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According to Arthur Guyton, MD Textbook of Medical Physiology

Click on a topic to go directly to it's answer

Basics Muscle Physiology
Contraction of Skeletal Muscles

Kinetic Chain
MD Care - Treatment Methods
Examination Findings
Problems Defining Trigger Points
Clinical Characteristics of Trigger Points
Contributing Factors to Trigger Points
History Taking


Basics Muscle Physiology

1. Approximately 50% of the body is muscle.
2. It makes up more than 60% of the mass of the body.
3. It is closely associated with ALL structures of the body and except for the brains, spinal cord and the interior of bones
4. It accounts for over 40% of body weight
5. Made up of 400 to 696 muscles depending on how detailed you get (Peroneus -vs.- longus and brevis)
6. Subject to greater wear and tear than any other structure
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ontraction of Skeletal Muscles

1. All skeletal muscles are made up of numerous fibers from 10 to 80 microns in diameter.
2. Fibers are subdivided into smaller and smaller units.
3. Fibers extend the full length of the muscles except in 2%.
4. "The mechanism of this (spasm) has not been elucidated to complete satisfaction even in experimental animals."
5. Structures locally are
  A. Muscle
  B. Tendon
  C. Fascia
  D. Ligament
6. Begins as a neuromuscular dysfunction -> histological dystrophic changes
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1. Each fiber is enervated by only one nerve ending located in the middle of the fiber.
2. Action potentials spread from the middle to the ends for concurrent contraction.
3. Multiple nerve endings are grouped into motor points.
4. An action potential causes the release of Ca+ which releases the muscle for contraction . . .
BUT actual contraction energy comes from ATP.
5. Surface action potential of motor units spreads to interior of muscle through Transverse Tubules.
6. T-Tubules continue surface membrane from exterior to interior for fluid and electrical transport.
7. Skeletal muscle fibers can not contract without an action potential.
8. Tone is tension short of actual contraction.
9. Tone is maintained by continued minimal enervation from the spinal cord AND feedback from local muscle spindle impulses transmitted through the posterior root to anterior root in a reflex arc to maintain tone.
10. Cut the posterior root and muscles become flaccid.
11. Sensory and motor nerves forms arc reflexes in the spine.
12. The arcs enervate as many as 4 and 5 levels up and down from their location
13. This aids in reflex protection mechanisms, muscle control and sensory feedback
14. It also can lead to referred pain patterns not consistent with dermatomes, etc.
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1. ATP energy for contraction is used up within 1 second . . .
2. 3 sources of replenishment are available . . .
  A. local creatine phosphate restores ATP immediately -> maintain contraction up to few seconds
  B. Mitochondria + carbohydrates, proteins & fats create new ATP inside cell membrane.
Mitochondria ATP production is called Kreb's or citric acid cycle.
Mitochondria production is slow
  C. Glycolysis - fats are converted to glucose and then to ATP - Slow process
3. Extended work of muscle cells leads to higher concentration of all substances locally.
4. Contraction can be maintained for several seconds with all in place.
5. Acute TPs usually release in a few seconds.
6. Chronic TPs can continue longer due to increased concentrations and amounts.
7. Dr. Travell, "The contractile activity would persist. . . as long as calcium and ATP were present. The sustained contractile force could in turn produce tension and hardness of the fibers that comprise the palpable band. The stimulus for reflex vasoconstriction of that region would be the need to control the runaway local metabolism."
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*** You must understand the action and location of mytotic groups to best diagnose and treat TPS ***
1. Contralateral Involvement
  A. Synergistic (Agonist) and Antagonistic muscle groups
  B. Mytotic Unit = group of agonist and antagonists for specific movements
2. Isotonic versus isometric contraction are different.
  A. Isometric (no movement) can be maintained longer due to reduced loss of efficiency from work.
  B. Think standing versus deep knee bends.
3. Muscle spindles - detect change in length and rate of change.
4. Golgi tendon organs - detect tension applied to muscle/tendon junction for stretch or contraction.
5. Both transmit tremendous amounts of information to spinal cord, cerebellum and cerebral cortex.
6. Both function to control muscles actions.
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Kinetic Chain

1. Muscle involvement at distance from pain
2. Contralateral muscles
3. Associative and accommodating muscles
4. Changes in biomechanics
5. Develops progressive TPs to Fibromyalgia
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Medical Care - Treatment for Trigger Points

