Where is Fibrocartilage Located in the Body?

The human body contains three distinct types of cartilage, each with a specific purpose. Fibrocartilage is known for its toughness and resistance to compressive forces. It is a unique hybrid tissue, combining the dense, fibrous characteristics of connective tissues like tendons with the firm, gel-like matrix of cartilage. This composition, rich in thick bundles of Type I collagen, gives it a structural resilience. Unlike the smooth, glassy hyaline cartilage that covers the ends of bones in joints or the pliable elastic cartilage of the ear, fibrocartilage provides stability in areas subject to intense pressure.

Locations in the Skeletal System

The most prominent locations of fibrocartilage are within the skeletal system, where it serves as a shock absorber and stabilizer. One primary site is in the spine, between the vertebrae. Here, it forms the annulus fibrosus, the tough outer layer of the intervertebral discs. This ring-like structure encases a softer, gel-like center, and together they cushion the spine against the forces of daily movement.

The knee joint contains two C-shaped pads of fibrocartilage called menisci. The medial and lateral menisci sit between the femur (thigh bone) and the tibia (shin bone). They are instrumental in distributing body weight across the joint, enhancing stability, and absorbing the impact that occurs during activities like running and jumping.

The pubic symphysis is the joint at the front of the pelvis, connecting its two halves. This joint is composed of a fibrocartilaginous disc that allows for very slight movement, which is important for absorbing shock during locomotion. The fibrocartilage in the pubic symphysis provides a strong yet slightly flexible connection, accommodating the transfer of forces between the lower limbs and the axial skeleton.

Locations in Other Joints

Beyond the major skeletal junctions, fibrocartilage is also present in other joints. The temporomandibular joint (TMJ), which connects the jawbone to the skull, contains a small fibrocartilaginous disc. This disc functions as a cushion between the bones, facilitating the motions for chewing and speaking, while protecting the joint surfaces from wear.

Joints connecting the clavicle (collarbone) to the skeleton also contain fibrocartilage. The sternoclavicular joint, where the clavicle meets the sternum, and the acromioclavicular joint, where it meets the shoulder blade, contain an articular disc. These pads improve the fit between the bones, absorb forces transmitted from the arm, and increase the stability of the shoulder girdle.

Function at Tendon and Ligament Insertions

A specialized location for fibrocartilage is where tendons and ligaments attach to bone. This junction is known as an enthesis. Fibrocartilage is present at these insertion points to manage the transition from flexible, elastic tissue to hard, rigid bone.

The presence of fibrocartilage creates a gradient in tissue properties, moving from the tendon or ligament, through fibrocartilage, and finally to bone. This gradual change in stiffness helps to distribute stress more evenly across the insertion site. By dissipating tensile forces from muscle contraction, this transition minimizes the risk of damage at these mechanically demanding points.