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Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 4 Injury Mechanism and Classification of Injury.

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Presentation on theme: "Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 4 Injury Mechanism and Classification of Injury."— Presentation transcript:

1 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 4 Injury Mechanism and Classification of Injury

2 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomic Foundations Anatomic position Joint movement –Sagittal plane –Frontal plane –Transverse plane Directional terms Movement Terms Anatomic position

3 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Mechanism of Injury Mechanism of Injury (MOI): How an injury occurs Components used to analyze MOI: –Application of force –Tissue type Severity of force

4 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Force Force: a push or pull acting on a body (e.g., gravity, friction) Force acting on a body causes: –Acceleration –Deformation Factors that determine injury: –Magnitude of force –Material properties of tissues involved

5 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Force (cont’d) Small load = elastic response Large load = plastic response Yield point = load exceeds the ultimate failure point of the tissue resulting in mechanical failure Anisotropic = material is stronger in resisting force from certain directions than others

6 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Mechanical Forces - Injury Compression –Force that crushes tissues Tension –Force that pulls and stretches tissues Shearing –Force that moves across the parallel design of the fibers Mechanisms of injury

7 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Stress Stress = Force x Surface area affected Same force over a large area vs. a small area can have very different results Stress

8 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Injury Types Acute Injury –Single force –Characterized by a definitive moment of onset –Force = macrotrauma Chronic Injury –Repeated forces –Characterized by becoming more problematic over time (Gradual onset over time) –Forces = microtrauma

9 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Check for Understanding! Movements in the sagittal plane include flexion, extension, abduction, and adduction. A.True B.False

10 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Check for Understanding! Which of the following is a correctly matched pair of terms? (Select all that apply) A.Adduction – movement away from the midline of the body B.Flexion – decreasing an angle C.Extension – increasing an angle D.Plantar flexion – movement of the forefoot toward the shin

11 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Check for Understanding! When tissues sustain a force, what are the primary factors that determine the occurrence of an injury? (Select all that apply) A.The magnitude of the force B.The direction of the force C.The material properties of the involved tissues D.The length of time the force is applied

12 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Check for Understanding! What are the three primary mechanical forces that produce injury?

13 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Soft Tissue Collagen –Primary component of skin, tendon, ligaments –Protein substance strong in resisting tensile forces –Wavy configuration that allows for an elastic type deformation or stretch but, otherwise, is inelastic

14 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Soft Tissue (cont’d) Elastin –Protein substance in connective tissue –Adds elasticity Collagen fibers

15 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Skin Epidermis –Multiple layers Dermis –Loose, multidirectional arrangement of collagen fibers

16 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Skin Injury Classification

17 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Skin Wounds Blisters –Accumulation of fluid between epidermis and dermis –Caused by repeated application of shear in one or more directions Skin bruises –Accumulation of blood within skin –Results from compression sustained during a blow

18 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Muscles Produce skeletal movement and maintain postural alignment Viscoelastic –Extensibility –Elasticity Muscle tissue

19 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Muscle (cont’d) Irritability: ability to respond to a stimulus –Electrochemical – nerve impulse –Mechanical – external blow Contractility: ability to develop tension –Isometric –Concentric –Eccentric

20 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Tendons Muscle to bone Dense connective tissue with unidirectional bundles of collagen & some elastin Collagen – parallel arrangement –Helps in resisting high, unidirectional tension loads from the attached muscle 2X as strong as muscle it serves Yield point 5-8% in length

21 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Tendons (cont’d) Collagen arrangements in tendon and ligament tissue

22 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Contusions MOI: compression Can be both deep and superficial Must be cautious and aware of more severe injuries associated with repeated blows S&S: –Onset - acute –Ecchymosis: if superficial –Hematoma –Restrictions in ROM –Pain – localized –Swelling –Associated nerve compression

23 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification for Contusions

24 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Strains Damage to muscle or tendon –Key factor: magnitude of force and structure's cross-sectional area MOI: –Abnormally high tensile force Most common site for tears: near the musculotendinous junction

25 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Strains

26 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Muscle Cramps and Spasms Involuntary muscle contraction Cramp: –Biochemical imbalance (dehydration) associated with muscle fatigue –Painful –Types Clonic – alternating contraction/relaxation Tonic – constant

27 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Muscle Cramps and Spasms (cont’d) Spasm: –Reflex action caused by: Biochemical imbalance or Mechanical blow to nerve or muscle

28 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Myositis and Fasciitis MOI: repeated movements irritate the tissues Myositis: –Inflammation of muscle tissue (e.g., shin splints) Fasciitis: –Inflammation of the fascia (e.g., plantar fasciitis)

