Posture Analysis In Biomechanics

POSTURE ANALYSIS
MADE BY:
Nishank Verma (MPT-Spotrs)
Shikha Kumari (MPT-Ortho)

posture
 Posture is the position & attitude of the body, relative
arrangement of body parts for specific activity or
characteristic work of bearing one’s own body weight.
 Good posture is that state of muscular and skeletal
balance which protects die supporting structures of
the body against injury or progressive deformity,
irrespective of the attitude (erect, lying, squatting, or
stooping) in which these structures are working or
resting.

Static and dynamic posture
 Posture can be either static or dynamic.
 static posture:, the body and its segments are
aligned and maintained in certain positions. Examples
standing, sitting, lying, and kneeling.
 Dynamic posture : in which the body or its segments
are moving—Examples walking, running, jumping,
throwing, and lifting..

POSTURE
a vertical line,
directly through the
center of gravity of
the body must fall
within the base of
support
the net torque about
each articulation of
the body must be
zero
Static
posture
that which is
adopted while the
body is in action,
or in the
anticipatory phase
just prior to an
action
Dynamic
posture

 An understanding of static posture forms the basis for
understanding dynamic posture.
 sustained maintenance of erect bipedal stance is
unique to human

Erect bipedal posture:
 Advantages :
1. allows persons to use their upper extremities for the
performance of large and small motor tasks.
 Distadvantages:
1. increases the work of the heart
2. places increased stress on the vertebral column
pelvis and lower extremities
3. reduces stability.

Various system for postural control
Central nervous visual vestibular musculo-
System system system skeletal
proactive system
reactive system

 In addition, postural control depends on information
received from receptors located in and around the joints
(in joint capsules, tendons, and ligaments), as well as
on the soles of the feet..

Postural control system
CNS
Visual
System
Musculoskeleton
System
Proprioception
System
Vestibular
System

Effects of Altered Inputs and
Outputs
 A more common example of altered inputs occurs when a person
attempts to attain and maintain an erect standing posture when a
foot has “fallen asleep.” “asleep” foot with the supporting surface, is
missing.
 In addition to altered inputs, a person’s ability to maintain the erect
posture may be affected by altered outputs such as the inability of
the muscles to respond appropriately to signals from the CNS.
 In sedentary elderly persons, muscles that have atrophied through
disuse may not be able to respond with either the appropriate
amount of force to counteract an opposing force or with the
necessary speed to maintain stability. Attempts at standing may
result in a fall because input regarding the position of the foot and
ankle, as well as information from contact of the

Perturbation
 A perturbation: is any sudden change in conditions that displaces the
body posture away from equilibrium.
 sensory perturbation: might be caused by altering of visual input,
such as might occur when a person’s eyes are covered unexpectedly.
mechanical perturbation: are displacements that involve direct
changes in the relationship of CoM to the BoS. These displacements
may be caused by movements of either body segments or the entire
body.
 The postural responses to perturbations caused by either platform
movement or by pushes and pulls are reactive or compensatory
responses in that they are involuntary reactions. These postural
responses are referred to as either synergies or strategies.

Types of synergies
Fixed support change in support head stabilizing
Synergies synergies strategy
hip synergy head stab. on
trunk
ankle synergy head stab. In
space

Ankle synergy
Forward movement of platform
causes bacward movement of the
body.as a consequence
displacement of the body’s COM
posterior to BOS.
use of the Ankle strategy is necessary
to bring the body’s COM back over the
BOS and reestabilish stability.

Posterior movement of the platform
causes anterior movt. Of the body
and as a consequence displacement of
the body’s COM anterior to the BOS.

Change in support synergy
Perturbation of erect stance equilibriumcaused by backward platform movement. The
person in this illustration is using a stepping strategy to keep from falling forward in
response to backward movement of the platform. Stepping forward brings the body’s
CoM over a new base of support.

Head stabilizing strategies
 These two strategies is for maintaining the vertical stability of the
head:
Head stabilization Head stabilization
in space (HSS) on trunk (HST).
 The HSS strategy is a modification of head position in anticipation of
displacements of the body’s CoG. The anticipatory adjustments to head
position are independent of trunk motion.
 The HST strategy is one in which the head and trunk move as a single
unit.

Kinetics and Kinematics
of Posture
 The muscle strategies in response to perturbations are examples of the active
internal forces employed to counteract the external forces that affect the
equilibrium and stability of the body in the erect standing posture.
 The external forces : inertia, gravity, and ground reaction forces (GRFs).
 The internal forces : produced by muscle activity and passive tension in
ligaments, tendons, joint capsules, and other soft tissue structures.
 For the body to be in equilibrium.
 External forces+internal forces+torques= ZERO
(i.e, acting on the body and its segments)
 Stability is maintained by keeping the body’s CoM over the BoS and the head in a
position that permits gaze to be appropriately oriented.

Inertial Forces
 In the erect standing posture, little or no acceleration
of the body occurs, except that the body undergoes a
constant swaying motion called postural sway or
sway envelope.
 The extent of sway envelope 12 degrees in the sagittal
for normal individual standing plane
with about 4” between the
feet 16 degrees in the
frontal
plane

 The inertial forces that may result from this swaying
motion usually are not considered in the analysis of
forces for static postures.
 Inertial forces must be considered in postural analysis
of all dynamic postures such as walking, running, and
jogging
 In which the forces needed to produce acceleration or
a change in the direction of motion are important for
understanding the demands on the body.

Ground Reaction Forces
 Whenever the body contacts the ground, the ground pushes back on the body.
This force is known as the GRF,and the vector representing it is known as the
ground reaction force vector (GRFV).
 The GRF is a composite (or resultant) force that represents the magnitude and
direction of loading applied to one or both feet.
The GRF is typically described as having three components:
 VERTCAL COMPONENENT HORIZONTAL
COMPONENT(along y-axis)
M-L direction
(along X-axis)
A-P direction

Ground Reaction Force Vector
•The resultant GRVF is equal in magnitude but opposite in direction to the
gravitational force in the ERECT standing posture.
•GRVF indicates the mag. and direction of LOADING applied to the foot.

Line of Gravity
 The LoG represents the force of gravity-on-person and is
generally equal in magnitude to and in the same direction as the
force of person-on-ground.
 In equilibrium during static stance, we would expect the force of
gravity-on-person (represented by the LoG) to be equal in
magnitude and opposite in direction to the GRF represented by
the GRFV.
 In many dynamic postures, the intersection of the LoG with the
supporting surface may not coincide with the point of
application of the GRFV.
 The horizontal distance from the point on the supporting
surface where the LoG intersects the ground and the CoP (where
the GRFV acts) indicates the magnitude of the external moment
that must be opposed to maintain a posture and keep the person
from falling.

Coincident Action Lines
 The coincident action lines
formed by the GRFV and the
LoG serve as a reference for
the analysis of the effects of
forces on body segments.
 The location of the LoG shifts
continually (as does the CoP)
because of the postural sway.
 As a result of the continuous
motion of the LoG, the
moments acting around the
joints are continually
changing. •Location of the combined action line
formed
by the ground reaction force vector (GRFV)
and the (LoG) in the optimal standing
posture.

Optimal posture
 Normal body structure makes
such an ideal posture impossible
to achieve, but it is possible to
attain a posture that is close to
the ideal.
 In an optimal standing posture,
the LoG is close to, but not
through, most joint axes.
 Slight deviations from the
optimal posture are to be
expected in a normal population
because of the many individual
variations found in body
structure.

Coincident Action Lines
 The coincident action lines formed by the GRFV and
the LoG serve as a reference for the analysis of the
effects of forces on body segments
 The location of the LoG shifts continually (as does the
CoP) because of the postural sway. As a result of the
continuous motion of the LoG, the moments acting
around the joints are continually changing.

Point to Remember
 The effect of external forces on body segments in the
sagittal plane is determined by the location of the LoG in
relation to the axis of motion of body segments.
 When the LoG passes directly through a joint axis, no
external gravitational torque is created around that joint.
 If the LoG passes at a distance from the axis, an external
gravitational moment is created. This moment will cause
rotation of the superimposed body segments around that
joint axis unless it is opposed by a counterbalancing
internal moment (an isometric muscle contraction)

 The magnitude of the gravitational moment of force
increases as the distance between the LoG and the joint
axis increases.
 The direction of the external gravitational moment of
force depends on the location of the LoG in relation to a
particular joint axis
 If the LoG is located anterior to a particular joint axis, the
gravitational moment will tend to cause anterior motion of
the proximal segment of the body supported by that joint.
 If the LoG is posterior to the joint axis, the moment will
tend to cause motion of the proximal segment in a
posterior direction .
 In a postural analysis, external gravitational torques
producing sagittal plane motion of the proximal joint
segment are referred to as either flexion or extension
moments.

