Axis: It is the line about which movement takes place. An imaginary straight line around which an object rotates is called axis.
Plane: It is the surface which lies at right angles to axis and in which the movement take place. These terms are used to facilitate the description of movement or direction.
Types of axes: They are 3 types of axes.
- Sagittal axis: It lies parallel to sagittal suture of skull, i.e. in a anterior-posterior direction. Movement at this axes occur in a frontal plane.
- Frontal or transverse axes: It lies parallel to transverse suture of skull. It is horizontal and at right angles to sagittal axes. Movement about frontal axes occurs in a sagittal plane.
- Vertical axes: It lies parallel to line of gravity. Movement about this axis is in
a horizontal plane.
Planes: There are three planes.
- Movement in horizontal plane (transverse plane): This plane divides the body into upper and lower halves. Movements in transverse plane occur parallel to ground. For example in rotation of the head, the nose moves parallel to ground. Rotatory movements in a transverse plane occur around a vertical axis of motion. Movement in the horizontal plane is not affected by gravity hence it is stated as gravity free movement. Weak muscles which unable to produce movement against gravity can often succeed in this plane.
- Movement in frontal plane (coronal plane): the frontal plane divides the body into front and back halves. Movements in the frontal plane occur side to side movements such as bringing the head to each of the shoulders. Rotatory motion in the frontal plane occurs around an anterior posterior axis.
- Movement in vertical plane (sagittal plane): An anteroposterior vertical plane passing through the body from front to back, dividing it in half. It is the plane that divides the body or body segment into the right and left parts. Movements in this plane include forward and backward motions such as nodding of the head. Rotatory motion in the sagittal plane occurs around a coronal axis.
- TEXT BOOK OF BIOMECHANICS AND EXERCISE THERAPY (Dr. C.NAGAVANI, M.P.T (Neuro) Assistant professor Susruta college of physiotherapy Dilshuknagar, Hyderabad.