Elbow

The elbow is a hinge that connects the humerus bone of your upper arm and the lower arm’s two bones — the radius and ulna. It primarily bends from a straight arm (called extension) to a bent arm (called flexion). The elbow joint also allows your forearm bones to twist, enabling the hand and fingers to do a wide range of movements.

The elbow joint is formed by the interaction of three bones: the bottom of the upper arm’s humerus bone and the tops of the two forearm bones, called the radius and the ulna. Many upper and lower arm muscles either cross or attach to the elbow by tendons, allowing the joint to move. Cartilage at the ends of the interacting bones lets them slide easily against each other.

An extensive network of fibrous ligaments connect the bones together to create a “capsule” around the joint to stabilize it. The bursa is a large slippery sac of fluid that sits on the bony end of the ulna (oleocrannon), which is the pointy part of your elbow. It provides cushioning to reduce friction between the bone surface and soft tissue.

Repeated stress to the joint causes pain, soft-tissue tears to muscles, tendons and ligaments, and fractures, including:

• Sports injuries like tennis elbow and golf elbow, which also affect workers like painters, plumbers, carpenters, and others who do repetitive movements that stress the joint structures.
• Inflammation-related conditions like arthritis, tendonitis, bursitis (inflammation of the bursa), and tendonitis.

Accidental fractures can happen any time, but they increase as we get older due to osteoporosis, muscle weakness, and vision and balance problems that lead to falls.