Joint Kinematics

Anatomical planes and axis are used to describe the human body in Joint Kinematics. The planes include, the Sagittal Plane, a plane parallel to the sagittal suture. The Sagittal plane divides the body into left and right. The transverse plane (also called the horizontal plane, axial plane, or trans axial plane) is an imaginary plane that divides the body into superior and inferior parts. And the Frontal (coronal) plane, which is any vertical plane that divides the body into ventral and dorsal (belly and back) sections.

In the study of Joint Kinematics,body segments are linked to each other at the joints. The joint structure determines the types of joint motions allowed at the joint. Joint motion is actually the relative motion of the distal segment to the proximal that together form a joint. Analytically speaking, it is advantageous to view joint motions as the relative motions between the rigid bodies. Body segments are considered to be ridged bodies, for the purpose of describing the motion of the body, such segments include, the the foot, shank (leg), thigh, pelvis, thorax, hand, forearm, upper-arm and head. Joints between adjacent segments include the ankle (talocrural plus subtalar joints), knee, hip, wrist, elbow and shoulder. Position is used to describe the location of the body segment in conjuncture to the axial planes stated above. A body segment or joint in space is measured in meters, and a related measure called "displacement" refers to the position with respect to starting position. In two dimensions, the position is given in Cartesian coordinates (system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular directed lines, measured in the same unit of length,) with horizontal variables followed by the vertical position. Heres a quick example of the use of Joint Kinematics and labeling movement. Kinematic measurements are limited in what they can tell us about the causes of motion is - for this we need to look at the kinetics. However, they do provide a description of the motion which can be valuable for certain purposes.