Fibrae

Fibrae is the plural form of fibra, a Latin word meaning fiber or filament. In scientific usage, fibrae denotes slender, threadlike elements that compose or support larger structures. The term appears in anatomical, histological, and botanical Latin terminology and is preserved in some traditional or Latinized names and descriptions.

In anatomy and histology, fibrae commonly refer to filaments such as nerve fibers (fibrae nervorum) and muscle fibers (fibrae musculares), as well as connective tissue components like elastic fibers (fibrae elasticae) and reticular fibers (fibrae reticulares). These filaments can be microscopic or submicroscopic and play roles in signal transmission, force generation, and the mechanical properties of tissues. In neuroanatomy, fibrae may describe individual axons or bundles of axons within a nerve or tract.

In botany and plant anatomy, fibrae describe long, filamentous plant cells that provide structural support and transport functions, including sclerenchyma fibers and phloem fibers. Such fibers contribute to the stiffness and integrity of stems, roots, and other organs.

Modern English usage tends to prefer the word fiber rather than fibra/fibrae, except when referring to classical or Latinized terms in anatomical or botanical contexts. The term fibrae remains of historical and descriptive value in how scientists document the presence and arrangement of threadlike elements within tissues.

See also: fibrous tissue, connective tissue, nerve fiber, muscle fiber, elastic fiber.