductor ending at the same spot, but more to the lateral side to abduct or spread the little pinky.

It could have been named a dorsal interosseous actually. The third one is the opponent's it opposes the pinkie starting at the carpal boom called Amato's and ending along metacarpal five. The last one is Parmar is brave is which is not really enabling any movement. So I will leave it out of this lecture. Now that you have ended this lecture, you have a good understanding of how the upper extremity act and I hope you have enjoyed this section. Section four will be about the muscles of the lower extremity.

I hope to see you there