The junctional zone of the uterus refers to which anatomical layer?

• A. Inner layer of the myometrium
• B. Endometrium
• C. Outer myometrium
• D. Cervical stroma

Answer: (A)

The junctional zone is the inner portion of the myometrium, the muscular wall of the uterus, located directly beneath the endometrium. It forms the boundary between the endometrium and the thicker outer myometrium. On imaging such as MRI, it appears as a distinct band between the bright endometrium and the darker outer myometrium and is clinically relevant in conditions like adenomyosis, where endometrial tissue can infiltrate this zone. Therefore, the correct layer is the inner layer of the myometrium. The endometrium is the lining of the uterine cavity, the outer myometrium lies farther from the cavity, and the cervical stroma is located in the cervix, not the uterine body.