29 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Tendinitis and Tenosynovitis Tendinitis: inflammation of a tendon –Related to aging and degenerative changes –S&S: pain and swelling with tendon movement Tenosynovitis: inflammation of the tendon sheath –Acute: rapid onset, crepitus, local swelling –Chronic: same as acute, thickened tendon, nodule formation in sheath

30 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Myositis Ossificans Mineral deposits in muscle associated with prolonged chronic inflammation –Ectopic calcification –Common site: quadriceps Calcific tendinitis: mineral deposits in the tendon

31 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Overuse Injuries Results from repetitive use Factors: –Intrinsic –Extrinsic

32 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Overuse Injuries (cont’d) Classification –Stage 1: pain after activity only –Stage 2: pain during activity, does not restrict performance –Stage 3: pain during activity, restricts performance –Stage 4: chronic unremitting pain, even at rest

33 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Considerations of Joints Articulation of two bones Classified by structure and function Structure –Cartilaginous –Fibrous –Synovial

34 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Considerations of Joints (cont’d) Function: based on the amount of movement allowed –Synarthoses –Amphiarthroses –Diarthroses

35 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Diarthrodial Joints Components –Articular cartilage –Joint (synovial) cavity –Articular capsule –Synovial fluid –Reinforcing ligaments Intrinsic or Extrinsic

36 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Diarthrodial Joints (cont’d) Joint components

37 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Articular Cartilage Ends of bones covered by hyaline cartilage…solid type of connective tissue More resistant to deformation than fibrous connective tissue and more resilient than bone No blood supply; nourished by synovial fluid

38 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Joint Cavity Filled with synovial fluid

39 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Articular Capsule Cuff of fibrous tissue –Primarily bundles of collagen Primary function: hold bones together Inner layer: synovial membrane –Produces synovial fluid that lubricates the joint.

40 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Synovial Fluid Functions –Lubricate joint –Reduce friction –Nourish joint

41 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Ligaments Bone to bone –Intrinsic –Extrinsic Maintain anatomical integrity and structural alignment Collagen and elastin intermixed (contain elastin – more elastic than tendons) –Viscoelastic

42 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Ligaments (cont’d) Resists large tensile loads along the long axis of the ligament and smaller loads from other directions – static stabilizers Fail in fast loading situations Strongest in their middle and weakest at their ends Healing process – slow due to a limited blood supply

43 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Diarthrodial Joints Plane Hinge Pivot Condyloid Saddle Ball-and-socket

44 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Injury to the Ligament Compromises the ability of the ligament to stabilize the joint MOI: –High tensile force S&S: –Pain; point tenderness; swelling; loss of function; instability

45 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Sprains

46 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Dislocations and Subluxations Joint forced beyond normal limits MOI: tension Increased susceptibility for chronic or recurrent dislocations S&S: –Pain –Swelling –Point tenderness –Deformity –Loss of limb function

47 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Osteoarthritis Degeneration of articular cartilage S&S: –Pain –Limited movement No definitive cause; rather, several contributing factors

48 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bursitis Inflammation of bursa Acute or chronic MOI: –Compression S&S: –Localized swelling –Point tenderness –Warm to touch

49 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Soft Tissue Injury Check for Understanding! The discoloration or swelling outside a joint in the surrounding soft tissue is termed: A.Bruising B.Ecchymosis C.Edema D.Effusion

50 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Soft Tissue Injury Check for Understanding! The ability of a muscle to be stretched or increased in length is termed: A.Contractility B.Elasticity C.Plasticity D.Extensibility

51 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Soft Tissue Injury Check for Understanding! Joint capsules are fluid-filled sacs that serve to reduce friction in the tissues surrounding the joints. A.True B.False

52 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Soft Tissue Injury Check for Understanding! Which of the following statements is true? (Select all that apply) A.A tear of a ligament is referred to as a sprain. B.A muscle spasm is brought on by a biochemical imbalance, sometimes associated with muscle fatigue. C.Overuse injuries are more often attributed to intrinsic rather than extrinsic factors. D.The onset of bursitis can be acute or chronic.