Sagittal plane
The anterior location of the LoG in relation to the ankle
joint axis creates an external dorsiflexion moment. The
arrow indicates the direction of the dorsiflexion
moment. The dotted line indicates the direction in
which the tibia would move if the dorsiflexion moment
were unopposed
The anterior location of the LoG in relation to the knee joint axis
creates an external extension moment. The arrow indicates the
direction of the extension moment. The dotted line indicates the
direction in which the femur would move if the extension
moment were unopposed.

Postural analysis
 Traditional method:
PLUMBLINE
 When viewing a standing posture, a plumb line is used as a line of reference. Why a plumb line?
 Because it represents a standard. Based on nature's law of gravity, It is a tool in the science of
mechanics.
 The simple device of a plumb line enables one to see the effects of the force of gravity.
 Invisible, imaginary lines and planes in space are the absolutes against which variable and relative
positions as well as movements are measured.
 In the study of body mechanics, plumb lines represent the vertical planes.
 With the anatomical position of the body as the basis, positions and movements are defined in
relation to these planes.

 The plumb line is a cord with a plumb bob attached to provide an absolutely
vertical line. The point in line with which a plumb line is suspended must be a
standard fixed point.
 Because the only fixed point in the standing posture is at the base, where the
feet are in contact with the floor, the point of reference must be at the base.
A movable point is not acceptable as a standard.
 The position of the head is not stationary; therefore,using the lobe of the ear as
a point in line with which to suspend a plumb line is not appropriate.
 The plumb line test is used to determine whether the points of reference of the
individual being tested are in the same alignment as the corresponding points
in the standard posture.
 The deviations of the various points of reference from the plumb line reveal the
extent to which the subject's alignment is faulty.

 For the purpose of testing, subjects step up to a suspended plumb line.
 In back view, they stand with the feet equidistant from the line.
 In side view, a point just in front of the lateral malleolus is in line with the
plumb line.
 Deviations from the plumb alignment are described as slight, moderate, or
marked rather than in terms of inches or degrees.
 During routine examinations, it is not practical to try determining exactly how
much each point of reference deviates from the plumb line.
 The standing position may be regarded as a composite alignment of a subject
from four views:
 front,back, right side and left side.

STANDARD POSTURE
Posterior to apex
of coronal suture
Through
EAM
& dens
Through
VB of LV
Through
sacral
promontoryPosterior to the
center of the hip
jt
Ant. To
knee
joint axis
Through
calcaneocuboid jt
Through ear lobes
Through bodies CV
Through shouder jt.
Through trunk
Through GT
Anterior to midline
knee
Anterior to lat
malleolus
Plumb
line
alignmen
t
Line of
Gravity

Sagittal Plane Alignment and Analysis
 ■ Ankle
 Neutral position : midway between
dorsiflexion and plantarflexion.
 The LoG anterior to the ankle joint axis.
 creates an external dorsiflexion moment
 It opposed by an internal plantarflexion
moment to prevent forward motion of the
tibia
 There are no ligamentous checks capable
of counterbalancing the external
dorsiflexion moment;
 Therefore, activation of the plantarflexors
creates the internal plantarflexion
moment to prevent forward motion of the
tibia.
 The soleus muscle contracts and exerts a
posterior pull on the tibia to oppose the
dorsiflexion moment
 If the force that the muscle can exert is
less than the gravitational moment, the
tibia will move the ankle into dorsiflexion
and the soleus muscle will undergo an
eccentric contraction while trying to
oppose the forward motion of the tibia.

 ■ Knee
 Neutral position: full extension,
 The LoG anterior to the knee joint
axis
 The anterior location of the LoG
creates an external extension
moment.
 The counterbalancing internal
flexion moment created by passive
tension in the posterior joint capsule
and associated ligaments to prevent
knee hyperextension.
 A small amount of activity has been
identified in the hamstrings.
 Activity of the soleus muscle may
augment the gravitational extension
moment at the knee through its
posterior pull on the tibia as it acts at
the ankle joint.

Hip and Pelvis
The hip is in a neutral position
The pelvis is level with no anterior or
posterior tilt .
In a level pelvis position, lines
connecting the symphysis pubis and
the ASISs are vertical, and the lines
connecting the ASISs PSISs are
horizontal.
The LoG passes slightly posterior to
the axis of the hip joint, through the
greater trochanter.
The posterior location of the LoG in
relation to the hip joint axis creates an
external extension moment at the hip
that tends to rotate the pelvis
(proximal segment) posteriorly on the
femoral heads.
Iliopsoas is acting to create an internal
flexion moment at the hip to prevent
hip hyperextension.

■ Lumbosacral Joint
 The average lumbosacral angle measured
between the bottom of the L5 vertebra
and the top of the sacrum (S1) is about
30 but can vary between 6 and 30.
Anterior tilting of the sacrum increases
the lumbosacral angle and results in an
increase in the shearing stress at the
lumbosacral joint and may result in an
increase in lordosis
 In the optimal posture, the LoG passes
through the body of the fifth lumbar
vertebra axis of rotation of the
lumbosacral joint.
 It creates a very slight extension moment
at L5 to S1 that tends to slide L5 and the
entire lumbar spine down and forward
on S1.
 This motion is is opposed primarily by
the ALL and the ILL. Bony resistance is
provided by the locking of the
lumbosacral zygapophyseal joints

Sacroiliac Joint
 . When the sacrum is in the optimal
position,
 The LoG passes slightly anterior to
the sacroiliac joints.
 The external gravitational moment
is created at the SI joints tends to
cause the anterior superior portion
of the sacrum to rotate anteriorly
and inferiorly, whereas the posterior
inferior portion tends to move
posteriorly and superiorly .
 Passive tension in the sacrospinous
and sacrotuberous ligaments
provides the internal moment that
counterbalances the gravitational
torque by preventing upward tilting
of the lower end of the sacrum.

Vertebal column
 In Lumbar and cervical
vertebrae LoG passes posterior
to the axis and in thorax vertebra
LoG passes anterior to the axis
 Gravitational movement tend to
increase the nalural curve
 longissimus dorsi, rotatores, and
neck extensor muscles are active
This suggests that ligamentous
structures and passive muscle
tension are unable to provide
enough force to oppose all
external gravitational moments
acting around the joint axes of
the upper vertebral column
 In the lumbar region, where
minimal muscle activity appears
to occur, passive tension in the
ALL and passive tension in the
trunk flexors apparently are
sufficient to balance the external
gravitational extension moment.

Saggital plane analysis
Joints Line of Gravity External Moment Passive Opposing Forces Active Opposing Force
Atlanto-occipital Anterior Flexion Ligamentum nuchae and
alar ligament; the tectorial,
atlantoaxialand posterior
atlanto-occipital membrane
Rectus capitus posteriormajor and
minor, semispinalis capitus and
cervi-cis, cervicis, and inferior
andsplenius capitis andsuperior
oblique muscles
Cervical Posterior Extension ALL, anterior anulus
fibrosus fibers, and
zygapophyseal joint capsules
Anterior scaleni, longus capitis and
colli
Thoracic Anterior Flexion PLL, supraspinous, and
interspinoussupraspinous,
and interspinous ligamant
Ligamentum flavum, longissimus
thoracis, iliocostalisthoracis,
spinalis thoracis, and semispinalis
thoracis
Lumbar Posterior Extension ALL,iliolumbar ligaments,
anterior fibers of the anulus
fibrosus, and zygapophyseal
joint capsules
Rectus abdominis and external and
internal oblique
Sacroiliac joint Anterior Nutation Sacrotuberous,
sacrospinous, ili-olumbar,
and anterior sacroiliac
ligament
Transversus abdominis
Hip joint Posterior Extension Iliofemoral ligament Ilipsoas
Knee joint Anterior Extension Posterior joint capsule Hamstrings, gastrocnemius
Ankle joint Anterior Dorsiflexion Soleus, gastrocnemius

Deviations from Optimal Alignment in the Sagittal Plane
 Any change in position or malalignment of one body segment
will cause changes to occur in adjacent segments, as well as
changes in other segments, as the body seeks to adjust or
compensate for the malalignment (closed-chain response to
keep the head over the sacrum).
 Large changes from optimal alignment increase stress or increase
force per unit area on body structures. If stresses are maintained
over long periods of time, body structures may be altered.
 Shortening of the ligaments will limit normal ROM, whereas
stretching of ligamentous structures will reduce the ligament’s
ability to provide sufficient tension to stabilize and protect the
joints.
 Prolonged weight-bearing stresses on the joint surfaces increase
cartilage deformation and may interfere with the nutrition of the
cartilage.
 Postures that represent an attempt to either improve function or
normalize appearance are called compensatory postures..

