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Flashcards in Biomechanics Deck (79)

Historical Emergence of Chiropractic

D.D. Palmer in 1895, stated that a subluxation is a vertebra that is out of its normal anatomical relationship with an adjacent vertebra, subluxation effects nerve and transmission, causes disease, body can heal itself


Divergence of Chiropractic

Vitalism; biological activity is controlled by a vital force of life principles that cannot be tested, the innate intelligence
this Innate intelligence is responsible for restoring health, subluxations can impinge these nerve roots
Mechanism; biological activity can be explained by physical and chemical laws and principles
inquiry of subluxations impact of body, sublux cause nerve impingement creating abnormal reflexes


Emergence of Difference in Chiropractic

Straight - focus on spine excluding ancillary therapies
Mixers - treatment of spine and extremities with full use of ancillary techniques


Technique Systems

step by step protocol for diagnosing and treatment - originate from the practice experience, is not easily testable b/c they are based on unquestionable principles
Prominent Named techniques - Activator, Gonsted, Thompson, CBP, Logan Basic, NUUCA, Applied Kinesiology, SOT


Biomechanical Model of Chiropractic

Biomechanics; the science concerned with the internal and external forces acting on a human body and the effects produced by these forces
Kinesiology; the science of human movement
- principles can be used to explain joint dysfunction, function of joint can be formulated and tested, provides framework of understanding spinal function and can be linked with information from other fields


Biomechanical Approaches to Joint assement

Static and Dynamic


Static Model

structural emphasis
hypothesis: alterations in position of adjacent bones create changes in mechanical function of a joint and neurological functions
diagnostic entities: subluxation-chiro anatomic disrelationship and orthopedic is a partial or incomplete dislocation, misalignment, malposition
diagnostic tools: static palpation, X-ray, posture evaluation
basis: straight spine is healthy spine, structure determines function
limitations: anomalies to bones, vertebral segments are correctly aligned even though there are signs of dysfunction, vertebral segments are compensating for biomechanical faults, posture, hand dominance and other biomechanical factors
advantages: used in acute conditions, limited motion exists, easily understood by patients


Dynamic Model

functional emphasis
hypothesis: alterations in motion, b/w adjacent bones result in altered mechanical and neurological function, muscles and ligaments contribute
diagnostic entities: jt. dysfunction, jt. restriction, jt. fixation
diagnostic tools: global range of motion, motion palpation, joint and end play, motion X-rays, posture and gait analysis
basis: mobile spine is a healthy spine, function is more significant than structure
limitations: less help for acute, relationship b.w areas in spine can be overlooked, postural and static stresses often overlooked, less helpful in areas with limited motion, limited motions due to coexisting diseases, lock of consistent interexaminer reliability
advantages: theory and concept consistent with current knowledge in other related health care disciplines, accounts for more components of the joint that become dysfunctional such as relationship b/w soft tissue changes and jt. dysfunction


UWS Approach

-Integrated biomechanical approach to the physical examination of the Neuro Musculo Skeletal system incorporating both structural and functional analysis
-Integration of ancillary therapies such as diet, exercise, physiotherapy and psychological support in overall assessment and treatment of the patient


Classical Components of Physical Exam

observation, palpation, percussion, auscultation


Components of the physical exam of NMS system

observation, range of motion, palpation, muscle testing, orthopaedic testing,neurological testing, percussion and auscultation


Pathomechanical Diagnosis and Definitions

Subluxation, Subluxation Syndrome, Joint Dysfunction, Joint Fixation, Joint Restiction



medical - a partial or complete dislocation
chiro - alteration of the normal dynamic, anatomic, and physiological relationships of contiguous articular structures


Subluxation Syndrome

a complex clinical syndrome with potential mechanical inflammatory vascular and neurobiologic pathological effects


Joint Dysfunction

joint mechanics showing disturbances of function without structural or positional change
3 types: joint hypomobility (restriction), joint hypermobility, clinical joint instability


Joint Fixation

articulation has become temporarily immobilized in a position (malposition), the immobilization of an articulation in a position of movement when the joint is at rest, or in a position of rest when the joint is in movement


Joint Restriction

sometimes called a subluxation
limitation of movement, describes the direction of limited movement in dysfunctional joints



Pain - location, quality and intensity
Assymetry - section or segmental
Range of Motion abnormality - increase or decrease of movement, assessed by motion palpation
Tone, Texture and Temperature - of the soft tissue
Special Tests - lab procedures, specific technique systems


