👉 Crenulation is a developmental stage in the human embryo, during which the inner lining of the developing embryo, known as the placenta, develops into a shell-like structure called the endometrium. This process occurs between 12 to 18 weeks after conception, and it's essential for the formation of the uterus (the womb) and other important structures within the body. Crenulations are characterized by thin, smooth cells that form from the developing embryo, which is then attached to
