Kinesiology of the musculoskeletal system: CH 1 : Getting started

This nonlinear or "toe" region of the stress-strain graph reflects what?

that collagen fibers within the stretched tissue(s) are initially wavy or crimped and must be drawn taut before significant tension is measured.

1 Newton is equal to

1 kg x 1 m/s^2

periarticular

area surrounding a joint; around articulations or joints

Convex

curving outward

Forces or loads that move, fixate, or otherwise stabilize the body also have the potential to

deform and injure the body

Forces or loads that move, fixate, or otherwise stabilize the body also have the potential to

deform and injure the body.

kinematic

description of motion

Eating and throwing a ball are common examples of ______ kinematics employed by the upper extremities

distal-on-proximal segment kinematics

Flexing the knee in preparation to kick a ball is a type of _____ kinematics

distal-on-proximal segment kinematics

Most routine movements performed by the upper extremities involve (2) This reflects

distal-on-proximal segment kinematics. the need to bring objects held by the hand either toward or away from the body.

habitual

done or doing constantly or as a habit

area under the curve of the stress-strain curve/graph represents

elastic deformation energy

Yield Point

elastic limit of tissue

As described by Newton's 2nd law, the quantity of a force (F) can be measured by the product of the __ that receives the push or pull, multiplied by the __ of the mass.

mass (m) Acceleration (a)

A joint is generally least congruent near its

midrange

active movement

motion caused by stimulated muscle The joint motion that results from muscle contraction.

Passive movement

motion produced by a source other than activated muscle (such as a push or pull from another person, the pull of gravity, tension in stretched connective tissue)

The proximal segment of a joint in the upper extremity is usually stabilized by whereas the distal segment does what?

muscles, gravity, or its inertia Rotates (relatively unconstrained)

Degrees of freedom

number of independent directions of movements allowed at a joint indicates the number of permitted planes of angular motion at a joint

The pair of articular surfaces within most joints "fits" best in how many positions. usually in or near where? (B) This position of maximal congruency is referred to as the joint's ___-__ ___

only 1 position; the very end range of a motion. (B) Close-Packed Position

At many joints, the amount of (passive) _____is used clinically to test the health of the joint. (2) Excessive ____of a bone relative to the joint may indicate what. (3) significant reduction in translation (accessory movements) may indicate what

(1) Translation; Translation (2) ligamentous injury or abnormal laxity (3) pathologic stiffness within the surrounding periarticular connective tissues

the concurrent roll-and-slide motion maximizes __ ___ of the abducting humerus and (B) minimizes the net ___between joint surfaces. (C) This mechanism is most important in joints which the articular surface is area of the ____ member of the joint exceeds that of the ___ member

(A) Angular displacement (B) Translation (C) Convex; Concave

this phenomenon of viscoelastic materials explains why a person is taller in the morning than at night. (B) Explain answer

(A) Creep (B) The constant compression caused by body weight on the spine throughout the day squeezes a small amount of fluid out of the intervertebral discs

Ligaments, are routinely strained within the lower limits of their (Elastic or Inelastic) Region. (B) Meaning what?

(A) Elastic Region (B) Meaning that the percentage of deformation (strain) that occurs as a result of the internal stress

Any tissue weakened by disease, trauma, or prolonged disuse may not be able to ___ the application of loads/forces frequently applied to the body. (B) For example, a promixal femur weakened by osteoporosis may fracture from the impact of a fall secondary to. (C) Fracture may also occur in a severely osteoporotic hip after

(A) Resist (B) compression or torsion (twisting), shearing, or bending of the neck of the femur (C) a very strong muscle contraction.

A (rolling or sliding) convex surface typically involves a concurrent, oppositely directed (rolling or sliding). (B) For example, the inferior-directed ____of the humeral head offsets most of the potential superior ____of the rolling humeral head.

(A) Rolling; Sliding (B) Slide; Migration

The humero-ulnar joint at the elbow is an example of a __ __ relationship between two articular surfaces. (B) The trochlea of the humerus is __, and the trochlear notch of the ulna is __.

