AT 359
Chapter 9 Outline - Mechanisms and Characteristics of Sports Trauma

Types of Tissue Stresses
    -Tension:
            -force that pulls or stretches tissue
    -Stretching:
            -stretching beyond the yield point leading to a rupture of tissue
            -ex: sprain, strain
    -Compression:
            -force that crushes tissue
            -ex: contusion
    -Shearing:
            -force that moves across the parallel organization of tissue
            -ex: laceration, abrasions, blisters
    -Bending:
            -force that causes tissue to bend or strain
            -ex: spiral fracture

Types of Tissue
    1) INERT - everything except muscle and/or tendon, ie. - fascia, ligaments, bone, cartilage, vessels, etc.
    2)CONTRACTILE - includes muscle and/or tendon

Wound Classifications
    -Blister:
            -continuous rubbing causes friction which produces a collection of fluid below or under epidermis
    -Abrasion:
            -epidermis and/or dermis is scraped away, exposing blood capillaries
            -slang terms - road rash, strawberry, rug burn
    -Incision:
            -skin has been sharply cut with nice, even edges
    -Laceration:
            -where skin has been torn irregularly
            -no even edges, they are jagged
            -will leave more of a scar
    -Avulsion:
            -same mechanism as laceration, but skin is torn away
            -tissue may be hanging on by a piece or strand of tissue
    -Puncture:
            -penetration by a sharp object
            -worry about infection/bacteria; should receive a tetanus shot if not current as with other wounds
    -Contusion:
            -crush to skin tissues
            -capillaries and/or veins are broken under the skin
            -can produce quite a bit of swelling and pain

MUSCULOSKELETAL INJURIES
    -Contusions
            -can be superficial or deep
            -can penetrate to bone (bone bruise) which typically produces more pain and swelling
            -impact causes pain and temporary paralysis from pressure on the motor and sensory nerves
            -ecchymosis usually forms

    -Strains
            -is a tear, stretch, or rip in muscle, tendon or fascia tissue
            -3 Grades used to classify with Grade1 being mild and Grade 3 severe
            -Grade 3 pain is usually intense at first but goes away quickly because of complete nerve fiber separation
            -Muscle tightness that does not go away is actually classified as a Grade 1 strain

            -Tendon injuries
                    -tendons will usually break down after a 6-8% increase in length from a tension force
                    -tendons are about twice as strong as the muscle they attach to so most injuries occur where the muscle     
                            and tendon meet or in the muscle belly itself
                    -early training causes collage resorption (tendon breakdown), so the tendons are very susceptible to injury
                            in the early phases of training program

            -Cramps
                    -usually due to dehydration/electrolyte imbalance combined with muscle fatigue
                    -2 Types: clonic - alternating contractions; tonic - full contraction that lasts awhile
                    -cramps can lead to muscle strain and will cause soreness in muscle after the episode

            -Overexertional Problems:
                    -Muscle Soreness:
                            -DOMS (Delayed Onset Muscle Soreness)
                                        -occurs 24 hrs after workout
                                        -s/s include stiffness, lack of flexibility and moderate to severe pain
                                        -treatment includes: ice, stretching and anti-inflammatories
                    -Muscle Stiffness:
                            -fatigue related, muscles are worked for long period of time
                            -will not stretch out                      
    
            -Myofascial Trigger Points
                    -hyper-sensitive areas of muscle that get tight in response to stress
                    -feel like "knots" within the muscle
                    -the "spasm" keeps blood from circulating freely to the muscle areas which keeps the muscle tight

            -Chronic Muscle Injuries:
                    -myositis/fasciitis- inflammation of muscle or fascial tissue
                            -ex: plantar fasciitis
                    -tendonitis - gradual onset, inflammation of tendon, degeneration of tendon itself
                            -s/s include: swelling, pain, crepitus
                    -tenosynovitis - inflammation of synovial sheath surrounding a tendon
                            -tendon will swell is size, crepitus will be present,  a "sticking" feeling when the tendon moves in the    
                             sheath
                    -ectopic calcification - chronically inflamed tissue
                             -myositis ossificans can occur in muscle directly over bone
                                            -bone formation within the muscle usually form repeated contusions
                                            -2 common sites: quadriceps or brachial muscles of arm
                    -atrophy and contracture -
                            -wasting away of muscle tissue caused by lack of use
                            -contracture results from muscle shortening in response to unyielding scar tissue

SYNOVIAL JOINTS
            -Joint capsule
                    -binds every diarthrotic joint together
                    -holds synovial fluid by way of synovial membrane
            -Ligaments
                    -hold bones together at joints
                    -purpose is to stabilize joint in one or more direction
                    -strongest in the middle and weakest at the ends
            -Articular Cartilage       
                  -3 types of cartilage:
                    1)hyaline (articular) - ex: ends of long bones in diarthrotic joints
                    2)fibrous - ex: meniscus of knee
                    3)elastic - ex: external ear
                  -cartilage does not have a direct blood supply - this is why most injured cartilage does not
                        heal
                  -purposes of cartilage:
                  -aid in motion control of joint, add stability to joint and transmits load more evenly &
                        smoothly across the articulating surface

Additional Synovial Structures
    -Fat -adipose tissue
            -form between the joint capsule and the synovial membrane
            -form in spaces between bones and move in and out of place upon movement

