biomechanics of spine and hip

1. SAURABH
BOT 2ND YEAR
Biomechanics of the Spine & Hip

2. Biomechanics of the Spine & Hip
 Movements of Spine
 Flexion, Rotation, Extension, Abd, Add.
 Hip Movements
 Elevation, Anterior & Posterior Tilt, Flexion,
Extension, Abd, Add, Hyperext, Hyperflex

3. Spinal Deviations
 Lordosis
 Kyphosis
 Scoliosis

4. Forces Acting On The Spine
 Forces Acting On The Spine Include:
 Body Weight
 Tension In The Spinal Ligaments
 Tension In The Surrounding Muscles
 Intraabdominal Pressure
 The Major Form Of Loading On The Spine Is:
 Axial

5. Upright Position
 Spinal Compression
 Resulting From:
 Body Weight + Weight Held
by Arms and Hands
 When Standing Upright
 Total Body Center of Gravity
Is Anterior to the Spinal
Column.
 Spine Is Placed Under
Constant Forward Bending
Moment.

6. Torque
 Defined: The Rotary Effect of a Force About An
Axis of Rotation, Measured as the Producer of
the Force and the Perpendicular Distance
Between the Force’s Line of Action And The Axis
 To Maintain An Upright Position
 Torque Is Counteracted by Tension in the Back
Extensor Muscles.

7. Spinal Muscles Role In Lifting
 Spinal Muscles Have Small
Moment Arms With Respect
To the Vertebral Joints.
 Have To Generate Large
Forces To Counteract the
Torque Produced About the
Spine by Body Weight and
Objects Being Lifted.
Erector Spinae
Muscles

8. Why Lift With The Legs?
 Back Muscles, With a
Moment Arm of
Approximately 6 cm, Must
Counter The Torque
Produced by the Weights
of the Body Plus Any
External Loads.

9. By The Erector Spinae Muscles With a Fm
6 cm?
 1 lb. = 4.448 Newtons
 Segment Weight Moment Arm
 Head 13 lbs. (58N) 25 cm
 Trunk 73.75 lbs. (328N) 10 cm
 Arms 18.2 lbs. (81N) 20 cm
 Box 24.95 lbs. (111N) 40 cm
 Torque at L5-S1=
 (328N)(10cm) + (81N)(20cm) + (58N)(25cm)
+ (111N)(40cm)
 = ?
 10,790 Ncm
 Force?
 0 = (Fm)(6cm) - 10,790 In static position, sum
 of the torques acting at any point is zero.
 Fm = 1798.33 N or (404.30 lbs.)

10. Problem for a 135 lb. Person
 How much force must be developed by the
erector spinae with a moment arm of 6 cm. From
the L5-S1 joint center to maintain the body in a
lifting position with segment moment arms as
Specified?
 Segment Weight Moment Arm
 Head 50 N 22 cm.
 Trunk 280 N 12 cm.
 Arms 65 N 25 cm.
 Box Lifted100 N 42 cm.
 Torque ?
 10,285 Ncm
 Fm = 1714 N or (393 lbs. Force)

11. What Does The Research Show? % Load Compression On L3 During the Upright Standing, Lying Down, and
Sitting.
 Compression Increases More with Spinal Flexion, and Increases Still Further
with a Slouched Sitting Position.

12. Common Injuries Of The Back
 Low Back Pain
 Soft Tissue Injuries
 Acute Fractures
 Stress Fractures
 Disc Hernia ions
 Whiplash Injuries

13. Low Back Pain
75%-80% of Americans Experience Low Back Pain
Sometime During Life.
Second Only to the Common Cold In Causing
Absence In The Workplace.
Mechanical Stress & Psychosocial.

14. BACK, SPINAL COLLUMN,
NECK
VERTEBRAL
COLLUMN
RIBS & STERNUM

15. SPINAL COLLUMN
7 CERVICAL
VERTEBRAE
12 THORACIC
5 LUMBAR
1 SACRUM - FUSED
1 COXCYC - 2
FUSED

16. JOINTS OF THE VERTEBRAL
COLLUMN
VERTEBRAL JOINTS
GLIDING JOINTS -
SLIGHTLY MOVABLE
SEPARATED BY
INTERVERTEBRAL
DISKS

17. THORACIC COMPLEX - RIBS
 12 SETS OF RIBS
 ARTICULATE WITH THE THORACIC
VERTEBRAE AND STERNUM
 7 PAIRS OF TRUE RIBS - ATTACH DIRECTLY
TO STERNUM
 5 PAIRS OF FALSE RIBS
 2 PAIRS OF FLOATING RIBS
 3 PAIRS ATTACH TO STERNUM VIA
COSTOCHONDRAL CARTLILAGE

