Bones and joints
The bones of the elbow are the humerus (the upper arm bone), the ulna (the larger bone of the forearm, on the opposite side of the thumb), and the radius (the smaller bone of the forearm on the same side as there is a second joint where the end of the radius (the radial head) meets the humerus. the thumb). radius has to rotate so that you can turn your hand palm up and palm down. At the same time, it has to slide against the end of the humerus as the elbow bends and straightens.
Articular cartilage is white, shiny, and has a rubbery consistency. It is slippery, which allows the joint surfaces to slide against one another without causing any damage.
The function of articular cartilage is to absorb shock and provide an extremely smooth surface to make motion easier. In the elbow, articular cartilage covers the end of the humerus, the end of the radius, and the end of the ulna.
There are several important ligaments in the elbow. Ligaments are soft tissue structures that connect bones to bones. In the elbow, two of the most important ligaments are the medial collateral ligament and the lateral collateral ligament. The medial collateral is on the inside edge of the elbow, and the lateral collateral is on the outside edge. Together these two ligaments connect the humerus to the ulna and keep it tightly in place as it slides through the groove at the end of the humerus. These ligaments are the main source of stability for the elbow. They can be torn when there is an injury or dislocation to the elbow. If they do not heal correctly the elbow can be too loose, or unstable
The ligaments around a joint usually combine together to form a joint capsule. A joint capsule is a watertight sac that surrounds a joint and contains lubricating fluid called synovial fluid. annular ligament that wraps around the radial head and holds it tight against the ulna. The word annular means ring shaped, and the annular ligament forms a ring around the radial head as it holds it in place.
The biceps tendon attaches the large biceps muscle on the front of the arm to the radius. It allows the elbow to bend with force. You can feel this tendon crossing the front crease of the elbow when you tighten the biceps muscle.
The triceps tendon connects the large triceps muscle on the back of the arm with the ulna. It allows the elbow to straighten with force, such as when you perform a push-ups.
As you can see, the elbow is more than a simple hinge. It is designed to provide maximum stability as we position our forearm to use our hand. When you realize all the different ways we use our hands every day and all the different positions we put our hands in, it is easy to understand how hard daily life can be when the elbow doesn't work well.