53 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Soft Tissue Injury Check for Understanding! Strains and sprains that produce moderate discomfort, tenderness, swelling, ecchymosis, detectable joint instability, and/or muscle weakness are categorized as: A.1 st degree B.2 nd degree C.3 rd degree D.Severe

54 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Bone Primary constituents: –Calcium carbonate –Calcium phosphate –Collagen –Water

55 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Bone (cont’d) Structure: –Diaphysis –Epiphysis –Membranes Periosteum –Medullary cavity –Apophysis Bone macrostructure

56 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Bone (cont’d) Bone growth: –Longitudinal Continues until epiphysis closes –Diameter Continues to grow throughout life –New bone formed via the periosteum; bone is resorbed around the medullary cavity Osteoblasts: form new bone Osteoclasts: resorb bone

57 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Bone (cont’d)

58 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical properties of Bone (cont’d) Composition –Cortical Compact bone tissue of high density (low porosity) Outside Can withstand greater stress but less strain –Cancellous Bone tissue of low density (high porosity) Inside Can tolerate more strain

59 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Injury Classifications Bone injury mechanisms

60 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Injury Classifications (cont’d) Fracture: Disruption in the continuity of bone S&S: –Rapid swelling –Ecchymosis –Deformity or shortening of the limb –Precise point tenderness –Grating or crepitus –Guarding or disability

61 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Injury Classifications (cont’d) Type of fracture dependent upon: –Force applied –The health and maturity of the bone at the time of injury Bone susceptible to: –Compression, tension, shear, bending, and torsion

62 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Types of Fractures

63 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Stress Fracture MOI: repeated lower magnitude forces Can become worse over time Begins as a small disruption in the outer layers of cortical bone and ending as complete cortical fracture with possible displacement

64 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Osteopenia Reduced bone mineral density Predisposes individual to fracture –Particularly stress fractures Possible causes: –Amenorrhea, hormonal factors, dietary insufficiencies

65 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Epiphyseal Injuries Classifications –Injury to growth plate could result in alteration in normal growth –Acute injury Types I-V Epiphyseal injuries

66 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Epiphyseal Injuries (cont’d) Osteochondrosis –Disruption of blood supply to epiphysis –Idiopathic –Causing necrosis and possible deformity –Example: Legg-Calvé-Perthes disease

67 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Classification of Epiphyseal Injuries (cont’d) Apophysitis –Osteochondrosis of apophysis –Idiopathic or traumatic avulsion fracture –Example: Sever’s disease Osgood-Schlatter disease

68 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! In a comminuted fracture, the bone fragments into several pieces. A.True B.False

69 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! Osteopenia is a condition: A.That is exclusive to an older adult population B.That predisposes an individual to stress fractures C.That only involves females D.That inhibits longitudinal bone growth

70 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! Epiphyseal injuries can include damage to the: (select all that apply) A.Epiphyseal plate B.Ligaments C.Articular cartilage D.The apophysis

71 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Nerves Nervous System –CNS: Brain Spinal cord –PNS: 12 pairs of cranial nerves 31 pairs of spinal nerves, along with their branches

72 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomical Properties of Nerves (cont’d) Spinal nerves –Roots Posterior – afferent Anterior – efferent Spinal nerves

73 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Nerve Injury Classifications MOI: Tensile or compression force Neurapraxia (grade 1) –Localized conduction block: temporary loss of sensation and/or motor –Resolves within days to a few weeks

74 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Nerve Injury Classifications (cont’d) Axonotmesis (grade 2) –Significant motor and mild sensory deficits –Lasts at least 2 weeks Neurotmesis (grade 3) –Motor and sensory deficit –Lasts up to 1 year

75 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Nerve Injury Classifications (cont’d) Compression: –More complex; dependent upon: Force magnitude and duration Direct or indirect Nerve injuries result in a variety of afferent symptoms –Hyperesthesia –Hypoesthesia –Paresthesia

76 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Nerve Injury Classifications (cont’d) Neuralgia –Chronic pain along nerve course Healing: if completely severed, healing does not occur

77 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins The Neurological Basis of Pain Sources –Somatic, visceral, and psychogenic Nociceptors: produce pain sensation –Mechanosensitive: initiate pain by acute trauma –Chemosensitive: causes persistent pain in chronic injuries and the early stages of healing

78 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins The Neurological Basis of Pain (cont’d) Fibers transmitting pain –A fibers –C fibers –T cells Gate control theory of pain

79 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins The Neurological Basis of Pain (cont’d) Factors than mediate pain –Brain production of opioid peptides and endorphins –Cognitive and affective filters Referred pain –Pain perceived at a location remote from the site actually causing the pain Radiating pain –Pain felt both at its source and along a nerve

80 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! The posterior branches are the afferent (sensory) nerves that transmit information from sensory receptors in the skin, tendons, ligaments, and muscles to the central nervous system. A.True B.False

81 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! ___________ is perceived at a location remote from the site of the tissues actually causing the pain. A.Radiating pain B.Cognitive pain C.Acute pain D.Referred pain

82 Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins Bone Tissue Injury Check for Understanding! Grade II nerve injuries that produce significant motor and mild sensory deficits that last at least two weeks are termed: A.Neurapraxia B.Axonotmesis C.Neurotmesis


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