longitudinais

Longitudinais is the plural form of the adjective longitudinal in Portuguese and Spanish, used as a noun in some contexts to denote elements oriented along the length of an object or organism. In English-language technical writing the term is sometimes anglicized as “longitudinals” and used to refer to such lengthwise components across disciplines.

In anatomy and biology, longitudinal structures run parallel to the long axis of a body part. Longitudinal muscle fibers, for example, occur in the walls of the gastrointestinal tract and in various skeletal muscles, contributing to movements along the axis of a limb or organ. Longitudinally oriented vessels and fibers also appear in connective tissues and other organs, where they coordinate lengthwise contraction and support.

In botany and histology, longitudinal orientation describes tissues or sections cut along the axis of a stem, root, or organ. Longitudinal sections reveal the arrangement of vessels, fibers, and cells along the length, complementing transverse (cross) sections for a full internal view.

In engineering and construction, longitudinais (often called longitudinal members) are elements that run along the length of a structure to provide stiffness and integrity. In ships, hulls use longitudinal stringers and frames; in aircraft, bridges, and buildings, longitudinal spars, ribs, and girders perform analogous roles.

The term is also used in other fields to emphasize direction along the length, as opposed to across the width (transverse) or around the circumference (circumferential).