The elbow is primarily a hinge-type joint whose function is to help us position our hand in space. When we flex our elbow it brings our hand towards our mouth and when it extends our hand moves away from our mouth.
There are three bones of the elbow. One is the humerus, or the upper arm bone. The other two bones make up the forearm. The ulna is the bone that is more towards our body when we have our arms at our side and the palms facing forward. It is attached to the side of the hand with the small finger on it. Finally, there is the radius which is the bone that is away from our body when we have our arms at our side and palms facing forward. It attaches to the side of our hand where the thumb is. This bone rotates around the ulna which allows us to turn our palms up or palms down.
Although the bones of the elbow joint interlock tightly they require the assistance of ligaments to hold them together. Ligaments are soft tissue structures that attach bones to bones, typically helping to stabilize a joint. There are two main ligaments of the elbow. The medial, or ulnar collateral ligament attaches to the bump, known as an epicondyle, on the medial, or inner part of our elbow that is close to our body and inserts on the upper part of the ulna. The lateral, or radial collateral ligament attaches to the bump on the lateral, or outer part of our elbow that is away from our body and inserts on the upper radius and ulna. These ligaments help to prevent our elbow from hinging side to side and can be injured in a fall. The ulnar collateral ligament can also be stretched over time from repetitive throwing such as occurs in baseball pitchers.
Tendons attach muscles to bone and allow our muscles to move our joints. There are two major tendons around our elbow. The biceps tendon is in the front of the elbow. You can feel this cord like structure if you place one hand on the front of your opposite elbow and then flex, or bend this elbow while keeping your palm up. The triceps tendon is on the back of the elbow and extends, or straightens the elbow.
The major muscles around the elbow include the biceps and triceps. The biceps is on the front of the upper arm and not only flexes, or bends the elbow but also helps to turn our palms up. The triceps is located on the back of the elbow and extends or straightens our arms. Most of the muscles that flex our fingers and wrist when we make a fist insert on the inner bump, or medial epicondyle, of the elbow. The muscles that straighten the fingers and wrist insert on the outer bump, or lateral epicondyle.
The nerves around the elbow are very close to the skin. The ulna nerve is behind the medial epicondyle and we are aware of it when we hit our “funny-bone”. The median nerve is in front of the elbow and the radial nerve is on the back, or posterior and lateral aspect of the elbow.
The major blood vessel around the elbow is the brachial artery. It is located on the front of the elbow. It then splits and becomes the radial and ulna arteries to our hand.