Detailed Study Notes on Osteokinematics, Arthrokinematics, and Biomechanical Principles
Curvilinear vs. Linear vs. Transitory
Curvilinear and linear motions are general, while transitory is specific to manual techniques.
Transitory is applicable mainly to manual therapy.
Planes of Motion and Axes
Wrist, shoulder, and hip movements occur in different planes, each with corresponding axes.
Movement analysis involves identifying the planes and axes involved.
Example: Touching the nose involves sagittal and frontal planes with movement around the frontal or sagittal axis.
Wrist
Determine the number of movements at the wrist.
Identify the plane of each movement.
Determine the axis of each movement.
Shoulder
Determine the number of planes of motion at the shoulder (three: sagittal, transverse, frontal).
Identify the corresponding axes for each plane.
Hip
Coming from a seated to standing position primarily involves one plane of movement: sagittal.
The axis for this movement is the frontal axis.
External and internal rotation and abduction/adduction are considered negligible for this class's purposes.
Addressing Complexity in Movement Analysis
Break down complex movements into simpler components.
Isolate and define specific segments within a system.
Example: Analyzing a doorknob turn involves shoulder flexion but isolating the wrist turn.
For quizzes and exams, focus on isolating and defining the specific movement segment.
Addressing Impostor Syndrome
Impostor syndrome is a self-created, debilitating feeling.
Develop confidence to overcome it.
Create opportunities to make mistakes when it's safe to do so.
Learn from mistakes to avoid repeating them.
The assignment provides two attempts to allow for learning from errors.
Osteokinematics vs. Arthrokinematics
Osteokinematics: Visible movement of bones in one or more planes.
Arthrokinematics: Movement occurring at the joint surfaces, not visible externally.
Arthrokinematic Motions
Roll: Curvilinear movement.
Glide: Linear movement.
Spin: Rotation around an axis.
Understanding these concepts is crucial for quizzes, assignments, the final exam, and orthopedics.
Example: Knee Extension
Osteokinematically: Knee extension.
Arthrokinematically: Rolling and gliding between the femur and tibia.
The patella exhibits linear or transitory movement.
Concave vs. Convex Surfaces
Concave on Convex: Concave joint surface moving on a convex surface.
Convex on Concave: Convex joint surface moving on a concave surface.
Importance: Impacts joint assessment, joint mobilization, and joint movement understanding.
Identifying Concave and Convex Surfaces
Concave surfaces have an open, cave-like shape.
Convex surfaces have a rounded or pointed shape.
Example: Knee Joint
Femur (distal end): Convex.
Tibia: Concave.
Open Chain vs. Closed Chain
Closed Chain: Femur (convex) moves on a stable tibia (concave) (e.g., squatting to standing).
Open Chain: Tibia (concave) moves on a stable femur (convex) (e.g., seated quad extension).
Most joints exhibit both open and closed chain movements depending on the specific action.
Example: Ankle Joint
Talus: Convex.
Tibia: Concave.
Degrees of Freedom
Degrees of freedom refer to the number of planes a joint can move in.
Shoulder: Three degrees of freedom (sagittal, frontal, transverse).
Knee: Primarily one degree of freedom (flexion and extension).
More degrees of freedom generally mean less stability.
Example: Sternocostal Joint
One degree of freedom (elevation and depression).
Very stable joint.
Dislocation requires significant force.
Shoulder (high degrees of freedom, low stability) is more prone to dislocation.
Relationship between Axis and Joints in Goniometry
Goniometry involves a stationary arm, a movement arm, and an axis related to an anatomical landmark.
There is an instantaneous center of rotation (joint center) that moves.
Goniometry measurements are based on a stationary axis, while the actual joint center moves during movement.
The clinical difference in goniometry measurements (2-3 degrees) accounts for this movement.
Osteokinematic vs. Arthrokinematic Motions
Osteokinematics: Larger movements (e.g., flexion, extension).
Arthrokinematics: Convex, concave, glide, and slide movements.
Arthrokinematics influences movement patterns; impaired arthrokinematics can affect motor control.
Clinical Implications
Example: Knee arthritis with limited knee flexion in the affected leg, potentially due to joint issues.
Treatment involves assessing joint translations and glides.
Shoulder impingement occurs if the scapula doesn't move properly, leading to the humerus hitting the acromion process.
Convex/Concave Principle
Relationship between articular surfaces and bone movement.
Concave on convex: Glide occurs in the same direction as the movement.
Convex on concave: Glide occurs in the opposite direction of the movement.
PTAs can assess but not mobilize joints.
