Biomechanics of the Spine Hip Movements of Spine

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

Spinal Deviations • Lordosis • Kyphosis • Scoliosis

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

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.

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.

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

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.

Question: How Much Torque Is Developed By The Erector Spinae Muscles With a Fm 6 cm? • 1 lb. = 4. 448 Newtons • Segment Weight – – Head Trunk Arms Box 13 lbs. (58 N) 73. 75 lbs. (328 N) 18. 2 lbs. (81 N) 24. 95 lbs. (111 N) Moment Arm 25 cm 10 cm 20 cm 40 cm • Torque at L 5 -S 1= • (328 N)(10 cm) + (81 N)(20 cm) + (58 N)(25 cm) + (111 N)(40 cm) • =? • 10, 790 Ncm • Force? • 0 = (Fm)(6 cm) - 10, 790 In static position, sum • of the torques acting at any point is zero. • Fm = 1798. 33 N or (404. 30 lbs. )

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 L 5 S 1 joint center to maintain the body in a lifting position with segment moment arms as Specified? • Segment – Head – Trunk – Arms – Box Lifted Weight 50 N 280 N 65 N 100 N Moment Arm 22 cm. 12 cm. 25 cm. 42 cm. • Torque ? • 10, 285 Ncm • Fm = 1714 N or (393 lbs. Force)

What Does The Research Show? • % Load Compression On L 3 During the Upright Standing, Lying Down, and Sitting. • Compression Increases More with Spinal Flexion, and Increases Still Further with a Slouched Sitting Position.

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

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.

BACK, SPINAL COLLUMN, NECK • VERTEBRAL COLLUMN • RIBS & STERNUM

SPINAL COLLUMN • 7 CERVICAL VERTEBRAE • 12 THORACIC • 5 LUMBAR • 1 SACRUM - FUSED • 1 COXCYC - 2 FUSED

JOINTS OF THE VERTEBRAL COLLUMN • VERTEBRAL JOINTS –GLIDING JOINTS SLIGHTLY MOVABLE • SEPARATED BY INTERVERTEBRAL DISKS

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

STERNUM • MANUBRIUM • BODY • XIPHOID PROCESS

MUSCLES OF THE BACK, NECK & ABDOMEN • DEEP POSTERIORS • ABDOMINALS • VERTEBRALS • SUPERFICIAL NECK MUSCLES

DEEP POSTERIORS • MOVEMENT - ROTATION, EXTENSION OF SPINAL COLLUMN

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

MUSCLES OF THE THORAX • DIAPHRAM • INTERNAL INTERCOSTALS • EXTERNAL INTERCOSTALS

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

PREVENTION OF INJURIES TO BACK • POSTURE - STANDING – HYPERLORDOSIS – KYPHOSIS • POSTURE - SITTING – CAUSING PAIN TO LUMBO/SACRAL AREA

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

LIFTING WITH PROPER TECHNIQUE • BACK KEPT ERECT • KNEES BENT • WEIGHT CLOSE TO BODY

• 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

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

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

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)

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

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

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)