Class 3

Question 1

What is a myofascial trigger point?

Answer 1

Hyper-irritable spot in skeletal muscle that is associated with hypersensitive, palpable nodule in taut band.

Question 2

What are the characteristics of a myofascial trigger point?

Answer 2

Spot is painful/tender on compression, can give rise to characteristic referred pain, weakness, reduced length & autonomic phenomena. Pain is described as dull, aching, & deep.

Question 3

How does a myofascial trigger point develop?

Answer 3

Develops when group of sarcomeres become stuck in shortened position. Exact mechanism is not fully understood, there are 3 predominant theories that are believed to explain presence of trigger points.

Question 4

What is the Energy Crisis hypothesis? ** Will NOT be tested on this, just know about contraction!

Answer 4

• Excess calcium (due to destruction of sarcoplasmic reticulum) produces sustained maximal contraction of sarcomere(s), which increases energy requirements, as well as compressing local vasculature.
• Increased energy demands + ischemia (lack of oxygen & therefore energy metabolism) = energy crisis.
• May be induced by strain or trauma.

Question 5

What is Motor Endplate Dysfunction Theory? ** Will NOT be tested on theory, just know about contraction!

Answer 5

• Increased acetylcholine release by presynaptic neuron causes increased release of calcium, resulting in sustained maximal sarcomere contraction.
• May be result of genetics or stress (increase SYNS firing)

Question 6

What is Integrated Hypothesis Theory? ** Will NOT be tested on theory, just know about contraction!

Answer 6

• Trauma/strain causes rupture of sarcoplasmic reticulum, resulting in uncontrolled release of calcium followed by sustained sarcomere contraction.
• Sustained contraction results in increased energy demand + compression of local blood vessels = energy crisis.
• ATP depletion, therefore no re-uptake of calcium into sarcoplasmic reticulum.
• Hypoxia decreases local pH which stimulates nociceptors, causing pain & increased SYNS firing. Chronic nociceptive activation can create sensitization in CNS
•Contraction>ischemia>pain>SYNS>Ach>Ca+>Contraction