Bend 90 degrees at the elbow.

The elbow joint, a complex and essential part of the human body, is a marvel of engineering and design. It is a hinge joint that allows for a wide range of motion in multiple directions, making it crucial for activities such as lifting, reaching, and twisting. The elbow's structure is composed of bones, ligaments, tendons, and muscles, all working together to create a stable yet flexible connection between the upper arm and forearm. One of the most significant features of the elbow joint is its ability to rotate. This rotation is facilitated by the trochlea, a concave surface on the humerus bone, which fits into the semilunar notch of the ulna bone. When the forearm is rotated, the radius bone also rotates around the ulna, allowing for a full range of motion. Another important aspect of the elbow joint is its stability. This stability is maintained by several ligaments, including the ulnar collateral ligament and the radial collateral ligament. These ligaments help to prevent excessive movement and provide support to the joint These ligaments help to prevent excessive movement and provide support to the joint These ligaments help to prevent excessive movement and provide support to the joint These ligaments help to prevent excessive movement and provide support to the joint1 4 90 degree elbow. The elbow joint is also prone to injury, particularly from sports or repetitive movements. Common injuries include sprains, strains, and fractures. To prevent these injuries, it is important to maintain good posture and use proper technique when performing activities that involve the elbow. In conclusion, the elbow joint is a complex and vital part of the human body. Its unique design allows for a wide range of motion while maintaining stability, making it essential for many daily activities. By understanding the anatomy and function of the elbow joint, we can better appreciate its importance and take steps to keep it healthy and strong.