Posture is a composite of the positions of all the joints of the body at a given moment and of the static postures alignment is best described in terms of the positions of the various joints and body segments. This chapter provides basic information on anatomical positions, axes, planes and movements of the joints. This information is essential when analyzing postural alignment. Posture can also be described in terms of muscle balance.


The anatomical position of the body is an upright posture, with the face forward, the arms at the sides, the palms facing forward and the fingers and thumb in extension. This is the reference position for the definitions and descriptions of the planes and axes of the body.


The zero position is the same as the anatomical position, except that the hands are facing the body and frontally The arms are halfway between supination and pronation.


Axes are lines, real or imaginary, around which movement occurs. Relative to the reference planes displayed On the next page there are three basic types of trees at right angles to each other:

1. A sagittal axis lies in the sagittal plane and runs horizontally from front to back. the movements of abduction and adduction occur around this axis in a coronal plane.

2. A coronal axis lies in the coronal plane and runs horizontally from side to side. the movements of flexion and extension occur around this axis in a sagittal plane.

3. A longitudinal axis extends vertically in the craniocaudal direction. Medial and lateral movements Horizontal rotation, abduction and adduction of the shoulder occur around this axis in the transverse direction airplane. Exceptions to these general definitions occur with respect to movements of the scapula, clavicle and thumb.


The three basic reference planes are derived from dimensions in space and form right angles to each other.


1. A sagittal plane is vertical and extends from front to back, deriving its name from the direction of the sagittal plane cranial suture. It can also be called the anteroposterior plane. The mid-sagittal plane, or mid-sagittal, divide the body into the right and left halves.

2. A coronal plane is vertical and extends from side to side, deriving its name from the direction of the coronal suture of the skull. It is also called the frontal or lateral plane and divides the body into an anterior and a posterior portion. 3. A transverse plane is horizontal and divides the body into upper (cranial) and lower (caudal) portions. The point where the three median planes of the body intersect is the center of gravity. Center of gravity: any mass or body is made up of a multitude of small attracted particles the earth according to the law of gravitation. This attraction of gravity on the particles of the body produces a system of practically parallel forces and the result of these forces acting vertically downwards is the weight of the body. It is possible to locate a point where a single force, equal in magnitude to the weight of the body and acting vertically upwards, it can be applied so that the body remains in balance in any position. This point is called the body's center of gravity and can be described as where it is located that the entire weight of the body can be considered concentrated. In an ideally aligned posture In a so-called average adult human, the center of gravity is considered to be slightly earlier than the first or second sacral segment.

Gravity Line: The gravity line is a vertical line that passes through the center of gravity.

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