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Injuries to the Tissues

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1 Injuries to the Tissues
Chapter 14 Injuries to the Tissues

2 OA 10.21 Differentiate between a primary injury and secondary injury

3 Objectives Introduce the terminology associated with injury classification Introduce biomechanical forces that cause injuries Explain biomechanical concepts for various tissues

4 Injury classification
Intrinsic Infection (viral, bacterial) Extrinsic Tissue stressed to the point of mechanical failure due to excessive force

5 Extrinsic injury classification
Primary Injury Direct immediate consequence of excessive force (trauma) Secondary Injury Delayed injury some time after initial trauma An accommodation to the primary injury

6 Extrinsic injury classification
Acute Injury Mechanical failure of soft tissue due to excessive force occurring in a single bout Sudden onset of short duration

7 Extrinsic injury classification
Chronic Injury Mechanical failure of soft tissue due to repeated micro-trauma occurring over an extended period of time Gradual onset and are of prolonged duration

8 Injury classification
Microtrauma Occurs with repeated submaximal forces over time, and the tissues are unable to adapt Macrotrauma Occurs when a single force exceeds the tissue’s failure point

9 Open vs. closed Open Closed Exposed Breaks the surface of the skin
Unexposed Any injury that does not involve disruption of the skin surface

10 Mechanical stresses Load/Stress Deformation/Strain
External/internal force acting on the tissue Force = Mass x Acceleration (F=ma) Deformation/Strain Extent of deformation under loading

11 load/deformation Mechanical force causes deformation
Degree of deformation depends on: Tissue composition Speed of applied load Frequency of loading Direction of loading Deformation Load

12 Yield point Load is greater than mechanical capabilities of the tissue
Elastic limit of the tissue has been reached Mechanical failure occurs Ultimate Failure Point Load Yield Point Elastic Region Plastic Region Deformation

13 Tissue stresses Five primary mechanical forces that cause injury
Tension Compression Bending Shear Torsion

14 Tissue stresses Can occur alone or in combination
Type of force = Mechanism of Injury (MOI)

15 tension Creates a pulling action trying to elongate the structure
Longitudinal “tearing” stress Overstretched tissue (i.e. valgus force)

16 Valgus force

17 compression Creates a pushing action tending to shorten the structure
Stress is applied at each end (i.e. FOOSH)


19 bending Loading about an axis – Combination of tension and compression

20 Shear force Force that acts perpendicular to the surface of a structure

21 Shear force

22 torsion Load applied causing structure to twist about an axis


24 Combined loading Tissue is seldom loaded in one mode only
Subjected to multiple indeterminate loads Geometric structure is irregular

25 forces

26 OA 10.22 Give an example of each of the 5 mechanical forces that cause injury.

27 Superficial injuries

28 Integumentary System Skin and structures derived from it
Hair, nails, sweat and oil glands

29 Functions Regulate body temperature Protects body Receives stimuli
Temp, pressure, pain Eliminates waste Sweat

30 Three Layers Epidermis: Most Superficial

31 Three Layers Dermis: Tough, Leathery Fibrous Connective Tissue
Partly Vascularized

32 Three Layers Subcutaneous (Hypodermis): Superficial Fascia
Mostly Fat (Insulate & Absorb Shock) Anchors Skin to Underlying Structures

33 Three Layers

34 Injurious Mechanical Forces
Friction Scraping Compression Tearing Cutting Penetrating

35 Open Vs. Closed Open Closed Exposed Breaks the surface of the skin
Unexposed Any injury that does not involve disruption of the skin surface

36 Abrasions Scraping away of the superficial tissue
Sliding or skidding across a surface Superficial in depth, large in area Bleeding is minimal, risk of infection is great


38 Laceration Irregular cut caused by tearing forces Jagged wound edges
Can be minor or very deep


40 Puncture Penetration of the skin by an object
Most susceptible to infection– why? Impaling = object is embedded & partially sticks out


42 Incision A clean, straight, knife-like cut
Commonly caused by a surgeon


44 Avulsion Tearing away of tissue, commonly paired with a laceration.
Flap avulsion – tissue is still connected


46 Calluses Skin thickening due to increased friction or intermittent pressure


48 Blister Excessive friction combined with shear forces causing fluid build-up under the skin

49 General Principles Of Wound Care

50 Chain of infection pathogen RESERVOIR HOST PORTAL OF EXIT
Infected individual PORTAL OF EXIT Nose, mouth, eyes, urinary/reproductive system, open wounds ROUTE OF TRANSMISSION Direct or indirect contact PORTAL OF ENTRY SUSCEPTIBLE HOST Very young and elderly are most susceptible pathogen

51 Universal Precautions
Those in direct contact must use protective equipment Non-latex gloves, gowns, aprons, masks & face shield, eye protection, CPR barriers Emergency kits should include gloves, CPR barrier, alcohol prep pads at minimum

