Joints in the Human Body<br />March 14, 2010<br />By: Alex Lee<br />Science A/B<br />1125220186690<br />You use your body everyday to exercise, do homework, play games or to eat. You may not realize it but your body is an incredible machine that allows you to do all those things and more. Your body can do so many things a robot can’t and you have the ability to control it. Babies have around 300-350 bones and as they grow, the bones fuse together to make stronger bones. There are 206 bones in total in the average adult and most of them are in the hands and feet. Because of all the little bones involved in the joints, you can move your body in incredible ways. The body is also its own hospital, healing the bones by connecting back together if they are broken or fractured. <br />You use your shoulder and arm everyday to run or to high-five your friend. The shoulder joint consists of the collar bone, shoulder blade, and the upper arm bone or the clavicle, scapula, and the humerus, where the humerus connects to the scapula. The glenohumeral joint is what people refer to as the shoulder and it is the ball and socket joint. This ball and socket is made by the movement between the lateral scapula and the head of the upper arm bone. The connections between the two are also pretty loose allowing it to move 360 degrees around, up and down and the most mobile joint in the human body. Because of this loose connection it is fragile and can dislocate easier than other joints in the body. That’s why you should always take care of your arm because it does you a great service but it is pretty fragile so keep it safe!<br />The elbow lets you bend your arm up and down so you don’t have to walk around like a zombie all day long. The elbow is a hinge joint like the hinge on your door which lets it swing forward and lock straight. The elbow is formed by three bones; the humerus, radius and ulna. The radius and ulna run side by side down your arm to the wrist starting from the elbow. The forearm can also twist a little to the left and this action can occur because of the radius and the ulna. The ulna remains still while the muscles allow the radius to roll around the ulna. This is called prone position. When force is used in the elbow, very little is transferred to the humerus, most of the force is transferred through the radius and another bone in the wrist spreading the force. Next time you catch your fall with your elbows, be grateful they could bend or you’d be in the hospital with two broken arms.<br />A wrist shot is exactly what it sounds like, a wrist shot. Right before you shoot the flick the wrist to lift the puck up into the air. The wrist has many more uses than just a wrist shot like pitching, or ping-pong and other activities. It takes you less than a second to tell your wirst to bend up, down or side to side yet there are so many bones that are involved.In scientific terms, the wrist is the carpus or the carpal bones and these “bones” are what form the wrist. There are in total, eight bones that make up the skeletal part of the wrist. The actual joint is formed between the carpus and the radius from the forearm. The wrist is a sliding joint and what this means is that the wrist is made up of many smaller bones that all move together to allow the wrist to move in multiple directions, allowing it to slide. In the sliding joint, there are two other that make up the sliding joint and that is the distal radioulnar joint, the proximal radioulnar joint, the radiocarpal joints and these are made up of several other bones including the articular disk and the ulnar and the radius. So take care of your wrist and make sure none of the joints I mentioned above break or you’ll be in trouble.<br />Your hip is very important and is the joint that allows you to do many things such as gymnastics. The hip is a more noticeable ball and socket joint. Acetabulofemoral joint is the scientific name for the three letter “hip” and its main function is to hold the body up in several positions. This joint is between the femur and the surface of the pelvis on the side of your body. The cartilage that covers the two joints are a special cartilage called the articular hyaline cartilage. This cartilage is very strong because if there wasn’t any, you could not walk without screaming in pain. Also, the acetabulum, or the socket, covers almost half of the ball in the joint unlike the shoulder where they are held together loosely. Remember that the hip is also a very important joint in the body and should be taken care of.<br />If it weren’t for your knee, you’d be walking around like a penguin. Forget about being first in line at the cafeteria but because we do have a knee, we can run, jump, dance and so many more. Your knee also absorbs shock when you land by bending to absorb the force just like a cushion. Your knee is a hinge joint like that of your elbow, just a lot bigger. More specifically, the term mobile troche-ginglymus means that the knee is a pivotal hinge joint which allows the knee to not only bend forward and backward, but let’s flexion and extension and a little bit of lateral rotation. The phrase “flex your arm” can describe flexion which can be described in a situation such as bringing the hand up and close to the shoulder while extension would be the opposite, straightening the arm. Surprisingly, the knee is also the most complicated joint in the body with the movement between the femur and the tibia and the femur and the patella. You should give your knee some more credit next time you get the winning goal in a soccer game.<br />Can you imagine walking or running without your ankle joint? Well of course you can’t because the ankle naturally and obviously stays parallel automatically because of gravity but if there was no ankle joint, it be near impossible to walk up hill, stairs, to run and a whole bunch of other things. The scientific term for ankle joint is the talocrural joint and this joint is a gliding joint. This joint attaches the two distal ends of two bones called the tibia and the fibula. The tibia is bigger and stronger than the fibula which is the thinnest of the long bones in the body. The fibula is also known as the calf bone and it is on the outside of your leg while the tibia is the main bone that connects your knee to your ankle. 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