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.
A fracture is a common injury to the elbow. Elbow fractures may result from a fall onto an outstretched wrist, a direct impact to the elbow, or a twisting injury. Elbow fractures cause severe pain, swelling, tenderness, and pain with movement. If a fracture is suspected, immediate intervention by your doctor is necessary. Surgery is often required if bone displacement is observed.
Although the elbows are not weight-bearing joints, they are considered to be most important for the functioning of the upper limbs. Hence, even minor trauma or disease affecting the elbow may cause pain and limit the movements of the upper limbs. Arthritis is one of the common disease conditions affecting the elbow joint.
A biceps tear can be complete or partial. Partial biceps tendon tears will not completely break the tendon while complete tendon tears will break the tendon into two parts. Tears of the distal biceps tendon are usually complete and the muscle is separated from the bone. Tears of the distal biceps tendon most often result from a sudden injury or lifting a heavy object.
The arm in the human body is made up of three bones that join to form a hinge joint called the elbow. The upper arm bone or humerus connects from the shoulder to the elbow to form the top of the hinge joint. The lower arm or forearm consists of two bones, the radius, and the ulna. These bones connect the wrist to the elbow forming the bottom portion of the hinge joint.
Osteochondritis dissecans is a joint condition in which a piece of cartilage, along with a thin layer of bone separates because of inadequate blood supply. The separated fragments are sometimes called “joint mice”. These fragments may be localized or may detach and fall into the joint space, causing pain and joint instability.
Little league elbow, also called medial apophysitis, is an overuse condition that occurs when there is overstress or injury to the inside portion of the elbow. It is commonly seen in children involved in sports activities that require repetitive throwing such as baseball.
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.
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. They can make elbow movement such as bending or rotation difficult.
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.
The common extensor tendon is a tough band of fibrous connective tissue that attaches to the lateral epicondyle of the humerus (long bone in the upper arm) at the elbow. Rupture or tear of the common extensor tendon is the most common acute tendon injury of the elbow. The most frequent pathology of the common extensor tendon is epicondylitis and is characterized by loss of normal tendon structure.
Elbow joint replacement, also referred to as total elbow arthroplasty, is an operative procedure to treat the symptoms of arthritis that have not responded to non-surgical treatments. The goal of elbow joint replacement surgery is to eliminate your pain and increase the mobility of your elbow joint.
Coronoid fractures are a break in the coronoid process of the ulna due to trauma or injury. A coronoid fracture of the ulna is a complex intraarticular fracture that is difficult to expose due to complex surrounding anatomical structures. Fractures of the coronoid rarely occur in isolation and often occurs in association with elbow dislocations and play a significant role in elbow instability.
Ligament reconstruction is considered in patients with ligament rupture. Your surgeon will make an incision over the elbow. Care is taken to move muscles, tendons, and nerves out of the way. The donor's tendon is harvested from either the forearm or below the knee. Your surgeon drills holes into the bones of the upper arm and forearm, around the elbow joint. The donor's tendon is inserted through the drilled holes in a pattern like that of the original ligament complex.
Ligament reconstruction is considered to treat ligament rupture. Your surgeon will make an incision over the elbow. Care is taken to move muscles, tendons, and nerves out of the way. The donor's tendon is harvested from either the forearm or below the knee. Your surgeon drills holes into the bones of the upper arm and the forearm, around the elbow joint. The donor's tendon is inserted through the drilled holes in a pattern like that of the original ligament complex.
Elbow fracture reconstruction is a surgical procedure employed to repair and restore the appearance and full function of a damaged elbow caused by severe trauma or injury. This may include repairing damaged structures or replacing missing or damaged structures with adjoining skin, muscles, ligaments, tendons, bones, or nerves to restore the appearance and function.
The ulnar nerve is one of the 3 main nerves in the arm that travels down from the neck through a bony protuberance inside the elbow (medial epicondyle), under the muscles of the forearm and down the hand on the side of the palm, towards the little finger. The ulnar nerve helps in controlling most of the hand muscles which carry out fine movements as well as some bigger forearm muscles which help in making a strong grip.
A distal humerus fracture is a condition that occurs when there is a break in the lower end of the humerus bone that commonly occurs as a result of severe trauma. Fracture of the distal humerus can affect the movement and function of your arm as well as your work and activities of daily living. Distal humerus fractures are quite common and occur in individuals of all ages from children to the elderly.
Olecranon fractures are described as a break in the bony tip of the elbow that sticks out when you bend your arm. A fracture of the olecranon bone can be very painful and make motion of the elbow difficult or impossible. This kind of fracture is common and normally happens in isolation (with no other injuries involved).
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.