■ Foot and Toes
 Claw Toes
 Claw toes is a deformity of the
toes characterized by
hyperextension of the (MTP)
joint, combined with flexion of
the (PIP) and distal (DIP) joints.
 The abnormal distribution of
weight may result in callus
formation under the heads of the
metatarsals or under the end of
the distal phalanx.
 The proximal phalanx may
subluxate dorsally on the
metatarsal head.
 Reduces the area of the BoS and,
as a result, may increase postural
sway and decrease stability .
standing position.

Etiologies of claw toes
 The restrictive shoes,
 Cavus-type foot,
 Muscular imbalance,
 Ineffectiveness of intrinsic foot muscles,
 Neuromuscular disorders,
 Age-related deficiencies in the plantar structures.

 Hammer Toes
 It is characterized by
hyperextension of the MTP
joint, flexion of the PIP joint,
and hyperextension of the DIP
joint
 Callosities may be found on
the superior of the PIP joints
over the heads of the first
phalanges and distal phalanges
 The flexor muscles are
stretched over the MTP joint
and shortened over the PIP
joint. The extensor muscles are
shortened over the MTP joint
and stretched over the PIP
joint.


Etiology of hammer toe
 . If the long and short toe extensors and lumbrical
muscles are selectively paralyzed, the instrinsic and
extrinsic toe flexors acting unopposed will buckle the
PIP and DIP joints and cause a hammer toe.

Knee
 Flexed Knee Posture
 The LoG passes posterior to the
knee joint axes.
 The posterior location of the
LoG creates an external flexion
moment at the knees
 It is balanced by an internal
extension moment created by
activity of the quadriceps
muscles .
 The tibiofemoral and
patellofemoral joints to greater
than normal compressive stress
and can lead to fatigue of the
quadriceps femoris and other
muscles .

consequences of a flexed-knee standing posture related to the ankle
and hip.
 knee flexion is accompanied by hip flexion and ankle
plantar flexion.
 At the hip, the LoG may pass anterior to the hip joint
axes, creating an external flexion moment.
 Internal extensor moment to balance the external
flexion moment acting around the hip.
 Increased soleus muscle activity may be required to
create an internal plantarflexion moment to
counteract the increased external dorsiflexion
moment at the ankle

 Hyperextended Knee
Posture (Genu
Recurvatum)
 LoG is located
considerably anterior to
the knee joint axis.
 Create an external
extensor moment acting at
the knee, which tends to
increase the extent of
hyperextension and puts
the posterior joint capsule
under considerable tension
stress
 The anterior portion of the
knee joint surfaces are
subject to degenerative
changes of the
cartilaginous joint surfaces

Etiology of kneehyperextension
 Limited dorsiflexion at the ankle
 Equinus foot
 Habitual( in childhood in which the child or
adolescent always elects to stand with hips and knees
hyperextended in the relaxed or swayback standing
posture).

 Excessive Anterior Pelvic Tilt
 In a posture in which the pelvis is excessively tilted ante-
riorly, the lower lumbar vertebrae are forced anteriorly.
 The upper lumbar vertebrae move posteriorly to keep the
head over the sacrum, thereby increasing the lumbar
anterior convexity (lordotic curve).
 The LoG is therefore at a greater distance from the lumbar
joint axes than is optimal and the extension moment in the
lumbar spine is increased
 The posterior convexity of the thoracic curve increases and
becomes kyphotic to balance the lordotic lumbar curve and
maintain the head over the sacrum.
 Similarly, the anterior convexity of the cervical curve
increases to bring the head back over the sacrum

Pelvis
 Excessive Posterior Pelvic Tilt
 In a posture in which the pelvis is excessively tilted
Posteriorly, the lower lumbar vertebrae are forced
Posteriorly.
 The upper lumbar vertebrae move anteriorly to keep
the head over the sacrum, thereby decreasing the
lumbar anterior convexity (Flatening of curve).
 . The posterior convexity of the thoracic curve
decreases and becomes less kyphotic to balance the
flat lumbar curve and maintain the head over the
sacrum.
 Similarly, the anterior convexity of the cervical curve
decreases to bring the head back over the sacrum

Consequences of excessive
anterior pelvic tilt
.
 Increases in the anterior convexity of the lumbar curve
during increases the compressive forces on the
posterior annuli
 adversely affect the nutrition of the posterior portion
of the intervertebral disks.
 excessive compressive forces may be applied to the
zygapophyseal joints.

Vertebral Column
 Lordosis and Kyphosis
 An abnormal increase in the normal posterior convexity may occur, and this
abnormal condition also may be called a kyphosis. This condition may develop
as a compensation for an increase in the normal lumbar curve,
 The kyphosis may develop as a result of poor postural habits or osteoporosis.
Dowager’s hump is found most often in postmenopausal women who have
osteoporosis.
 The LoG passes at a greater distance from the thoracic spine, and the
gravitational moment arm increases.
 The anterior vertebral body collapse causes an immediate lack of anterior
support for a segment of the thoracic vertebral column, which bends forward,
causing an increase in the posterior convexity (the hump) and an increase in
compression on the anterior aspect of the vertebral bodies
 Compression on the anterior aspects of the vertebral bodies and anterior
annulus increases, and the posterior aspect is subjected to tensile stresses in
the fibers of the posterior annulus and apophyseal joint capsules.
 Causes decrease in height.

Trunk • Kyphosis-Lordosis
Forward head
Increased cervical
lordosis
Scapula Abducted
Increased
thoracic kyphosis
Increased lumbar
lordosis
Anterior pelvic tilt
Knees slightly
hyperextended
Ankles slightly
plantarflexed
Short and Tight:
• Neck extensors
• Hip flexors
• Low back
Lengthened and
Weak:
• Neck flexors
• Hamstrings
• Erector spinae
• Possibly
abdominals

Lordotic SpinePostural fault Anatomical
Position of joint
Muscles in
Shortened Position
Muscles in
Lengthened
Position
Lordotic Posture
Flat-Back Posture
Sway back
posture(Pelvis
displaced
forward,upper trunk
backward)
Lumbar spine
hyperextension
Pelvis ,anterior tilt
Hip joint flexion
Lumbar spine flexion
Pelvis ,posterior tilt
Hip joint Extension
Lumbar spine
position depends on
level f posterior
displacement of uper
trunk and pelvis
Posterior tilt
Hip joint extension
Lower backErector
spinae
Internal oblique
Hip flexors
Anterior Abdominals
Hip Extensors
Upper
abdominals,rectus
and internal oblique
Abdominals,External
oblique lateral
Hip extensors
Lower back erector
spinae
HipFlexors
Lower
abdominals,external
oblique
Hip flexors

Possible Effects of Malalignment on Body StructureDeviation Compression Distraction Stretchin
g
Shortening
Excessive
anterior tilt
of pelvis
Posterior aspects
of vertebral bodies
Interdiskal
pressure atL5 toS1
increased
Lumbosacral angle
increased Shearing
forces at L5 to S1
Likelihood of
forward slippage of
L5 on S1 increased
Abdomin
al
muscles
Iliopsoas,lumbar
extensors
Excessive
Lumbar
lordosis
Posterior vertebral
bodies and facet
joints
Interdiskal
preesure increased
Anterior annulus
fibers
Anterior
longitudi
nal
ligament
Posterior
longitudinal
ligament
Interspinous
ligaments
Ligamentum flavum
Lumbar extensors
Excessive
dorsal
kyphosis
Anterior Vertebral
bodies
Intradiskal
pressure increased
Facet joint capsules
and posterior
annulus fibers
Dorsal
back
extensors
Posterior
ligaments
Scapular
muscles
Anterior
longitudinal
ligament
Upper abdominal
muscles
Anterior shoulder
girdle musculature

Sway back posture
 If the gravitational extension moment at the hip were allowed to
actwithout muscular balance, as in a so-called relaxed or
swayback posture.
 Hip hyperextension ultimately would be checked by passive
tension in the iliofemoral, pubofemoral, and ischiofemoral
ligaments.
 In the swayback standing posture, the LoG drops farther behind
the hip joint axes than in the optimal posture .
 The swayback posture does not require any muscle activity at
the hip but causes an increase in the tension stresses on the
anterior hip ligaments, which could lead to adaptive lengthening
of ligaments i
 Diminished demand for hip extensor activity, the gluteal
muscles may be weakened by disuse atrophy if the swayback
posture is habitually adopted.

Trunk • Sway-back
Forward head
Increased cervical
lordosis
Increased
thoracic kyphosis
Decreased lumbar
lordosis
Posterior pelvic tilt
Knees slightly
hyperextended
Ankles neutral
Short and Tight:
• Upper abdominals
• Intercostals
• Hamstrings
Lengthened and
Weak:
• Neck flexors
• Hip flexors
• Thoracic
extensors
• Lower abdominals

Trunk • Flat back
Forward head
Increased cervical
lordosis
Decreased
kyphosis
Decreased lumbar
lordosis
Posterior pelvic tilt
Knees slightly
hyperextended
Ankles slightly
plantarflexed
Short and Tight:
• Neck extensors
• Abdominals
• Hamstrings
Lengthened and
Weak:
• Neck flexors
• Back extensors
• Hip flexors

■ Head
 Forward Head Posture
 A forward head posture is one in which the head is
positioned anteriorly and the normal anterior cervical
convexity is increased.
 The apex of the lordotic cervical curve at a considerable
distance from the LoG in comparison with optimal posture.
 . The constant assumption of a forward head posture
causes abnormal compression on the posterior
zygapophyseal joints and posterior portions of the
intervertebral disks and narrowing of the intervertebral
foramina in the lordotic areas of the cervical region.

Cont.
 The cervical extensor muscles may become ischemic
because of the constant isometric contraction required to
counteract the larger than normal external flexion moment
and maintain the head in its forward position.
 The structure of the temporo mandibular joint may
become altered by the forward head posture, and as a
result, the joint’s function may be disturbed.
 In the forward head posture, the scapulae may rotate
medially, a thoracic kyphosis may develop, the thoracic
cavity may be diminished, vital capacity can be reduced.
 overall body height may be shortened.

Head and Neck
• Flat neck
▫ Dec cervical lordosis
▫ Inc flexion of the
occiput on the atlas
▫ Retraction of the
mandible
▫ Exaggerated
military posture

Head, Neck, Shoulders and Scapula
 Upper crossed syndrome
 The occiput and C1/C2 will
hyperextend with the head
being pushed forward
 The lower cervical to 4th
Thoracic vertebrae will be
posturally stressed
 Rotation and abduction of
the scapulae occurs

Forward Head Posture
Forward head Anterior location of LoG causes an increase in
the flexion moment, which requires constant
isometric muscle tension to support head
Stretch of suprahyoid muscles pulls mandible
posteriorly into retrusion
Muscle ischemia, pain, and fatigue and
possible protrusion of nucleus pulposus
Retruded mandible position causes
compression and irritation of retrodiskal
pad and may result in inflammation and
pain
Reduction in range of motion
Increase in cervical
lordosis
Narrowing of intervertebral foramen and com-
pression of nerve roots Compression of
zygapophyseal joint surfaces and
increase in weight-bearing Compression of
posterior annulus fibrosus Adaptive shortening
of the posterior ligaments Adaptive lengthening
of anterior ligaments Increase in compression
on posterior vertebral bodies at apex of cervical
spine
Damage to spinal cord and/or nerve roots
leading to paralysis
Damage to cartilage and increased
possibility of arthritic changes; adaptive
shortening and possible formation of
adhesions of joint capsules with subsequent
loss of ROM
Changes in collagen and early disk
degeneration; diminished ROM at the
intervertebral joints
Decrease in cervical flexion ROM
Decrease in cervical extension ROM and
decrease in anterior stability
Medial rotation of
the scapula
Adaptive lengthening of upper posterior back
muscles
Adaptive shortening of anterior shoulder
muscles
Osteophyte formation
Increase in dorsal kyphosis and loss of
height
Decrease in vital capacity and ROM of
shoulder and arm

LOG Passes through Posterior View

HANDEDNESS PATTERN
RIGHT HANDEDNESS LEFT HANDEDNESS

HANDEDNESS PATTERN
 Handedness patterns related to posture may begin at
an early age.
 The slight deviation of the spine toward the side
opposite the higher hip may appear as early as 8 or 10
years o f age.
 There tends to be a compensatory low shoulder on the
s i d e of the higher hip.
 In most cases , the low shoulder is less significant
than the high hip.
 Usually shoulder correction tends to follow
correction of lateral pelvic tilt, but the reverse does
not necessarily occur.

Deviation of alignment in the Frontal Plane
 Any asymmetry of body segments caused either by
movement of a body segment or by a unilateral
postural deviation will disturb optimal muscular and
ligamentous balance.
 Symmetrical postural deviations, such as bilateral.

Foot and toes
 Pes Planus (Flat Foot)
 Normally the plumb line should lie equidistant from
the malleoli.
 The malleoli should appear to be of equal size and
directly opposite from one another.
 When one malleolus appears more prominent or lower
than the other and calcaneal eversion is present, it is
possible that a common foot problem known as pes
planus, or flat foot, may be present.

Pathomechanics of pes planus
 The displacement of the talus causes
depression of the navicular bone,
tension in the calcaneonavicular ligament
lengthening of tibialis posterior muscle.

Continue
 The extent of flat foot may be estimated by
noting the location of the navicular bone in
relation to the head of the first metatarsal.
 Normally, the navicular bone should be
intersected by the Feiss line.
 Flat foot results in a relatively overmobile foot
that may require muscular contraction to
support the osteoligamentous arches during
standing.
 It also may result in increased weight-bearing
on the second through fourth metatarsal
heads with subsequent plantar callus
formation, especially at the second metatarsal.
 Weight-bearing pronation in the erect
standing posture causes medial rotation of the
tibia and may affect knee joint function.

Pes cavus
 The medial longitudinal arch of the
foot, instead of being low (as in flat
foot), may be unusually high. A high
arch is called pes cavus.
 Pes cavus is a more stable position
of the foot than is pes planus.
 The weight in pes cavus is borne on
the lateral borders of the foot, and
the lateral ligaments and the
peroneus longus muscle may be
stretched.
 In walking, the cavus foot is unable
to adapt to the supporting surface
because the subtalar and transverse
tarsal joints tend to be near or at the
locked supinated position.

Hallux valgus
 Definitions
 Hallux valgus deformity – This deformity is defined as a lateral
deviation of the hallux (great toe) on the first metatarsal .
 The deviation of the hallux occurs primarily in the transverse
plane.
 The deformity often also involves rotation of the toe in the
frontal plane causing the nail to face medially (ie, eversion).
 These two deviations have led to the use of different terms to
describe the deformity. it is often called "hallux valgus" (HV)
"hallux abductovalgus (HAV)."
 Hallux abductus (or hallux valgus) angle – The angle created by
the bisection of the longitudinal axis of the hallux and the
longitudinal axis of the first metatarsal . A hallux abductus (HA)
angle of greater than 15 degrees was considered abnormal.

Continue
 Such deformities are not always symptomatic, and some cases of an HA angle
greater then 15 degrees occur naturally due to the shape of the articular surfaces
involved
 Contemporary research suggests an HA angle of 20 degrees or greater is
abnormal .
 Intermetatarsal (IM) angle – The angle determined by the bisection of the
longitudinal axes of the first and second metatarsals. An IM angle less than 9
degrees is considered normal.
 Hallux valgus involves the first ray.
 First ray — No muscles originate on the first metatarsal and insert into the
phalanx to directly stabilize the first metatarsophalangeal (MTP) joint. The
abductor and adductor hallucis muscles pass medially and laterally to the MTP
joint respectively, but they are located nearer to the plantar surface Thus, any
force pushing the proximal phalanx laterally, or the metatarsal head medially, is
relatively unrestrained and can create a valgus deformity.
 The first metatarsal is held in alignment by a splinting action of the abductor
hallucis muscle medially and by the lateral pull of the peroneus longus acting
at the base of the metatarsal .

knees
 Genu valgum (knock knee) is considered to be a nor-
mal alignment of the lower extremity in children from
2 to 6 years of age.
 However, by about 6 or 7 years of age, the physiologic
valgus should begin to decrease, and by young
adulthood, the extent of valgus angulation at the knee
should be only about 5 to 7.

