| Mechanisms and Characteristics of Sports Trauma |
| MECHANICAL INJURY - Trauma; A physical injury or wound sustained in sport and produced by an external or internal force. Tissue Properties Load; Outside force or forces acting on tissue Stress; The internal reaction or resistance to an external load. Strain; Extent of deformation of tissue under loading Viscoelastic; Any material whose mechanical properties vary depending on rate of load. - Human tissue is viscoelastic-it has both viscous and elastic properties. Yield point; Elastic limit of tissue Mechanical failure; Elastic limit of tissue is exceeded, causing tissue to break. - The five tissue mechanical stresses that can lead to sports injuries are; o Tension; force that pull or stretches tissue o Stretching; beyond yield point leads to rupturing of soft tissue or fracturing of bone o Compression; a force crushes tissue o Shearing; a force that moves across the parallel organization of the tissue o Bending; force on horizontal beam or bone that places stresses within structure, causing it to bend or strain. SOFT-TISSUE TRAUMA - Non-contractile o Skin o Joint capsular o Ligament o Fascia o Cartilage o Dura mater o Nerve roots - Contractile o Muscle o Tendon o Bony insertion SKIN INJURIES - A break in the continuity of the soft parts of body structures caused by a trauma to these tissues. Anatomical Characteristics - It represents the body’s largest organ system and consists of two layers-epidermis and dermis (corium) - A skin lesion that is characterized by a skin elevation with serofluid is called a vesicle Injurious Mechanical Forces - Friction or rubbing, scraping, compression or pressure, tearing, cutting, and penetrating. Wound Classification - Friction Blister - Abrasion - Skin Bruise – Caused by compressive force - Laceration – Identified by jagged edges & bleed freely – clean in lengthwise direction - Skin Avulsion - Incision - Puncture Wound SKELETAL MUSCLE INJURIES Anatomical Characteristics - The ability to contract - Irritability - Conductivity - Elasticity. - Three types of muscles are within the body o Smooth - Peristalsis o Cardiac o Striated (skeletal) - Sarcoplasm (cytoplasm); semifluid substance within the fiber cell - Myofibrils are surrounded by endomysium, fiber bundles are surrounded by perimysium, and entire muscle is covered by the epimysium. - Aponeurosis (connective tissue) is derived from the fibrous wrapping of a muscle. - Motor unit = Neuron, Motor end plate, and Muscle fibers Muscle Injury Classification Acute Muscle Injuries - Contusions - Strains - External force created by muscle depends on; o Angle of pull of muscle (ie, when muscle pulls at right angles to bone it’s moving, muscular force will be optimal) o Length of muscle (tension developed with contraction is greatest if muscle is at its maximum resting length to start) o Velocity of the muscle shortening (as the speed of shortening increases, the force decreases) Tendon Injuries - Tendon contains wavy parallel collagenous fibers that are organized in bundles surrounded by gelatinous material that decreases friction. - Tendon can produce and maintain a pull from 8,700 - 18,000 lb/square inch. - A breaking point occurs after a 6 ~ 8 % increase in length. Muscle Cramps and Spasms - A cramp is a painful involuntary contraction of a skeletal muscle or muscle group. - Cramps have been attributed to a lack of water or other electrolytes in relation to muscle fatigue. - A spasm is a reflex reaction caused by trauma of the musculoskeletal system. - Clonic type; with alternating involuntary muscular contraction and relaxation in quick succession - Tonic type; with rigid muscle contraction that lasts a period of time. Overexertion muscle Problems - Muscle soreness o The two major types of muscle soreness associated with severe exercise and acute and delayed. o Often caused by eccentric muscle contraction - Muscle stiffness - Muscle cramps - Muscle guarding o Spasm o Spasticity Chronic Musculotendinous Injuries - Myositis/fasciitis; Inflammation of muscle tissue/fascia – Caused by returning activity too soon - Tendinitis; Inflammation of tendon-muscle attachments, tendons, or both. - Tenosynovitis; Inflammation of the Synovial sheath surrounding a tendon - Ectopic calcification (Myositis Ossificans); Located in a place different from normal. o X-ray shows 2~4 weeks after contusion - Atrophy and Contracture SYNOVIAL JOINTS Anatomical Characteristics - Immovable (synarthrotic) – Suture articulation - Slightly movable (amphiarthrotic) - Freely movable (diarthrotic) – Joint capsules & synovial membrane (e.g., shoulder) - Synovial articulations consist of four features; o Capsule or ligaments o Capsule is lined with a Synovial membrane o The opposing bone surfaces contain hyaline cartilage o There is a joint space (Joint cavity) Joint Capsule - It is extremely strong and can withstand cross-sectional forces of 500 kg/cm2 Ligaments - Constant compression or tension will cause ligaments to deteriorate; intermittent compression and tension will increase strength and growth. Synovial Membrane and Synovial Fluid - Lining the Synovial articular