Clinical Presentation of Joint Dysfunction/Subluxation

Causes are: Macrotrauma - single traumatic event
Microtrauma - repeated minor cumulative events
Posture - anterior head carriage


Diagnosis of Clinical Conditions

Joint Dysfunction - presence of joint pathomechanics without further pathophysiologic process
Joint dysfunction and disease - a causal relationship exists b/w the joint pathomechanics and other conditions thru somatoautonomic reflexes (Somatosomatic reflex, Somatoviceral reflex, viceralsomatic reflex)
Joint dysfunction and disease - Both existing independently, no apparent causal relationship exists


Physical Assessment of Joint Dysfunction and Subluxation

Global Range of Motion
Static Palpation
Motion Palpation



Superficial, Posture Gait


Global Range of Motion

The evaluation of a joint or spinal regional movement in all its ranges of movement comparing to standards of goniometry and Inclinometry


Static Palpation

The act of feeling with the hands. The application of variable pressure through the surface of the body for the purpose for determining the shape, size, consistency, position, mobility and health of the tissues beneath. Includes static palpation of soft tissue (Dermal and sub dermal layers), bone and cartilage


Motion Palpation

Palpatory diagnosis of passive and active segments joint range of motion. There are 3 parts to it:
-The range of joint motion
-Interpretation of Joint Motion


Objectives of Motion palpation

are to find quantity of the joint movement, quality of the movement thru motion, joint play against resistance, end feel and pain symptoms during the motion of that joint


Range of Joint Motion

is a known continuum that can show each range of the joint movement. Parts include Joint play, active ROM, passive ROM, Physiological barrier, End play, Elastic barrier Paraphysiological space, and anatomical limit


Interpretation of Joint Motion

-End play; each joint has a characteristic end feel, can be palpated in normal or abnormal conditions, palpated in abnormal only
-Painful arc; pain during normal arc of joint
-Capsular pattern; injuries to joint capsule that lead to predictable patterns of end play (Cyriax)
-Noncapsular pattern; Injuries to only one part of the joint capsule lead to predictable patterns of end play restrictions
-Hypermobility - joints that move too much


Palpation of joint in normal and abnormal condition

Capsular - firm but giving; resistance builds with lengthening, like stretching a piece of leather
Ligamentous - like capsular but may have a slightly firmer quality
Soft Tissue approximation -Giving, squeezing quality; results from the approximation of the soft tissues
Bony - Hard, nongiving abrupt stop
Muscular - Firm but giving, build elongation; not as stiff as capsular or ligamentous


Palpation of joint in abnormal condition only

Muscle spasm - guarded, resisted by muscle contraction. The end feel cannot be assessed b/c of pain and/or guarding
Interarticular - bouncy, springy quality
Empty - Normal end feel resistance is missing; end feel is not encountered at normal point, and/or the joint dysfunction demonstrates unusual give and deformation


Muscle Testing

-clinical assessment of strength of a muscle to evaluate the integrity of the muscle tissue and its nerve supply
-not muscle testing in the AK sense
-has a grading system
-Clinical significance shows signs of strong and painful, weak and painful, and weak and painless


Grading System of muscle testing

0 - no muscular contraction detected
1 - Trace of contraction
2 - Can move body part without force of gravirt applied
3 - Able to resist gravity (lift body part)
4 - Able to resist gravity against some resistance
5 - Able to reisst gravity against full resistance


5 major systems of naming Abnormal Joint position and movement




used to designate static listings
based on static palpation and x ray markings
P is 1st, R/L is 2nd, and I/S is 3rd
Follow the SP



uses to designate static listings
based on static palpation and x ray markings
R/L is 1st, P is 2nd and I/S is 3rd
follow the TP



used to designate static listings
based on static palpation and x ray markings
standard joint motion terminology to describe position of a joint
uses the term "malposition" at the end of the phrase
can be used to describe flex, ext, lateral flex and ext, rotation and listhesis



used to designate dynamic listings
based on motion palpation and or dynamic x ray markings
uses the term restriction at the end of the phrase and has the markings for mild, moderate and marked



can be used to designate static or dynamic listings
reference point is anatomical position
based on the Cartesian orthogonal coordinate system to anything away from neutral is + and back towards centre is -ve
clockwise rotation is +ve


Relationship b/w Static and Motion

Thisese two can not be equated



branch of mechanics that deals with the motion of a body without references to the forces that produce the motion



branch of mechanics that deal with the ratlins b/w the force system acting on a body and the changes it produces in the body motion



