The document summarizes the biomechanics of the lumbar spine. It describes the anatomy including the vertebrae, discs, curves, and ligaments. It discusses the movements including flexion, extension, lateral flexion, and rotation. It also outlines the kinetics and kinematics of compression, shear, and the various motions. Common conditions like lumbar lordosis are explained. Range of motion values and an example case study on lumbar stenosis are provided. Physiotherapy management focuses on strengthening the core and avoiding extension.

1. BIOMECHANICS
OF
LUMBAR SPINE
PRESENTED BY: KOMAL
Mpt 1 sem

2. • 33 vertebrae
• 23 intervertebral disks
• Curves :Primary curves and Secondary curves
• Body – Massive
• – Transverse diameter > anterior diameter & height
• – Supports compressive loads
• Vertebral foramen - Triangular.
• Superior articular facet -concave.
• Inferior articular facet - convex.
• Transverse Process : long, slender; extends horizontally
• Accessory process : Posterioinferior part of root of transverse process ( rough elevation)
• Pedicles : short and strong
• Laminae : short and thick
• Spinous process : broad, thick, extends horizontally
• Mamillary processes : located on posterior edge of each superior zygapophyseal facet
• Intervertebral Disks • Largest
• Fifth lumbar vertebra is a transitional vertebra
OSTEOLOGY

3. LIGAMENTS
• Anterior longitudinal ligament
-strong and well developed
• Posterior Longitudinal Ligament
- only a thin ribbon like structure
• Ligamentum flavum
- thickened
-resist separation of laminae
• Supraspinous ligament
-Well developed only in upper lumbar region
- Most common termination site - L4 or may terminate at L3
-absent at L5/S1
• Intertransverse ligaments
- not true ligaments in lumbar area
- replaced by the iliolumbar ligament at L4
• Interspinous ligament
-least overall stiffness
• . Iliolumbar Ligaments
-Series of bands extend from tips and borders of transverse processes of L4 and L5
- attach bilaterally on iliac crests of pelvis
-3 bands: ventral / anterior
dorsal / posterior
sacral

4. Muscles
Back muscles can be divided into four functional groups: flexors, extensors, lateral flexors and
rotators.
• EXTENSORS:
Erector spinae
Multifidus
• FLEXORS:
Psoas Major
Psoas Minor
Iliacus
• LATERAL FLEXORS AND ROTATORS:
Internal And External Oblique
Intertransverse
Quadratus Lumborum

5. VASCULAR SUPPLY
• Arterial supply: lumbar arteries
• Venous supply : lumbar veins

6. NERVE SUPPLY
• L1 spinal nerve provides sensation to groin and genital area and helps to move hip muscles.
• L2, L3 and L4 spinal nerves provide sensation to the front part of thigh and inner side of lower
leg. These nerves also control hip and knee muscle movements.
• L5 spinal nerve provides sensation to the outer side of lower leg, the upper part of foot and the
space between first and second toe. This nerve also controls hip, knee, foot and toe movements.

7. KINETICS
Compression:
• Lumbar region provides support for weight of upper part of body in
static as well as in dynamic situations
• Lumbar region must also withstand tremendous compressive loads
produced by muscle contraction LOG and thus change forces acting on
lumbar spine
• Lumbar interbody joints share 80% of load, Zygapophyseal facet joints
in axial compression share 20% of total load.
• This percentage can change with altered mechanics: with increased
extension or lordosis.
• Also, with degeneration of intervertebral disk, Zygapophyseal joints will
assume increased compressive load.

8. Shear:
• upright standing position,
• lumbar segments are subjected to anterior shear forces caused by: -
lordotic position - body weight - ground reaction forces
• Resisted by direct impaction of inferior zygapophyseal facets of the
cranial vertebra against superior zygapophyseal facets of caudal
vertebrae.
• more the superior zygapophyseal facets of the caudal vertebra face posteriorly,
greater the resistance they are able to provide to forward displacement, because
the posteriorly facing facets lock against the inferior facets of the cranial vertebra.

9. KINEMATICS
• Movts available: flexion, extension, lateral flexion, and rotation.
• Gliding- anterior to posterior, medial to lateral and torsional
• Tilt- anterior to posterior, lateral directions
• Distraction and compression
Lumbar flexion
• More limited than extension
• Maximum motion at lumbosacral joint
• Anterior tilting and gliding of superior vertebra occurs
• Increases diameter of intervertebral foramina
• Flexion generates compression forces on anterior side of disc tending to
migrate nucleus pulposus posteriorly
• Limited by tension in posterior annulus fibrosus and posterior ligament
system

10. Lumbar Extension
• Increase in lumbar lordosis
• Posterior tilting , gliding of superior vertebra
• Lumbar extension reduces the diameter of intervertebral foramina
• Fewer ligaments checks extension
• During lumbar extension nucleus pulposus displaces anteriorly
Lateral Flexion
• Superior vertebra laterally tilts, rotates and translates over vertebra below
• Annulus fibrosus is compressed on concavity of curve and stretched on
convex side
• Nucleus pulposus migrate slightly towards convex side of bend

