The elbow is a complex joint formed by the articulation of three bones – the humerus, radius, and ulna. The elbow joint helps in bending or straightening of the arm to 180 degrees and lifting or moving objects.
The bones of the elbow are supported by:
- Ligaments and tendons
- Blood vessels
Bones and Joints of the Elbow
The elbow joint is formed at the junction of three bones:
- The humerus (upper arm bone) forms the upper portion of the joint. The lower end of the humerus divides into two bony protrusions known as the medial and lateral epicondyles, which can be felt on either side of the elbow joint.
- The ulna is the larger bone of the forearm located on the inner surface of the joint. It articulates with the humerus.
- The radius is the smaller bone of the forearm situated on the outer surface of the joint. The head of the radius is circular and hollow, which allows movement with the humerus. The articulation between the ulna and radius helps the forearm to rotate.
The elbow consists of three joints, namely:
- The humeroulnar joint is formed between the humerus and ulna and allows flexion and extension of the arm.
- The humeroradial joint is formed between the radius and humerus and allows movements like flexion, extension, supination, and pronation.
- The radioulnar joint is formed between the ulna and radius bones and allows rotation of the lower arm.
Articular cartilage lines the articulating regions of the humerus, radius, and ulna. It is a thin, tough, flexible and slippery surface that acts as a shock absorber and cushion to reduce friction between the bones. The cartilage is lubricated with synovial fluid, which further enables the smooth movement of the bones.
Muscles of the Elbow Joint
There are several muscles extending across the elbow joint that help in various movements. These include the following:
- Biceps brachii: Upper arm muscle, enabling flexion of the arm
- Triceps brachii: Muscle in the back of the upper arm that extends the arm and fixes the elbow during fine movements
- Brachialis: Upper arm muscle beneath the biceps, which flexes the elbow towards the body
- Brachioradialis: Forearm muscle that flexes, straightens and pulls the arm at the elbow
- Pronator teres: Muscle that extends from the humeral head, across the elbow, and towards the ulna, and helps to turn the palm facing backward
- Extensor carpi radialis brevis: Forearm muscle that helps in movement of the hand
- Extensor digitorum: Forearm muscle that helps in movement of the fingers
Ligaments and Tendons of the Elbow
The elbow joint is supported by ligaments and tendons, which provide stability to the joint.
Ligaments are a group of firm tissues that connect bones to other bones. The most important ligaments of the elbow joint are the:
- Medial or ulnar collateral ligament: Comprised of triangular bands of tissue on the inner side of the elbow joint
- Lateral or radial collateral ligament: A thin band of tissue on the outer side of the elbow joint
- Annular ligament: Group of fibers that surround the radial head, and hold the ulna and radius tightly in place during movement of the arm
Together, the medial and lateral ligaments are the main source of stability and hold the humerus and ulna tightly in place during movement of the arm.
The ligaments around a joint combine to form a joint capsule that contains synovial fluid.
Any injury to these ligaments can lead to instability of the elbow joint.
Tendons are bands of connective tissue fibers that connect muscle to bone. The various tendons that surround the elbow joint include:
- Biceps tendon: attaches the biceps muscle to the radius, allowing the elbow to bend
- Triceps tendon: attaches the triceps muscle to the ulna, allowing the elbow to straighten
Nerves of the Elbow
The main nerves of the elbow joint are the ulnar, radial and median nerves. These nerves transfer signals from the brain to the muscles that aid in elbow movements. They also carry sensory signals such as touch, pain, and temperature back to the brain.
Any injury or damage to these nerves causes pain, weakness or joint instability.
Blood Vessels Supplying the Elbow
Arteries are blood vessels that carry oxygen-pure blood from the heart to the hand. The main artery of the elbow is the brachial artery that travels across the inside of the elbow and divides into two small branches below the elbow to form the ulnar and the radial artery.
The elbow is a complex joint of the upper limb, formed by the articulation of the long bone of the upper arm or humerus, and the two bones of the forearm - the radius and ulna. It is one of the important joints of the upper limb and is involved in basic movements such as bending and extending the arm and rotating the forearm.
Hyperextension injury of the elbow occurs when the elbow joint is bent beyond its normal range of motion, causing damage to the bones and ligaments of the elbow. It may also cause elbow dislocation. The condition is more common in tennis, football, weight-lifting and contact sports.
Your elbow is a joint made up of three bones held together by muscles, ligaments, tendons, and cartilage. It is both a hinge and pivot joint allowing you to bend and rotate your elbow freely. Loose bodies in your elbow are small pieces of bone or cartilage that have broken off and are lying or floating free within the joint.
Radial head fractures are very common and occur in almost 20% of acute elbow injuries. Elbow dislocations are generally associated with radial head fractures. Radial head fractures are more common in women than in men and occur more frequently in the age group of 30 to 40 years.
UCL repair with an internal brace is a surgery that involves the use of collagen-coated tape (internal brace) surgically placed at the site of the damaged UCL ligaments. It provides better resistant and a faster recovery compared to traditional reconstruction surgery that involves the use of graft tissue from your body.
Golfer's elbow is a condition associated with pain on the inside of the elbow where tendons of your forearm attach to the bony prominence (medial epicondyle). It is also called medial epicondylitis and is caused by injury or irritation to the tendons which can become painful and swollen.
The biceps is a large muscle located in the front of your upper arm and runs from the shoulder to the elbow joint. It is attached to the bones of the shoulder and elbow by tendons. The distal biceps is the area where the biceps is attached to the forearm bone in the elbow.