SPINAL BIOMECHANICS POSTURE ANALYSIS POSTURE Keep in mind
SPINAL BIOMECHANICS POSTURE ANALYSIS
POSTURE • Keep in mind the spine is found at the posterior aspect of the body, behind the center of gravity • Center of gravity lies: – – – – Through the atlanto-occipital joint Tragus of the ear Anterior humeral head Anterior-inferior edge of T 11 Greater trochanter Just behind the patella Through the lateral malleoli
DURING POSTURAL ANALYSIS… • Usually stance is asymmetrical if not intentional. • The weight of the body is borne by the skeleton aided by the action of intrinsic back muscles • Sway occurs during stance. • Postural sway of the vertebral column on the pelvis is controlled by the erector spinae, and the rectus abdominis. • 80% of the contraction occurs in the E. S. , whereas only 20% of contraction occurs in the abdominals, as confirmed by EMG studies. • In scoliosis, E. S. contraction is higher on the convex side.
AFFECTS OF AXIAL COMPRESSIVE FORCES • Increases from the C/S to the L/S • Lumbar problems are common--#1 reason to see a Chiropractor
HOW DO MUSCLES BECOME IMBALANCED? • Skeletal misalignment- triggers other muscles to be recruited to restore normal posture • Joint pain or malformation- imbalance in stance and gait • Ligamentous injury/instability- recruits muscles to support the joint • Muscle fatigue- recruits other muscles to contract to accomplish the same movement, often resulting in myofascial trigger points
BEGINNING POSTURE ANALYSIS • Work from the “ground-up”: – Check for any lower extremity deformity that may be creating imbalance above
EXAMINE THE FEET • • • LONGITUDINAL ARCH PRONATION SUPINATION MEDIAL MALLEOLI LEVELS ACHILLES TENDON POSITION SIGNS OF LIGAMENTOUS LAXITY
Pes Planus Pes Cavus
REASONS BEHIND TOE-IN & TOE-OUT • TOE-IN – INTERNAL TIBIAL ROTATION Blount's disease – TIBIA VARUS – INCREASED INTERNAL ROTATION of FEMUR —often due to muscular contraction/imbalance • TOE-OUT – BILATERAL- SACRAL ANTERIORITY – UNILATERAL- PELVIC ANTERIORITY – INCREASED EXTERNAL ROTATION of FEMUR—often due to muscular contraction/imbalance
EXAMINE THE KNEES • FLEXED – Hamstring spasm – Quad weakness – Acute low back pain • HYPEREXTENDED – Ligamentous – Anterior compression fracture
KNEES GENU VARUS GENU VALGUS
Q – ANGLE (Quadriceps) • Wide Hips (female runners) • Knock Knees (·Genu valgum) • Pronation of the feet • Subluxating Patella • High riding patella (patella alta) • Weak Vastus Medialis An abnormally high Q-Angle can cause stress on the entire kinetic chain of the lower extremity causing many conditions from low back pain to foot pain. D. Robert Kuhn, DC, Terry R. Yochum, DC, Anton R. Cherry, Sean S. Rodgers
Imbalance of Hip Rotators • Leg length discrepancies and foot pronation may lead to: • Iliotibial band syndrome • Piriformis syndrome • Recurrent muscle strains (hamstring and groin pulls) can be an indicator of asymmetry in structural alignment.
HIP MUSCLES… • Transfer ground-reaction forces from legs to trunk during gait • Supply coordinated propulsion • Provide balanced stability for the pelvis and spine • Through repetitive use patterns and after injuries, hip muscles may become shortened and/or weak [1] Kim D. Christensen, DC, CCSP, DACRB
THIGH AND PELVIS • BULK OF HAMSTRINGS • GREATER TROCHANTERS • PELVIC TILT, SWAY (antalgia), TORTION- AS or PI • ILIAC CREST LEVELS • PSIS LEVELS • SACRAL ROTATION (S 2—PSIS distance) • GLUTEAL MUSCLES- Deeper Dimpling
POSTURAL ANALYSIS P-A View • Sacral Base– Level – Held in place by innominate bones – Dependant upon equal leg lengths • What can go wrong? – Sacral deformity» Transitional segment » Plateau base – Anatomical short leg » Congenital » Acquired – Functional » Due to muscle imbalance » Due to pelvic distortion
BODY RESPONDS IN A PREDICTABLE MANNER • Attempts to restore balance: – Eyes on horizontal plane “Righting Reflex” – Equally distributing weight to center of gravity
VERTICAL PLANE of LUMBAR SPINE • • • SPINOUS ALIGNMENT SECTIONAL TOWERING CURVATURE LORDOSIS PARASPINAL MUSCLE TONICITY SKIN DISCOLORATION
THORACIC OBSERVATIONS SPINOUS ALIGNMENT SECTIONAL TOWERING CONVEXITY or SCOLIOSIS + ADAM’S SIGN KYPHOSIS RIB HUMP SCAPULAR WINGING (myopathies, shoulder instability, Serratus anterior weakness) • POSTERIOR SCAPULA (scoliosis) • HIGH SHOULDER/TRAP • INTERNAL ROTATION HUMEROUS • •
NECK and HEAD OBSERVATIONS • • • C 2 SPINOUS ALIGNS WITH S 2 TUBERCLE? MASTOID PROCESS LEVELS HEAD TILT OR ROTATION ANTERIOR HEAD CARRIAGE LORDOSIS MUSCLE TONE
LATERAL VIEW • SACRUM: Inclines from 26 -56º from horizontal – LUMBAR: Levels off at L 4 superior body surface (Apex), continues posteriorly in upper L/S – THORACIC: Gradual reversal of curve: body wedging to create kyphosis at apex (T 4 -T 6) – CERVICAL: Curve reverses again: apex (C 4) • What constitutes postural abnormality? – Any Variation in the AP or Lat » Pelvic unleveling » Spinal segment unleveling • Produces imbalance & altered weight imposition
Kendall, et. al.