A line around which rotary movement takes place or along which translation occurs
X axis- coronal plane, movement around sagittal
Y axis- vertical axis, movement around transverse
Z axis- sagittal, movement around coronal



A flat surface determined by the position of 3 points in space


Plane Motion

motion in which all point of rigid body move parallel to a fixed plane


Out of Plane Motion

motion in which all point of a ridigbody do not move in a single plane


Intantaneous Axis of Rotation

at every instant this is a pt that does not move
axis is perpinducular to plane of motion
found at intersection of perpendicular bisectors of tangential vectors
used to describe vertebral movement
can describe any plane of motion
to describe out of plane HAM is used (helical axis of motion)


Motion Segment

smallest spinal segment exhibiting biomechanical characteristics similar to those of the entire spoke. It consists of two adjacent vertebrae and their interconnecting joints and ligaments


Coupled Motion

The consistent association of one motion (translation and rotation) about one axis with another motion about a second axis
cannot produce one motion without the other one, lateral flexion with rotation in the cervical spine


Degrees of Freedom

The number of ways in which a body can move.
1 degree of freedom would be translation or rotation about one axis
The spine exhibits 6 degrees of freedom having 3 in the axis of rotation and 3 translations along the axis



The resting or neutral position of a joint, when the capsule is most relaxed and the greatest amount of play is possible.



The position of a joint when the capsule and ligaments are maximally tightened and there is a maximal contact b/w the articular surfaces


Joint Classifications

Kinesiologic (MacConaill)



Fibrous - little if any movement, formed by fibrous tissues
suture, syndesmosis, gomphosis
Cartilaginous - limited movement, formed by cartilage
synchrondrosis (hyaline cartilage), symphysis (fibrocartilagenous)
Synovial - freely moveable, joints with articular cartilage, ligaments and a joint capsule
nonaxial (plane), uniaxial (ginglymus, trocoid), biaxial (condyloid, ellipsoid, sellar), triaxial (spheroid)



Synarthrosis - negligible movement, fibrous
Amphiarthrosis - limited movement, cartilaginous
Diarthrosis - freely moveable, synovial



assumption joints do not conform to true geometric shapes
all joint surfaces can be considered part of an ovoid shape
ovoid joint surfaces can be either convex or concave
all joint surfaces can be classified into two basic geometric forms
b/c of joint ovoid shape, opposing joint surfaces are essentially non congruent and are completely congruent in only one position-the close-packed position


Two forms of kinesiologic Joints

Simple Ovoid - simplest (roundest) and least specialized movement
-unmodified or triaxial like at the hip
-modified or biaxial where it is ellipsoid
Complex Ovoid - convex joint surface in one plane with a concave joint surface in the plane perpendicular to it
-unmodified or biaxial or saddle like in the thumb
-modified or uniaxial like in the elbow, a hinge


Traditional Classification of Joint Movement




linear translation, one bone gliding or sliding in relation to an adjacent bone with minimal oration or angular movement



an increase or decrease in angle formed between two bones
Flexion, Extension, Lateral Flexion, Adduction, Abduction.



movement occurring around a longitudinal axis of a bone



movement of a bone circumscribing a cone


MacConaill's Classification of Joint Movement

mainly concerned with movements occurring at the joint surfaces
Convex/Concave rule



The study of movement occurring between two bones
Mechanical axis- a line passing thru the moving bone at the starting position of a movement. THe mechanical axis passes thru the centre of the opposing joint surface and is perpendicular to it.
Spin- rotational movement around the mechanical axis
pure spin is when the rotation occurs around the stationary mechanical axis
Swing - movement occurring b.w bones where the mechanical axis traces a path of a chord (straight line) or arc (curved line) on the opposing joint surface



Study of movements occurring b/w opposing joint surfaces
Roll- movement in which new equidistant points on one surface come into contact with new equidistant points on another surface
Slide - movement in which a single contact point on the moving surface contacts various point on the opposing surface
Distraction - separation of the joint surfaces
Compression- approximation of the joint surface where it is coming together


Convex / Concave rule

relates to the expected coupling of roll and slide movements
if a concave surface moves on a convex surface we will have a slide and roll occurring in the same direction
if a convex surface moves on a concave we will have roll and slide occurring in opposite directions


General Principles of Posture

Posture is the biomechanics interaction b/w an organism and gravity
Ideal posture should provide adequate support for the structures and systems of the body while requiring a minimum amount of muscular contraction
Postural distortion may give rise to a variety of symptoms, syndromes and dysfunction patterns
Postural evaluation is an essential part of the examination of the patient with neuromusculoskeletal complaints


