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Force-time history of chiropractic adjustment

Module 6 Effects Produced by Spinal Manipulation (Herzog Chapter 5) Biomechanics of Gait (Nordin Chapter 18 & web downloads) Biomechanics of the Shoulder (Nordin Chapter 12) Biomechanics (TECH 71613) James W. DeVocht, DC, PhD. Force-time history of chiropractic adjustment. Herzog Fig 5-1.

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Force-time history of chiropractic adjustment

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  1. Module 6Effects Produced by Spinal Manipulation (Herzog Chapter 5) Biomechanics of Gait (Nordin Chapter 18 & web downloads)Biomechanics of the Shoulder (Nordin Chapter 12)Biomechanics (TECH 71613) James W. DeVocht, DC, PhD

  2. Force-time history of chiropractic adjustment Herzog Fig 5-1 100 – 200 msec for most manual adjustments

  3. Measurable responses elicited by chiropractic adjustments 1. Mechanical responses 2. Neuromuscular reflex responses 3. Physiologic responses Herzog page 195

  4. 1. Mechanical Response Herzog Fig 5-4

  5. Mechanical Response as a function of timeof T10 & T12 for thrust on transverse processof T11 in an unembalmed, post rigor, human cadaver Herzog Fig 5-5

  6. 2. Neuromuscular Reflex Responses (reflex pathway for muscle spindle) Ia a Can be inhibitory or excitatory Herzog Fig 5-6

  7. Capsule mechanoreceptor response Spindle reflex response Herzog Fig 5-7

  8. EMG Reflex Response 50 – 200 msec Herzog Fig 5-8 Dt: delay from beginning of thrust to beginning of EMG response Response typically lasts 100-400 msec, then disappears

  9. Simultaneous Responses to SM Herzog Fig 5-9 (Manual Thrust on T4) Herzog Fig 5-10 (Activator Thrust on T6) VAG: cavitation response LAT: latissimus dorsiT6 & T4: levels of spinalis

  10. Time Delays Regarding EMG values Dt: thrust onset to 1st EMG Dt1: 1st EMG to onset of muscle force Dt2: muscle force onset to peak muscle force Herzog Fig 5-12

  11. Release of muscle spasm Herzog Fig 5-13

  12. Activator Adjusting Instrument with accelerometer attached

  13. Taking surface EMG data during Activator treatment

  14. Release of muscle spasm DeVocht, 2003 JMPT, 26(7), 421-425

  15. EMG Data from Pre-Post Treatment

  16. Can be generated by fast or slow thrust(more likely with fast thrust) 3. Physiologic effect produced during SM:Articular noise (audible release) Herzog page 204

  17. Schematic representation of force-displacement curve (includes audible release) Herzog Fig 5-13

  18. http://www.youtube.com/watch?v=LxtAeGtL9SE boiling: Model of Joint Cavitation A: Normal joint with no external loadsB: Initial distention, ligament invaginatesC: Tensile force up, snaps ligament back which now has some slack in itD: Volume has increased, bubbles formE: Ligament tightens as tensile force continuesF: Stable situation with increased volume and joint space Brodeur 1995, Fig 8JMPT, 18:3, p 160

  19. Joint separation before & after cavitation Brodeur 1995 Fig 4JMPT, 18:3, p 157

  20. Is an audible release necessary? Sound or feel of cavitation often used as indication that the adjustment was “successful” Many chiropractors will repeat an adjustment if there was no discernable “release” Herzog page 206

  21. Force-time histories of 2 attempts for cavitation - 2nd attempt usually has higher peak force- Usually has higher rate of force application- Often does result in cavitation 1st attempt: dotted line2nd attempt: solid line Herzog Fig 5-15

  22. Recent studies suggest that there is little if any clinical significance concerning whether or not an audible pop occurs in connection with a spinal manipulation Flynn 2006JMPT 29:1 p 44

  23. Transverse Divisions of the Foot forefoot midfoot “instep” hindfoot (talus & calcaneus)

  24. Longitudinal Divisions of the Foot Lateral Foot - calcaneus - cuboid - metatarsals & phalanges of toes 4 & 5 Medial Foot - talus - navicular - cuneiforms - metatarsals & phalanges of toes 1, 2, & 3

  25. Ankle Joint: Pure Hingecomprised of tibia, fibula, & talusmortise joint: rectangular space between medial & lateral malleoli

  26. Full Gait Cycle, or Stride(refers to movement of one leg) Stance phase - Foot in contact with floor - 60% of cycle when walking Swing phase (40% when walking) - Foot has no contact with the floor - 40% of cycle when walking Nordin page 440

  27. Sequence of Gait Cycle (walking) TO: toe off (left & right) HC: heel contact (left & right) Nordin Fig 18-1

  28. Stance Phase has 6 Parts 1. Initial contact (hind foot touches floor) 2. Loading (sole contact floor, body weight shifts) 3. Midstance (tibia rotates over talus) 4. Terminal stance (weight shifts from hind & mid to forefoot) 5. Pre-swing (weight shifts to contralateral leg) 6. Toe off (forefoot leaves the floor) Nordin page 440-1

  29. Center of pressure changes during stance phase from www.drpribut.com/sports/spgait.html

  30. Swing Phase has 3 parts 1. Initial swing (from toe off until opposite stance foot) 2. Mid-swing (ends when tibia is vertical) 3. Terminal swing (ends when heel contacts the floor) Nordin page 441

  31. Neumann Fig 15-13 Total vertical displacement about 5 cm Total medial-lateral displacement about 4 cm

  32. Spatial sequence of gait cycle (running) Nordin Fig 18-2

  33. Windlass Effect

  34. Talofibular & Calcaneofibular Ligaments commonly injured lateral view tennis accident (35 sec) http://video.google.com/videoplay?docid=-4399476076864988236&q=broken+ankle+tennis&total=9&start=0&num=100&so=0&type=search&plindex=5

  35. Biomechanics of the Shoulder(involves 4 articulations) Nordin Fig 12-1

  36. Sternoclavicular Joint Articulation with first rib Nordin Fig 12-4

  37. Movements of the Sternoclavicular Joint Nordin Fig 12-5

  38. Acromioclavicular Joint Nordin Fig 12-6

  39. Glenohumeral Joint Tendon of the long head of the biceps lies down in the bicipital groove Nordin Fig 12-8

  40. Glenoid Labrum(provides 50% of depth of glenohumural joint) Nordin Fig 12-10

  41. SLAP lesion(Superior Labrum from A – P) Nordin Fig 12-11

  42. Scapulothoracic Articulation Nordin Fig 12-13

  43. Musculature Between Scapula & Thorax(stabilizes scapula – prevents winging) http://www.youtube.com/watch?v=HepHiQOsT-E Nordin Fig 12-14 http://www.youtube.com/watch?v=814TZ4WUEKk

  44. Lateral bending of spine enhancesability to position upper extremity Nordin Fig 12-15

  45. Rotator Cuff Musculature(4 muscles) Nordin Fig 12-17

  46. Primary motions of the shoulder Nordin Fig 12-2

  47. Optimal motion of the shoulder(in plane of long axis of the scapula) Nordin Fig 12-3

  48. Forward elevation or abduction of armrequires synchronous rotation of scapula Nordin Fig 12-22 http://www.youtube.com/watch?v=hGOTf3Xl6Qs&mode=related&search=

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