FROM THE SIDE KYPHOSIS LORDOSIS
NORMAL RANGES of MOTION • Varies – Age – Activity • EVALUATE: As a total unit; comparing symmetry more than degrees – Break it down by section—if blocked in one section may lead to hypermobility in another – Look for: • Abnormal coupling of motion (rotation with flexion) • Bilateral symmetry; smoothness & ease of motion
MOTION T/L C FLEXION 90 60 EXTENSION 40 50 UNILAT ROTATION 30 80 UNILAT 35 45 FLEXION
SACROILIAC KINETICS
THE SACROILIAC JOINT A Controversial Topic Complicated Anatomy and Biomechanics: 1. Small ROM 2. Passive movement 3. Stress-relieving joint
MOTION IN THE S/I JOINT • No gross excursion (except due to severe trauma) � Movement: absorption Normal physiological effect of shock – Obvious movement during ambulation-Sacral nutation • Clear osseous limitation– Interlocking ridges & grooves – Strong reinforcing ligaments – Key-stone in arch stability • Age Factors in degree of motion: – Flexible—to—Ankylosis
Gillett’s test … Demonstrates pelvic motion by comparing PSIS motion B/L: • • Fixation Pseudo-ankylosis Fusion Lumbar or hip muscle hypertonicity
Pelvis Tips and Rotates in Accommodation… A response to dysfunction above or below Leads to: • • Abnormal: unequal weight into each S/I joint leading to… • Pelvic distortion • Eccentric weight imposition into each S/I joint • Abnormal posture • Abnormal gait
PELVIC DISTORTION IS PREDICTABLE… • Predictable patterns of accommodation have been demonstrated as a response to imbalance both above and below. • Therefore, pelvic distortion is often not a primary subluxation, but a compensatory, secondary distortion
PRIMARY SUBLUXATION IN THE LUMBAR SPINE (Secondary S/I Dysfunction) n IVD HERNIATION n CURVATURE OR SCOLIOSIS n TRANSITIONAL SEGMENT n. ALTERED SAGITTAL CURVE n. FUNCTIONAL: GROSS MUSCULAR
PRIMARY DISTORTION DUE TO LOWER LIMB DEFICIENCY (Secondary S/I Dysfunction) • ANATOMICALLY SHORT FEMUR OR TIBIA • GENU VARUM OR VALGUS • PRONATION • FLAT FOOT • HIP, KNEE, ANKLE OR FOOT PAIN
PRIMARY Sacroiliac Fixation • Chronic stress to the S/I joints leads to: – Repetitive microtraumas – Gross muscular compensation—holding joint in the fixed malposition • May eventually lead to : – Sclerotic changes
PRIMARY Sacroiliac Instability • Sprain • Pregnancy & Child Birth • Pubic Symphysis Dysfunction
CHARACTERISTICS OF S/I PAIN • • • Painful to walk Ascending or descending stairs Standing from a sitting position Hopping or standing on involved leg Sharp pain that awakens the patient from sleep upon turning in bed
What Research Has Shown • L/S may refer pain to S/I • S/I ROM: – Decreases with age – Minimal compared to spine • Pain can= – 1° Fixation, Instability or – 2° Accommodation
CONTINUED S/I JOINT STRESS… • May lead to true fixation in its misalignment— becoming a primary subluxation – Prolonged accommodation to chronic spinal subluxation and postural abnormality or leg deficiency may lead to • Fixation • Gross muscular change • Sclerosis
OTHER ENTITIES CAUSING S/I JOINT PAIN • Pelvic disorders- Prostatitis, Interstitial Cystitis, or breast, lung or prostate metastasis • Enteric disorders- Iliopsoas abscess (Diabetes, UTI) • Inflammatory arthrotides or “Spondyloarthropathies”- A. S, Lupus, Reactive Arthritis (“Reiter’s”), Crohn’s disease
EXAMINATION 1. 2. 3. 4. 5. 6. Observation Primary Stress Tests Leg Length Tests Weight Bearing Kinetic Tests Secondary Stress Tests Orthopedic Tests
I. OBSERVATION Pages 88 -90 1. Postural Analysis: 1. Pelvic tilt (Anterior or Posterior) 2. Lateral pelvic tilt 3. Any structural asymmetry 2. Check for landmark: 1. Alignment 2. Tenderness 3. Belt Test: Test to R/O lumbar involvement
REINERT SPECIFIC LISTINGS FOR PELVIC DISTORTIONS AS RELATED TO THE SACROILIAC JOINT • • • POSTERIOR POSTERO-INFERIOR ANTERIOR ANTERO-SUPERIOR
II. PRIMARY STRESS TESTS
LEG LENGTH
WEIGHT-BEARING KINETIC TESTS
Sacral Compression Test Forced Counternutation
GAENSLEN’S TEST
YEOMAN’S TEST
FABER PATRICK’S TEST
HIBB’S TEST
PRONE PALPATION
MOTION PALPATIONComparing Symmetry 1. PRONE PASSIVE: Spring S/I joints 2. SEATED PASSIVE: Spring S/I joints 3. PRONE ACTIVE: Stabilize S/I joints and ask patient to extend lower limb while knee remains extended
CONCLUSION • Determine if S/I pain is 1° or 2 ° • Once this is achieved, the doctor can determine the appropriate treatment
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