Which vertical plane would not pass through the midline and divides the structure into unequal parts?

• A. Parasagittal Plane
• B. Midsagittal Plane
• C. Sagittal Plane
• D. Frontal Plane

Answer: (A)

Vertical planes run lengthwise and relate to how the body is divided left-to-right. A midsagittal (median) plane passes exactly through the body's midline, splitting it into equal left and right halves. Any vertical plane parallel to this but offset from the midline is a parasagittal plane, and because it sits off-center, it divides the structure into unequal portions. The frontal (coronal) plane, while also vertical, cuts the body into anterior and posterior parts rather than left and right, so it doesn’t describe the left-right unequal division linked to being off the midline. So the plane that does not pass through the midline and results in unequal parts is the parasagittal plane.