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 assists in lifting or moving objects.
The bones of the elbow are supported by
- Ligaments and tendons
- Blood vessels
Bones and Joints of the elbow joint:
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. The curved shape of the ulna 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 connection between the ulna and radius helps the forearm to rotate.
The elbow consists of three joints from articulation of the three bones namely:
- Humeroulnar joint is formed between the humerus and ulna and allows flexion and extension of the arm.
- Humeroradial joint is formed between the radius and humerus and allows movements like flexion, extension, supination and pronation.
- Radioulnar joint is formed between 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 by 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: this muscle extends from the humeral head, across the elbow, and towards the ulna, and helps to turn the palm facing backwards
- Extensor carpi radialis brevis: forearm muscle that helps in the movement of the hand
- Extensor digitorum: forearm muscle that helps in the movement of the fingers
Elbow joint ligaments and tendons:
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.
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.
- Annular ligament: These are a group of fibres that surrounds the radial head, and holds the ulna and radius 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 fibres that connect muscle to bone. The various tendons which 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 joint:
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 the sensory signals like touch, pain, and temperature back to the brain.
Any injury or damage to these nerves causes pain, weakness or joint instability.
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 biceps muscle, located in the front of the upper arm allows you to bend the elbow and rotate the arm. Biceps tendons attach the biceps muscle to the bones in the shoulder and in the elbow.
The biceps muscle is located in front of your upper arm. It helps in bending your elbow, rotational movements of your forearm and in maintaining stability in the shoulder joint. The biceps muscle has two tendons, one of which attaches it to the bone in the shoulder and the other attaches at the elbow. The biceps tendon at the elbow is called the distal biceps tendon.
The elbow is a hinge joint made up of 3 bones – humerus, radius and ulna. The bones are held together by ligaments to provide stability to the joint. Muscles and tendons move the bones around each other and help in performing various activities. Elbow dislocation occurs when the bones that make up the joint are forced out of alignment.
An athlete uses an overhand throw to achieve greater speed and distance. Repeated throwing in sports such as baseball and basketball can place a lot of stress on the joints of the arm, and lead to weakening and ultimately, injury to the structures in the elbow.
The elbow contains a large, curved, pointy bone at the back called the olecranon, which is covered by the olecranon bursa, a small fluid-filled sac that allows smooth movement between the bone and overlying skin. Inflammation of this bursa leads to a condition called olecranon bursitis.
The ulnar nerve travels down the back of the elbow behind the bony bump called the medial epicondyle, and through a passageway called the cubital tunnel. The cubital tunnel is a narrow passageway on the inside of the elbow formed by bone, muscle, and ligaments with the ulnar nerve passing through its centre. The roof of the cubital tunnel is covered with a soft tissue called fascia.
Osteochondritis dissecans is a joint condition in which a piece of cartilage, along with a thin layer of the bone separates from the end of the bone 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.
Cubital Tunnel Syndrome is a condition characterized by compression of the ulnar nerve in an area of the elbow called the cubital tunnel.
Tennis elbow is the common name used for the elbow condition called lateral epicondylitis. It is an overuse injury that causes inflammation of the tendons that attach to the bony prominence on the outside of the elbow (lateral epicondyle). It is a painful condition occurring from repeated muscle contractions at the forearm that leads to inflammation and micro-tears in the tendons that attach to the lateral epicondyle.
Golfer's elbow, also called Medial Epicondylitis, is a painful condition occurring from repeated muscle contractions in the forearm that leads to inflammation and microtears in the tendons that attach to the medial epicondyle. The medial epicondyle is the bony prominence that is felt on the inside of the elbow.
The elbow is formed by the junction of the humerus (upper arm bone), and radius and ulna (forearm bones). These three bones articulate to form the elbow joint, which is held and supported by muscles and strong ligaments called the lateral ligament (on the outer side) and ulnar collateral ligament (on the inner side). Injury to these ligaments causes elbow instability and dislocation of the joint.
The forearm is made up of 2 bones, namely, the radius and ulna. The primary function of your forearm is rotation i.e., the ability to turn your palm up and down. The fracture of the forearm affects the ability to rotate your arm, as well as bend and straighten the wrist and elbow.
The radius (bone on the thumb side) and ulna (bone on the little-finger side) are the two bones of the forearm. Forearm fractures can occur near the wrist, near the elbow or in the middle of the forearm. Apart from this, the bones in children are prone to a unique injury known as a growth plate fracture.
The elbow is a region between the upper arm and the forearm. The elbow joint is made up of 3 bones. The distal (lower) end of the humerus bone in the upper arm joins with the radius and ulna bones in the forearm to form the elbow joint. The elbow joint is very important for the movement of your arms and for coordination of daily activities. Injury in the distal humerus can cause impairment in the function of the elbow joint.
Three bones, the humerus, radius and ulna, make up the elbow joint. Elbow fractures may occur from trauma, resulting from various reasons; some of them being a fall on an outstretched arm, a direct blow to the elbow, or an abnormal twist to the joint beyond its functional limit.
The elbow is a junction between the forearm and the upper arm. The elbow joint is made up of 3 bones namely the humerus bone in the upper arm which joins with the radius and ulna bones in the forearm. The elbow joint is essential for the movement of your arms and to perform daily activities. The head of the radius bone is cup-shaped and corresponds to the spherical surface of the humerus.
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 biceps muscle is located in front of your upper arm. It helps in bending your elbow as well as in rotational movements of your forearm. Also, it helps to maintain stability in the shoulder joint. The biceps muscle has two tendons, one of which attaches it to the bone in the shoulder and the other attaches at the elbow.
Elbow arthroscopy, also referred to as keyhole or minimally invasive surgery is performed through tiny incisions to evaluate and treat several elbow conditions.