Anatomists and clinicians use a standardized set of directional terms to describe the location of structures in the body precisely. The front of the body is called anterior, or ventral, while the back is called posterior, or dorsal; for example, the sternum lies anterior to the heart, and the spine lies posterior to the sternum. Superior means toward the head or upper, while inferior means toward the feet or lower, so the heart is superior to the stomach. Medial refers to a position toward the midline of the body, and lateral refers to a position away from the midline; the nose, for instance, is medial to the ears.
Other directional terms describe distance from a point of attachment. Proximal means closer to the point of attachment or trunk of the body (for example, the elbow is proximal to the wrist), while distal means farther from that attachment (the fingers are distal to the wrist). The terms ipsilateral and contralateral describe sides relative to a reference point: ipsilateral means on the same side of the body, and contralateral means on the opposite side. Depth is described as superficial (closer to the surface or skin) or deep (farther from the surface, more internal); the ribs, for example, are superficial to the lungs, while the heart is deep to the sternum.
Body position during examinations and procedures is described with two additional terms. In the supine position, the patient lies flat on their back, face up, while in the prone position the patient lies flat on the abdomen, face down. The body is also commonly divided by anatomical planes, which are imaginary flat surfaces used as references. The sagittal plane divides the body into left and right portions, the coronal or frontal plane divides the body into anterior and posterior portions, and the transverse or axial plane divides the body into superior and inferior portions. These planes form the basis for describing imaging studies, surgical approaches, and anatomical cross-sections.