52 Universal Precautions
Doubling gloves is suggested with severe bleeding

53 Universal precautions
Use Personal Precautions Extreme care must be used with glove removal Glove Removal

54 Universal precautions
Use Personal Precautions Wash hand & skin surfaces Proper Hand Washing

55 Supplies to have on hand
Non-latex gloves Sterile 4”x4” gauze pads/sponges Sterile saline solution Non-adherent pads Antiseptic/antibiotic ointment Non-adherent cohesive tape Optional: soap, water, hand sanitizer, hydrogen peroxide, cinder suds, nitrotan

56 bleeding 3 types of external bleeding
Venous – dark red blood, slowly flowing Capillary – bright red, seeping/oozing Arterial – bright red, spurts or streams

57 Controlling bleeding For all types of bleeding direct pressure must be applied to the area Blood takes 4-6 minutes to clot

58 Controlling bleeding Use a sterile gauze pad/compress to collect the blood If saturated, add additional gauze as needed Never remove and replace, always add!

59 Controlling bleeding Arterial bleeding is a medical emergency
Direct pressure must be applied until EMS arrives Elevation can help slow blood loss Body part placed above level of the heart Exceptions: fractures & spinal injuries

60 Controlling bleeding Indirect pressure can slow blood loss
Pressure points proximal to the injury must be compressed

61 Controlling bleeding An ice pack causes vasoconstriction (narrowing of blood vessels), slowing bleeding

62 Wound cleansing Debridement - removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue.

63 Wound cleansing Cleansing and debriding a wound prevents infections and increases healing time.

64 OA 10.23 List in order the four methods for controlling bleeding.

65 Wound cleansing Remove any dirty bandages, clothing, etc. from the wound Apply a solution to irrigate the wound Saline, sterile water, etc. Clean the wound with circular motion starting at the center and working outwards Irrigate the wound once more to remove all dirt & debris Dry the area with sterile gauze Cover the wound with a sterile dressing

66 Wound cleansing Wound Cleansing

67 Applying bandages & dressings
Dressing = contact with the wound Bandage = holds dressing in place

68 Applying bandages & dressings
Bandages and dressings decrease the risk of infection if properly applied and maintained Must cover the wound entirely and stay in place Allow for normal movement and activity Absorb blood and drainage Protect the wound from further injury

69 Bandage & dressing types
Dressings: Non-adherent pads Vasiline gauze Telfa pads Adaptic pads Xeroform gauze

70 Bandage & dressing types
Bandages Sterile gauze ABD dressings Rolled gauze Oval eye pads Adhesive bandages

71 Applying dressings Select the proper dressing
Ensure the wound is cleansed Apply antibiotic ointment to the dressing Place dressing directly over the wound

72 Applying bandages Select appropriate bandage
Allows movement Remains sturdy Remove jewelry, clothing, etc. near bandage site Circulation can be impaired with swelling Leave fingers & toes exposed To check circulation

73 Applying bandages Cover the dressing entirely
Apply bandage snugly, but not too tightly Apply in the position they will remain in Secure loose ends with tape, or tuck them in


75 Wound care management Patient instructions Keep wound clean and dry
Change dressings daily Remove and replace if wet Watch circulation of the limb; seek medical help if circulation is impaired Watch for signs of infection

76 Signs of infection Redness Swelling Increased pain
Red streak up the arm or leg Foul-smelling odor Elevation in temperature over the wound or surrounding tissue

77 OA 10.24 List the 6 signs of infection

78 Tissue stresses Five primary mechanical forces that cause injury
Tension Compression Bending Shear Torsion

79 Tissue stresses Can occur alone or in combination
Type of force = Mechanism of Injury (MOI)


81 Five Major Functions Of The Skeleton
Protection of vital soft tissues Support human posture Movement by serving as points of attachment for muscles Storage for minerals Hemopoiesis – the process of blood formation that occurs in the red bone marrow

82 Mechanical properties of bone
Wolff’s Law: bone will adapt to the loads under which it is placed.

83 Mechanical properties of bone
Direction of Loading Strongest in compression Weak in tension Weakest in shear Compression > Tension > Shear

84 Mechanical properties of bone
Bone size ↑ size of bone (mass) = ↑ bone strength Greater area to distribute mechanical stresses

85 Mechanical properties of bone
Bone shape Sudden shape changes are areas where mechanical stresses are most concentrated Weak points/Stress risers

86 Bone growth Epiphyseal growth plate
Cartilaginous disk near the end of each long bone Dependent on plate Injury can prematurely close the plate causing loss of length

