During pregnancy, ultrasounds are commonly used to monitor fetal development. One area that is often examined is the cisterna magna, which is a fluid-filled space located at the back of the brain. The size of the cisterna magna can vary from person to person, and it can also change throughout different stages of pregnancy. In general, a cisterna magna measurement between 2-10mm is considered within the normal range. However, it's important to note that these measurements can vary depending on factors such as gestational age and individual differences. If your ultrasound report indicates that your baby's cisterna magna measurement falls within this range, it is likely considered normal for this stage of pregnancy. It's always best to consult with your healthcare provider who can provide you with more specific information based on your individual circumstances.