Cartilage is present in the wrist and is fundamental to the joint’s structure and function. This specialized connective tissue is strong yet flexible, serving to protect bone endings and facilitate movement throughout the body. The wrist is a highly complex joint made up of many small bones, relying heavily on this tissue for its stability and vast range of motion. Understanding the different types of cartilage in the wrist helps explain how this joint moves efficiently and what happens when it is injured.
The Presence and Types of Wrist Cartilage
The wrist complex contains two primary types of cartilage, each situated in specific anatomical locations. Articular cartilage, also known as hyaline cartilage, coats the ends of the bones where they meet to form a joint, including the ends of the radius and ulna, and all eight carpal bones. This tissue is typically white, shiny, and rubbery, though it is thinner compared to the cartilage in large weight-bearing joints like the knee.
The second major type is fibrocartilage, which forms the Triangular Fibrocartilage Complex (TFCC). The TFCC is located on the ulnar side of the wrist, acting as a soft tissue attachment that covers the end of the ulna bone. This complex includes a disc-like structure that articulates between the distal ulna and two small wrist bones, the lunate and triquetrum. The central portion of the TFCC is typically thin and has a poor blood supply, which impacts its ability to heal after injury.
How Wrist Cartilage Enables Movement
Articular cartilage permits the remarkably smooth and extensive movements of the hand and forearm. Its smooth, lubricated surface significantly reduces friction between the articulating bones, allowing them to glide past one another without causing damage. This low-friction environment is necessary for the wrist to perform actions like flexion, extension, and side-to-side movements.
The cartilage also functions as a shock absorber, helping to distribute pressure across the joint surfaces when the wrist is subjected to forces. The TFCC, in particular, plays a substantial role in this capacity, transmitting approximately 20% of the axial load from the hand and carpus to the ulna. It also acts as a primary stabilizer of the distal radioulnar joint, the connection between the two forearm bones, ensuring stability during rotational movements of the forearm.
Common Issues Related to Wrist Cartilage Damage
Damage to the cartilage in the wrist can occur due to acute trauma, such as falling onto an outstretched hand, or as a result of degenerative processes over time. Traumatic injuries frequently affect the Triangular Fibrocartilage Complex, leading to a TFCC tear. A tear in this complex can result in instability, pain on the pinky-finger side of the wrist, and a noticeable clicking or popping sensation with movement.
Degenerative conditions, like osteoarthritis, involve the gradual breakdown of the articular cartilage that covers the bone ends. This erosion causes the normally smooth surfaces to become rough, increasing friction and leading to pain, swelling, and a diminished range of motion. The loss of this cushioning layer means the bones are less protected, which can lead to long-term joint damage.
Symptoms of cartilage damage often include pain that worsens with gripping, twisting motions, or weight-bearing activities, and a reduction in grip strength. Because cartilage has a limited capacity for self-repair, especially in the central, avascular areas of the TFCC, these injuries often require careful management to prevent ongoing symptoms and instability.