Chapter 9 Musculoskeletal System Disorders Copyright 2019 by

Review of Musculoskeletal System: Bones Classified by shape Long bones Ø Short bones Ø Flat bones Ø Irregular bones Ø Bone tissue consists of: Matrix Ø Mature bone cells (osteocytes) Ø Bone-producing cells (osteoblasts) Ø Bone-resorbing cells (osteoclasts) Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 2

Bone Types of bone tissue Compact—outer covering of bone Ø Cancellous (spongy)—interior of bone Ø Other bone structures Periosteum—connective tissue covering over the bone Ø Endosteum—osteoblast-rich lining of medullary cavity Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 3

Structure of Bone Copyright © 2019 by Elsevier Inc. All rights reserved. 4

Structure of a Long Bone Copyright © 2019 by Elsevier Inc. All rights reserved.

Skeletal Muscle Copyright © 2019 by Elsevier Inc. All rights reserved. 6

Functions of Skeletal Muscle Facilitate body movement. Maintain body position. Stabilize joints. Produce heat.

Characteristics of Skeletal Muscle Usually under voluntary control Bundles of protein fibers covered by connective tissue Well supplied with nerves and blood vessels Stimulation occurs at myoneural junction. Myoglobin stores oxygen in fibers. Glycogen stored for energy Attachments—directly to periosteum or by tendon Cells do not undergo mitosis after birth. Copyright © 2019 by Elsevier Inc. All rights reserved. 8

Connective Tissue Coverings of Skeletal Muscle Epimysium Ø Perimysium Ø Connective tissue surrounding the entire muscle Connective tissue surrounding muscle fascicles Endomysium Ø Connective tissue around individual muscle fibers Copyright © 2019 by Elsevier Inc. All rights reserved. 9

Skeletal Muscle Motor unit Ø Motor neuron in the spinal cord and all muscle fibers innervated by the neurons Neuromuscular junction Ø Synapse between the motor neuron nerve fiber and muscle fiber • Neurotransmitter—acetylcholine (ACh) • Breakdown of ACh by cholinesterase; anticholinesterases will interfere with the breakdown of ACh. Copyright © 2019 by Elsevier Inc. All rights reserved. 10

Neuromuscular Transmission and Muscle Contraction Arrival of the action potential Depolarization of the presynaptic terminal Calcium influx Exocytosis of the neurotransmitter (ACh) Diffusion of neurotransmitter to postsynaptic receptors—attachment Generation of muscle action potential Release of calcium from sarcoplasmic reticulum Power stroke—contraction of muscle fiber Copyright © 2019 by Elsevier Inc. All rights reserved. 11

Neuromuscular Junction Copyright © 2019 by Elsevier Inc. All rights reserved. 12

Joints Connection between bones Accomplished by tendons and ligaments Little blood supply Ø Healing

Classification Synarthroses Ø Amphiarthroses Ø Immovable • Example: cranial sutures Slightly movable • Example: ribs to sternum Diarthroses Ø Freely movable • Example: shoulder Copyright © 2019 by Elsevier Inc. All rights reserved. 14

Synovial Joint Articular cartilage—covering over ends of bones Synovial membrane—produces synovial fluid that fills space between ends of bones Articular capsule—consists of synovial membrane, a fibrous capsule Ligaments—reinforce capsule, links bones, supports joint Menisci—lateral pads in some joints to stabilize Bursae—fluid-filled sacs to add extra cushion Copyright © 2019 by Elsevier Inc. All rights reserved. 15

Normal Synovial Joint Copyright © 2019 by Elsevier Inc. All rights reserved. 16

Musculoskeletal Diagnostic Tests For bone disorders: radiography, bone scanning For muscular disorders: electromyography (EMG), biopsy For joint disorders: radiography, arthroscopy, magnetic resonance imaging (MRI), examination of synovial fluid Copyright © 2019 by Elsevier Inc. All rights reserved. 17

$Fracture A fracture is a break in the integrity of a bone. Fractures occur$

Fracture A fracture is a break in the integrity of a bone. Fractures occur because of trauma, neoplasms, or increased stress on bones. Fractures are charted using the # sign. Copyright © 2019 by Elsevier Inc. All rights reserved. 18

Classification of Fractures Complete: bone broken, forming separate pieces Incomplete: bone only partially broken Open (compound): skin broken Closed: skin not broken Simple: single break, maintaining alignment and position Comminuted: multiple fractures and bone fragments Compression: bone crushed or collapsed into small pieces Copyright © 2019 by Elsevier Inc. All rights reserved. 19