87 Mechanisms of bone injuries
Pure tensile forces Compression forces Bending

88 Three-point bending ↑ distance from center = ↑ bending moment
Tensile Force Compressive Force


90 Skeletal injuries

91 Bone injuries Periostitis Bone contusion
Inflammation of the periosteum, usually from contusion Bone contusion Bruising of the bone tissue Very painful Slow to heal – typically 6-8 weeks

92 Live Injuries Proper Field Set-Up Femur ACL Knee Broken Leg

93 OA 10.28 Describe the properties of bone that make it strongest, weakest, and most prone to injury.

94 Bone injuries Fracture
Any disruption in the continuity of the bone or periosteum

95 Bone injuries Description of Fracture Site
Extent – partial, complete, hairline Configuration - type Relationship of fragments – displaced, non-displaced Relationship to external environment – closed, compound

96 Incomplete Fracture

97 Undisplaced Fracture

98 Displaced Fracture

99 Open (Compound) Fracture

100 Bone trauma classification
Type Etiology Transverse Direct Blow Spiral Rotation on planted foot Oblique One end fixed, other sudden torsion Comminuted Blow or fall in awkward position Depressed Flat bones, direct blow

101 Bone trauma classification
Type Etiology Greenstick Incomplete Fx, skeletally immature (convex) Longitudinal Splits along length, jumping from height Serrated Direct blow, jagged edges Contrecoup Side opposite to point of impact Impacted Compressive force on long axis of bone

102 Transverse Fracture

103 Spiral Fracture

104 Oblique Fracture

105 Comminuted Fracture

106 Depression Fracture

107 Greenstick Fracture

108 Longitudinal fracture

109 Serrated fracture

110 Impacted Fracture

111 Other fractures Some fractures have names based on founder, mechanism, common type Bennett’s fracture Maisonneuve fracture Boxer’s fracture Bankart fracture Pott’s fracture Many, many more

112 Bennett’s fracture

113 Maisonneuve fracture

114 Boxer’s fracture

115 Bankart fracture

116 Pott’s fracture

117 Stress Fractures Also called march, fatigue, & spontaneous fractures
Weight bearing bones become weaker before they become stronger

118 Stress Fractures Typical causes in sports:
Coming back too soon after injury or illness Changing events without proper training Starting initial training too quickly Changing habits or the environment

119 Stress Fracture

120 Avulsion Fracture

121 Avulsion Fracture

122 Joints (Articulations)
All joints are comprised of capsular tissue surrounding the joint itself Strong, fibrous tissue Synovial joints Capsular tissue Articular cartilage at ends of bones Synovial membrane & fluid Muscles affecting the joint

123 Synovial Joints Synovial Membrane & Fluid
Membrane made of connective tissue for articular capsule Fluid is secreted & absorbed in membrane; acts as lubricant

124 Synovial Joints Articular Cartilage
Connective tissue providing support Hyaline (nasal septum), fibrous (vertebral disks & menisci), & elastic (ear) Aids in motion control, stability, and load transmission for joints


126 Functional Synovial Joint Characteristics
Synovial Joint Stabilization Provided by skeleton, ligaments, joint capsules and muscles Reflex contraction of muscles to prevent overstretch

127 Functional Synovial Joint Characteristics
Articular Capsule & Ligaments Elastic fibers as opposed to contractile Fast protective response time Ligaments are strongest in center of ligament

128 Synovial Joint Trauma Constant compression or tension can lead to ligament or capsular deterioration Intermittent compression or stress can increase strength

129 Synovial Joint Trauma Tension, torsion, or twisting forces that exceed yield point will lead to injury Articular cartilage failing to properly transmit load may lead to failure

130 Synovial Joint Injury Classification
Acute Joint Injuries Joint Sprains Stretch or tear of stabilizing connective tissue Severity Grading

131 Synovial Joint Injury Classification
Acute Joint Injuries Acute synovitis Injury to synovial membrane of joint Result of contusion or sprain

132 Synovial Joint Injury Classification
Acute Joint Injuries Subluxations & dislocations Disruption of the joint capsule & membrane or joint surfaces

133 Synovial Joint Injury Classification
Chronic Joint Injuries Osteochondrosis Degenerative changes in ossification centers of epiphyses of bones Joint (OCD) or tuberosity (apophysitis)

134 Synovial Joint Injury Classification
Chronic Joint Injuries Osteoarthritis Wearing down of cartilage Most often in weight-bearing joints

135 OA 10.30

136 Synovial Joint Injury Classification
Chronic Joint Injuries Bursitis Caused by overuse or external compression/trauma

137 Synovial Joint Injury Classification
Chronic Joint Injuries Capsulitis & synovitis Degenerative tissue changes

138 Bursitis Fluid filled sac in places where friction occurs
Between bony prominences and tendons

139 Tendons and Ligaments Functions Inert Structures Tendons Ligaments
Execute joint motion by transmitting mechanical forces from muscles to bones Ligaments Join bones and provide stability to joints Inert Structures Non-contractile structures (passive tissues) Unable to actively generate forces

