capsularis

Capsularis is a Latin-derived term used in anatomical nomenclature to indicate a relationship to a capsule. In practice, it functions as an adjective rather than the name of a distinct structure, appearing in compound terms to describe something related to a capsule.

The best-known use is decidua capsularis, a component of the maternal endometrium during pregnancy. Decidua capsularis refers to the portion of the decidua that forms a capsule around the implanted conceptus and its chorionic sac. This region overlies the developing embryo and chorion and interacts with the amnion. As gestation progresses, the decidua capsularis expands and eventually fuses with the decidua parietalis, leading to obliteration of the uterine cavity. The fusion helps accommodate fetal growth while maintaining placental attachment at the decidua basalis.

Beyond decidua capsularis, the term capsularis appears infrequently in other anatomical phrases to denote a relation to a capsule, but there is no widely recognized standalone structure named capsularis. Its usage is largely limited to obstetric and embryological contexts and, in broader anatomy, serves as a descriptive modifier rather than a proper noun.

See also: decidua, placenta, endometrium, decidua basalis, decidua parietalis.