Other Types of Fractures Impacted Ø Pathologic Ø one end forced into adjacent bone results from weakness Stress: fatigue fracture Depressed—skull fractured and forced into brain Transverse fracture Linear fracture Oblique fracture Spiral fracture Copyright © 2019 by Elsevier Inc. All rights reserved. 20

Types of Fractures Copyright © 2019 by Elsevier Inc. All rights reserved. 21

Pathophysiology of Bone Fractures initiate an inflammatory response and hemostasis. Bleeding Ø Edema causes stretching of periosteum (if it is intact) and swelling of soft tissues → severe pain. Ø Release of bradykinin and other chemical mediators also contributes to pain. Ø Clot forms at fracture site. Ø Systemic signs of inflammation may occur. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 22

Healing of Bone Fracture Hematoma—fibrin network is formed. Phagocytic cells remove debris. Fibroblasts lay down new collagen fibers. Chondroblasts form new cartilage. Formation of procallus (fibrous collar) Osteoblasts generate new bone. Procallus is replaced by bony callus. Remodeling of bone, with return to use Copyright © 2019 by Elsevier Inc. All rights reserved. 23

Healing of Fracture Copyright © 2019 by Elsevier Inc. All rights reserved. 24

Factors Affecting Bone Healing Amount of local damage Proximity of bone ends. Presence of foreign material or infection Blood supply to fracture site Systemic factors, such as age, nutrition, anemia Copyright © 2019 by Elsevier Inc. All rights reserved. 25

Complications Muscle spasms Infections Ischemia Fat emboli Nerve damage Failure to heal or development of deformity during healing Residual effects such as osteoarthritis Copyright © 2019 by Elsevier Inc. All rights reserved. 26

Compartment Syndrome Edema within one area of compartment of the limb that is between layers of dense connective tissue (fascia) Ischemia and infarction of tissue may occur because of compression of arterial blood supply. Dead tissue may become gangrenous, requiring amputation. A tight cast can cause compartment syndrome! Copyright © 2019 by Elsevier Inc. All rights reserved. 27

Treatments of Fractures Closed reduction—pressure to restore bone position Open reduction—surgery to align and/or insert pins, screw rods, or plates to align Copyright © 2019 by Elsevier Inc. All rights reserved. 28

Dislocations Separation of two bones at a joint, with loss of contact between articulating surfaces Usually accompanied by significant soft tissue damage to ligaments and tendons Distortion of joint usually evident May recur repeatedly, requiring surgery Copyright © 2019 by Elsevier Inc. All rights reserved. 29

Dislocations (Cont. ) Copyright © 2019 by Elsevier Inc. All rights reserved. 30

Sprains and Strains Sprain—a tear in a ligament Strain—a tear in a tendon Avulsion—ligaments or tendons completely separated from bony attachments Immobilization often used to prevent tissue damage and promote healing Copyright © 2019 by Elsevier Inc. All rights reserved. 31

Other Joint Injuries Overuse injuries Ø Muscle tears Repetitive strain injuries—injuries that develop over a period of time in which the same movement is repeated Massage Ø Keyboard, mouse Ø Running or jogging Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 32

Diagnosis of Joint Injuries History of joint use and any trauma Physical examination of joint, including range of motion Radiography or MRI Arthroscopy may be done, accompanied by treatment. Copyright © 2019 by Elsevier Inc. All rights reserved. 33

Treatment of Joint Injuries RICE Rest Ø Immobilization Ø Compression Ø Elevation Ø Nonsteroidal antiinflammatory drugs (NSAIDs) Physiotherapy Massage of surrounding tissue Copyright © 2019 by Elsevier Inc. All rights reserved. 34

Muscle Tears Can occur as a result of a trauma or overextension or overstressing of the muscle Repeated injuries will result in fibrous scar tissue replacing normal structures. Three degrees of muscle tears First degree • Involves only a small percentage of muscle fibers Ø Second degree • Involves much of the muscle but is not a complete tear Ø Third degree • A complete tear across the width of the muscle Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 35

Bone Disorders Copyright © 2019 by Elsevier Inc. All rights reserved. 36

Osteoporosis Decrease in bone mass and density Occurs in two forms Primary • Idiopathic • Age 50+ years • Decreased sex hormones • Decreased calcium intake Ø Secondary • As a complication of another disorder Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 37

Pathophysiology Bone resorption exceeds formation. Results in loss of compact bone Diagnosed with bone density scans Can cause compression fractures of vertebrae, wrist, or hip Can lead to kyphosis and scoliosis Copyright © 2019 by Elsevier Inc. All rights reserved. 38