140 Mechanical Properties of Tendon
Composed of mostly collagen fibers High resistance to tensile forces Location Strongest in mid-point Weakest at myo-tendinous and osteo-tendinous junctions Due to changes in tissue composition

141 Tendon Injuries Tendinitis – inflammation of the tendon
Chronic injury due to repetitive motion or overuse Appears as dull, aching pain before/during/after exercise Occurs with crepitus

142 Tendon Injuries Tenosynovitis – inflammation of the synovial sheath
More severe form of “-itis” injury

143 Tendon Injuries Strain / Rupture – overload of the tendinous junction

144 Tendon Injury Attaches muscle to bone
Usually double the strength of the muscle it serves Acute strain Tendonitis

145 Mechanisms of Tendon Injuries
High magnitude, single load, tensile forces Acute strain or rupture Low magnitude, repetitive load, tensile forces Tendinitis or tenosynovitis Dynamite vs. Axe

146 Mechanical Properties of Ligaments
Greater proportion of elastic collagen fibers than in tendon Less resistant to tensile forces Greater deformation occurs prior to mechanical failure

147 Mechanical Properties of Ligaments
Frequency of Loading Repeated loading  Mechanical Weakening  instability Direction of Loading Resists tensile forces

148 Mechanisms of Ligament Injuries
High magnitude, single load, tensile forces Acute sprain or rupture Low magnitude, repetitive load, tensile forces Constant tensile forces lead to ligamentous deterioration Chronic instability

149 Mechanisms of Ligament Injuries

150 Grades of Ligamentous Injury
Degree Etiology End Feel Instability First Mild overstretching, no tissue disruption Firm None Second Partial disruption or macrotearing of the ligament Definite (soft) Slight to Moderate Third Complete disruption Severe

151 Skeletal Muscle Composed of contractile cells Function
Generates force to drive motion Dynamic stability of joints

152 Skeletal Muscle Tensile Forces
Produces active and passive tensile forces Active tension  contraction Passive tension  stretched past resting length

153 Skeletal Muscle Injuries
Strains Contusions Muscle lacerations Myositis Atrophy Contracture DOMS Spasm Contracture Shortening of the muscle

154 Muscle Injury Acute Contusions
Sudden traumatic blow with compressive force Superficial or deep tissue affected Rated by the ability of muscle to produce ROM

155 Muscle Injury Acute Strains Stretch or tear in muscle
Abnormal muscle contraction Mineral imbalance or dehydration Fatigue Strength imbalance

156 Muscle Injury Acute Muscle spams (cramps) Clonic - intermittent
Tonic – constant Contracture May lead to strains DOMS

157 Muscle Injury Chronic Myositis Fasciitis Myositis ossificans
Inflammation of muscle Fasciitis Inflammation of fascia within the muscle Myositis ossificans Repeat trauma Calcium deposits within the muscle Can resorb in 9-12 months

158 Mechanisms of Muscle Injuries
High magnitude, single load, tensile forces Acute strains or ruptures Low magnitude, repetitive load, tensile forces Degenerative effect Dynamite vs. Axe

159 Grades of Muscle Injuries
Degree Etiology Signs/Symptoms First Overstretching or microtearing of muscle or tendon Mild loss of strength, swelling, ecchymosis, point tenderness Second Further stretching and partial tearing of muscle or tendon fibers Symptoms are more severe, greater function loss Third Complete rupture Severe symptoms, loss of muscle function, possible palpable defect

160 Nerve Injuries Compression or tensioning of neural structure
Secondary to direct blow Acute swelling in enclosed space Pathology which compromises space for nerve Anesthesia no sensation Paresthesia tingling, burning, numbness Hyperesthesia hypersensitivity

161 Nerve Injuries Anesthesia – absent sensation
Paresthesia – diminished sensation Hyperesthesia – over-sensation Anesthesia no sensation Paresthesia tingling, burning, numbness Hyperesthesia hypersensitivity

162 Neuropraxia “Burners” or “stingers”
Transient and reversible loss in nerve function Secondary to trauma or irritation Mechanical deformation of the nerve Disruption of nerve fibers & signals Short-lived sensory and motor deficits (seconds-two weeks)

163 A shortstop is hit in the shin by a batted ball that took a bad hop
What kind of force is involved? What type of injury is likely to have occurred?

164 A football player sustains repeated blows to his left quadriceps muscle
What type of injury could be sustained from repeated compressive forces to the muscle?

165 A basketball player steps on another player’s foot and sustains a lateral ankle injury
What forces are applied? What type of injury has occurred?

166 An alpine skier catches his right ski tip and severely twists the lower leg
What type of serious injury could be created by this mechanism?

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