Normal vs. Pathological Joints
Focus on normal joints; reverse total shoulder joints (convex scapula, concave humerus) are not covered.
Convex on Concave Example
Inferior glide of the humeral head during shoulder abduction.
Anterior glide of femur during knee flexion.
Hand Analogy
Use hands to represent convex and concave surfaces to visualize movement and glide direction.
Concave on Convex Example
Posterior glide of the tibial plateau during knee flexion.
Importance of Gliding
Without proper glide, joints roll off surfaces, leading to impingement and other issues.
Smooth motion requires both rolling and gliding.
Clinical Application Example
Baseball player with limited shoulder internal rotation:
Define the movement (shoulder internal rotation).
Identify the plane and axis.
Determine arthrokinematics (convex on concave).
Assess and treat by mobilizing in the posterior plane.
Review: Shoulder Abduction
Convex on concave (humerus on glenoid fossa).
Superior roll, inferior glide.
Kinematics: Describing Motion
Kinematics describes movement without considering forces.
Key terms: speed, acceleration, velocity.
Qualitative vs. Quantitative Analysis
Qualitative: Describes the quality of motion (fast, slow, good, bad).
Quantitative: Measures the quantity of motion (time, distance).
Terminology
Position, coordinate systems, scalars, vectors, distance, displacement, speed, velocity, acceleration.
Scalars vs. Vectors
Scalars: Magnitude only (e.g., speed).
Vectors: Magnitude and direction (e.g., velocity, force).
Vectors also have a point of application and orientation.
Distance vs. Displacement
Distance: Total path traveled.
Displacement: Change in position.
Linear vs. Angular Motion
Linear: Change in distance.
Angular: Change in angle.
Speed and Velocity
Speed: Distance over time (scalar).
Velocity: Displacement over time (vector).
Acceleration
Change in velocity over time.
Positive acceleration, constant velocity (acceleration zero), negative acceleration (deceleration).
Clinical Implications
Deceleration injuries (ACL tears, hamstring strains are much more common).
Hamstring strength and cadence in running.
Understanding kinematics in neurological injuries (e.g., concussions).
Deceleration Injuries
Deceleration= Negative Acceleration contextual and depends on the situation
Brain deceleration impact on skull upon rapid deceleration
Directions
How is the segment moving (Anterior and/or Posterior)?
Moving forward/ backward (superiorly vs. inferiorly)?
Direction of the roll during arthrokinematic motions.
Segment Movements
Tibia is in segment moving on the femur.
The carpal bones moving on the radius of ulna.
The talus moving on the tibia, proximal hallux joint on distal hallux joint.
Curvilinear vs. Linear vs. Transitory
Curvilinear and linear motions are general classifications describing the path of movement, while transitory is more specific and often used in the context of manual therapy techniques.
Transitory motion is particularly relevant in manual therapy, where therapists apply specific, localized movements to address joint restrictions or tissue dysfunction. These motions are neither purely linear nor curvilinear but involve a combination of both.
Planes of Motion and Axes
Movements at the wrist, shoulder, and hip occur in specific planes (sagittal, frontal, transverse), each with a corresponding axis of rotation (mediolateral, anteroposterior, vertical).
Movement analysis entails identifying the planes in which the movement occurs and the axes around which the movement rotates. This is fundamental in understanding biomechanics and motor control.
Example: Touching the nose involves movements primarily in the sagittal and frontal planes, with rotation occurring around the frontal (mediolateral) or sagittal (anteroposterior) axis, depending on the specific component of the movement.
Wrist
Movements at the wrist include flexion, extension, radial deviation, ulnar deviation, pronation, and supination.
Flexion and extension occur in the sagittal plane around the mediolateral axis. Radial and ulnar deviation occur in the frontal plane around the anteroposterior axis. Pronation and supination involve the transverse plane around the vertical axis.
Shoulder
The shoulder joint exhibits movements in three planes of motion: sagittal (flexion/extension), transverse (internal/external rotation, horizontal abduction/adduction), and frontal (abduction/adduction).
Corresponding axes for each plane: mediolateral for sagittal, vertical for transverse, and anteroposterior for frontal.
Hip
Transitioning from a seated to standing position primarily involves movement in the sagittal plane, characterized by hip extension.
The axis of rotation for this sagittal plane movement is the frontal axis (mediolateral axis).
While external and internal rotation, as well as abduction and adduction, can occur at the hip, they are often considered negligible or secondary when analyzing the primary motion of standing up for the simplicity of the course.
