HIP REPLACEMENT - VIDEOS

(hip replacement surgery, with animations, detailed information on what to expect before, during and after the surgery, and video of rehabilitation exercises and aids.)


(Total hip replacement is a common hip surgery that involves complications including joint dislocation, implant loosening, and fractures)



(Orthopaedic surgeon Dr. Gregory Hicken performs a total hip replacement on an 83 year old female patient with the assistance of a computer-aided surgical navigation system by Stryker on Dec. 11 at Cache Valley Specialty Hospital.)


(Hip Replacement Using Antero-Lateral Approach)

Anthropometry Basics

Book Title : BASIC TERMS IN ANTHROPOMETRY

Contents

1.)Anthropometric Measurement
2.)Hanavan Model
3.)Anthropometric measurement form
4.)Density
5.)Average Density
6.)SkinFold Test
7.)Body Mass Index
8.)Degree of freedom
9.)Elasticity Definition
10.)Coefficient of Elasticity
11.)Strain
12.)Stress
13.)Center of gravity
14.)Moment of inertia
15.)Inertia Tensor
16.)Anthropometry


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ANTHROPOMETRY

Anthropometry is the scientific study of the measurements of the human body. It refers to the measurement of living human individuals for the purposes of understanding human physical variation.

Anthropometry plays an important role in industrial design, clothing design, ergonomics, and architecture, where statistical data about the distribution of body dimensions in the population are used to optimize products. Changes in life styles, nutrition and ethnic composition of populations lead to changes in the distribution of body dimensions (example, the obesity epidemic), and require regular updating of anthropometric data collections.

Dynamics Basics

Book Title : BASIC TERMS IN DYNAMICS

Contents

1.)Dynamics
2.)Newton's First Law
3.)Newton's second Law
4.)Newton's third law
5.)Momentum
6.)Momentum Conservation
7.)Free Body Diagram
8.)Torque
9.)Work
10.)Mechanical Energy
11.)Energy Conservation
12.)Power
13.)Pressure


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DYNAMICS

Dynamics is the branch of mechanics concerned with the motion of bodies under the action of forces.

PICTURES OF HUMAN DYNAMICS MEASUREMENT:

KINEMATICS BASICS

Book Title : BASIC TERMS IN KINEMATICS

Contents

1.) Kinematics
2.) Orientation In Space
3.) Coordinate Systems
4.) Angle
5.) Euler Angles
6.) Kinematic Chains
7.) Position
8.) Velocity
9.) Acceleration
10.)Angular Acceleration
11.)Orientation During Trampoline Jump
12.)Relative Segmental Orientation
13.)Full Kinematic Description


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KINEMATICS

Kinematics is the branch of mechanics concerned with the motion of objects without reference to the forces which cause themotion.


HUMAN KINEMATIC MODELING


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Bones Biomechanics

Bones are anisotropic but are approximately transversely isotropic. In other words, bones are stronger along one axis than across that axis, and are approximately the same strength no matter how they are rotated around that axis.

The stress-strain relations of bones can be modeled using Hooke's law, in which they are related by elastic moduli, e.g. Young's modulus, Poisson's ratio or the Lamé parameters. The constitutive matrix, a fourth order tensor, depends on the isotropy of the bone.
σij = Cijklεkl


HOOKE's LAW
Hooke's law of elasticity is an approximation that states that the amount by which a material body is deformed (the strain) is linearly related to the force causing the deformation (the stress).

Circulation Biomechanics

Blood flow can be modeled by the Navier-Stokes equations. Whole blood can often be assumed to be an incompressible Newtonian fluid. However, this assumption fails when considering flows within arterioles. At this scale, the effects of individual red blood cells becomes significant, and whole blood can no longer be modeled as a continuum. When the diameter of the blood vessel is slightly larger than the diameter of the red blood cell the Fahraeus–Lindqvist effect occurs and there is a decrease in wall shear stress. However, as the diameter of the blood vessel decreases further, the red blood cells have to squeeze through the vessel and often can only pass in single file. In this case, the inverse Fahraeus–Lindqvist effect occurs and the wall shear stress increases.

Navier-Stokes equations
The Navier-Stokes equations, describe the motion of fluid substances such as liquids and gases. These equations establish that changes in momentum in infinitesimal volumes of fluid are simply the sum of dissipative viscous forces (similar to friction), changes in pressure, gravity, and other forces acting inside the fluid. This is an application of Newton's second law.

They are one of the most useful sets of equations because they describe the physics of a large number of phenomena of academic and economic interest. They may be used to model weather, ocean currents, water flow in a pipe, flow around an airfoil (wing), and motion of stars inside a galaxy. As such, these equations in both full and simplified forms, are used in the design of aircraft and cars, the study of blood flow, the design of power stations, the analysis of the effects of pollution, etc. Coupled with Maxwell's equations they can be used to model and study magnetohydrodynamics.

The Navier-Stokes equations are differential equations which, unlike algebraic equations, do not explicitly establish a relation among the variables of interest (e.g. velocity and pressure), rather they establish relations among the rates of change. For example, the Navier-Stokes equations for simple case of an ideal fluid (inviscid) can state that acceleration (the rate of change of velocity) is proportional to the gradient (a type of multivariate derivative) of pressure.

