Structural Organization of Human Body

The basic functional unit of the human body is the cell. Similar cells are organized into tissues to perform common functions. Two or more different types of tissue constitute an organ, which performs a specific function for the body. A system, which is made up of a group of organs, is the most complex unit of the body. The highest level of organization is the organism, the living human being.

Body Planes and Directions

In anatomical terms, the human body is divided into three major planes.

Sagittal planes: vertical planes through the longitudinal axis of the trunk, divides the body into right and left halves.

Frontal planes: vertical planes at right angles to sagittal planes, divides the body into front (anterior) and back (posterior) portions.

Transverse planes: horizontal planes at right angles to the other two planes, divides the body into upper and lower parts.

In additional to the three planes, there are a number of anatomical terms that help identify direction:

ventral (anterior): front surface of the body dorsal (posterior): back surface of the body superior: refers to the head end inferior: refers to the end opposite the head medial: nearer to the midline lateral: further from the midline proximal: nearer to the source or point of attachment distal: further from the source or point of attachment