Fibrocartilage

White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions; to the former of these constituents it owes its flexibility and toughness, and to the latter its elasticity. It is the only type of cartilage that contains type I collagen in addition to the normal type II.

When examined under the microscope it is found to be made up of fibrous connective tissue arranged in bundles, with cartilage cells between the bundles; the cells to a certain extent resemble tendon cells or dense irregular connective tissue, but may be distinguished from them by being surrounded by a concentrically striated area of cartilage matrix, their lacunae, and by being less flattened.

Fibrocartilage is found in the pubic symphysis, meniscus, and annulus fibrosus. During labor, relaxin loosens the pubic symphesis to aid in delivery, but this can lead to later joint problems.

The white fibrocartilages admit of arrangement into four groups—interarticular, connecting, circumferential, and stratiform.