Predisposing Factors Age 50+ years Decreased mobility or sedentary lifestyle Hormonal factor Excess corticosteroids or parathyroid hormone (PTH) Ø Deficit of estrogen or testosterone Ø Deficits of calcium, vitamin D, or protein Cigarette smoking Small light bone structure Ø That is, Asian or European ancestry Excessive caffeine intake Copyright © 2019 by Elsevier Inc. All rights reserved. 39

Treatment Dietary supplements Fluoride supplements Bisphonates Calcitonin Human parathyroid hormone Weight-bearing exercise Raloxifene or tamoxifen Other medications are under investigation. Surgery to reduce kyphosis Copyright © 2019 by Elsevier Inc. All rights reserved. 40

Rickets and Osteomalacia Result from deficit of vitamin D and phosphates Causes—dietary deficits, malabsorption, intake of phenobarbital, lack of sun exposure In children, leads to weak bones and other skeletal deformities In adults, may lead to soft bones, resulting in compression fractures Copyright © 2019 by Elsevier Inc. All rights reserved. 41

Paget Disease Occurs in adults older than 40 years Exact cause has not yet been established. Bone destruction replaced by fibrous tissue Pathologic fractures are common. In vertebrae—can result in compression fractures and kyphosis In skull—increased pressure resulting in headaches and compression of cranial nerves → severe pain Copyright © 2019 by Elsevier Inc. All rights reserved. 42

Osteomyelitis Bone infection caused by bacteria or fungi Signs and symptoms Local inflammation and bone pain Ø Fever and excessive sweating Ø Chills Ø General malaise Ø Treatment Antibiotics Ø Surgery may be required. Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 43

Abnormal Curvatures of the Spine Lordosis Ø Kyphosis Ø Swayback—curving inward at the lower back Hunchback or humpback—abnormally rounded upper back Scoliosis Ø S- or C-shaped—sideways curve to the spine Copyright © 2019 by Elsevier Inc. All rights reserved. 44

Kyphosis (A); Lordosis (B) Copyright © 2019 by Elsevier Inc. All rights reserved. 45

Causes of Lordosis Achondroplasia Obesity Discitis Slipping forward of the vertebrae Copyright © 2019

Causes of Kyphosis Poor posture Spina bifida Congenital defects Spinal tumor or infections Scheuermann

Treatment Medication for pain and inflammation Weight loss Wearing a brace Exercises and physical

Bone Tumors Common site of secondary tumors from breast, lung, or prostate tumors Most primary tumors termed sarcomas are malignant. Osteosarcoma—most common primary neoplasm of bone Occurs in the shaft of long bones of the leg Ø Common in children, adolescents, and young adults Ø Bone pain at rest is a warning sign for this cancer! Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 49

Osteosarcoma Copyright © 2019 by Elsevier Inc. All rights reserved. 50

Tumors (Cont. ) Chondrosarcomas—arise from cartilage cells; more common in adults Ewing sarcoma is common in adolescents and usually occurs in the shaft of long bones. Copyright © 2019 by Elsevier Inc. All rights reserved. 51

Bone Tumors metastasize to lungs early in the course of the disease. Treatment Excision of tumor if possible Ø Surgical amputation if excision is not feasible Ø Chemotherapy to reduce metastasis Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 52

Muscular Dystrophy (MD) Group of autosomal recessive disorders Degeneration of skeletal muscle over time Duchenne MD or pseudohypertrophic MD most common type; affects young boys Copyright © 2019 by Elsevier Inc. All rights reserved. 53

Signs and Symptoms With Duchenne MD Ø Weakness in pelvic girdle Ø early motor weakness waddling gait, difficulty climbing stairs Gower maneuver—pushing up to erect position Tendon reflexes reduced Deformities develop, such as kyphoscoliosis. Respiratory infections common Cardiac myopathy occurs commonly. Copyright © 2019 by Elsevier Inc. All rights reserved. 54

Diagnostic Tests Identification of common genetic abnormalities Elevated creatine kinase levels Electromyography Muscle biopsy Blood test shows abnormal dystrophin levels. Copyright © 2019 by Elsevier Inc. All rights reserved. 55

Treatment No curative treatment available Moderate exercise to maintain motor function Supportive appliances Physiotherapy and occupational therapy to maximize function and adaptation Massage Ø Ventilator Ø reduces pain and stiffness in case of respiratory failure Research being done on genetic therapies Copyright © 2019 by Elsevier Inc. All rights reserved. 56

