How do joints work? Detailed answer

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How do joints work? Detailed answer

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How do joints work?

If we didn't have joints, it would be impossible to live the way we live. We could only be in a lying position, we would not be able to move our head, legs, hands, we would not be able to move even one finger! The ability to move naturally exists thanks to the joints. Joints are in the movable joints of bones, allowing them to move relative to each other. Joints allow bones to move smoothly with very little friction.

Joints are connections between bones. The bones at the joints are covered with cartilage in such a way that friction between the bones is minimal. In addition, a whitish liquid resembling egg white is hidden in the joint. It's called synovial fluid and acts like oil in a car, reducing friction. When the joint is at rest, very little synovial fluid is produced, and the joint creaks as it moves.

There are 4 most important types of joints in humans. One of them is the ball joint. This is the shoulder joint. It is of great importance to us. With the help of the shoulder joint, we move the arm. The hip joint is the largest ball-and-socket joint. But this joint is very tight, and therefore the range of motion is limited. The second type of joint is the elliptical joint. In such a joint, the ovoid bulge corresponds to an ellipsoidal notch. The wrist joint, for example, is of this kind. It allows you to make oval movements better than circular ones.

A variation of this joint is the saddle joint, in which the bones can only move in two directions: back and forth and side to side. The third type of joint is the block joint. The bones of this joint can move "back and forth" in one direction. This joint is like a door or a jackknife. The joints between the bones of our fingers are blocky.

The last type of joint is cylindrical. Cylindrical joints allow the bones to rotate laterally. They are located at the base of the skull, so we can rotate our heads. With the help of the joints located in the elbows, it is possible, for example, to rotate the key in the lock.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

How would you fly through the asteroid belt?

They would look at both, but they would hardly have encountered at least something.

Contrary to what you've seen in bad sci-fi movies, asteroid belts are, for the most part, pretty deserted. Lively compared to the rest of space, but still deserted.

Generally speaking, the gap between large asteroids (capable of causing significant damage to a spacecraft) is approximately two million kilometers.

And although there are whole groups of asteroids called "families" - these are those that formed relatively recently from a larger celestial body - maneuvering inside the asteroid belt is not at all difficult. In fact, if you choose a completely random course and at the same time encounter at least one asteroid, you can consider yourself very lucky.

But if this happens, you will certainly want to give this asteroid a name.

To date, the International Astronomical Union has a special Committee on the Nomenclature of Small Celestial Bodies, consisting of fifteen members, responsible for overseeing the naming of the steadily expanding state of minor planets. As recent examples show, this is not at all such a serious occupation. Judge for yourself:

(15887) Daveclarke, (14965) Bonk, (18932) Robinhood, (69961) Milosevic, (2829) Bobbop, (7328) Seanconnery, (5762) Wenkee, (453) Tea, (3904) Honda, (17627) Humptybolt, (9941) Iguanodon, (9949) Brontosaurus, (9778) Isabellalende, (4479) Charlieparker, (9007) James Bond, (39415) Janestin, (11548) Jerry-Lewis, (19367) Pink Floyd, (5878) Charlene, ( 6042) Cheshire Cat, (4735) Gary, (3742) Sunshine, (17458) Dick, (1629) Pecker and (821) Fanny. (Bonk - "fuck" (in the most interesting sense of the word) wanky - "masturbate" Dick - in English both a male name and a "dick" pecker - "beak" and, again, "penis" fanny - " female ass" (if not worse).)

Smith, Jones, Brown, and Robinson are all official asteroid names, as are Bikki, Bass, Bok, Lick, Qui, Hippo, Mister Spock, Roddenberry, and Suissair.

Eccentricity in naming planets is nothing new. For example, Pluto was named Pluto in 1930 by an eleven-year-old schoolgirl from Oxford named Venetia Burney: her grandfather, then a librarian at Oxford University, passed the suggestion made by his granddaughter at breakfast to his good friend Herbert Hall Turner, Oxford professor of astronomy.

Perhaps 2003 UB313 will eventually be renamed Rupert, the name given by Douglas Adams to the tenth planet in the solar system in his book The Hitchhiker's Guide to the Galaxy. It didn't happen either. Literally a day before the sudden death of Adams in 2001, another asteroid was named (18610) Arthur Dent. And now Adams has his own celestial body: (25924) Douglasadams.

Test your knowledge! Did you know...

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copper display 01.06.2008

Materials scientists from Illinois came up with a simple technology for growing copper nanowires. No matter how much they said that carbon nanotubes would become the very material that would make it possible to create a flat and bright display, however, for some reason, things would never come to practice.

In the meantime, materials scientists are improving the technology for producing metal whiskers - the thinnest crystals, the forest of which can be grown on a substrate. In particular, scientists from the University of Illinois, led by Professor Kekyen Kim, have learned how to grow forests from copper wires with a diameter of 70 to 250 nm.

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