Skeletal system: Difference between revisions

The '''skeletal system''' has many different functions that are neccesary for vertebrates to survive. It provides support for the overall body. It offers a place for muscle and tendons to attach. It provides a great amount of protection for the vital organs inside of the creature. Movement is also helped by the skeletal system, which adds leverage for increased range of motion. And finally, the bones of the skeletal system continuously produce blood cells.

The ball and socket joint allows for increased range of movement. The best examples of this type of joint are the shoulder and hip joints. Even though the shoulder is considered a ball and socket joint, the hip is considered the most "true" ball and socket joint because the ball is almost completely enclosed by the socket. The shoulder is more like a ball resting inside of a shallow dip, rather than being fully encompassed. This does, however, offer increased movability and range, at the cost of being easier to pop out of joint or being injured. Shoulder problems are very common because of this joint structure. In fact, 13.7 people in the United States had treatment for shoulder-related problems in 2003.[http://www.pueblo.gsa.gov/cic_text/health/shoulderqa/shoulderqa.htm]

The glide joint is similar to the ball and socket joint in terms of the range of movement, but there is no actual ball and socket. An excellent example of this is a person's wrist, which has extreme movability but no bulky ball and socket like the shoulder. Glide joints are also very delicate, and can be easily damaged. They are also very weak, and cannot apply very much  force by themselves. For example, try lifting a 30 lb weight with your whole arm, and then try lifting the same weight using just your wrist. Gliding joints are useful, but lack a lot of support that allows other joints to apply more force.