Planes of Movement.
When the body is in the standard anatomical position, standing erect with the palms facing forward, it can be divided into three imaginary planes.
These planes help clarify and specify movements.
The sagittal plane divides the body into left and right halves. The descriptive terms medial and lateral correlate to the sagittal plane; the actions of flexion and extension occur along this plane.
The midline, or midsagittal plane, runs down the center of the body, dividing the sagittal plane in two symmetrical halves.
The frontal, or coronal, plane divides the body into front and back portions. The terms anterior and posterior relate to the frontal plane. The actions of adduction and abduction happen along this plane.
Dividing the body into upper and lower parts is the transverse plane. The terms superior and inferior refer to the transverse plane. Rotation happens within this plane.
Directions and Positions
Specific terms are used to help communicate location, direction, and position of body structures.
These terms replace more general references like “up there” or “north of here,” which are less precise and can be confusing.
Each direction is paired up with its complementary direction. Superior refers to a structure closer to the head. Inferior means closer to the feet. “The shoulders are superior to the knees.”
“The knees are inferior to the shoulders.”
The terms cranial, or closer to the head, and caudal, meaning closer to the buttocks, are used when referring to structures on the trunk. For example, “The umbilicus is caudal to the clavicles.” “The clavicles are cranial to the umbilicus.”
Medial and lateral describe the position of structures relative to the median sagittal plane and the sides of the body. For example, the thumb is lateral to the little finger.
Proximal and distal are used with reference to being closer to or farther from a structure’s origin, particularly in the limbs. For example, the hand is distal to the elbow joint. These terms are also used to describe the relative positions of branches along the course of linear structures, such as airways, vessels, and nerves. For example, distal branches occur farther away toward the ends, whereas proximal branches occur closer to and toward the origin.
Cranial (toward the head) and caudal (toward the tail) are sometimes used instead of superior and inferior, respectively
Rostral is used, particularly in the head, to describe the position of a structure with reference to the nose. For example, the forebrain is rostral to the hindbrain.
The reference image to the left is in the standard reference position of the body where we describe locations of structures.
The anatomical position includes: