By: Khushali Jogani
The Sarvajanik College Of Physiotherapy
What is core
Models for spinal stabilization
Muscles of core
Biomechanics of core muscles
What is core?
CORE is defined as a clinical manifestation in
which a delicate balance of movement and
stability occurs simultaneously.
The “core” has been described as a box with the
abdominals in the front, paraspinals and gluteals
in the back, the diaphragm as the roof, and the
pelvic floor and hip girdle musculature as the
Attention to core is important because it serves
as a muscular corset that works as a unit to
stabilize the body and spine, with and without
In short, the core serves as the center of the
functional kinetic chain.
Stabilization of lumbar spine is provided by the
passive support of the osseoligamentous
structures, the support of the muscle system,
and control of the muscle system by the central
Interrelated parameters of spinal stability need
to be considered due to the multisegmental
nature of the lumbar spine.
Control of spinal orientation, which relates to the
maintenance of the overall posture of the spine
against imposed forces and compressive loading.
Control of the intersegmental relationship at the
local level (i.e.lumbar segmental control),
irrespective of changes in the overall orientation
of the spine.
Control of lumbopelvic orientation
The main function of lumbopelvic hip region is to
transfer the loads generated by the body weight
and gravity during standing, walking and sitting.
Panjabi introduced an innovative model for the
spinal stabilization system(effective load transfer)
which serves as an appropriate model for
understanding the entity of spinal stability and
It included passive, active and neural control
systems and all these three systems produce
approximation of joint surfaces which is essential
if stability is to be insured.
The amount of approximation required is
variable and and difficult to quantify as it
depends on individual’s structure and forces
they need to control.
The integrated model of function is been
proposed for managing impaired function.
It has four components:
1. Form closure
- It was coined by Vleeming and snijders.
- All joints have variable amount of form closure.
- Depending on individual’s anatomy –decides the
- Form of lumbar spine, pelvis &hip are included.
The Lumbar region
-torsion or rotation
The pelvic girdle
2. Force Closure
If the articular surfaces of the lumbar spine, pelvic
girdle, and hip were constantly and completely
compressed, mobility would not be possible.
However, compression during loading is variable
and therefore motion is possible and stabilization
This is achieved by increasing compression across
the joint surface at the moment of loading
The amount of force closure required depends on
the individual's form closure and the magnitude
of the load. The anatomical structures responsible
for force closure are the ligaments,muscles, and
3. Motor control
By active subsystem of panjabi model, muscles
provides the mechanism by which control
system may modulate the stability of spine.
Stability of spine is important because
movement is important for optimal spinal
Movement is required to assist in dissipation of
forces and to minimize the energy expenditure.
Lumbopelvic stability is provided by the core
Bergmark has categorised the trunk muscles
into local and global muscle system.
Local muscle system stabilises the spinal
segment whereas global muscle system act as
guy ropes to support the vertebrae
Anterolateral abominal paraspinal
wall and abdominal muscles of
cavity lumbar region
Anterolateral abominal wall and abdominal
Global muscles(obliquus internus abdominis,
obliquus externus abdominis, rectus abdominis
Diaphragm and pelvic floor
-Four slings of muscle system stabilizes the pelvis
-posterior, anterior, longitudinal, lateral slings
-Individual muscles are important for regional
stabilization and mobility and it is necessary to
understand how they connect and function
-Muscle contraction-production of forces-transfer of
forces-transfer of load-increases the stiffness of SIJ
-Global muscle-integrated sling system.
-participation of muscle in more than one sling-
overlap & interconnect-depending on task
-obliquus externus abdominis make a powerful
contribution to control of buckling forces
-contribution to lumbopelvic movement and
stabilization is based on moment arm and
direction of forces.
-if high loads are unpredictable, muscles on both
sides are coactivated to stiffen the trunk.
- Due to transverse orientation of muscle it has
limited ability to flex, extend or laterally flex the
- Limited moment arm to contribute to rotatory
- Contribution through spinal buckling.
- Though contribution is small,it produces very
- Modulation via intra-abdominal pressure(IAP),
fascial tension and compression of sacaroiliac
-IAP in daily activities
-abdominal cavity as ‘pressurized balloon’
-production of extension torque and offset of
flexion moment by abdominal muscle
-TrA is the most active of abdominal muscles in
-concurrent flexion and extension moments may
increase spinal stiffness like co-contraction.
-IAP increase spinal stiffness
-thoracolumbar fascia and contribution to spinal
-TrA muscle and its attachment to thoracolumbar
-Mechanics of thoracolumbar fascia
-control of intersegmental motion via lateral
tension in thoracolumbar fascia.
-stabilization of lumbar spine in coronal plane via
tension in middle layer of thoracolumbar fascia.
-mechanism of stability of sacro-iliac joint is
dependent on compression between ilium and
Diaphragm and pelvic floor
-contribution through IAP and restriction of
movement of abdominal viscera for spinal
Posterior abdominal wall
-it has tendency to overactivity and tightness
-two separate muscles and contribution of
posterior fibres for control of intervertebral
-its medial fibres through the attachment to
lumbar vertebral transverse processes is capable
of providing segmental stability via its
-control of neutral zone
-control of lordosis
-tensioning the thoracolumbar fascia
-control of shear forces
Control of neutral zone
-lumbar muscles increase the spinal segmental
stiffness and control of neutral zone
-increased combined muscle activation
-muscle forces decrease the sagittal plane
displacement ,anterior rotation and
-load bearing surface of zygoapophyseal joints
-intersegmental nature of multifidus
Control of lordosis
-spinal curves efficient to deal with force of gravity
-role of mulitifidus
-local and global muscles increase the capacity of
spine to withstand the compressive forces
Tensioning the thoracolumbar fascia
-muscle enhance the spinal stability by increasing
stiffness of spinal segment
-thoracolumbar fascia contributes to lumbar
stabilization by increasing the bending stiffness
Control of shear forces
-shear forces are those that cause the vertebrae to
slide with respect to one another
-control of anterior shear forces
-Provided by passive elements as well as muscles
-lumbar extensor muscles helps in controlling
Carolyn Richardson,Paul Hodges,Julie Hides
Therapeutic exercise for lumbopelvic
stabilization. second edition.
Diane Lee,Paul Hodges,The pelvic Girdle,an
approch to the examination and treatment of
the lumbopelvic-hip region.Third edition.
Carolyn Richardson,Gwendolen Jull, Julie
Hides,Paul Hodges. Therapeutic exercise for
spinal segmental stabilization in low back pain