Elbow

The elbow is more than a simple hinge. It is designed to provide maximum stability as we position our forearm to use our hand. If the elbow is not functioning well, daily life can be very difficult as our use of the hands is severely limited.

Anatomy of the Elbow

The elbow is made up of the following structures:

• Bones and joints,
• Ligaments and tendons,
• Muscles,
• Nerves, and
• Blood vessels

Bones and Joints

The elbow itself is essentially a hinge joint, meaning it bends and straightens like a hinge. The bones of the elbow are the humerus , the ulna and the radius.

There is a second joint where the end of the radius meets the humerus. This joint is complicated because the 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.

The joint is even more complex because the radius has to slide against the ulna as it rotates the wrist as well. As a result, the end of the radius at the elbow is shaped like a smooth knob with a cup at the end to fit on the end of the humerus.

Articular cartilage is the material that covers the ends of the bones of any joint. Articular cartilage can be up to one-quarter of an inch thick in the large, weight-bearing joints.Its function is to absorb shock and provide an extremely smooth surface to make motion easier.

Ligaments

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. They 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.

Muscles and Tendons

The main muscles in the elbow are the biceps, the triceps, the wrist extensors and the wrist flexors

There are several important tendons around the elbow. 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.

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-up.

Nerves

Three main nerves begin together at the shoulder: the radial nerve, the ulnar nerve, and the median nerve.

These nerves carry signals from the brain to the muscles that move the arm. The nerves also carry signals back to the brain about sensations such as touch, pain, and temperature.

Blood Vessels

The largest artery in the elbow is the brachial artery that travels across the front crease of the elbow. If you place your hand in the bend of your elbow, you may be able to feel the pulsing of this large artery.

The brachial artery splits into two branches just below the elbow: the ulnar artery and the radial artery that continue into the hand. Damage to the brachial artery can be very serious because it is the only blood supply to the hand.

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