(A) convex-concave relationship (B) Convex; Concave

Acceleration

Change in velocity divided by the time it takes for the change to occur Rate at which velocity changes

Pronation Kinematic chain

1. Pelvis: (R) CCW; Fwd Translation; Anterior Rotation 2. Hip: Flexion; Adduction; Internal Rotation 3. Knee: Flexion; Valgus; Tibial Internal Rotation 4. Ankle: Dorsiflexion 5. Subtalar: Calcaneal Eversion; Talar Adduction and Plantarflexion 6. Midtarsal: Unlocking 7. First Ray: Unlocking

A joint can have up to ____ degrees of angular freedom, corresponding to what

3 the three cardinal planes.

Swing phase

40% of the gait cycle in which the reference extremity is not in contact with the ground

Most healthy tendons fail at about__-_% beyond their prestretched length

8-13%

The offsetting roll-and slide arthrokinematics that occur at a joint during movment is analgous to a car (spinning or rolling) on a shet of ice. (B) In this example, The potential for the tire to rotate forward on the icy pavement is offset by a continuous sliding of the tire in the opposite direction to the intended rotation.

A car tire spinning on a sheet of ice

Center of Gravity

A fixed point in a material body through which the resultant force of gravitational attraction acts.

Motor unit

A motor neuron and all of the muscle fibers it innervates

The ability of periarticular connective tissues to __ and __ loads is an important topic of research within PT.

Accept and Disperse

Abnormal translation within a joint typically affects the quality of the ____ movements, potentially causing what

Active increased intra-articular stress and microtrauma

The area under this region of the stress-strain curve represents elastic deformation energy

Area under the curve of the elastic region

The area under this region of the stress-strain curve represents plastic deformation energy

Area under the curve of the plastic region

The pivot point for angular motion of the body or body parts is called what. (2) The ___is at the point where motion of the rotating body is ___

Axis of rotation axis; zero

Movement of the human body as a whole is often described as a translation of the body's ___ ___ ___ which is found generally just anterior to what?

Center of Mass anterior to the sacrum

Accessory movements are typically minimal in a joint's close or loose packed position.

Close

In this position, most ligaments and parts of the capsule are pulled taut, providing natural stability to the joint.

Close-Packed position

In this type of kinematic chain movement, the proximal segment moves freely, while the distal segment remains fixed.

Closed Kinematic chain

A squat is an example of what kind of kinematic chain

Closed kinematic chain (I.E. proxmial on distal segment kinematic movement)

As a rough estimation, the axis (or pivot point) can be assumed to pass through the ____member of the joint.

Convex

The ____members of most joints, like the humeral head at the shoulder, are imperfect spheres with changing ___ ___. (2) This means what?

Convex surface curvatures That the axis of rotation changes throughout motion because the convex part of the joint is not a perfect sphere and the concave part is also not perfectly shaped.

(A) During a convex-on-concave movement, the ___surface rolls and slides in (opposite or same) directions. (B) During a concave-on-convex movement, the ___surface rolls and slides in (opposite or similar) directions

Convex; Opposite (B) Concave; Similar

One phenomenon of a viscoelastic material is ____, which describes what?

Creep; describes a progressive strain of a material when exposed to a constant load over time (I.E. material deforms over time so long as a constant load is applied)

A closed kinematic chain describes a situation in which the __ segment of the kinematic chain is fixed to the earth or another immovable object. The proximal segment therefore

Distal segment Proximal segment moves freely in a closed kinmatic chain movement

Name of the initial nonlinear and subsequent linear regions of the stress-strain curve/graph

Elastic Region

T or F; elastic energy has no important functions within joints in a static position

False; It contributes to the stabilization of joints even in a static position

T or F; Most tissues within the musculoskeletal system demonstrate no degree of viscoelasticity

False; they demonstrate at least some degree of

In order to balance the torque equilibrium equation, A muscle must produce a force much ( greater or Less) than the opposing external force.