Pathomechanics of genu valgum
 In genu valgum, the mechanical
axes of the lower extremities are
displaced laterally. If the extent
of genu valgum exceeds 30 and
persists beyond 8 years of age,
structural changes may occur.
 As a result of the increased
external torque acting around
the knee, the medial knee joint
structures are subjected to
abnormal tensile or distraction
stress, and the lateral structures
are subjected
 To abnormal compressive stress
 The patella may be laterally
displaced and therefore
predisposed to subluxation.

 The foot also is affected as the
gravitational torque acting on
the foot in genu valgum tends to
produce pronation of the foot
 Accompanying stress on the
medial longitudinal arch and its
supporting structures.
 Abnormal weight-bearing on
the posterior medial aspect of
the calcaneus (valgus torque).
 Additional related changes may
include flat foot, lateral tibial
torsion, lateral patellar
subluxation, and lumbar spine
contralateral rotation.

Genuvarum
 Genu varum (bowleg) is a condition
in which the knees are widely
separated when the feet are together
and the malleoli are touching.
 Some extent of genu varum is
normal at birth and during infancy
up to 3 or 4 years of age.
 Physiologic bowing is symmetrical
and involves both the femur and the
tibia.
 Cortical thickening on the medial
concavity of both the femur and
tibia may be present as a result of
the increased compressive forces,
and the patellae may be displaced
medially.

Squinting or cross-eyed patella:
 Squinting or cross-eyed patella:(patella that faces medially)
is a tilted/rotated position of the patella in which the
superior medial pole faces medially and the inferior pole
faces laterally.
 This abnormal patella position may be present in one or
both knees and may be a sign of either increased femoral
torsion(patella that faces medially) is a tilted/rotated
position of the patella in which the superior medial pole
faces medially and the inferior pole faces laterally.
 This abnormal patella position may be present in one or
both knees and may be a sign of either increased femoral
torsion (excessive femoral anteversion) or medial tibial
rotation.
 The Q-angle may be increased in this condition, and
patella tracking may be adversely affected.

Grasshopper-eyes patella
 Grasshopper-eyes patella refers to a high,laterally dis-
placed position of the patella in which the patella faces
upward and outward.
 An abnormally long patella ligament may be responsible
for the higher than normal position of the patella (patella
alta).
 Femoral retroversion or lateral tibial torsion may be
responsible for the rotated position of the patella.
 Grasshopper-eyes patella leads to abnormal patella
tracking and a decrease in the stability of the patella.

Squinted and Grasshoppereyes
Patella

Vertebral Column
 Scoliosis
 If one or more of the
medial-lateral structures
fails to provide adequate
support, the column will
bend to the side.
 The lateral bending will be
accompanied by rotation
of the vertebrae because
lateral flexion and rotation
are coupled motions below
the level of the second
cervical vertebra.

 lateral deviations of a series of vertebrae from the
LoG in one or more regions of the spine may
indicate the presence of a lateral spinal curvature
in the frontal plane called a scoliosis .
 scoliosis is usually identified as a lateral curvature of
the spine in the frontal plane, the deformity also
occurs in the transverse (as vertebrae rotate) and
sagittal planes (as the column buckles).

classifications of curves:
Functional curve structural curve
or
Non structural curve infantile(3yrs)
or juvenile(3-10yrs)
idiopathic or adolescent(10-20yrs)
postural adult(20 yrs)

Adolescent idiopathic scoliosis
 The adolescent idiopathic scoliosis (AIS) type makes up
the majority of all scolioses and affects up to 4% of
school children worldwide.
 The curves in scoliosis are named according to the
direction of the convexity and location of the curve.

 AIS involves changes in the structure of the vertebral
bodies, transverse and spinous processes,
intervertebral disks, ligaments, and muscles.
 Asymmetrical growth and development of the
vertebral bodies lead to wedging of the vertebrae.
 Growth on the compressed side (concavity) is
inhibited or slower than on the side of the convexity of
the curve.

 Scoliosis
 Lateral deviation of the spine
 Deformity
 Structural
 Fixed deformity
 Apical vertebrae
 Vertebral body on convex
 Spinous process on concave
 Non-structural
 Flexible deformity
 Positional, functional, postural
Trunk

How is scoliosis detected?
Forward bending test
Skyline view

Physical Assessment of Scoliosis By
Scoliometer
 1. View the person from behind, standing erect
 2. Ask the person to extend his arms forward and
place hands together with palms flat against each
other
 3. Ask the person to bend forward slowly, stopping when
the shoulders are level with the hips. For best view, your
eyes should be at the same level as the back.

 4. Before measuring with the Scoliometer, adjust the
height of the person’s bending position to the level where
the deformity of the spine is most pronounced. For
example, a curve low in the lumbar spine will require that
the person bend further forward than one which is present
in the thoracic or upper spine.
 5. Lay the Scoliometer across the deformity at right
angles to the body, with the “0” mark over the top of
the spinous process.

 6. Note: If there is asymmetry in both the upper and
lower back, two Scoliometer readings will be
necessary.
 7. The screening examination is considered positive if the
reading on the Scoliometer is 5 degrees or more at any level
of the spine. Persons in this category should be referred
immediately for further medical evaluation (orthopedic
surgeon).

 8 A change of 3 degrees or more of a scoliometer
measurement indicates a possible curve progression.
 A change of 2 degrees or less usually indicates only
minor variation in posture. It should be noted
however, that in some patients, curve progression may
occasionally occur without a change in the clinical
measurement.

Description of the curve
1. Named according to convexity
2. Major curve - most significant
curve
3. Minor curve - compensatory
curve
4. Double major curve-2 major
curves that are both
structural
5. Transitional vertebrae - neutral
vertebra between 2 curves
6. Apex of the curve - greatest
rotation, farthest from the
midline

How is severity of scoliosis measured?
 Angle of curvature
Risser-Ferguson method Cobb method

How is progression of scoliosis measured?
 Nash-Moe Scale

Sitting posture
 Analysis of Sitting Postures
 Analysis of standing posture, we saw that moments at the spine and
extremity joints were created when the LoG was at a distance from
either a portion of the vertebral column or the axes of the extremity
joints.
 The greater the distance that the LoG was from the joint axes, the larger
the moment that was created and, as a result, the more muscle activity
and/or passive tension in ligaments and joint capsules that was
required to maintain equilibrium and a stable posture.
 The necessary increase in muscle activity resulted in more energy
expenditure and increased loads on body structures.

 sitting postures are more complex than
standing postures.
 The same gravitational moments as in
standing posture must be considered.
 In addition, we must consider the
contact forces that are created when
various portions of the body interface
with various parts of chairs, such as
head, back, and foot rests, and seats.
 The location and amount of support
provided to various portions of the body
by the chair or stool may change the
position of the body parts and thus the
magnitude of the stresses on body
structures.

Different sitting postures
Active erect Relaxed erect slumped slouched
 Muscle activity, interdiskal pressures, and seat
interface pressures in the active erect sitting posture
will be compared to forces in relaxed erect, slumped,
and slouched sitting and to erect standing postures.

Muscle Activity
 The LoG passes close to the joint axes of the head and spine in active erect sitting posture.
 In the slumped posture, the LoG is more anterior to the joint axes of the cervical, thoracic, and
lumbar spines than it is in either active or relaxed erect sitting.
 Muscle activity in active erect sitting>>> relaxed erect sitting or slumped sitting
 In contrast to these expectations, researchers have found that maintaining an active erect sitting
posture requires not only a greater number of trunk muscles but also an increased level of activity in
some of these muscles than in both relaxed erect and slumped postures.
 O'Sullivan and associates used EMG to monitor activity in the superficial lumbarmultifidus, thoracic
erector spinae, and internal oblique abdominal muscles in erect and slumped sitting postures. These
authors found a significantly greater amount of activity in these muscles in erect sitting than in
slumped sitting.

Comparision of Sitting Posture

Flexion Relaxation (FR)
phenomenon The flexion relaxation (FR) phenomenon may
provide a possible reason why the slumped sitting
posture requires less muscle activity than does the
active erect sitting posture.
 Flexion relaxation is a sudden cessation of
muscular activity, as manifested by electrical
silence of the back extensors during trunk flexion
in either sitting or standing postures.

Continue
 In relaxed erect sitting, the LoG is only slightly anterior
from its position in active erect sitting. In the slouched
posture, the LoG is posterior to the spine and hips, but
body weight is being supported by the back of the
chair, and so less muscle activity is required than in
active erect posture .

Evidence Based
 In a study by Callaghan and Dunk, FR occurred in the thoracic erector spinae
muscles (thoracic components of the longissimus thoracis and iliocostalis
lumborum) in 21 of 22 subjects in slumped sitting and relaxed erect sitting but
not in active erect sitting.
 Muscle activity in the lumbar erector spinae remained the same in both
postures. The authors postulated that the passive tissues were able to assume
the load in the relaxed erect and slumped postures and that was why the
thoracic erector spinae muscles ceased their activity.
 Muscle activity in the active erect sitting posture is also greater than in both
relaxed erect and slouched sitting.
 In relaxed erect sitting, the LoG is only slightly anterior from its position in
active erect sitting.
 In the slouched posture, the LoG is posterior to the spine and hips, but body
weight is being supported by the back of the chair, and so less muscle activity is
required than in active erect posture.


Interdiskal Pressures and Compressive Loads on the
Spine
direct measurement
(insertion of pressure sensitive
sensors or transducers)
indirect measurement
(spinal shrinkage,creep)
calculation of compressive forces
by EMG

 Active erect sitting cause higher pressures in the
disk between L4 and L5 >> slumped sitting.
As it requires co-contractions of trunk extensors
(erector spinae muscles) and flexors (abdominal
muscles).
 Direct interdiskal pressure measurements :
 40% increase in pressures in the disk between
L4and L5 in erect sitting in comparison with erect
standing.(nachesmon).

Muscle Activity in Sitting versus
Standing Postures
 The amount of muscle activity employed to maintain a
particular posture affects the amount of interdiskal
pressure and energy expenditure.
 Increases in muscle activity cause increases in interdiskal
pressures and decreases in muscle activity are accompanied
by decreases in interdiskal pressures.
 Callaghan and McGill97 noted that the upper and lower
erector spinae muscles shifted to higher levels of activity
during active erect sitting than during standing. This
increase in muscle activity has been attributed in part to the
differences in the extent of lumbar lordosis observed
between sitting and standing.

Sitting V/S Standing
 Sitting forces the pelvis into a posterior tilt and, as a result,
causes a reduction in the lumbar curve in comparison with that
observed in standing.
 In one radiographic study of 109 patients, the average lumbar
curve (L1 to S1) was 15 less in active erect sitting than was an
average lumbar curve of 49 in the same population in standing
posture.
 The LoG would be farther away from the apex of the joint axes of
the lumbar vertebrae in a flexed or more kyphotic lumbar spine
than in a lordotic lumbar spine
Therefore, one would expect that more muscle activity would
be required to maintain the active erect sitting posture than to
maintain standing.

Seat Interface Pressures
 Studies have shown that individuals with physical disabilities
(myelomeningocele and paraplegia) have significantly higher seat interface
pressures than do people without such disabilities.
 The higher maximum seat interface pressures observed in individuals with SCI
than in healthy individuals have been attributed to asymmetrical ischial
loading resulting from spinal/pelvic deformities and atrophy of soft tissue over
the ischium.
 Kernozek et al. studied peak interface pressures in a group of 75 elderly persons
with different body mass indices (BMIs). Peak seat interface pressures were
found to be highest in the thin elderly persons (ones with the lowest BMI), who
had the least amount of soft tissue over the ischium These individuals probably
had a smaller contact area with more concentration of pressure than did
individuals with a greater body mass with increased surface contact area and
better pressure distribution.

Continue
 The fact that seat interface pressure has been found to
be a good indicator of subcutaneous stress
demonstrates the importance of minimizing seat
interface pressure.
 Changes in the position of the body, position of the
chair, and the type of seat cushion employed can be
employed to minimize the interface pressure.

Effects of Changes in Body Posture
 Changes in the posture of the body such as forward
and lateral trunk flexion can be effective means of
reducing seat interface pressures in individuals who
must spend long periods of time in a wheelchair.
 Maximum seat interface pressures could be reduced
from neutral position values by 9% when the trunk
was flexed forward to 50 degrees and reduced on the
unweighted side by 30% to 40% when the trunk was
laterally flexed to 15 degrees.

Effects of Alterations in the
Position of the Chair
 Alterations in the angulation of the chair’s back rest in
combination with footrest and seat inclinations are another
method utilized to reduce seat interface pressure.
 Also, cushions of various compositions and depths are used
to reduce seat interface pressures. Materials used in the
composition of cushions include synthetic materials, air,
water, and gels of various kinds. Cushion thicknesses up to
8 cm have been found to be successful in reducing
maximum subcutaneous stress inferior to the ischial
tuberosity, but increasing the thickness beyond 8 cm failed
to cause an additional decrease in seat interface pressure.

LOG Passes Through Various
Position

 When a person is in proper alignment, an imaginary
straight line can be drawn connecting the person’s
nose, breastbone (sternum), and pubic bone.
 Alignment in bed should be approximately the same
as when standing.
 (A) Proper body alignment for a person lying on the
back (supine).
 (B) Proper body alignment for a person lying on the
side (lateral).
 (C) Proper body alignment for a person lying on the
stomach in bed (prone).

POSTURE IN LYING DOWN
 Supine accentuates kyphosis
 Prone position accentuates lordosis
 Sidelying position straightens spine

Lying On Your Stomach
 Extended periods of "stomach lying" should be
avoided.
 Excessive stress is placed on the joints of the low back
and because excessive rotation must take place in the
neck.
 Neck pain, back pain, headaches, dizziness, as well as
arm paresthesias are commonly experienced when in
this position for an extended period of time.
 If you must lie in this position to relieve pain or for
some other reason, keep one leg bent with the same
side arm raised with approximately 90 degrees of
flexion at the shoulder and elbow joints.

Lying On Your Back
 Most people find lying on their back to be a relatively
comfortable position.
 For individuals suffering from back problems, placing
a folded pillow underneath the knees will help reduce
tension in the lower back and make this position more
tolerable.
 Some individuals may also find placing a small pillow
or towel under their lower back to be helpful.
 This will help to maintain the natural curve of the
lumbar spine.

Lying On Your Side
 Lying on your side is a favored position by many
individuals.
 It may also be a comfortable position that provides
relief for individuals with back problems.
 A pillow which fills the gap between the head/neck
and the bed should be used to keep the head and neck
in line with the rest of the spine.
 Placing a pillow between the knees will help reduce
lumbar and pelvic torsion.
 Women with larger hip and small waists will find a
small pillow under the waist will prevent lateral
bending of the spine while lying on the side.

Effect Of Pillow On Various Position

 Interdiskal pressures are less in lying postures than in standing and sitting postures.
 Wilke and colleagues measured interdiskal pressures over a 24hour period from a pressure
transducer implanted in the nucleus pulposus of the nondegenerated disk between L4 and
L5 of a 45-year-old healthy man.
 Interdiskal pressures in supine lying (0.10 MPa) were less than in either lying prone (0.11
MPa) or lying on the side (0.12 MPa), and in all of these postures the interdiskal pressure
was less than in sitting and standing postures.
 Lying prone with the back extended and supported on one’s elbows had the largest
interdiskal pres-sure (0.25 MPa) among the lying postures tested and was only slightly
less than in slouched sitting (0.27 MPa).
 Rohlmann and associates conducted a study of the bending moments on spinal fixation
devices in 10 patients. Movements in the lying posture such as lifting an extended arm or
leg in the supine and prone posi-tions did not raise the bending moments above bend-ing
moments in standing . However, when the patients raised both extended legs in the supine
position, peak bending moments exceeded the moments in the standing posture.

Surface Interface Pressures

 In order for pressure-relieving surfaces to be effective,
they should be able to reduce the interface pressure
below capillary closing pressure (12 mm Hg).
 Blood flow may be compromised, and this may result
in tissue breakdown.
 A uniform pressure distribution over the entire
available surface is desirable to prevent sections of
increased pressure over certain areas.

Pregnancy
 Poor posture in Pregnancy Is due to
 Weight Gain
 Softening of Ligament and Connective tissue
 Shifting of COG more low and anteriorly

Consequences of shifting of CoG
 LOG shift more anteriorly leads to:
 Flat Foot
 Hyperextension of knee
 Anterior pelvic tilt
 Increase Lumbar Lordosis
 Increase Kyphosis
 Protraction of Shoulder
 Increase Cervical Lordosis

 The Lumbar angle Increase by an average of 5.9degree
 The anterior pelvic tilt increased by 4 degree
 Above changes lead to increase lumbar lordosis
,kyphosis cervical lordosis
 These change in posture help to maintain CoM over
BoS

Occupation and Recreation
 Each particular occupational and recreational activity has unique
postures and injuries associated with these postures.
 Bricklayers, surgeons, carpenters, and cashiers assume and
perform tasks in standing postures for a majority of the working
day.
 Others, such as secretaries, accountants, computer operators,
and receptionists, assume sitting postures for a large proportion
of the day.
 Performing artists often assume asymmetrical postures while
playing a musical instrument, dancing, or acting.
 Running, jogging, and long-distance walking are dynamic
postures with which very specific injuries are associated.

