1. Chapter 9: Mechanisms and Characteristics of Musculoskeletal and Nerve Trauma

2. Mechanical Injury
Trauma is defined as physical injury or wound, produced by internal or external force
Mechanical injury results from force or mechanical energy that changes state of rest or uniform motion of matter

3. Tissue Properties ______ __________
An external force acting on the body causing internal reactions within the tissues
__________
Ability of a tissue to resist a load
Greater stiffness = greater magnitude load can resist
Internal resistance to a load
Internal change in tissue (i.e. length) resulting in deformation

4. Figure 9-1

5. Body tissues are ____________ and contain both viscous (fluid like) and elastic (stretchy) properties
Yield point
Point at which elasticity is almost exceeded is the yield point
If deformation persists, following release of load permanent or plastic changes result
When yield point is far exceeded mechanical failure occurs resulting in __________

6. Tissue Loading ________ ____________
Force that pulls and stretches tissue
____________
Force that results in tissue crush – two forces applied towards one another
Force that moves across the parallel organization of tissue
Figure 9-2

7. ________
Two force pairs act at opposite ends of a structure (4 points)
Three forces cause bending (2 points)
Already bowed structures encounter axial loading
Loads caused by ________ in opposite directions from opposite ends
Shear stress encountered will be perpendicular and parallel to the loads
Figure 9-2

8. Traumatic vs. Overuse Injuries
Nature of physical activity dictates that over time injury will occur
Debate over acute vs. chronic injuries
When injury is ________ – something has initiated the injury process
Injury becomes ________ when it doesn’t properly heal
Could define relative to mechanism
Traumatic (i.e. a direct blow) vs. Overuse (i.e. repetitive dynamic use over time)

9. Musculotendinous Unit Injuries
High incidence in ________
Anatomical Characteristics
Composed of contractile cells that produce movement
Possess following characteristics
Irritability
Contractility
Conductivity
Elasticity

10. Three types of muscle Cardiac Smooth __________(skeletal)
Skeletal Muscle
Three types of muscle
Cardiac
Smooth
__________(skeletal)
Figure 9-3

11. Muscle Strains Stretch, tear or rip to muscle or adjacent tissue
Cause is often obscure
Abnormal muscle contraction is the result of 1)failure in reciprocal coordination of ________ and __________, 2) electrolyte imbalance due to profuse sweating or 3) strength imbalance
May range from minute separation of connective tissue to complete tendinous avulsion or muscle rupture

12. Muscle Strain Grades
__________ - some fibers have been stretched or actually torn resulting in tenderness and pain on active ROM, movement painful but full range present
__________- number of fibers have been torn and active contraction is painful, usually a depression or divot is palpable, some swelling and discoloration result
__________- Complete rupture of muscle or musculotendinous junction, significant impairment, with initially a great deal of pain that diminishes due to nerve damage
Pathologically, strain is very similar to contusion or sprain with capillary or blood vessel hemorrhage

13. Muscle Cramps Muscle Guarding
Painful involuntary skeletal __________ contraction
Occurs in well-developed individuals when muscle is in shortened position
Experienced at night or at rest
Muscle Guarding
Following injury, muscles within an effected area contract to splint the area in an effort to minimize pain through limitation of motion
____________ muscle contraction in response to pain following injury
Not spasm which would indicate increased tone due to upper motor neuron lesion in the brain

14. Muscle Spasms A reflex reaction caused by trauma Two types
________ - alternating involuntary muscular contractions and relaxations in quick succession
________ - rigid contraction that lasts a period of time
May lead to muscle or tendon injuries

15. Muscle Soreness
____________ in strenuous exercise resulting in muscular pain
Generally occurs following participation in activity that individual is unaccustomed
Two types of soreness
________-onset muscle soreness - accompanies fatigue, and is transient muscle pain experienced immediately after exercise
__________-onset muscle soreness (DOMS) - pain that occurs ___-___hours following activity that gradually subsides (pain free 3-4 days later)
Potentially caused by slight microtrauma to muscle or connective tissue structures
Prevent soreness through gradual build-up of intensity

16. Tendon Injuries
Wavy parallel collagenous fibers organized in bundles - upon loading
Can produce and maintain 8, ,000 lbs/in2
Collagen straightens during loading but will return to shape after loading
Breaking point occurs at 6-8% of increased length
Tears generally occur in ________ and not ________

17. Repetitive stress on tendon will result in ____________ and ____________, causing fibroblasts influx and increased collagen production
________ microtrauma may evolve into ________ muscle strain due to reabsorption of collagen fibers
Results in weakening tendons
Collagen reabsorption occurs in early period of sports conditioning and immobilization making tissue susceptibility to injury – requires __________ loading and __________

