What does "atresia" signify in a medical context?

In a medical context, "atresia" specifically refers to a condition where an anatomical passage or opening is absent or blocked, signifying occlusion. This term is often used to describe congenital conditions where normal duct structures fail to develop properly, resulting in a complete or partial closure. For example, you may encounter it in phrases like "esophageal atresia," which indicates that the esophagus does not fully develop, leading to a partial or complete blockage.

Understanding that atresia highlights the absence or obstruction of a passage is crucial in differentiating it from terms that describe other conditions. The other options do not align with this definition: combining forms pertain to medical terminology used to create words related to tumors, surgical openings refer to specific procedures or incisions made intentionally, and joining in a seam relates to stitching or connecting materials, which do not pertain to anatomical or pathological conditions. Thus, the definition reflecting occlusion accurately encapsulates the essence of atresia in medical terminology.