1. Pharmaceuticals
  A. Muscle relaxants
  B. Antidepressants
  C. Hypnotics
  D. Analgesics
  E. Thyroid stimulants
  F. Oxytocin & DHEA
2. Contraindications & non-effectives
  A. Zopiclone
  B. Prozac
  C. Trancopal
  D. Valium, etc.
  E. Steroids
  F. Narcotics
3. Prolotherapy
  A. Rational - Stimulates collagen
  B. Causes blood vessel dilation
  C. Increases fibroblasts (healing cells)
  D. Weakened tissues stretch too much => pain
4. Contraindications - cortisone and estrogen => inhibits process
5. Dry needling
  A. Microtrauma => bleeding => collagen formation (natural process)
6. Wet needling
  A. Dextrose
  B. Glycine
  C. Lidocaine
  D. Lignocaine
7. Trigger Point therapy
  A. Rational - eliminates nodule pain
  B. Difference - focus and location with overlap
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Examination Findings for Trigger Points

1. Descriptions - Patient's Words
  A. Deep Ache
  B. Tight
  C. General pain
  D. Stiff
  E. Weakness
  F. Lack of Stamina / Energy
  G. Better after moving
  H. Worse after sleeping or sitting >½ hour
2. Grading
  A. MSP = Myospasm - use what you are used to for abbreviation.
  B. Grading 0 to 4
  C. 0 = No Trigger Points even on examination
  D. 1 = TPs found on examination with minimal pain but not felt on normal activity
  E. 2 = TPs found on examination with moderate to severe pain or may have objective signs but not felt during normal activity
  F. 3 = TPs found on examination with patient acknowledging pain but no objective signs
  G. 4 = TPs found on examination with explicit objective signs
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Problems Defining Trigger Points

1. Different definitions of "pain" - achy, sharp, tight, deep, etc.
2. Different organ association - muscles, fascia, nerves, bone
3. Different and not always associative timing with causes
4. Latent -vs.- active or acute
5. Localized -vs.- referred pain
6. Timing of acuteness - recent -vs.- distant initial cause and -vs.- current activation
7. Chronic -vs.- acute condition
8. Examiner's lack of understanding, skill and experience (elephant and blind men)
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Clinical Characteristics of Trigger Points

2. *** Normally do not follow dermatome, myotome or sclerotome patterns***
3. Hyper irritable spot in the muscle band - may be anywhere
4. Exceptional pain on compression
5. Generally, but not always, refers pain when active
6. Latent TPs increase pain and speed of onset during muscle use.
7. Found in any muscle, group of muscles, age, sex or ethnic group
  A. Infants with colic - abdominal TPs corrected with vapocoolant spray
  B. Children with sore muscles = TPs found
  C. Athletes often have latent TPs
  D. Workers with Repetitive type of work develop TPs
8. Usually deep, dull, achy sensation from 1 to 10 / 10
9. Rarely completely symmetrical in body
10. Rarely found in joint capsules and ligaments (Prolotherapy)
11. Generally quickly activated by
  A. Acute overload
  B. overwork fatigue
  C. direct trauma
  D. chilling
  E. leaving a muscle shortened
12. Sometimes activated by visceral organs
  A. Heart attack => shoulder pain
  B. Cholelithiasis => Abdominal pain
  C. Renal colic => flank pain
13. Can vary in intensity from day to day and hour to hour
14. Condition outlasts precipitating cause
15. Often becomes recurrent
16. Disrupts sleep
17. Causes muscle weakness and unreliability
18. Stiffness - especially after non-movement for 30+ minutes
19. Causes shortening of muscle = restriction of ROM
20. Precipitates depression
21. It may reduce but TPs almost never self resolve.
  A. Become latent ready to flare up again
  B. Still findable when latent

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Contributing Factors to Trigger Points

1. Sudden Trauma
2. Excessive exercise
3. Chilling or body area
4. IVD injuries
5. Systemic Conditions (gall bladder, heart attack, appendicitis, stomach irritation)
6. Immobility
7. Muscle strain - overuse or repetitive
8. Generalized fatigue - chronic fatigue
9. Nutritional deficiencies
10. Obesity
11. Depression
12. Anxiety
13. Poor posture
14. Poor biomechanics
15. Repetitive motion
16. Hypoglycemia
17. Hypothyroidism
18. Menopause
19. Short Leg Syndrome
20. Misfitting furniture
21. Misfitting shoes / clothes
22. Jerkiness of movement
23. Viral illness
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History Taking

1. Onset
2. Occurrences - Chronicity
3. Provocative
4. Palliative
5. Quality
6. Quantity
7. Referral locations
8. Severity
9. Timing - How often, long, time of day
10. Timing - What activities in prior 48 hours
11. Patient Descriptions
12. Use pain drawing or get specific area of pain complaint
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