Types of Muscular Dystrophy Copyright © 2019 by Elsevier Inc. All rights reserved. 57

Fibromyalgia Group of disorders characterized by pain and stiffness Affecting muscles and surrounding soft

Pathophysiology No obvious signs of inflammation or degeneration Unknown cause Predisposing and aggravating factors Onset is higher in women age 20 to 50 years. Ø History of physical or psychological trauma or chronic pain Ø Sleep deprivation Ø Stress Ø Fatigue Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 59

Signs and Symptoms Generalized aching pain Marked fatigue Sleep disturbances Depression In some individuals, irritable bowel syndrome or urinary symptoms due to interstitial cystitis Copyright © 2019 by Elsevier Inc. All rights reserved. 60

Treatment Treatment Stress avoidance or reduction Regular exercise in the morning Pace activity and rest as needed Applications of heat or massage Analgesic drugs Low doses of antidepressants Ø NSAIDs Ø New drugs—pregabalin (Lyrica) Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 61

Joint Disorders Copyright © 2019 by Elsevier Inc. All rights reserved. 62

Osteoarthritis Degenerative—wear and tear joint disease May be the result of increased weight-bearing or lifting Incidence increasing Genetic component identified in research with mice Copyright © 2019 by Elsevier Inc. All rights reserved. 63

Pathophysiology Articular cartilage is damaged. Surface of cartilage becomes rough and worn. Tissue damage causes release of enzymes, accelerating disintegration of cartilage. Subchondral bone may be exposed. Cysts, osteophytes, or new bone spurs develop. Copyright © 2019 by Elsevier Inc. All rights reserved. 64

Pathophysiology (Cont. ) Osteophytes and cartilage break off. Joint space becomes narrower. Secondary inflammation of surrounding tissue Loss of normal range of joint motion Pain with weight-bearing and use Copyright © 2019 by Elsevier Inc. All rights reserved. 65

Pathologic Changes with Osteoarthritis Copyright © 2019 by Elsevier Inc. All rights reserved. 66

Etiology Causes Primary form Ø Secondary form Ø weight-bearing, obesity, aging follows trauma or repetitive use Genetic factors thought to play a role. Weight-bearing joints most frequently affected but finger joints also involved. Copyright © 2019 by Elsevier Inc. All rights reserved. 67

Signs and Symptoms Aching pain with weight-bearing and movement Joint movement is limited. Recreational and social activities become limited because of pain. Walking is difficult. Predisposition to falls In temporomandibular joint (TMJ) syndrome, mastication and speaking are difficult. Bony enlargement of distal interphalangeal joints Copyright © 2019 by Elsevier Inc. All rights reserved. 68

Treatment Stress on joint minimized by use of adaptive devices such as a cane Pacing activity Mild exercise program to maintain fitness and joint function Supports such as hand brace to facilitate movement Orthotic Inserts in shoes Copyright © 2019 by Elsevier Inc. All rights reserved. 69

Treatment (Cont. ) Massage therapy Physiotherapy Acupuncture Occupational therapy Glucosamine chondroitin supplements Injection of synthetic synovial fluid (hyaluronic acid) NSAIDs Analgesics Arthrotomy to stabilize joint Surgical joint replacement Copyright © 2019 by Elsevier Inc. All rights reserved. 70

Rheumatoid Arthritis Considered an autoimmune disorder Causes chronic systemic inflammatory disease Higher incidence in women than in men Affects all age groups Copyright © 2019 by Elsevier Inc. All rights reserved. 71

Pathophysiology Synovitis Ø Pannus formation Ø creates unstable joint Fibrosis Ø granulation tissue spreads Cartilage erosion Ø marked inflammation, cell proliferation calcifies and obliterates joint space Ankylosis Ø joint fixation and deformity develop if untreated. Copyright © 2019 by Elsevier Inc. All rights reserved. 72

Other Changes Frequently occur around the joints Atrophy of muscles Bone alignment shifts Muscle spasms caused by inflammation and pain Contractures and deformity develop. Copyright © 2019 by Elsevier Inc. All rights reserved. 73

Rheumatoid Arthritis Copyright © 2019 by Elsevier Inc. All rights reserved. 74

Typical Deformity in a Hand with Rheumatoid Arthritis Copyright © 2019 by Elsevier Inc.

