Human Anatomy and Physiology - I. V. Gayvoronsky 2011

Object and Methods of Research
Planes, Axes, and Major Landmarks in Anatomy

In anatomy, the shape and Structure OF THE human body are examined in relation to an upright posture. In this position, the palms of the hands are turned forward, known as the "anatomical position". Consequently, terms such as "upper and lower ends", "anterior (ventral) and posterior (dorsal) surfaces" are used to describe Parts and Regions of the body, while "external and internal surfaces" are used with respect to Body Cavities.

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Fig. 2.1. Axes and Planes of The Human Body:

1 — vertical axis; 2 — sagittal axis; 3 — sagittal plane; 4 — median plane; 5 — frontal plane; 6 — frontal axis; 7 — horizontal plane

To determine the topography (Location) of Organs, a three-dimensional coordinate system is used, providing a volumetric description. For this purpose, three reference planes are conventionally passed through the human body: horizontal, sagittal, and frontal (Fig. 2.1).

The horizontal plane divides the body into upper and lower parts, whereas the sagittal plane divides it into right and left parts. The sagittal plane that divides the human body into two symmetrical halves is called the median plane. The frontal plane runs perpendicular to the sagittal plane, dividing the body into anterior and posterior parts. Horizontal, sagittal, and frontal planes can be drawn through any point on the body's surface.

To describe THE POSITION OF body parts relative to the median plane, the terms "medial" and "lateral" are used. Medial (medialis) means "situated closer to the median plane", while lateral (lateralis) means "farther from it". The terms "right" (dexter), "left" (sinister), "superficial" (superficialis), and "deep" (profundus) are self-explanatory.

To denote spatial relationships on the limbs, the terms "proximal" (proximalis)—meaning "situated closer to the attachment point of the limb to the trunk"—and "distal" (distalis)—meaning "farther from it"—are used.

To determine the directions of movement in joints, conventional axes are established: frontal, sagittal, and vertical (longitudinal). The frontal and sagittal axes lie within their respective frontal and sagittal planes. The vertical axis runs through the human body in a superior-inferior direction. Joint movements occur around these designated axes.

To describe the topographical relationships of organs, anatomical landmarks on the human body are utilized. Most commonly, these are individual skeletal bones (vertebrae, Ribs, clavicle, scapula, limb bones, Skull bones) or specific bony prominences and features (spines, tubercles, lines, processes, crests, etc.). When bony landmarks in a given region are poorly defined or deeply situated, the borders of contracted Muscles or major Blood Vessels are used as reference points.