CONTINUUM MECHANICS

It is often appropriate to model living tissues as continuous media. For example, at the tissue level, the arterial wall can be modeled as a continuum. This assumption breaks down when the length scales of interest approach the order of the micro structural details of the material.

The basic postulates of continuum mechanics are :
1.) Conservation of linear and angular momentum,
2.) Conservation of mass, conservation of energy, and
3.) Entropy inequality.
Solids are usually modeled using "reference" or "Lagrangian" coordinates, whereas fluids are often modeled using "spatial" or "Eulerian" coordinates. Using these postulates and some assumptions regarding the particular problem at hand, a set of equilibrium equations can be established. The kinematics and constitutive relations are also needed to model a continuum.

Second and fourth order tensors are crucial in representing many quantities in electromechanical. In practice, however, the full tensor form of a fourth-order constitutive matrix is rarely used. Instead, simplifications such as isotropy, transverse isotropy, and incompressibility reduce the number of independent components. Commonly-used second-order tensors include the Cauchy stress tensor, the second Viola-Kirchhoff stress tensor, the deformation gradient tensor, and the Green strain tensor. A reader of the mechanic's literature would be well-advised to note precisely the definitions of the various tensors which are being used in a particular work.

DEFINITION:
1.)Continuum mechanics
Continuum mechanics is a branch of physics (specifically mechanics) that deals with continuous matter, including both solids and fluids (i.e., liquids and gases).

2.)Solid Mechanics
Solid mechanics is the study of the physics of continuous solids with a defined rest shape.

3.) Fluid Mechanics
Fluid mechanics (including Fluid statics and Fluid dynamics) deals with the physics of fluids. An important property of fluids is viscosity, which is the force generated by a fluid in response to a velocity gradient.

4.) Length Scale
Length scale is a particular length or distance determined with the precision of one order (or a few orders) of magnitude.

5.)Linear Momentum
Momentum (SI unit kg m/s) is the product of the mass and velocity of an object.The law of conservation of momentum is a fundamental law of nature, and it states that the total momentum of a closed system of objects (which has no interactions with external agents) is constant.

6.)Conservation of Mass
The law of conservation of mass/matter, also known as law of mass/matter conservation (or the Lomonosov-Lavoisier law), states that the mass of a closed system of substances will remain constant, regardless of the processes acting inside the system.

7.)Conservation of Energy
The conservation of energy states that the total amount of energy in an isolated system remains constant, although it may change forms, e.g. friction turns kinetic energy into thermal energy. In thermodynamics, the first law of thermodynamics is a statement of the conservation of energy for thermodynamic systems, and is the more encompassing version of the conservation of energy. In short, the law of conservation of energy states that energy can not be created or destroyed, it can only be changed from one form to another, such as when electrical energy is changed into heat energy.

8.)Entropy
Entropy is a measure of the uniformity of the distribution of energy.

9.)Lagrangian and Eulerian coordinates
In fluid dynamics and finite-deformation plasticity the Lagrangian reference frame is a way of looking at fluid motion where the observer follows individual fluid particles as they move through space and time. Plotting the position of an individual particle through time gives the pathline of the particle. This can be visualized by sitting in a boat drifting down a river.

The Eulerian reference frame is a way of looking at fluid motion that focuses on specific points in the space through which the fluid moves. This can be visualized by sitting on the bank of a river and watching the water pass your location. Values about the fluid flow are determined as vectors at discrete locations.

They are related by the Convective derivative or Lagrangian derivative (sometimes called the material derivative):


This tell us the rate of change of F whilst moving with the fluid at velocity u.

10.)Kinematics
Kinematics is a branch of mechanics which describes the motion of objects without the consideration of the masses or forces that bring about the motion. By contrast, dynamics is concerned with the forces and interactions that produce or affect the motion.

Kinematics studies how the position of an object changes with time. Position is measured with respect to a set of coordinates. Velocity is the rate of change of position. Acceleration is the rate of change of velocity. Velocity and Acceleration are the two principal quantities which describe how position changes.

The simplest application of kinematics is to point particle motion (translational kinematics or linear kinematics). The description of rotation (rotational kinematics or angular kinematics) is more complicated. The state of a generic rigid body may be described by combining both translational and rotational kinematics (rigid-body kinematics). A more complicated case is the kinematics of a system of rigid bodies, possibly linked together by mechanical joints. The kinematic description of fluid flow is even more complicated, and not generally thought of in the context of kinematics.

Biomechanics- Applications

1.)The study of biomechanics ranges from the inner workings of a cell to the movement and development of limbs, the vasculature, and bones. As we develop a greater understanding of the physiological behavior of living tissues, researchers are able to advance the field of tissue engineering, as well as develop improved treatments for a wide array of pathologies.

2.)Biomechanics as a sports science, kinesiology, applies the laws of mechanics and physics to human performance in order to gain a greater understanding of performance in athletic events through modeling, simulation, and measurement.