Addressing Complexity in Movement Analysis
Complex movements are often a combination of movements in multiple planes. Breaking these down into simpler components allows for a more precise analysis.
Isolating and defining specific segments within a system helps to focus on the key elements contributing to the movement. This is particularly useful in clinical scenarios.
Example: Analyzing the motion of turning a doorknob involves multiple joints and muscle actions. It includes shoulder flexion, elbow flexion, forearm pronation/supination, and wrist movements. For analytical purposes, it can be simplified by isolating the wrist turn to understand the mechanics at that specific joint.
When addressing movement analysis in quizzes and exams, prioritize isolating and defining the specific movement segment requested by the instructor to demonstrate a clear understanding of biomechanical principles.
Addressing Impostor Syndrome
Impostor syndrome is a psychological pattern where individuals doubt their accomplishments and have a persistent fear of being exposed as a fraud. It's a self-created, often debilitating feeling that can hinder performance and learning.
Building confidence is essential to overcoming impostor syndrome. Recognize your strengths, acknowledge your accomplishments, and challenge negative self-talk.
Create opportunities to make mistakes in a safe environment. This allows for learning and growth without the pressure of high stakes.
Learning from mistakes is a critical component of skill development. Analyze errors, understand the underlying causes, and adjust your approach accordingly. Embracing mistakes as learning opportunities can reduce anxiety and improve performance.
The assignment provides two attempts to allow for learning from errors, encouraging students to view mistakes as opportunities for improvement rather than as failures.
Osteokinematics vs. Arthrokinematics
Osteokinematics: Refers to the visible movement of bones in one or more of the cardinal planes (sagittal, frontal, transverse). These movements are typically described as flexion, extension, abduction, adduction, and rotation.
Arthrokinematics: Describes the movement occurring at the joint surfaces, which are not visible externally. These movements are essential for proper joint function and full range of motion.
Arthrokinematic Motions
Roll: A rotary or curvilinear movement where multiple points on one surface make contact with multiple points on another surface.
Glide: A translatory or linear movement where one point on a joint surface contacts multiple points on another surface.
Spin: A rotary movement where a single point on one joint surface rotates on a single point on another joint surface.
A comprehensive understanding of these arthrokinematic concepts is crucial for success in quizzes, assignments, the final exam, and clinical practice in orthopedics.
Example: Knee Extension
Osteokinematically: Knee extension involves the straightening of the knee joint, increasing the angle between the femur and tibia.
Arthrokinematically: Knee extension involves a combination of rolling and gliding between the convex femoral condyles and the concave tibial plateaus.
The patella, positioned anterior to the knee joint, exhibits linear or transitory movement during knee extension, gliding superiorly within the trochlear groove of the femur.
Concave vs. Convex Surfaces
Concave on Convex: Describes a joint where the concave joint surface is moving on a stationary convex surface.
Convex on Concave: Describes a joint where the convex joint surface is moving on a stationary concave surface.
Understanding this relationship is important as it has significant implications for joint assessment, joint mobilization techniques, and comprehending normal joint movement patterns.
Identifying Concave and Convex Surfaces
Concave surfaces are characterized by an open, cave-like shape, resembling the interior of a bowl or socket.
Convex surfaces have a rounded or pointed shape, similar to the exterior of a ball or dome.
Example: Knee Joint
Femur (distal end): The femoral condyles are convex, presenting a rounded surface that articulates with the tibia.
Tibia: The tibial plateau is concave, featuring a slightly cupped surface that receives the femoral condyles.
Open Chain vs. Closed Chain
Closed Chain: In a closed chain movement, the distal segment of the limb is fixed or stabilized, causing movement at the proximal segment. Example: when squatting where the femur (convex) moves on a stable tibia (concave).
Open Chain: In an open chain movement, the distal segment of the limb is free to move in space, while the proximal segment remains relatively stable. For example, a seated quad extension, the tibia (concave) moves on a stable femur (convex).
Most joints in the body exhibit both open and closed chain movements depending on the specific action or activity being performed. The distinction is important for understanding muscle activation patterns and joint mechanics.
Example: Ankle Joint
Talus: The talus is convex, articulating with the concave surface of the tibia.
Tibia: The distal end of the tibia forms a concave surface that articulates with the talus.
Degrees of Freedom
Degrees of freedom refer to the number of independent planes in which a joint can move. Each plane of motion represents one degree of freedom.
Shoulder: The shoulder joint possesses three degrees of freedom, allowing movement in the sagittal (flexion/extension), frontal (abduction/adduction), and transverse (internal/external rotation) planes.