18. STERNUM
MANUBRIUM
BODY
XIPHOID PROCESS

19. MUSCLES OF THE BACK, NECK &
ABDOMEN
DEEP POSTERIORS
ABDOMINALS
VERTEBRALS
SUPERFICIAL NECK
MUSCLES

20. DEEP POSTERIORS
MOVEMENT - ROTATION,
EXTENSION OF SPINAL
COLLUMN

21. ABDOMINALS
 TRANSVERSE
ABDOMINUS -
DEPRESSION OF
ABDOMEN
 RECTUS ABDOMINUS -
SPINAL FEXION
 INTERNAL / EXTERNAL
OBLIQUES - ROTATION,
LATERAL FLEXION
(ABDUCTION -
ADDUCTION)

22. MUSCLES OF THE THORAX
DIAPHRAM
INTERNAL INTERCOSTALS
EXTERNAL
INTERCOSTALS

23. INJURIES TO LOWER SPINE,
PELVIS, HIP - CAUSES
 DISK DEGENERATION - Herniation or General
Degeneration
 JOINT DISFUNCTION - Primarily @ Sacroiliac
 Usual Cause - Lack of Normal Movement - Often Disputed
 STRETCHED OR STRAINED LIGAMENTS - ie:
Supraspinous Ligaments
 LACK OF STRENGTH
 Hamstrings, Erector Spinae, Abdominals, Hip Flexors

24. PREVENTION OF INJURIES TO
BACK
 POSTURE - STANDING
 HYPERLORDOSIS
 KYPHOSIS
 POSTURE - SITTING
 CAUSING PAIN TO LUMBO/SACRAL AREA

25. PROPER SITTING TECHNIQUE -
Should Not Be Done Over Long
Periods Of Time
 HIPS SHOULD BE FLEXED
 LEGS SHOULD NOT BE EXTENDED
 BACK SHOULD NOT BE OVERLY ARCHED

26. LIFTING WITH PROPER
TECHNIQUE
 BACK KEPT ERECT
 KNEES BENT
 WEIGHT CLOSE TO BODY

27. STRENGTHENING EXERCISES
 MANY BACK PROBLEMS ARE CAUSED BY WEAK MUSCLES ABOUT
THE HIP AND ABDOMINALS
 WEAK MUSCLES PREDISPOSE BACK TO HYPERLORDOSIS
 INCORRECT SIT-UPS MAY CAUSE HYPERLORDOSIS - CAUSED BY
SHORTENED ILIOPSOAS
 STRETCHING - HAMSTRINGS - ILIOPSOAS - QUADRICEPS

28. LUMBAR SPINE EVALUATIONS
 STANDING EVALUATION
 FLEX FORWARD -
PALPATING SPINOUS
PROCESSES &
TRANVERSE
PROCESSES
 SITTING ALIGNMENT
 PATELLULAR REFLEX -
LUMBAR 4
INVOLVEMENT
 ACHILLES REFLEX -
SACRAL 1
INVOLVEMENT

29. LYING ON BACK
 TEST ABDOMINALS - RECTUS ABDOMINUS ,
ILIOPSOAS (HIP FLEXORS)
 (STATIC W/ STABILIZED THIGHS - HIP FLEX AT
45 DEGREES
 STRAIGHT LEG RAISE
 PAIN WHEN TESTING UNAFFECTED SIDE -
POSSIBLE HERNIATED DISK
 PAIN WHEN TESTING AFFECTED SIDE -
POSSIBLE SCIATIC NERVE STRETCHED

30. LYING ON BACK (CONTINUED)
BOWSTRING SIGN
TO TEST FOR SCIATIC NERVE -
USE PRESSURE TO
POPLITEAL (BACK OF KNEE)
GAINSLENS SIGN
TO TEST SACRO-ILIAC
LESSIONS (SWITCHBLADE
LEGS WHILE ON SIDE)

31. OTHER PROBLEMS OCCURING
WITH THE SPINE
 SOFT TISSUE TRAUMA - CONTUSIONS
 NERVE INFLAMATION OR COMPRESSIONS - FROM DISK
PROTRUSIONS
 FRACTURES TO THE SPINOUS OR TRANSVERSE PROCESSES
 SPONDYLOLYSIS (FRACTURE TO INTERARTICULAR PROCESS
 SPONDYLOLISTHESIS (FORWARD SLIPPAGE OF THE VERTEBRA

32. OTHER PROBLEMS OCCURING
WITH THE SPINE (CONTINUED)
GROIN STRAINS
HIP POINTE.RS
HIP DISLOCATIONS

33. REHABILITATION OF BACK AND
HIP INJURY
 ICE MESSAGE
 MOVEMENT TO REGAIN FLEXIBILITY &
RANGE
 STRENGTHENING EXERCISES
 SIT UPS & CRUNCHES (WORK OBLIQUES AS WELL)
 PELVIC TILTS - (FLATTENING OF BACK AGAINST
FLOOR)
 HIP LIFTS - (FROM LYING ON BACK POSITION)
 BACK EXTENTIONS - TO 90 DEGREES
 PSOAS & HAMSTRING STRETCH - (KNEES TO
CHEST)