In simple terms, a joint is an area of the body where two or more bones are joined together using a network of muscles, tendons, ligaments, and cartilage. Muscles are attached to bones with tendons (flexible, fibrous cords of tissue). Muscles create movement in the joint, and they also help stabilize the joint. Smooth articular cartilage encases the bones in the joint and helps promote friction-free movement, while pads of cartilage help absorb shock. Ligaments are tough bands of fibrous tissues that bind the joint together. The entire joint is surrounded by a sheath or a glove of strong fibrous material called the joint capsule. The synovial lining of the joint capsule secretes tiny amounts of fluid that lubricate the joint. In addition, some joints (such as in the shoulder and the knee) are supplemented by bursa sacs (bursae), little fluid-filled sacs that help cushion the joint and reduce friction.
The human body has many different kinds of joints from simple a hinge joint such as the elbow to very complex joints such as the hip and shoulders which can move in many different directions. In addition, some joints must be able to withstand tremendous weights and forces; the knee, for example, must support the weight of the entire body as it moves through space. Furthermore, pressure on the knee is magnified when you run, climb stairs, or walk on an uneven surface.
No comments:
Post a Comment