A small, often microscopic, tissue element in the form of a small beam, strut or rod, generally having a mechanical function, and usually but not necessarily composed of dense collagenous tissue. On histological section, a trabecula can look like a septum, but in three dimensions they are topologically distinct, with trabeculae being roughly rod or pillar-shaped and septa being sheet-like. Trabeculae are usually composed of dense fibrous tissue, i.e. mainly of collagen, and in most cases provide mechanical strengthening or stiffening to a soft solid organ, such as the spleen. They can be composed of other materials, such as bone or muscle[WP].