Joints and Body Movements
Laszlo Vass, Ed.D. Version 42-0014-00-01
What is the purpose of this exercise? In this exercise I will exam how joints function and thereby discover how they allow for movement in the body. Joints are where two bones come together. The joints hold the bones together and allow for movement of the skeleton. All of the bones, except the hyoid bone in the neck, form a joint. Joints are often categorized by the amount of motion they allow. Some of the joints are fixed, like those in the skull, allow for no movement. Other joints, like those between the vertebrae of the spine, allow for some movement. Most of the joints are free moving synovial joints. In this exercise I will exam how joints function and thereby discover how they allow for movement in the body. Are there any safety concerns associated with this exercise? If so, list what they are and what precautions should be taken. Basic lab precautions, including keep a clean workspace and washing your hand when dealing with raw poultry. In order to ensure that this occurs layout the equipment beforehand in a clean sterile environment and follow safe work practices.
Exercise 1: Questions
A. As you observe the skull, explain how the structure of the sutures between the cranial bones is related to the overall function of the cranium. Children’s heads needs to squeeze through the birth canal during delivery, humans during infancy have evolved with a soft skull composed of many different bony plates that meet at regions called cranial "sutures". These sutures also allow the skull to grow rapidly during the first year of life, at which time the bones start to slowly fuse together. This allows the skull to continue to protect the skull during early development.
B. Why are synarthroses an important component of fibrous joints? These joints are weight bearing and the joints provide stability and cushioning. Synarthrotic joint is to provide a stable union between bony surfaces. The suture and synchondrosis actually become more stable when ossification of the joint takes place.
Exercise 2: Questions
A. Cartilaginous joints exhibit amphiarthroses. Why is this important? Amphiarthroses provides an articulation between bony surfaces that permits limited motion and is connected by ligaments or elastic cartilage, such as that between the vertebrae.
B. Structurally, how are cartilaginous joints similar?
Cartilaginous joints are connected entirely by cartilage. Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. Cartilaginous joints also form the growth regions of immature long bones and the intervertebral discs of the spinal column.
Exercise 3: Questions
A. Which type of synovial joint has the least amount of movement? Plane joints permit sliding or gliding movements in the plane of articular surfaces. The opposed surfaces of the bones are flat or almost fat, with movement limited by their tight joint capsules.
B. Why are diarthroses important for synovial joints? Diarthrosis permits a variety of movements. All diarthrosis joints are synovial joints and the terms diarthrosis and synovial joint are considered equivalent.
C. Which synovial joint is most movable? A ball and socket joint is a joint in which the distal bone is capable of motion around an indefinite number of axes, which have one common center. It enables the bone to move in a 360° angle.
D. What are the four structural characteristics that all synovial joints share? Synovial joints all have synovial fluid, articular cartilage, articular capsule, synovial membrane, capsular ligaments, blood vessels, and sensory nerves.
Exercise 4: Questions
A. Which of the body movements was the most difficult to perform? Why? Inversion which is a gliding joint and provides little...
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