What does the below diagram indicate?

The above image shows the placental villi penetrating through the myometrium and getting attached to the serosa. Hence, this is known as placenta percreta. Placenta Accreta syndromes include any placental implantation with abnormally firm adherence to myometrium because of paial or total absence of decidua basalis and imperfect development of the fibrinoid. The increased risk conveyed by previous uterine trauma (eg., cesaerean delivery) may be paially explained by an increased vulnerability of the decidua to trophoblast invasion following incision into the decidua. Microscopically, placental villi are anchored to muscle fibers rather than to decidual cells. Decidual deficiency then prevents normal placental seperation after delivery. Variants of placental accreta syndromes are classified by the depth of trophoblastic growth: Types Definition Placenta accreta Villi are attached to the myometrium Placenta increta Villi invade the myometrium Placenta percreta Villi penetrate through the myometrium and to or through the serosa In cases of first- and second-trimester accreta syndromes, there is usually hemorrhage that is the consequence of coexisting placenta pre. MR imaging can be used as an adjuct to sonography to define anatomy, degree of invasionn, and possible ureteral or bladder involvement. Ref: Williams Obstetrics 24th edition pgno: 805