 Different sitting postures and their effects on intra
diskal pressures in the lumbar spine have been
analyzed.
 Wheelchair postures and the effects of different
degrees of anterior-posterior and lateral pelvic tilt on
the vertebral column and trunk muscle activity in
sitting postures in selected work activities also have
been investigated.
 A large portion of the research suggests that many
back problems are preventable because they result
from mechanical stresses produced by prolonged static
postures in the forward stooping or sitting positions
and the repeated lifting of heavy loads.

 Many of the injuries sustained during both
occupational and recreational activities belong to the
category of "overuse injuries.“
 This type of injury is caused by repetitive stress that
exceeds the physiologic limits of the tissues.
 Muscles, ligaments, and tendons are especially
vulnerable to the effects of repetitive tensile forces,
 whereas bones and cartilage are susceptible to injury
from the application of excessive compressive forces.
 Professional musicians violin, piano, cello, and bass
players were frequently affected by back and neck
problems.

 The majority of problems were associated with the
musculotendinous unit, and others involved bones, joints,
bursae, and muscle
 String players experienced shoulder and neck problems
caused by the maintenance of abnormal head and neck
positions
 Flute players had shoulder problems associated with
maintaining an externally rotated shoulder position that
has to be assumed for prolonged periods during
performances and practices.
 Peripheral nerve disorders, including thoracic outlet
syndrome, ulnar neuropathy at the elbow, and carpal
tunnel syndrome, also appear to be common playing-
related disorders

Continue
 Cultural patterns of modern civilization add to the
stresses on the basic structures of the human body by
imposing increasingly specialized activities.
 It is necessary to provide compensatory influences to
achieve optimum function under our mode of life.

Student posture
 If a back pack is carried by a
strap over the left shoulder child
keep that shoulder raised t keep
the strap from slipping off there
wiil be a tendency for the spine
to curve toward left
 Children assume a sidelying
position on the bed to do their
homework a RT. Handed person
wiil lie on left side, such a
position place the spine in a left
curve
 Children forward head posture
adapted due to reading lead to
compensatory kyphosis and

Cont.
 Poor sitting posture lead
to habitual adaptation
which result in
malalignment of spine

Posture in computer worker
 POOR POSTURE  GOOD POSTURE

Posture in playing artist
 Constant maintenance of
posture during the
practise time and playing
time lead to adaptation
of such posture

Factor affecting Posture in children
 Nutritional factor (rickets vit.-D deficiency)
 Defects
 Disease
 Disability(Visual ,Auditory,Skeletal
Neuromuscular,Muscular)
 Environmental factor
 Devlopmental factor
 Most postural deviation in the growing child fallin to the
category of devlopmental deviation .pattern became
habitual ,result in postural faults

Normal postural devlopment
 FROM BIRTH TO 1 YEAR OF AGE
 In the newborn, the spine remains "C" curved;
throughout the first year of life
 The first A-P curve develops in the neck as the head is
held erect and strength for cervical extension develops
.
 Straightening of the thoracic spine occurs when sitting
can be maintained.
 The normal lumbar lordosis begins to develop parallel
with the ability to walk without assistance at about 13
months.

 BETWEEN 1 AND 2 YEARS OF AGE
 During the second year of life, the child learns to stand
upright and to balance both A-P and laterally.
 For stability, he stands and walks with a wide stance to
widen the base of support. This is enhanced by diapers,
which increase the distance between the upper thighs.
 During early todler when walking is unsteady, the child
leans forward to help forward progression, the legs are
partly flexed, and the arms are abducted and slightly flexed
at the elbows.
 Postural reflexes are well established, allowing for greater
skill in propulsion and balancing in the erect position.
 At this age, the legs will be held closer together, but there
will still be a degree of flatfootedness, a prominent
abdomen, and an exaggerated lordosis.

Normal Development of Vertebral
Column

 BETWEEN 2 AND 6 YEARS OF AGE
 Between the ages of 2 and 6 years, the necessity for
lateral balance is maintained by torsion of the tibia
exhibited by a degree of knock-knees which should
correct itself by the age of 6.
 The abdomen becomes less prominent, and the foot
develops a longitudinal arch.
 The knees may show distinct hyperextension in
standing.
 The pelvis is tilted downward and forward 30°–40°.

 The abdomen protrudes.
 The lumbar area is usually lordotic, but may lean back
sharply from the lumbosacral area.
 The scapulae are braced back by the trapezius
muscles, often winged.
 The dorsal area is mildly kyphotic, and the buttocks
protrude.
 . A mild "sway-back" condition during this
developmental stage should not be confused with a
developmental defect.

 PUBERTY
 Prior to puberty, the limbs grow faster than the
trunk.
 The rate of trunk and extremity growth is about the
same at puberty.
 The trunk continues to grow after the extremities
slow their rate of growth in the post puberty period.
 This changes the ratio of sitting to standing height.
Sitting height is about 70% of total height at birth and
about 52% for 16-year-old girls and 14-year-old boys.
 Thus, postural adjustments must be made during the
growth period to adapt to gravitational forces .

Knee position during
developmental stage

 ADOLESCENCE
During the adolescent spurt of growth, changes in body
proportions occur to adjust to gravity.
 The pelvic tilt decreases to 20°–30°.
 The knees are slightly bent, but the earlier hyperextension
is not necessary to balance a prominent abdomen.
 Posture becomes less mobile, and the postural patterns
become stabilized.
 If proper adaptive mechanisms fail, an adolescent "round
shoulders" condition may be present with a neck projected
forward and a head that is extended.

Feet
 When a small child begin to stand or walk the foot is
flat
 By the age of 6 or 7 year there is good arch formation
 Asses by podograph and footprint

Etiology of flatfoot
 Flat longitudinal arch may persist as a fixed fault or
because of foot strain.
 Improper shoes
 Habit of walking with the feet in out-toeing position.
 Childs foot is pronated and bear weight on inner side
of the foot.

knees
 Hyperextension
 It is a fairly common fault associated with firm
ligamentous support.
 Persist as a postural habit correction made by postural
training.

 Hyperextension of Knee
 Anterior Pelvic Tilt

 Increase Lumbar Lordosis
 Increase Kyphosis

 Increase cx Lordosis

knockknee
 Knock knee is common in children and usually first
observed when child began to stand.
 It exist if ankle are 2 inches a part when the kneesare
touching
 It is nonexistent by the age of 6-7 years.
 Knockknee children may stand with one knee
slightlyflexed and the other slight hyperextended so
that the knees overlap to keep the feet together.

Mechanism of Knock knee
 Knock knee Result from Lat.rotn of Femur.
 Supination Of Feet.
 Hyperextension of Knee.
 With Lat.rotatn the axis of knee jt.is oblique to the
coronal plane and hyperextension result in adduction
at knee.

Bowlegs
 Bowlegs is an alignment fault in which the knees are
seprated when the feet are together.
 Bowleg types
 Postural bowleg
 Structural bowleg

Postural bowleg
 Postural bowing is a deviation associated with knee
hyperextension and hip medial rotation.
 Postural bowlegs may be compensatory for knockknee
 Knockknee child stands with the legs thrust back in to
hyperextension the resultant postural bowing of the
legs will let the feet be brought together without
having the knee overlap.

How to differentiate between
postural and structural
 Postural bowlegs usually disappears when an
individual is reccumbent .
 Structural bowing does not disappear on reccumbent
position.
 Postural bowing record can be made in standing
 Structural bowing record can be made in back lying
position.

Mechanism of Postural bowleg
 Bowleg result from Med.rotatn of femur.
 Pronation of feet.
 Hyperextension of knee.
 When femur med.rotate,the axis of motion for flexion
and extension is oblique to coronal plane .
 From this axis hyperextension occur in posterolateral
direction Resulting in sepration of Knee Apparent
Bowleg.

Scoliosis
 Scoliosis is the lateral
curvature of Spine
 In children cause is
idiopathic.
 Detect by suspending a
plumb line in line with
the 7th cx vertebra or the
buttock creases help in
ascertaining the
curvature of spine.