Etiology Exact cause not known Genetic factor is present. Familial predisposition Some links to

Signs and Symptoms Inflammation, first in the fingers or wrists Joints red and swollen Sensitive to touch as well as painful Joint stiffness Joint movement impaired Malocclusion of the teeth may develop from TMJ involvement as the condyle is damaged. Copyright © 2019 by Elsevier Inc. All rights reserved. 77

Systemic Effects Marked fatigue Depression Malaise Anorexia Low-grade fever Iron deficiency anemia that is

Treatment Balance between rest and moderate activity Heat and cold applications Physical and occupational therapy NSAIDs Glucocorticoids for severe inflammation Analgesia for pain Disease-modifying antirheumatic drugs, such as gold salts, methotrexate, hydroxychloroquine Biologic response–modifying agents, such as infliximab, rituximab, anakinra Copyright © 2019 by Elsevier Inc. All rights reserved. 79

Juvenile Rheumatoid Arthritis (JRA) Several different types Onset more acute than adult form Large

Juvenile Rheumatoid Arthritis (JRA) (Cont. ) Still disease (systemic form)—fever, rash, lymphadenopathy, hepatomegaly, joint involvement Second form of JRA causes polyarticular inflammation. Third form of JRA involves four or fewer joints but causes uveitis (inflammation of iris, ciliary body, and choroid of eye). Copyright © 2019 by Elsevier Inc. All rights reserved. 81

Infectious Arthritis Also known as septic arthritis Develops in single joint Joint is red, swollen, painful, with decreased movement Causes Direct introduction of bacteria into joint, such as trauma, nonsterile injection, surgery Ø Secondary infection because of bacteremia Ø Treatment with antimicrobials over sustained period; often requires IV administration Copyright © 2019 by Elsevier Inc. All rights reserved. 82

Gout Also known as gouty arthritis Results from deposits of uric acid and crystals in the joint, causing inflammation Formation of tophus—large hard nodule of urate crystals Tophi cause local inflammation and occur after the first attack of gout. Copyright © 2019 by Elsevier Inc. All rights reserved. 83

Gout: Urate Crystals Copyright © 2019 by Elsevier Inc. All rights reserved. 84

Gout (Cont. ) Uric acid and crystals form because of inadequate renal excretion, chemotherapy, metabolic abnormality, and/or genetic factors. Inflammation causes redness, swelling, and pain. Treated by reducing uric acid levels with drugs and dietary changes Diagnosed by examination of synovial fluid and blood tests Ø Note: Use of NSAIDs prior to blood tests will cause a false-negative result. Copyright © 2019 by Elsevier Inc. All rights reserved. 85

Ankylosing Spondylitis Chronic, progressive, inflammatory condition Affects sacroiliac joints, intervertebral spaces, costovertebral joints More common in men age 20 to 40 years Cause has not yet been determined—thought to be an autoimmune disorder with a genetic basis Copyright © 2019 by Elsevier Inc. All rights reserved. 86

Pathophysiology The vertebral joints first become inflamed. Fibrosis and calcification or fusion of the joints Inflammation begins in the lower back. Kyphosis develops. Osteoporosis is common. Lung expansion may be limited at this stage, as calcification of the costovertebral joints reduces rib movement. Copyright © 2019 by Elsevier Inc. All rights reserved. 87

Signs and Symptoms Low back pain Morning stiffness As calcification develops, the spine becomes more rigid, and flexion, extension, and rotation of the spine are impaired. Some individuals (about one third of patients) develop systemic signs such as fatigue, fever, and weight loss. Uveitis, particularly iritis (inflammation in the eye), is a common additional problem. Copyright © 2019 by Elsevier Inc. All rights reserved. 88

Characteristic Posture and Sites of Ankylosing Spondylitis Copyright © 2019 by Elsevier Inc. All

Other Inflammatory Joint Disorders Copyright © 2019 by Elsevier Inc. All rights reserved. 90

Bursitis Inflammation of the bursae associated with bones, muscles, tendons, and ligaments of various joints Most common cause Ø Repetitive motion on a particular joint Diagnosis Physical examination Ø Ultrasound and/or MRI Ø Treatment options Rest Ø Antiinflammatory drugs Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 91

Synovitis Inflammation of the synovial membrane Movement of joint is restricted and painful. Diagnosis Swollen, red, and warm joint Ø Analyzing synovial fluid (for signs of infections) Ø Treatment Antiinflammatory drugs Ø Identification and treatment of underlying cause Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 92

Tendinitis Irritation or inflammation of the tendon Manifestation Ø Cause Ø Single trauma or repetitive motion Diagnosis Ø Dull ache and mild swelling Made by physical examination Treatment Rest, application of ice Ø Pain relievers—maybe antiinflammatory drugs Ø Physical therapy Ø Copyright © 2019 by Elsevier Inc. All rights reserved. 93