Greater

In general, the slope of a stress-strain relationship when placed under tension or compression (increases or decreases) throughout its elastic range as the rate of the loading increases

Increases

The force that stretches a healthy ligament, is met by an ___Tension generated within the elongated (stretched) tissue

Intrinsic

The stress-strain curve of a viscoelastic material is or is not sensitive to the rate of loading of the tissue

It is sensitive to the rate of loading

refers to a series of articulated segmented links, such as the connected pelvis, thigh, leg, and foot of the lower extremity.

Kinematic Chain

lever systems with an MA ____ ___1 are able to balance the torque equilibrium equation by an internal (muscle) force that is less than the external force. A. Greater Than B. Less Than C. Equal to

Less Than

Third-class levers always have an MA (Greater or Less) than 1.

Less than

A force that acts on the body is often referred to generically as a

Load

Arthrokinematics

Motion between articular surfaces of joints

standard unit of force

Newton (N)

The proximal segment is fixed while the distal segment moves freely in what kind of kinematic chain?

Open kinematic chain

Distal segment moves freely in an open or closed kinematic chain

Open kinematic chain (movement/exercise)

_____describes the motion of bones relative to the three cardinal (principal) planes of the body

Osteokinematics

The proximal femur weakened by __, may fracture from the impact of a fall secondary to compression or torsion (twisting), shearing, or bending of the neck of the femur.

Osteoporosis

tension in stretched connective tissue is an example of what kind of motion

Passive Movement

Bones rotate around a joint in a plane that is ____to an axis of rotation

Perpendicular

The area under the curve of the plastic region of the stress-curve represents

Plastic Deformation energy

Point where strain of a tissue is so significant that microscopic failure has occurred and the tissue remains permanently deformed

Plastic deformation

This physical behavior of an overstretched (or overcompressed) tissue is known as

Plasticity

units of stress are similar to ____:

Pressure (N/mm2)

A tire rotating across a stretch of pavement is an analogy for which arthrokinematic movement?

Roll

Multiple points along one rotating articular surface contact multiple points on another articular surface. This is which arthrokinematic movement? A. Roll B. Slide C. Spin D. Abduction

Roll (or rock)

Which two arthokinematic movements typically occur concurrently during an osteokinematic motion, such as during the abduction of the humerus?

Roll-and-Slide

Extension of the knee demonstrates a combination of ___&___ with ___ arthrokinematics. (B)The femoral condyle is ___, and the tibial plateau is slightly ___.

Roll-and-slide with Spin Convex; Concave

What are the 3 Fundamental movements between joint surfaces (I.E. what are the 3 fundamental arthrokinematics movements) (B) These movements occur as a ____ surface moves on a ___ surface, and vice versa

Roll: multiple points contact multiple points Slide: single point contacts multiple points Spin: single point contacts single point (B) Convex; Concave

_____ , in contrast to translation, describes a motion in which an assumed rigid body moves in a circular path around some pivot point. (2) As a result, all points in the body simultaneously rotate in the same angular direction (e.g., ____and ___) across the same # of ____

Rotation (2)Clockwise; Counterclockwise; Degrees

A nonrotating tire skidding across a stretch of icy pavement is an analogy for which arthrokinematic movement?

Slide

A single point on one articular surface contacts multiple points on another articular surface. This is which arthrokinematic movement? A. Roll B. Slide C. Spin D. Abduction

Slide/glide

A toy top rotating on one spot on the floor is an analogy for which arthrokinematic movement?

Spin

What is the primary mechanism for joint rotation when the longitudinal axis of a moving bone intersects the surface of its articular mate at right angles?