18. Tendinitis
__________ onset, with diffuse tenderness due to __________microtrauma and degenerative changes
Obvious signs of swelling and pain
Key to treatment is ______
May require substitution of activity in order to maintain fitness without stressing injured structure
Without proper healing condition may begin to degenerate and be referred to as __________
Less inflammation, more visibly swollen with stiffness and restricted motion
Treatment involves __________ and strengthening
Figure 9-5

19. Tenosynovitis Inflammation of synovial sheath
In ______ case - rapid onset, crepitus, and diffuse swelling
Chronic cases result in ____________ of tendon with pain and crepitus
Often occurs in long flexor tendon of the digits and the biceps tendon
Due to nature of injury anti-inflammatory agents may be helpful

20. Myofascial Trigger Points
Discrete, hypersensitive nodule within tight band of muscle or fascia
Classified as latent or active
Develop as the result of mechanical stress
Either acute trauma or ____________
May lead to development of stress on muscle fiber = formation of trigger points

21. Active trigger point Causes ______ at ______
Applying pressure = pain = ______ sign
Tender to palpation with referred pain
Tender point vs. trigger point
Found most commonly in muscles involved in postural support

22. Contusions Result of sudden blow to body
Can be both ______ and __________
Hematoma results from blood and lymph flow into surrounding tissue
Localization of extravasated blood into clot, encapsulated by connective tissue
Speed of healing dependent on the extent of damage
Chronically inflamed and contused tissue may result in generation of calcium deposits (myositis ossificans)
Prevention through protection of contused area with __________

24. Atrophy and Contracture
Atrophy is wasting away of muscle due to immobilization, inactivity, or loss of nerve functioning
Contracture is an abnormal __________ of muscle where there is a great deal of resistance to passive stretch
Generally the result of a __________ injury which impacts the ________, resulting in accumulation of scar tissue

25. Synovial Joints Injuries
Each joint has both ________ or ____________ cartilage and a fibrous connective tissue capsule
Additional synovial joint characteristics
Capsule and ligaments for ________
Capsule is lined with synovial membrane
Hyaline cartilage
Joint cavity with synovial ________
Blood and nerve supply with muscles crossing joint
Menisci (fibrocartilage)

26. Figure 9-8

27. Ligament Sprains
Result of traumatic joint twist that causes stretching or tearing of connective tissue
Graded based on the severity of injury
__________- some pain, minimal loss of function, no abnormal motion, and mild point tenderness
__________- pain, moderate loss of function, swelling, and instability with tearing and separation of ligament fibers
__________- extremely painful, inevitable loss of function, severe instability and swelling, and may also represent subluxation

28. Can result in joint effusion and swelling, local temperature increase, pain and point tenderness, ecchymosis (change in skin color) and possibly an avulsion fracture
Greatest difficulty with grade 1 & 2 sprains is restoring stability due to stretched tissue and inelastic scar tissue which forms
To regain joint stability strengthening of muscles around the joint is critical

29. Dislocations and Subluxations
Result in separation of bony articulating surfaces
Subluxation
Partial dislocations causing ____________ separation of two bones
Bones come back together in alignment
Dislocations
HIGH level of incidence in ________ and __________
Occurs when at least one bone in a joint is forced out of alignment and must be ________ or __________ reduced
Gross deformity is typically apparent with bilateral comparison revealing asymmetry

30. Dislocation (cont.) Figure 9-9
Stabilizing structures of the joint are disrupted
Joint often becomes susceptible to subsequent dislocations
__-_____ is the only absolute diagnostic technique (able to see bone fragments from possible avulsion fractures, disruption of growth plates or connective tissue)
Dislocations (particularly first time) should always be considered and treated as a fracture until ruled out
“Once a dislocation, always a dislocation”
Figure 9-9

31. Osteoarthritis Figure 9-10
__________ away of hyaline cartilage as a result of normal use
Changes in joint mechanics lead to joint degeneration
Commonly affects weight bearing joints but can also impact shoulders and cervical spine
Symptoms include ______ (as the result of friction), __________, prominent morning pain, localized tenderness, creaking, grating
Either generalized joint pain or localized to one side of the joint
Figure 9-10

32. Bursitis Bursa are fluid filled sacs that develop in areas of friction
Sudden irritation can cause acute bursitis, while overuse and constant external compression can cause chronic bursitis
Signs and symptoms include ________, ______ and some loss of function
Repeated trauma can lead to calcification and degeneration of internal bursa linings
Figure 9-11

33. Bone Injuries Anatomical Characteristics
Dense connective tissue matrix
Outer compact tissue
Inner porous cancellous bone including Haversian canals
Figure 9-12