Types of scoliosis
 Idiopathic scolioses are
catagorized by age at onset
 Infantile (0 to 3 years).
Juvenile (4 to 10 years).
Adolescent (older than 10
years).
The adolescent idiopathic
scoliosis (AIS) type makes
up the majority of all
scoliosis and affects up to
4% of schoolchildren
worldwide.

Examination of Scoliosis
 Essential part of examination
is observation of the back
during movement.
 The subject bends forward
and then returns slowly to the
upright position.
 If there is a structural curve,
some fullness (prominence)
will be noted on the side of
the convexity of the curve.
 The fullness will be on one
side only if there is a single
curve, (i.e. Ccurve).

Scoliosis Measure by Cobb Angle

 In a double curve, (i.e. S-
curve) as in a right
thoracic,left lumbar, there
will be fullness on the right
inthe upper back and on the
left in the low back area.
 In a functional curve, however,
there may be no evidence of
rotation in forward bending.
This is especially true if the
functional curve is caused by
lateral pelvic tilt that results
from hip abductor or
abdominal muscle
imbalance.

Malalignment in Scoliosis
 Possible failure of support
as a result of a defect in
muscular and/or
ligamentous support
systems during a period of
rapid growth .
 Creation of an external
lateral flexion moment.
 Deviation of the vertebrae
with rotation
 Compression of the
vertebral body on the side
of the concavity of the
curve.

Continue
 Inhibition of growth of
vertebral body on the side of
the concavity of the curve in a
still immature spine
 Wedging of the vertebra in a
still immature spine
 Head out of line with sacrum
 Compensatory curve
 Adaptive shortening of trunk
musculature on the concavity
 Stretching of muscles,
ligaments, and joint capsules
on the convexity

Postural
Fault
Anatomical
Position
of Joints
Muscles in
Shortened
Position
Muscles in
Lengthened
Position
Slight left
C-curve,
thoracolumbar
scoliosis
Thoracolumar
spine: lateral
flexion, convex
Toward left
Right lateral
trunk
Muscles
Left psoas major
Left lateral
trunk muscles
Right psoas
major
Prominent
or high
right hip
Pelvis, lateral
tilt,high on
right
Right hip joint,
adducted
Left hip joint,
Abducted
Right lateral
trunk
muscles
Left hip
abductors
and fascia lata
Right hip
adductors
Left lateral
trunk muscles
Right hip
abductors,
especially the
gluteus medius
Left hip
adductors

Advance Technique To Assess
Posture
 Video Analysis
 2-D ,3-D Technique
 Posturography
 Postural Analysis Grid Chart
 Various posture analysis software like posture pro

NPI Posture Pro Posture Analysis Software System
 NPI’s Posture Pro Postural Assessment software (Latest Version NPI Posture Pro 8e) is
the latest and most advanced postural analysis software.
 This indispensable health-screening tool provides professionals the ability to
quantitatively document a client/patients posture providing unparalleled analysis. The
capabilities of the software extend beyond a detailed postural analysis including:
 Posture Number™ - Only NPI Posture Pro is Based on a posture scoring system, a client
or patients posture is calculated to provide their Total Posture Number which helps keep
track of any improvements/relapses of posture over time.
 AutoDetect - automatically performs a posture screening or examEffects of Time -
Posture is NOT self-correcting. Show clients-patients what they might look like over time
without performing posture correction exercises.
 Loss of Height Calculations due to poor posture
 Additional Spine Forces Measurement - Explains the extra stresses from poor posture
 Quick Compare - Quickly compare current and past posture exams
 Posture Pro is the most popular posture analysis system in the world.

TEMPLO 2D Posture analysis
 Determine and visualize the major body axes of patients in up to three
analyses.
 we can integrate the 2D posture analysis seamlessly into the motion analysis
software TEMPLO and thus is a fast-to-use instrument for the measurement of
posture.
 The 2D posture analysis is standard with two cameras from a dorsal and lateral
perspective.
 The operation with one camera is possible, also. CONTEMPLAS offers an
analysis terminal where you can store your equipment and with which the
cameras are positioned correctly already. This terminal can be upgraded with a
c-attachment for 3D posture analysis at any time.
 Expand the range of your analyses by a variety of predefined analysis
protocols. For example, you can add a third, ventral perspective or use the
muscle function test according to Matthias, popular in science, for assessing
posture.

Module 3D posture analysis
 Scientific postural analysis in three dimensions
 With its fixed installation, the 3D postural analysis offers a
very precise, scientific analysis system.
 Three dimensions the 3D postural analysis offers
significantly more exact and above all more significant data
pertaining to posture.
 It differs from the 2D postural analysis in that three
cameras are used to record the posture. This means that
the customer’s posture is recorded and analysed from three
separate perspectives at the same time.
 In order to avoid simply taking a snapshot of the posture
the subject turns around 45° each time.

The Postural Analysis Grid Chart
 The Postural Analysis Grid Chart is the number one solution to assess, document
and educate patients / clients of your objective findings.
 Available in two sizes: 35.5″ x 84″ for a wall “Original”, and 24″ x 78” for a door the “Space
Saver”. Both charts contain: color images, checklists, tables, dominate eye test, skeletal
illustrations and postural images in the anterior, lateral and posterior views.
 A postural analysis chart is most effective when used in conjunction with a plumb line,
Plumb Bob and Set Up Kit – Includes everything needed to get started immediately.
Ensures patients are accurately positioned and photos are taken from the correct angle.
 A posture chart is essential to performing a fast assessment and developing a
comprehensive goal oriented plan. Retain existing and attract new business with Postural
Analysis Photos.
 Perform fast accurate postural analysis
 Document posture before, during and after a series of treatments or sessions.
 Quickly determine a plan based on your objective findings
 Two practical and convenient sizes
 Quick and easy setup

Posturography
 Posturography
 Posturography quantifies postural control in stance in either static or dynamic
conditions.
 Computerized dynamic posturography (CDP), also called test of balance
(TOB), is a non-invasive, specialized, new clinical assessment technique used
to quantify the central nervous system´s adaptive mechanisms (sensory, motor
and central) involved in the control of posture and balance, both in normal
(such as in physical education and sports training) and abnormal conditions
(particularly in the diagnosis of balance disorders asdand in physical therapy
and aspostural education).
 Due to the a complex interactions among sensory, motor, and also central
processes involved in posture and balance, CDP requires different protocols in
order to differentiate among the many defects and impairments which may
affect the patient's posture control system.

POSTURE A N D PAIN
 Painful conditions associated with faulty body mechanics are so
common that most adults have some firsthand knowledge of
these problems. Painful low backs have been the most frequent
complaints, although cases of neck, shoulder, and arm pain have
become increasingly prevalent (1,3,5).
 With the current emphasis on running, foot and knee problems
are common (7,8). When discussing pain in relation to postural
faults, questions are often asked about why many cases of faulty
posture exist without symptoms of pain, and why seemingly mild
postural defects give rise to symptoms of mechanical and
muscular strain.
 The answer to both depends on the constancy of the fault.

 Cases of postural pain are extremely variable in the manner of
onset and in the severity of symptoms.
 In some cases, only acute symptoms appear, usually as a result of
an unusual stress or injury. Other cases have an acute onset and
develop chronically painful symptoms. Still others exhibit
chronic symptoms that later become acute.
 Measures to relieve pain are indicated for these patients.
 Only after acute symptoms have subsided can tests for
underlying faults in alignment and muscle balance be done and
specific therapeutic measures be instituted.

 IDENTIFYING THE CURVATURE
 Proper diagnosis is important. A misjudgment can lead to unnecessary x-rays and stressful treatments
in children not actually at risk for progression. Unfortunately, although measurements of curves and
rotation are useful, no test exists yet to determine whether a curve will progress.
 Inclinometer (Scoliometer). An inclinometer, also known as a scoliometer, measures distortions of the
torso. The procedure is as follows:
 The patient bends over, arms dangling and palms pressed together, until a curve can be observed in
the upper back (thoracic area).
 The Scoliometer is placed on the back and measures the apex (the highest point) of the upper back
curve.
 The patient continues bending until the curve can be seen in the lowerback (lumbar area). The apex
of this curve is also measured.
 Measurements are repeated twice, with the patient returning to a standing position between
repetitions.
 If results show a deformity, the patient will probably need x-rays to determine the extent of the
problem.
 Some experts believe the scoliometer would make a useful device for widespread screening.
Scoliometers, however, indicate rib cage distortions in more than half of children who turn out to
have very minor or no sideways curves. They are therefore not accurate enough to guide treatment.


Posture Analysis In Biomechanics

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