Spinning

(A) Another primary way that a bone rotates is by a ____of its articular surface against the articular surface of another bone. (B) Some examples of this include

Spinning (B) The radius of the forearm spinning against the capitulum of the humerus during pronation of the forearm , internal/external rotation of the 90° abducted glenohumeral joint, and flexion and extension of the hip

During flexion/extension of the knee, the femur ___ internally slightly as the femoral condyle __and ___relative to the fixed (stationary) tibia

Spins Roll-and-Slides

Phase of walking when the limb is planted on the ground under the load of body weight

Stance Phase

The ratio of the stress (Y) caused by an applied strain (X) in the ligament is a measure of its ____ which is often called what?

Stiffness Youngs modules

On The Stress-Strain curve/graph, The vertical (Y) axis of the graph is labeled ____, which denotes What?

Stress Stress refers to the internal resistance generated as the ligament resists deformation, divided by its crosssectional area.

under a relatively slight strain (stretch), the ligament produces only a small amount of ____ (___) Refer to graph of ____-___ relationship

Stress (Tension) Stress-Strain Relationship graph/curve

This Graph shows the tension generated by a generic ligament (or tendon) that has been stretched to a point of mechanical failure.

Stress-Strain curve/relationship graph

Phase of walking when the limb is advancing forward

Swing Phase

loads (or forces) most frequently applied to the musculoskeletal system

Tension Compression Bending Shearing Torsion Combined loading (torsion and compression)

Arthrokinematics at the glenohumeral joint during abduction

The contracting supraspinatus rolls the convex humeral head against the slight concavity of the glenoid fossa. the roll directs the osteokinematic path of the abducting shaft of the humerus.

Tension Force

The force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends

Elastic region

The range in which a certain material extends elastically and that can return to its original shape

Stress-Strain Curve

The relationship between the stress and strain that a particular material displays

Osteokinematics

The relationship of the movement of bones around a joint axis

Stress (mechanical )

The resistance force generated internally by a ligament or other tissue as it resists deformation divided by the tissues CSA (Cross-sectional area)

Loose-packed position

The resting position where the joint is under the least amount of strain. all other joint positions, less contact area between surfaces

describes a linear motion in which all parts of a rigid body move parallel to and in the same direction as every other part of the body

Translation

Units of meters or feet are used for ____, and degrees or radians are used for ____.

Translation Rotation

All synovial joints in the body possess at least some ____, driven actively by ____or passively because of what?

Translation Muscle because of the natural laxity within the structure of the joint

Depending on the location of the axis of rotation, A first-class lever can have an MA equal to, less than, or greater than 1. T or F

True

Fracture can occur in a severely osteoporotic hip after a very strong muscle contraction. T or F

True

Healthy tissues are typically able to partially resist changes in their structure and shape. T or F

True

T or F; plastic (deformation) energy, unlike elastic deformation energy is not recoverable in its entirety even when the deforming force is removed

True

T or F; A persons center of mass translates through space

True but it is powered by muscles that rotate the limbs

T or F; each axis shifts slightly throughout ROM (2) The axis of rotation would remain stationary only under what conditions?

True if the convex member of a joint were a perfect sphere, articulating with a perfectly reciprocally shaped concave member

T or F; The lower extremities routinely perform both proximal-ondistal and distal-on-proximal segment kinematics. (B) These kinematics reflect, in part, the two primary phases of walking:

True (B) Stance Phase and Swing Phase

Healthy tissues are typically able to partially resist changes in their structure and shape. T or F (B) A force that stretches a healthy ligament for example is met by what?

True an intrinsic tension generated within the elongated (stretched) tissue

The point on the stress-strain curve when the tissue partially or completely separates and loses its ability to hold any level of tension.

Ultimate Failure Point

Tissues in which the physical properties associated with the stress-strain curve change as a function of time are considered ___.

Visocelastic

A tissue that is elongated beyond its physiologic range eventually reaches its

Yield Point

At this point on the stress-strain curve, any increased strain results in only marginal increased stress (tension).

Yield Point

At this point on the stress-strain curve, overstrained tissue experiences Plastic deformation. (B) Meaning what?

