lecture 7 Flashcards
muscle fatigue, injury, and healing
what is muscle strain?
when tension exceeds the weakest structure element
where would the muscle strain be located?
located near the muscle tendon junction 0.1 mm-3mm proximity
what causes muscle strain?
sudden over stretch or contraction and limb deceleration
what happens when you have a sudden over stretch or contraction, limb deceleration…MOI?
Failure of Golgi Tendon Organ may play a significant role in muscle strain
Insufficient warm-up may contribute to muscle strain
Contributory Causes: corticosteroid injections, previous injury, disease
what contributes to a muscle strain?
corticosteroid injections, previous injury, disease
how many degrees of muscle strain are there?
3
what is the first degree (mild) of muscle strain?
also known as strained muscle where fibers have been stretched or torn and pain is felt with full ROM but full range still present
what can we note about the structure with a first degree muscle strain?
minimal structural damage and minimal hemorrhage
what is the second degree (moderate) of muscle strain?
also known as a pulled muscle where fibers have been torn and active contraction is painful, depression palpable, some swelling and discoloration result
what can we note about the structure with a second degree muscle strain?
partial tissue tear, significant loss of function and hemorrhage
what is the third degree (severe) of muscle strain?
also known as a torn muscle where there is complete rupture of muscle or musculotendinous junction, significant impairment, with initially a great deal of pain that diminishes due to nerve damage
what can we note about the structure with a third degree muscle strain?
complete tear, total loss of function, extensive hemorrhage
what can we note about the impairment of third degree muscle strain?
impairment starts off with a lot of pain but dulls down due to nerve damage
what can be done about tendon ruptures?
large tendon will require surgery
what are muscle cramps and spasms?
painful involuntary contraction
attributed to dehydration/electrolyte imbalance
may lead to muscle or tendon injury
how does muscle guarding work?
Following injury, muscles within an effected area contract to splint the area in an effort to minimize pain through limitation of motion
Involuntary muscle contraction in response to pain following injury
how does muscle soreness work?
overexertion in strenuous exercise resulting in muscular pain and generally occurs following participation in activity that individual is unaccustomed with
what are the two types of soreness?
acute onset muscle soreness
delayed onset muscle soreness
what is acute onset muscle soreness?
accompanies fatigue, and is transient muscle pain experienced immediately after exercise
what is delayed onset muscle soreness?
pain that occurs 24-48 hours following activity that gradually subsides (pain free 2-3 days later)
what can cause delayed onset muscle soreness?
Potentially caused by slight microtrauma to muscle or connective tissue structures
what can cause a muscle contusion?
blow to muscle results in muscle tearing then to a hematoma with a severe contusion sometimes difficult to distinguish from a complete tear
what are the types of muscle contusions?
intermuscular and intramuscular hematoma
what is an intermuscular hematoma?
bleeding between muscle fascia
how is the intermuscular hematoma characterized?
Early migration of ecchymosis (a discoloration of the skin resulting from bleeding underneath) to distal part of limb
how do intermuscluar hematomas generally heal compared to intramuscular hematomas?
heal more quickly than intramuscular hematomas
what is a intramuscular hematoma?
bleeding within a muscle bundle
how do we characterize an intramuscular hematoma?
more confined and localized, inflammatory response is exaggerated and there is an increased risk of myositis ossificans, residual scarring and compartment syndrome
what is a specialized kind of intramuscular hematoma discussed in class, often times very severe?
compartment syndrome
how does compartment syndrome develop?
it begins with a hemorrhage then increased pressure in the muscle unit leading into decreased blood flow resulting in ischemia, necrosis and gangrene
what can cause compartment syndrome?
excessive exercise induced muscle damage
describe compartment syndrome pain?
palpable tightness, shiny skin appearance often needing of surgery within 12 hours of damage
what are the general stages in the healing of muscle trauma?
Inflammatory (Days 0-2)
Fibroplastic Proliferation (Days 3-6)
Fibroplastic Proliferation (Days 7-14)
Remodeling Maturation (Days 15-60)
describe the healing process for stage 1?
- Cell Disruption → hemorrhage & edema
- Myofibular retraction and nerve axon damage
- Mononuclear cell invasion → increased inflammation
- Phagocytosis
describe the healing process for stage 2?
- Increased rate of collagen synthesis by fibroblasts
- Muscle regeneration from “Satellite” cells
- Pulsed ultrasound
describe the healing process for stage 3?
- Muscle fibers bridging begins (increased danger of re-injury)
- Tensile strength approximately 50% of normal
- Contraction is still inhibited by edema and pain
describe the healing process for stage 4?
- High maturation of collagen and increase in tensile strength
- Replacement of initial or inferior tissue
- Permanent loss of tissue tensile strength is 7%
describe the treatment process for stage 1?
- RICE (Rest, Ice, Compress, Elevate)
- Immobilization and protection
- NSAID drugs
describe the treatment process for stage 2?
- Partial ROM exercise
- Gentle resistance work
describe the treatment process for stage 3?
- Increased resistance work
- Progress to full ROM exercise
- Ultrasound and heat modalities
describe the treatment process for stage 4?
- Progression of activity (increased intensity and duration)
what cells are activated in damaged muscle?
satellite cells are activated, they replicate, migrate on basement membranes and fuse to form new muscle fibers
Muscles cells and invading inflammatory cells release…
Growth factors and cytokines
these cells are also known as the fountain of youth?
satellite cells
review slides on satellite cells for the healing of muscle injury
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