septums

Septum (plural septums or septa) is a wall or partition that divides a cavity, organ, or tissue into two parts. In anatomy, septa function to separate compartments and can be made of cartilage, bone, or connective tissue. Several well-known septa occur in humans and other animals, and the concept appears in other kingdoms as well.

Common examples in humans include the nasal septum, cardiac septa, and brain structures. The nasal septum divides the two nasal cavities and is formed anteriorly by cartilage and posteriorly by bone, with the perpendicular plate of the ethmoid and the vomer contributing to its rigid frame. It supports the nose’s shape and airflow, and deviations can cause nasal obstruction or related symptoms.

The heart contains two main septa: the interatrial septum, which separates the two atria, and the interventricular septum, which divides the two ventricles. These walls develop during embryogenesis from endocardial cushions and muscular tissue. Defects in these septa, such as atrial or ventricular septal defects, can alter blood flow and may require medical attention.

In the brain, the septum pellucidum is a thin membrane that separates the anterior horns of the lateral ventricles. It is normally present in most individuals, though agenesis or cysts can occur and may be associated with other anomalies.

Other septa occur in biology beyond the circulatory and nervous systems. In fungi, septa are cross-w walls that partition hyphae into cells, often with pores that allow cytoplasm and organelles to pass between compartments. In embryology, structures such as the septum transversum contribute to organ formation (for example, diaphragm development).