Knee: The knee joint primarily functions with one degree of freedom, allowing flexion and extension in the sagittal plane. However, some rotation is possible in the flexed position.
Generally, joints with more degrees of freedom offer greater mobility but tend to be less stable, while joints with fewer degrees of freedom are more stable but have limited movement capabilities.
Example: Sternocostal Joint
The sternocostal joint, where the ribs articulate with the sternum, has one degree of freedom, primarily allowing elevation and depression of the ribs during respiration.
This limited range of motion contributes to the sternocostal joint's stability. Dislocations are rare and typically require substantial force, such as in cases of significant trauma.
In contrast, the shoulder joint, with its high degrees of freedom and relatively shallow articulation, is more prone to dislocation, highlighting the inverse relationship between mobility and stability.
Relationship between Axis and Joints in Goniometry
Goniometry is the clinical technique used to measure joint angles and range of motion. It involves a stationary arm, a movement arm, and an axis aligned with an anatomical landmark.
The axis in goniometry is related to the instantaneous center of rotation (joint center), which moves as the joint progresses through its range of motion. This movement is not fixed but changes dynamically with joint position.
While goniometry measurements are based on a stationary axis, the actual joint center moves during movement. This discrepancy can result in a small degree of measurement error.
The clinical difference observed in goniometry measurements (2-3 degrees) accounts for the movement of the instantaneous center of rotation during joint motion. Clinicians should be aware of this variability when interpreting goniometric data.
Osteokinematic vs. Arthrokinematic Motions
Osteokinematics: Focuses on larger, more visible movements such as flexion, extension, abduction, and adduction. These movements occur in the cardinal planes and are easily observed and measured.
Arthrokinematics: Involves the smaller, accessory movements occurring within the joint, such as convex and concave movements, gliding, and sliding. These movements are essential for normal joint function but are not visible externally.
Arthrokinematics has a significant influence on overall movement patterns. Impaired arthrokinematics can lead to altered joint mechanics, compensatory movements, and ultimately, dysfunctions in motor control.
Clinical Implications
Example: A patient with knee arthritis may exhibit limited knee flexion in the affected leg. This limitation could be attributed to underlying joint issues affecting arthrokinematic motions.
Treatment strategies often involve assessing joint translations and glides to restore normal arthrokinematics. Mobilization techniques, such as joint mobilizations or manipulations, may be used to address restrictions.
Shoulder impingement can occur if the scapula does not move properly during shoulder elevation. This altered scapulohumeral rhythm can lead to the humerus impinging against the acromion process, resulting in pain and limited range of motion. Addressing scapular kinematics is crucial in managing shoulder impingement.
Convex/Concave Principle
The convex/concave principle describes the relationship between the shapes of articular surfaces and the direction of bone movement during joint motion.
Concave on convex: When a concave joint surface moves on a stationary convex surface, the glide occurs in the same direction as the bone movement.
Convex on concave: When a convex joint surface moves on a stationary concave surface, the glide occurs in the opposite direction of the bone movement.
Physical therapist assistants (PTAs) are trained to assess joint motion and apply certain mobilization techniques under the supervision of a physical therapist. However, PTAs are typically not authorized to perform joint mobilizations requiring advanced skill and judgment.
Normal vs. Pathological Joints
The principles discussed primarily apply to normal, healthy joints. Reverse total shoulder joints, where the configuration is altered (convex scapula, concave humerus), are not typically covered in introductory biomechanics courses.
Convex on Concave Example
During shoulder abduction, the humeral head (convex) glides inferiorly on the glenoid fossa (concave) to maintain joint congruity and prevent impingement.
During knee flexion, the femur (convex) glides anteriorly on the tibia (concave) as the knee bends.
Hand Analogy
Using hands to represent convex and concave surfaces can aid in visualizing movement and glide direction. One hand can represent the convex surface, while the other hand represents the concave surface. Moving the hands in accordance with the convex/concave principle can enhance understanding.
Concave on Convex Example
During knee flexion, the tibial plateau (concave) glides posteriorly on the femur (convex) as the knee bends.
Importance of Gliding
Without proper glide, joints may roll off surfaces, leading to abnormal joint mechanics, impingement, and other musculoskeletal issues.
Smooth, pain-free joint motion requires both rolling and gliding to occur in a coordinated manner. Restrictions in gliding can result in compensatory movements and decreased function.
Clinical Application Example
Baseball player with limited shoulder internal rotation:
Define the movement (shoulder internal rotation). This involves identifying the specific motion that is restricted or impaired.