34. Bone Functions Types of Bone ______ support Organ protection
Movement (through joints and levers)
________ storage
Formation of blood cells (hematopoiesis)
Types of Bone
Classified according to shape
______ bones - skull, ribs, scapulae
________ bones - vertebrae and skull
______ bones- wrist and ankle
______ bones (humerus, ulna, tibia, radius, fibula, femur) - bones most commonly injured

35. Gross Structures __________ -shaft - hollow and cylindrical
- covered by compact bone
- medullary cavity contains yellow
marrow and lined by endosteum
__________ - composed of cancellous bone and has hyaline cartilage covering
- provides areas for muscle attachment
__________- dense, white fibrous covering which penetrates bone via Sharpey’ fibers
- contains blood vessels and osteoblasts

36. Bone Growth
Ossification occurs from synthesis of bones organic matrix (work of osteoblasts and osteoclasts)
Involves growth of diaphysis and the epiphyseal growth plates (towards one another)
As cartilage matures, immature ____________ replace to ultimately form ________ bone
Deforming forces, premature injury and growth plate dislocation can ________ growth patterns and/or result in __________ of bone
At full size, bone maintains state of balance between osteoblastic and -clastic activity

37. Changes in activity and hormonal levels can alter balance
Bone loss begins to exceed external bone growth overtime
As thickness decreases, bones are less resistant to forces --____________

38. Bone Fractures Classified as either closed or open
________ fractures are those where there is little movement or displacement
________ fractures involve displacement of the fractured ends and breaking through the surrounding tissue
Serious condition if not managed properly
Signs & symptoms
Deformity, ________, point tenderness, ________, pain on active and passive movements
Possible crepitus
__-____ will be necessary for definitive diagnosis

39. Mechanism of Injury Types of fractures
Fracture may be direct (at point of force application) or indirect
Sudden violent and forceful muscle contraction
Types of fractures
_________
Comminuted
Transverse
Spiral
Depressed
Figure 9-13

40. Less common types of fractures
________
Separation of bone fragment from cortex via pull of ligament or tendon
________ fracture
Serrated fracture
Contrecoup fracture

41. Stress fractures
No specific cause but with a number of possible causes
Overload due to muscle contraction, altered stress distribution due to muscle fatigue, changes in surface, rhythmic repetitive stress vibrations
Early detection is difficult- bone scan is useful, __-___ is effective after _________ weeks

42. Typical causes include
Coming back to competition too soon after injury
Changing events without proper conditioning
Starting initial training too quickly
Changing training habits (surfaces, shoes….etc)
Variety of postural and foot conditions
Signs and symptoms
Focal tenderness and pain, (early stages)
Pain with activity, (later stages) with pain becoming constant and more intense, particularly at night, (exhibit a positive percussion tap test)
Common sites involve ______, ________, metatarsal shaft, __________, femur, pars interarticularis, ribs, and humerus
Management varies between individuals, injury site and extent of injury

43. Epiphyseal Conditions
Three types can be sustained by adolescents (injury to growth plate, articular epiphysis, and apophyseal injuries)
Occur most often in children ages years old
Classified by Salter-Harris into five types (see illustration on next slide)
Apophyseal Injuries
Young physically active individuals are susceptible
Apophyses are traction epiphyses in contrast to pressure epiphyses.
Serve as sites of origin and insertion for muscles
Common avulsion conditions include Sever’s disease and __________-__________disease

44. Figure 9-15

45. Osteochondrosis
Also known as osteochondritis dissecans and apophysitis (if located at a tubercle/tuberosity)
Causes not well understood
Degenerative changes to epiphyses of bone during rapid child growth

46. Nerve Trauma
Abnormal nerve responses can be attributed to injury or athletic participation
The most frequent injury is neuropraxia produced by direct trauma
Lacerations of nerves as well as compression of nerves as a result of fractures and dislocations can impact nerve function

47. Nerve Injuries __________ and ________ are primary mechanisms
May be acute or chronic
Physical trauma causes pain and can result in a host of sensory responses (_______, burn, ______, muscle weakness, ________ ______)
Long term problems can go from minor nerve problems to ________

48. Microtrauma and Overuse Syndrome
Injuries as a result of abnormal and repetitive stress and microtraumas fall into a class with certain identifiable syndromes
Frequently result in limitation or curtailment of sports involvement
Often seen in ________, ________, and ________ activities
Some of these injuries while small can be debilitating
Repetitive overuse and stress injuries include
________ tendinitis, shin splints, ______ fx, Osgood-Schlatter's disease, ________ and ________ knee, patellar chondromalacia and apophyseal avulsion