11. Spinal Rotation
• Rotation causes movement of vertebral arch in opposite direction
• Ipsilateral facet joints go for gapping and contralateral facet joints for impaction
• Axial rotation to right, between L1 and L2 for instance, occurs as left inferior articular facet of L1
approximates or compresses against left superior articular facet of L2.
• Limited due to shape of zygapophyseal joints
• Also restricted by tension created in stretched capsule of apophyseal joints and stretched fibres
within annulus fibrosus
• Amount of rotation available at each vertebral level is affected by position of lumbar spine
• When flexed, ROM in rotation is less than when in neutral position
• The posterior anulus fibrosus and PLL limit axial rotation when spine is flexed
• The largest lateral flexion ROM and axial rotation occurs between L2 and L3

12. LUMBOSACRAL ANGLE
• Ferguson’s angle
• formed by the fifth lumbar vertebra and first sacral
segment
• The first sacral segment , which inclined anteriorly and
inferiorly forms an angle with the horizontal
• normal :35-40⁰

13. ANTERIOR AND POSTERIOR TILT
• Anterior pelvic tilt is when the front of the pelvis drops in relationship to the back of
the pelvis. For example, this happens when the hip flexors shorten and the hip
extensors lengthen. It is also called lumbar hyperlordosis.
• Posterior pelvic tilt is the opposite, when the front of the pelvis rises and the back of
the pelvis drops. For example, this happens when the hip flexors lengthen and the hip
extensors shorten, particularly the gluteus maximus which is the primary extensor of
the hip.

14. IMPORTANCE OF LIGAMENTS AND FUNCTION
• ILLIOLUMBAR LIGAMENT:The iliolumbar ligaments as a whole are very strong and play a
significant role in stabilizing the fifth lumbar vertebra (preventing the vertebra from anterior
displacement) and in resisting flexion, extension, axial rotation, and lateral bending of L5 on
S1.It plays an important role in the stability of the lumbosacral junction.
• INTERSPINOUS LIGAMENT: It allows the fibers to buckle laterally to both sides
when the spinous processes approach each other during extension.
• SUPRASPINOUS LIGAMENT: The ligament is positioned further away from the axis
of rotation and due to its attachments to the thoracolumbar fascia, it will have more
effect in resisting flexion than all the other dorsal ligaments.
• ANTERIOR LONGITUDINAL LIGAMENT: It limits extension of the lumbar vertebral
column and reinforce the intervertebral disc.
• POSTERIOR LONGITUDINAL LIGAMENT : It limits flexion of the lumbar vertebral column
and reinforces the intervertebral disc.
• LIGAMENT FLAVUM: It limits forward flexion especially more in limbar region.

15. LUMBAR LORDOSIS
• exaggeration of the lumbar curve
• associated with weakened abdominals (relative to extensors)
• characterized by low back pain
• prevalent in gymnasts, figure skaters, swimmers (flyers)

16. LUMBAR ROM
• FLEXION: 0-60
• EXTENSION : 0-25
• LATERAL FLEXION: 0- 20
• AXIAL ROTATION: 0-18

17. CASE STUDY
• CASE REPORT :The patient was a 53-year-old female who was observed in
an orthopedic outpatient consultation with a complaint of lumbalgia in the
L5–S1 region in situations of constant loading, with irradiation to both legs.
The condition had been evolving for around two years, despite
conservative therapy consisting of analgesia, NSAIDs, muscle relaxants and
physiotherapy, which had been instituted by the family doctor. The patient
reported having neurogenic claudication. She did not have any previous
history of trauma.
• She reported having personal antecedents of a disc hernia, which was
present in two segments of the lumbar spine (L3–L4 and L4–L5), and
having undergoing classical lumbar discectomy

18. MRI of the lumbar spine (sagittal slice), in which lumbar
stenosis can be seen at L2–S1
MRI of lumbar spine (axial slice), in which narrowing of the
spinal canal can be seen at the levels (A) L4–L5 and (B) L5–
S1.

19. • EXAMINATION :On physical examination, she presented pain on palpation of the
lumbar spine apophyses and paravertebral masses. She was bilaterally positive for
Lasègue's sign. A neurological examination revealed a foot inclined to the right.
• INVESTIGATION :Lumbar MRI showed a bulging intervertebral disc, hypertrophy of
the joint facets and yellow ligaments at the levels L2–L3, L3–L4, L4–L5 and L5–S1,
which caused narrowing of the spinal canal, with impairment of the roots of L4, L5
and S1 .Electromyography was also performed on the lower limbs, and this revealed
severe radiculopathy at L5 and S1.
• DIAGNOSIS : From this, a diagnosis of lumber stenosis at L2–L3, L3–L4, L4–L5 and
L5–S1 was established, associated with neurological deficits, and surgical treatment
was proposed.
• TREATMENT : The patient underwent lumbar recalibration of L2–L3 and L3–L4 by
means of the Senegas technique at L4–L5 and L5–S1 with laminectomy and fixation
using transpedicular screws and posterolateral arthrodesis, with an autologous bone
graft

20. PHYSIOTHERAPY MANAGEMENT
• Improve strength, endurance and tone of abdominal muscle.
• Back ergonomics avoiding extension attitude are taught.
• Lumbar corset should be used provide back support.
• Emphasis on flexion exercise and generalized flexion attitude avoiding extension.
• Gentle passive manipulation technique.
• Lumbar traction to releave spasm.
• Walking on inclined treadmill.
• Harness supported treadmill ambulation.
• Strong isometric exercise for abdomen.
• Single Knee to chest exercise.
• Spinal flexion exercise.
• Hamstring stretching performed by extending the knee with hip flexed 90*.
• Hip flexor stretching is performed by maintains posterior pelvic tilt while in a half kneeling posture.
• Mini squats for general lower extremity strengthing exercises.