Identify the plane and axis. Shoulder internal rotation occurs in the transverse plane around the vertical axis.
Determine arthrokinematics (convex on concave). During shoulder internal rotation, the convex humeral head moves on the concave glenoid fossa.
Assess and treat by mobilizing in the posterior plane. Mobilization techniques targeting the posterior glide of the humeral head can help restore normal arthrokinematics and improve shoulder internal rotation.
Review: Shoulder Abduction
Convex on concave (humerus on glenoid fossa). During shoulder abduction, the convex humeral head moves on the concave glenoid fossa.
Superior roll, inferior glide. As the humerus abducts, it rolls superiorly while simultaneously gliding inferiorly to maintain joint congruity and prevent impingement.
Kinematics: Describing Motion
Kinematics is the branch of mechanics that describes motion without considering the forces that cause the motion. It focuses on the geometry of movement.
Key terms in kinematics include position, velocity, acceleration, and displacement. These terms are used to quantify and describe the characteristics of motion.
Qualitative vs. Quantitative Analysis
Qualitative: Involves describing the quality of motion using subjective terms such as fast, slow, smooth, or uncoordinated. This type of analysis relies on observation and interpretation.
Quantitative: Involves measuring the quantity of motion using objective measures such as time, distance, velocity, and acceleration. This type of analysis relies on instrumentation and mathematical calculations.
Terminology
Important kinematic terms include: position (location in space), coordinate systems (reference frames), scalars (magnitude only), vectors (magnitude and direction), distance (total path traveled), displacement (change in position), speed (rate of motion), velocity (rate of displacement), and acceleration (rate of change of velocity).
Scalars vs. Vectors
Scalars: Quantities that have magnitude only, without regard to direction, e.g., speed, distance, mass, and temperature.
Vectors: Quantities that have both magnitude and direction, e.g., velocity, force, displacement, and acceleration. Vectors also have a point of application and orientation, which are critical in biomechanical analysis.
Distance vs. Displacement
Distance: The total path traveled by an object during its motion, regardless of direction. It is a scalar quantity.
Displacement: The change in position of an object, measured as the straight-line distance between the initial and final points, along with the direction. It is a vector quantity.
Linear vs. Angular Motion
Linear: Motion in a straight line, characterized by a change in distance or displacement. It is also known as translational motion.
Angular: Motion around an axis of rotation, characterized by a change in angle. It is also known as rotational motion.
Speed and Velocity
Speed: The rate at which an object covers distance, calculated as distance divided by time. It is a scalar quantity.
Velocity: The rate at which an object changes its position, calculated as displacement divided by time. It is a vector quantity.
Acceleration
Acceleration is the rate of change of velocity over time. It can be positive (speeding up), negative (slowing down or decelerating), or zero (constant velocity).
Positive acceleration indicates that the velocity is increasing, constant velocity means there is no change in velocity (acceleration is zero), and negative acceleration (deceleration) indicates that the velocity is decreasing.
Clinical Implications
Deceleration injuries, such as ACL tears and hamstring strains, are common in sports and other activities involving rapid changes in velocity. Understanding the biomechanics of deceleration can help prevent such injuries.
Hamstring strength and cadence in running are important factors in preventing hamstring strains. Proper conditioning and technique can reduce the risk of injury.
Understanding kinematics is also crucial in assessing and managing neurological injuries, such as concussions. Kinematic analysis can provide valuable insights into motor control deficits and recovery progress.
Deceleration Injuries
Deceleration = Negative Acceleration, but it is contextual and depends on the situation. The frame of reference matters when interpreting acceleration values.
Brain deceleration impact on the skull upon rapid deceleration can result in concussions or traumatic brain injuries. The forces generated during rapid deceleration can cause the brain to collide with the inner surfaces of the skull.
Directions
Determining the direction in which a segment is moving (anterior and/or posterior) is essential for understanding joint and body mechanics. This directional analysis helps in identifying movement impairments and guiding treatment strategies.
Determining whether a segment is moving forward or backward (superiorly vs. inferiorly) aids in assessing joint alignment and identifying postural abnormalities.
Assessing the direction of the roll during arthrokinematic motions is crucial for understanding joint mechanics and guiding mobilization techniques. The direction of the roll influences the direction of the glide, which is essential for normal joint function.
Segment Movements
Analyzing segment movements involves assessing the relative motion between adjacent body segments. This assessment helps in identifying movement dysfunctions and guiding intervention strategies.
Examples:
The tibia is a segment moving on the femur during knee movements.
The carpal bones move on the radius and ulna during wrist movements.