Yield Point (B) that microscopic failure as occured and the tissue is permanently deformed

impetus

a moving force, impulse, stimulus

The clinical term "tightness" usually implies what?

a pathologic condition of abnormally high stiffness (I.E. Low flexibility/elasticity)

Young's modules

a property of a material that tells us how easily it can stretch and deform and is defined as the ratio of stress (σ) to strain (ε). A measure of a materials stiffness (How easily it can or cannot stretch/deform)

A kinematic chain refers to what?

a series of articulated segmented links, such as the connected pelvis, thigh, leg, and foot of the lower extremity.

what does measuring a force yield of a body?

acceleration of the body, and vice versa

Movement of the body, regardless of translation or rotation, can be described as

active or passive

orthogonal

adj. Having or determined by right angles.

stretch-shortening cycle (SSC)

an eccentric-concentric coupling phenomenon in which muscle-tendon complexes are rapidly and forcibly lengthened, or stretch loaded, and immediately shortened in a reactive or elastic manner employs both the energy storage of the SEC and stimulation of the stretch reflex to facilitate maximal increase in muscle recruitment over a minimal amount of time

In the relaxed glenohumeral joint, for example, the humerus can be passively translated slightly

anterior-posteriorly, medial-laterally, and superior-inferiorly

From a kinesiologic perspective, a force can be considered as what. (B) Forces therefore provide the ultimate impetus for ___ and __of the body

as a push or pull that can produce, arrest, or modify movement (B) Movement and stability

Kinematics

branch of mechanics that describes the motion of a body, without regard to the forces or torques that may produce the motion.

most articular surfaces of bones are either __or __. (B) Depending on which bone is moving, a __surface may __on a __surface or vice versa. (C) Each scenario presents a different ___&___ arthrokinematic pattern.

concave or convex (B) Convex; rotate; concave (C) Roll-and-slide

The convex-concave relationship of most articulations improves what? (B) Increases what? (C) and helps guide the motion between what?

congruency (fit), increases the surface area for dissipating contact forces, and helps guide the motion between the bones.

for the shoulder, during a convex-on-concave movement, the ___surface rolls and slides in (opposite or similar) directions. the contradirectional slide offsets much of the ___tendency inherent to the rolling convex surface.

convex; opposite Translation

Most joint surfaces, are at least slightly ____, with one surface being relatively ____and one relatively _____

curved Convex Concave

In the lower extremity, the loose-packed positions of the major joints are biased toward ___.

flexion

A classic example of a joint combining roll-and-slide arthrokinematics with arthrokinematic spinning is

flexion/extension of the knee

Joint Reaction Force

force that exists at a joint, developed in reaction to the net effect of internal and external forces

Joint Reaction Force

force that exists at a joint, developed in reaction to the net effect of internal and external forces; includes contact forces between joint surfaces, as well as forces from periarticular structures.

Three cardinal planes

frontal (coronal), sagittal, transverse (horizontal)

F = ma shows what?

given a constant mass, a force is directly proportional to the acceleration of the mass:

For many joints in the lower extremity, the close-packed position is associated with a ___function. At the knee, for example, the close-packed position includes full ____, which is approached while standing. The combined effect of the maximal joint congruity and stretched ligaments helps to provide what to the knee

habitual Extension transarticular stability

concurrent

happening at the same time; parallel

All positions other than a joint's close-packed position are referred to as the joint's? (B) In these positions, the ligaments and capsule are relatively (taut or slacked), allowing an increase in ___movements.

loose-packed positions Slacked accessory

In general, the articulation of two or more bony or limb segments constitutes a ___. (B) Movement at a ___can therefore be considered from two perspectives

joint (B) (1) the proximal segment can rotate against the relatively fixed distal segment, and (2) the distal segment can rotate against the relatively fixed proximal segment both types can and often do occur simultaneously however

Close packed position

joint orientation for which the contact between the articulating bone surfaces is maximum