Development of Spinal Curves

At birth, the spine is a single C shaped curve with the convexity posterior
Cervical lordosis develops as the extensor muscles become stronger as the infant begins to sit
The cervical lordosis is further accentuated when the child begins crawling
The lumbar curve develops as the child begins to stand and attempts to walk. The iliopsoas muscle pulls the lumbar spine into lordosis by its attachment to the lumbar spine and the femur


Ideal Posture in Lateral View

The gravity line should pass: thru ear lob, thru GH joint, b/w front and back of chest, thru IF joint, ant to midline of knee, anterior to lateral malleolus
Should be no rotation of trunk
Should have normal curvets
Scapulae should lie against the thoracic wall
ASIS should be in the same vert plane as pubic symphasis
Hips, knees, and ankles in neutral position


Ideal Posture PA or AP

iliac crest level, shoulders level, no lateral body sway, no neutral body sway, gluteal cheeks level, no scoliosis, no femur rotation, tibia straight, feet straight, scapulae even, head level


Spine Curves and Pelvic Tilt affecting Posture

Neutral - when the ASIS and pubic symphasis are aligned in the same vertical plane it means there will be normal lordotic curvature
Anterior Pelvic Tilt - when the ASIS is anterior to pubic symphasis, the lordotic curve will increase
Postioer Pelvic Tilt - when the ASIS is posterior to the pubic symphasis, the lordotic curve will decrease


Musculature affecting pelvic Tilt and Spinal curves
Lateral View

will cause abnormalities when the muscles are hypertonic (tight)
Back extensors - increase lumbar lordosis, ant pelvic tilt
Glut Max - post pelvic tilt, decrease LL
Hamstrings - post pelvic tilt, decrease LL
Abdominals - post pelvic tilt, decrease LL
Iliopsoas - Ant pelvic tilt, increase LL
TFL - ant pelvic tilt, increase LL
Rectus Femoris - ant pelvic tilt, increase LL


Muscles affecting lumbars and pelvis from AP view

Quadratus Lumborum - elevate iliac crest, lumbar scoliosis
Gluteus medius - abducts thigh, may cause depression of ipsilateral iliac crest
Thigh Adductors - adduct thigh, may cause elevation of ipsilateral iliac crest


Other muscular effects on posture

Foot everters - fibularis muscles
Foot Inverters - tibialis posterior, flexor digitorum longus, flexor hallucis longus
Soleus - plantar flexes foot, weakness in muscle may cause ankle dorsiflexion accompanied by knee flexion
Gastrocnemius - planta flexes ankle and prevents hyperextension of knee, weakness cause hyperextension of knee
Shortened MR of the arm - palms face posteriorly
Seeratus Anterior - winging of the scapula


Scoliosis & how it is classified

lateral curvature in the normally straight vertical line of the spine
4 ways to determine Classification of scoliosis:
-Named according the shape of the curve and its location in the spine, C or S shaped and named to side of convexity
-Structural, the curve is built into the spine by change in vert bone shape, curve doesn't straighten, idiopathic
-Functional, curve resulrs fromsome biomechanical factor, vertebrae are normal, curve can be straightened
To determine if it is structural vs functional - Adams test using a screening tool and having patient bend forward, Radiographic analysis


Scapular position with Posture

check the positional variations of the scapula by:
normal, abduction, adduction and elevation, winging, tilting and rotation


Leg and Knees with posture from an AP PA view

Femur Position: normal - patella facing forward, Externally rotated - patella facing lateral, Internally rotated - patella facing medial
Knee Position - normal, bowlegged (genu varum), knock-kneed (genu valgum)


Leg and Knees with posture from a lateral view

Knee position: normal alignment, hyperextension (gastric), flexion (soles)


Feet with posture

Pronation/ Eversion - lateral malleolus is medial to lateral edge of the heel
Supination/Inversion - lateral malleolus is lateral to the lateral edge of the heel


Common Postural Faults

Sway back posture: increases thoracic curve (long kyphosis), increased LL, posterior pelvic tilt and ant displacement, hips are extended with gluteal fold visible
Kyphosis-Lordosis Posture: increase kyphosis, increases LL, ant pelvic tilt, hips are flexed
Flat Back Posture: decreased thoracic curve, decrease lumbar curve, posterior pelvic tilt, hips are extended
Military Posture: chest is elevated, increased LL, and ant pelvic tilt