BIOMECHANICS-Introduction

Biomechanics is the research and analysis of the mechanics of living organisms or the application and derivation of engineering principles to and from biological systems. The research and analysis can be carried forth on multiple levels, from the molecular, wherein biomaterials such as collagen and elastin are considered, all the way up to the tissue and organ level. Some simple applications of Newtonian mechanics can supply correct approximations on each level, but precise details demand the use of continuum mechanics.

Aristotle wrote the first book on biomechanics, De Motu Animalium, or On the Movement of Animals. He not only saw animals' bodies as mechanical systems, but pursued questions such as the physiological difference between imagining performing an action and actually doing it. Some simple examples of biomechanics research include the investigation of the forces that act on limbs, the aerodynamics of bird and insect flight, the hydrodynamics of swimming in fish, the anchorage and mechanical support provided by tree roots, and locomotion in general across all forms of life, from individual cells to whole organisms. The biomechanics of human beings is a core part of kinesiology.

Applied mechanics, most notably thermodynamics and continuum mechanics, and mechanical engineering disciplines such as fluid mechanics and solid mechanics, play prominent roles in the study of biomechanics. By applying the laws and concepts of physics, biomechanical mechanisms and structures can be simulated and studied.

It has been shown that applied loads and deformations can affect the properties of living tissue. There is much research in the field of growth and remodeling as a response to applied loads. For example, the effects of elevated blood pressure on the mechanics of the arterial wall, the behavior of cardiomyocytes within a heart with a cardiac infarct, and bone growth in response to exercise, and the acclimative growth of plants in response to wind movement, have been widely regarded as instances in which living tissue is remodelled as a direct consequence of applied loads.

Relevant mathematical tools include linear algebra, differential equations, vector and tensor calculus, numerics and computational techniques such as the finite element method.

The study of biomaterials is of crucial importance to biomechanics. For example, the various tissues within the body, such as skin, bone, and arteries each possess unique material properties. The passive mechanical response of a particular tissue can be attributed to characteristics of the various proteins, such as elastin and collagen, living cells, ground substances such as proteoglycans, and the orientations of fibers within the tissue. For example, if human skin were largely composed of a protein other than collagen, many of its mechanical properties, such as its elastic modulus, would be different.

Chemistry, molecular biology, and cell biology have much to offer in the way of explaining the active and passive properties of living tissues. For example, in muscle contractions, the binding of myosin to actin is based on a biochemical reaction involving calcium ions and ATP.

KINESIOLOGY

Kinesiology and Biomechanics

Kinesiology has been traditionally defined as the study of human movement from the point of view of physical sciences (Luttgens & Hamilton, 1997). It has two main areas: anatomical kinesiology and mechanical kinesiology. The former deals with the mechanical aspects of the human body while the latter deals with the mechanical aspects of the human motion.

Biomechanics is defined as application of the mechanical principles in the study of living organism . The main interest in this field of study is mechanical analysis of the biological systems such as the human.

Kinesiology is very similar to biomechanics as long as the main area of application is the human. So we can use both terms interchangeably.

Nowadays, people tend to use the term kinesiology for more broader meaning: the study of human movement. They have identified several additional areas such as psychological kinesiology, physiological kinesiology, etc. The term kinesiology replaces the traditional term physical education. In this regard, biomechanics is more specific to refer to both the areas of anatomical kinesiology and mechanical kinesiology.

BIOMECHANICS DEFINITION

BIOMECHANICS is defined as the area of study wherein the knowledge and methods of biomechanics are applied to the structure and function of the living human system. BIOMECHANICS of human movement can be defined as the interdiscipline which describes, analyses and assesses human movement

BIOMECHANICS & SPORT BIOMECHANICS

BIOMECHANICS

Biomechanics is a diverse interdisciplinary field, with branches in Zoology, Botany, Physical Anthropology, Orthopedics, Bioengineering and Human Performance. The general role of Biomechanics is to understand the mechanical cause-effect relationships that determine the motions of living organisms. In relation to sport, Biomechanics contributes to the description, explanation, and prediction of the mechanical aspects of human exercise, sport and play.

SPORT BIOMECHANICS

Sport Biomechanics is the sport science field that applies the laws of mechanics and physics to human performance, in order to gain a greater understanding of performance in athletic events through modeling, simulation and measurement. It is also necessary to have a good understanding of the application of physics to sport, as physical principles such as motion, resistance, momentum and friction play a part in most sporting events.

BIOMECHANICS

Biomechanics combines engineering and the life sciences by applying principles from classical mechanics to the study of living systems.

FEW TOPICS OF BIOMECHANICS

1.)Strength of biological materials
2.)Biofluid mechanics in cardiovascular and respiratory systems
3.)Material properties & Interactions of medical implants and the body
4.)Heat & mass transfer into biological tissues
5.)Kinematics & Kinetics applied to study human gait
6.)Biomechanics of exercise fitness
7.)Biomechanics of Joints
8.)Biomechanics of scoliosis
9.)Biomechanics of skin
10.)Biomechanics of human spine
11.)Biomechanics of tooth and jaw