The slight passive translations that occur in most joints are referred to as accessory movement (AKA ____ ___) and are commonly defined in ___ ___ directions

joint play three linear directions

These positions are generally not used during prolonged standing, but frequently are during long periods of immobilization, such as extended bed rest.

loose-packed joint positions

The humeral head translating upward and impinging on the tissues in the subacromal space during abduction is an example of what. (B) The migration alters the relative location of the __ _ __, which may alter the effectiveness of what?

pathologic example of a convex surface rolling without an offsetting slide (B) Axis of Rotation; the muscles that cross the glenohumeral joint

strain (mechanical)

percent increase in a tissue's stretched length relative to its original, length; ratio of a tissue's deformed length to its original length.

The ability of ___connective tissues to accept and disperse loads is an important topic of research within physical rehabilitation.

periarticular

productive antagonism

phenomenon in which relatively low-level tension within stretched connective tissues performs a useful function

Axis of rotation

pivot point for angular motion of the body or body parts

One method of measuring the ability of a CT to tolerate a load is to

plot the force required to deform an excised tissue

primary variables related to kinematics

position, velocity, acceleration

Descending into a squat position is an example of _____ kinematics

proximal-on-distal segment kinematics

flexing and extending the elbows while performing a pull-up is what kind of kinematic movement

proximal-on-distal segment kinematics

The __-__ nature of viscoelastic connective tissues may protect surrounding structures within the musculoskeletal system.

rate-sensitivity

Translation can occur in either a Straight line (_____) or a curved line (____).

rectilinear curvilinear

two kinematic perspectives are shown for knee flexion in Fig. 1.6. A term such as knee flexion, for example, describes only the ___motion. It does not describe what however

relative does not describe which of the two segments is actually rotating. (often necessary to state the bone that is considered the rotating segment)

One primary way that a bone rotates through space is by a ____ of its articular surface against another bone's articular surface

rolling

Types of motion

rotary: object tied to fixed point and turns around that point; ex: biceps curl; translatory: object not tied down, moves linearly all parts same direction and speed; ex: slide forearm across the table; curvilinear: combo of rotary and transitory; general plane: linear and rotary happen simultaneously

kinematic chain

series of articulated segmented links, such as the connected pelvis, thigh, leg, and foot of the lower extremity

An open kinematic chain describes

situation in which the distal segment of a kinematic chain, (such as the foot in the lower limb), is not fixed to the earth or another immovable object. Distal segment is free to move

In the knee the ___motion that occurs with flexion and extension occurs automatically & is linked to the mechanically to the primary motion of ____. (B) the obligatory __rotation is based on what? (C) The conjunct __helps to securely lock the knee joint when fully extended.

spinning extension (B) spinning; the shape of the articular surfaces at the knee. (C) Rotation

The horizontal (X) axis of the stress-strain curve/graph is labeled what? (B) Which is refers to what?

strain (B) Strain refers to percent increase in a tissue's stretched length relative to its original unstretched length Note: Can also be used to measure the stress caused by compresion rather than tension (stretching)

joint play

the laxity or elasticity of a joint capsule that allows movement of the joint surfaces within the capsule arthrokinematic movement that happens between joint surfaces when an external force creates passive motion at the joint Nonvoluntary movement, (accessory movement)

Angular motion

the motion of a body about a fixed point or fixed axis

Strain

the percent deformation of a material in response to stress (either elongation due to tension force or compression due to compression force) relative to the materials original length

In general, the slope of a stress-strain relationship when placed under tension or compression increases throughout its elastic range as what increases?

the rate of loading

For most movements of the limbs or trunk, the axis of rotation is located within or very near

the structure of the joint.

the shoulder has how many degrees of angular freedom

three

The shoulder has how many axis of rotation. (2) Why?

three because it can perform movement in all 3 planes

The terms "open" and "closed" with regards to kinematic chain are used to indicate what

whether the distal end of an extremity is fixed to the earth or some other immovable object.

A net force is ___when the acceleration of the mass is zero.

zero