Interatrialis

Interatrialis refers to a structure or condition located between the atria of the heart. In human anatomy, it most commonly describes the interatrial septum, a muscular wall that divides the left and right atria. This septum is crucial for separating oxygenated blood in the left atrium from deoxygenated blood in the right atrium during fetal development. After birth, the foramen ovale, a hole within the interatrial septum that allows blood to bypass the lungs, typically closes.

When the interatrial septum fails to close completely after birth, it can result in an atrial septal defect (ASD). An ASD is a congenital heart defect where there is an abnormal opening between the left and right atria. This allows oxygenated blood from the left atrium to flow into the right atrium, mixing with deoxygenated blood. The severity of symptoms associated with an ASD depends on the size of the defect. Small ASDs may cause no symptoms and close on their own, while larger defects can lead to shortness of breath, fatigue, and an increased risk of heart problems later in life.

In certain contexts, "interatrialis" might also be used to describe a path or communication that exists or forms between the atria. For example, during fetal circulation, the foramen ovale represents a direct interatrial communication. Medical literature may use the term to refer to abnormal connections or pathways that develop or persist between the atrial chambers.