Which plane divides the body into equal right and left halves?

• A. Sagittal
• B. Mid-sagittal
• C. Coronal/ frontal
• D. Transverse/ horizontal

Answer: (B)

The concept here is planes of the body—the imaginary flat surfaces used to describe sections. The plane that runs vertically through the midline and splits the body into equal right and left halves is the mid-sagittal plane. It’s a specific sagittal plane that passes exactly along the body's center, so the two sides are mirror images. A sagittal plane, in general, can run to one side of the midline and produce unequal left and right portions, which is why it’s not always equal. Some contexts also call this same plane the median plane.

In contrast, the frontal (coronal) plane divides the body into front (anterior) and back (posterior) portions, while the transverse (horizontal) plane divides it into top (superior) and bottom (inferior) parts.