Isterna

Isterna is a Latin-derived term used in anatomy and cell biology to denote a cistern—a dilated sac or reservoir. It serves as a generic label for fluid-filled spaces and organelle compartments that store or pool substances such as lymph or cerebrospinal fluid.

In human anatomy, the cisterna chyli is a notable example. It is a dilated sac at the origin of the thoracic duct, located in the posterior abdomen near the L1–L2 vertebrae. It collects lymph from the intestinal and lumbar trunks and channels it into the thoracic duct, acting as a lymphatic reservoir.

The cerebellomedullary cistern, commonly called the cisterna magna, is another well-known cisterna. It is a large subarachnoid cistern at the base of the skull, between the medulla oblongata and the cerebellum. It receives cerebrospinal fluid from the fourth ventricle and communicates with the surrounding subarachnoid space.

In cell biology, cisterna (plural cisternae) refers to flattened, membrane-bound sacs within organelles, notably the cisternae of the endoplasmic reticulum and the Golgi apparatus. These structures participate in the trafficking, modification, and sorting of proteins and lipids.

The term derives from Latin cisterna, meaning tank or reservoir. It is used in various anatomical contexts, and the plural cisternae is standard in scientific writing.