Biomechanics of the Spine & Hip

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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 When Standing Upright
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. = Newtons Segment Weight Moment Arm Head 13 lbs. (58N) 25 cm Trunk lbs. (328N) 10 cm Arms 18.2 lbs. (81N) 20 cm Box 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 = N or ( lbs.)

Problem for a 135 lb. Person Torque ? 10,285 Ncm
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 Lifted 100 N 42 cm. Torque ? 10,285 Ncm Fm = 1714 N or (393 lbs. Force)

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.

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 - 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)