    -Articular Disks
            -fibrocartilaginous disks are found in some joints where two planes of movement exist
            -they are usually referred to as a meniscus
   
    -Nerve Supply - joints have an abundant nerve supply
            -mechanoreceptors are located in the ligaments and joint capsules
            -mechanoreceptors sense where the joint is in space or how it is positioned

6 Types of Synovial Joints
    1) Ball and socket                 Shoulder, Hip
    2) Hinge                                  Knee, Elbow
    3) Pivot                                    Cervical atlas & axis
    4) Ellipsoidal                           Wrist
    5) Saddle                                Carpometacarpal joint of thumb
    6) Gliding                                Joints between carpal or tarsal bones
         
Synovial Joint Injury Classification
        -ACUTE JOINT INJURIES
            -Joint Sprains
                    -can damage ligaments, articular capsule and synovial membrane
                    -effusion from blood and synovial fluid cause swelling
                    -ligaments and joint capsules heal slowly because of poor blood supply
                    -hard to differentiate between injury to ligaments or tendons, sometimes it's both
                    -repeated sprains to the same area will lead to chronic inflammation and arthritis
                    -synovitis occurs from irritation to the synovial membrane
                    -dislocations
                            -s/s - loss of function, deformity is usually present, swelling and tenderness and
                            muscle spasms
                            -first time dislocations should be x-rayed because avulsion fractures are common
                            with first time dislocations

        -CHRONIC JOINT INJURIES
            -Osteochondrosis
                    -associated in children more where fast growth occurs
                    -aseptic necrosis results from no circulation to the epiphyseal area of the bone causing
                            parts of cartilage to fracture
                    -osteochondritis dissecans (joint mice) and apophysitis are common types

            -Osteoarthritis
                    -articular cartilage is worn down over a period of time resulting in degeneration
                    -most commonly found in the weight bearing joints: lumbar spine, knee, hips, ankles
                    -repeated trauma to joint will speed up the arthritic process

            -Bursitis, Capsulitis and Synovitis
                    -bursitis is either acute or chronic
                    -common in the: knee, shoulder and elbow
                    -capsulitis refers to a chronic inflammation of the shoulder
                                -can lead to "frozen shoulder" (adhesive capsulitis)
                    -synovitis refers to an acute condition
                   
BONE TRAUMA
        -5 Functions of Bones:
              1)body support
              2)organ protection
              3)movement
              4)calcium storage
              5)formation of blood cells (hematopoiesis)

        -Bone Injuries
                -anatomical weak spots
                        -bones are weaker where they suddenly change shape, ex: clavicle
                -Different types of bone fractures:
                        -depressed, ex: skull fx
                        -greenstick, ex: clavicular fx
                        -impacted, ex: bone ends are driven into each other, occures from fall from great height
                        -longitudinal, ex: bone splits along length, usually from jumping from a great height
                        -spiral, ex: skiing injury where foot is planted and body twists
                        -oblique, ex: similar to spiral, same mechanism
                        -serrated, ex: direct blow causes bone ends to have jagged edges
                        -transverse, ex: direct blow causing a break straight across bone at a right angle
                        -comminuted, ex: crush fx, dropping a weight on big toe, breaks into several pieces
                        -contrecoup, ex: fx occurs on opposite side of blow
                        -blowout, ex: fx to wall of eye orbit caused by a blow to the eye
                        -avulsion, ex: separation of bony prominence away from bone at site of ligament or
                                tendon attachment

                -Stress Fx's
                        -typical causes:
                                1)coming back too soon after an injury or illness
                                2)going from one event to another without proper training in second event
                                3)starting initial training too quickly
                                4)changing environment or habits - running surface, new shoes, etc.
                        -acutely, stress fx's do no show up on x-rays
                        -callus formation forms at about 3-4 weeks and can be seen on x-ray
                        -bone scans can be done to diagnose a stress fx early on
                        -as stress fx develops, pain becomes worse and constant, even at night
                       
                -Epiphyseal fx's
                        -termed "Salter-Harris"
                        -5 types varied by fracture and amount of displacement
                        -Apophyseal injuries - originates at tubercles or tuberosities where ligs/tendons attach
                                    -ex: Sever's Disease and Osgood Schlatter's Disease

NERVE TRAUMA
                -Nerves are injured one of two ways:  traction (stretching) or compression (pinching)
                -Neuritis - inflammation of a nerve; can be mild (tingling) or severe (paralysis)
                -Referred pain - pain at site other than injury

BODY MECHANICS AND INJURY SUSCEPTIBILITY
Factors that predispose someone to injury:
        -hereditary/genetics
        -congenital or acquired defects
        -poor technique or skills
        -conditioning/training level
        -postural deviations - chronic pain is not normal; there is something usually wrong mechanically
                that causes the pain all of the time.  Ex: chronic back pain in athlete for several years - may
                be related to hip/leg mechanical problems.
 

Web Sites for further study/learning:
www.per.ualberta.ca/biomechanics - biomechanic journals

www.ccsd.k12.wy.us/CCHS_web/sptmed/fstaider.htm - Cramer First Aider

www.medmedia.com/med.htm - Wheeless' Textbook of Orthopedics