capsule is a Synovial membrane made of connective tissue with flattened cells and villi (small projections) on its inner aspect. Articular Cartilage o Hyaline o Fibrous o Elastic - Motion Control - Stability - Load Additional Synovial Joint Structures Fat Articular Disks Nerve Supply - Mechanoreceptors (encapsulated nerve endings) provide information about the relative position of the joint and are found in the fibrous capsule and ligaments. - Mechanoreceptors are myelinated, whereas nonmyelinated fibers are pain receptors or blood vessel suppliers. - Motor point = Nerve attaches to a muscle Types of Synovial Joints - Ball-and-socket; shoulder and hip - Hinge; elbow – flexion & extension only - Pivot; cervical atlas and axis, proximal ends of radius and ulna – rotation around an axis - Ellipsoidal; wrist – elliptical convex head in an elliprical concave socket - Saddle; carpometacarpal joint of thumb – concavo-convex - Gliding; between carpal and tarsal bones & vertebrae – gliding back and forth - Uniaxial; Radioulnar articulation & Interphalangeal joints of fingers Functional Synovial Joint Characteristics Synovial Joint Stabilization - Hilton’s law, which states that the joint capsule, the muscles moving that joint, and the skin overlying the insertion of the muscles have the same nerve supply. Articular Capsule and Ligaments Synovial Joint Trauma - Capsule (Acute) Tension/compression – Sprain/Dislocation/Subluxation/Synovial swelling - Capsule (Chronic) Tension/compression/shearing – Capsulitis/Synovitis/Bursitis - Articular cartilage (hyaline) (Chronic) Compression/shearing – Osteochondrosis/Traumatic arthritis o To regenerate, active movement is necessary Synovial Joint Injury Classification Acute Joint Injuries - Sprains - Acute Synovitis - Subluxations, dislocations, and diastasis o A first-time dislocation should always be considered a possible fracture Chronic Joint Injuries - Osteochondrosis - Traumatic arthritis o Athletes with improperly immobilized joint injuries or who are allowed to return to activity before proper healing has occurred may eventually be afflicted with arthritis. - Bursitis, Capsulitis, and Synovitis - Bursitis o Inflammation of bursa at sites of bony prominences between muscle and tendon - Capsulitis Synovitis - False joint; Abnormal movement along length of a bone caused by a fracture or incomplete fusion SKELETA TRAUMA Anatomical Characteristics Bone Functions - Bony support - Organ protection - Movement (through joints and levers) - Calcium reservation - Formation of blood cells (hematopoiesis) Types of Bone - Flat; Skull, ribs, scapulae - Irregular; Vertebral column, skull - Short; wrist, ankle - Long; humerus, ulna, femur, tibia, fibula, phalanges Gross Structures - Epiphysis (spongy bone) - Diaphysis (compact bone) o Endosteum o Medullary (marrow) cavity - Periosteum; tissue covering, contains blood supply to the bone Microscopic Structures - Calcium salts impregnate the intercellular substance of bone, making it hard. - Osteocytes are found in small, hollow spaces called lacunae. - Trabecula is supportive structure of bones Bone Growth - Bone ossification occurs from the synthesis of bone’s organic matrix by osteoblasts, followed immediately by the calcification of this matrix. Bone Injuries Anatomical Weak Points - Stress forces become concentrated at points at which a long bone suddenly changes shape and direction. Load Characteristics - Long bones can be stressed by tension, compression, bending, torsion, and shearing - The weakest part of long bone in children is the epiphyseal plate Bone Trauma Classification - Periostitis; Inflammation of the periosteum can result from contusion. - Acute bone fractures - Depressed fracture - Greenstick fracture - Longitudinal fracture - Oblique fracture - Serrated fracture - Spiral fracture - Transeverse fracture - Comminuted fracture - Conterecoup fracture - Blowout fracture - Avulsion fracture - Stress fractures - Epiphyseal conditions o Musculoskeletal injury to a child or adolescent should always be considered a possible Epiphyseal condition - Apophyseal injuries - A Salter type V epiphyseal fracture is a crush injury to the epiphysis - Impacted fracture – one part of bone telescopes on the other art of bone NERVE TRAUMA Nerve Injuries - Nerve trauma can be produced by overstretching or compression - Neuritis; a chronic nerve problem, can be caused by a variety of forces that usually have been repeated or continued for a long period of time. - A neurapraxis is the Demyelination of the axon sheath of a nerve fiber. This condition will cause a failure of the nerve to conduct impulses, causing redness and swelling of the area - Nerve endings are located in dermis - Rheobase; Nerve excitation level - Nerve contusion the lingers, causing hyperthesia, is dealt with straightening exercise BODY MECHNICS AND INJURY SUSCEPTIBILITY Microtrauma and Overuse Syndrome Postural Deviations OTHER CONSIDERATIONS - Hematoma is an accumulation of blood at the site of an injury - Periorbital ecchymosis can be caused by a basilar artery rupture - If pain in a joint increases during the day, the cause is edema |