The directional references allow the body to be divided along three imaginary planes. The frontal plane runs parallel to the long axis of the body produces anterior and posterior sections. The frontal plane is sometimes referred to as the coronal (kor-O-nal) plane, particularly when dealing with sections through the skull. The sagittal (sa-GI-tal) plane also runs parallel to the long axis of the body, but produces left and right sections. When the plane passes through the midline of the body, and equal left and right sections are produced, the term midsagittal is used. When any other sagittal section is produced, the term parasagittal is used. The transverse (or horizontal) plane is perpendicular to the long axis of the body, and produces superior and inferior sections.
These planes, and the sections that they produce, provide an opportunity to explore the three-dimensional relationships between anatomical structures. Numerous medical imaging techniques including x-rays, ultrasound, and magnetic resonance imaging (MRI) provide sectional views of the internal structures of the body.