Musculoskeletal System PDF

Al-makassed collage medical surgical for nursing Musculoskeletal system Aysha Adnan Hoshyia BSN,MPH Assessment of musculoskeletal system:  On completion of this chapter, the student will be able to:  Describe the basic structure and function of the musculoskeletal system. ...

Al-makassed collage medical surgical for nursing Musculoskeletal system Aysha Adnan Hoshyia BSN,MPH Assessment of musculoskeletal system:  On completion of this chapter, the student will be able to:  Describe the basic structure and function of the musculoskeletal system.  Discuss the significance of the health history to the assessment of musculoskeletal health.  Describe the significance of physical assessment to the diagnosis of musculoskeletal dysfunction.  Specify the diagnostic tests used for assessment of musculoskeletal system function.  The musculoskeletal system includes the bones, joints, muscles, tendons, ligaments, and bursae (fluid-filled sac found in connective tissue, usually in the area of joints). The functions of these components are highly integrated; therefore, disease in or injury to one component adversely affects the others. For instance, an infection in a joint (septic arthritis)causes degeneration of the articular surfaces of the bones within the joint and local muscle atrophy.  Structure and Function of the Skeletal System:  The musculoskeletal system provides protection for vital organs, including the brain, heart, and lungs  provides a framework to support body structures.  makes mobility possible, Muscles and tendons hold the bones together and joints allow the body to move.  Tendons attach muscles to bones. They also move to produce heat that helps maintain body temperature.  Movement facilitates the return of deoxygenated blood to the right side of the heart.  The musculoskeletal system serves as a reservoir for immature blood cells and essential minerals, including calcium, phosphorus, magnesium, and fluoride. More than 98% of total body calcium is present in bone. Structure and Function of the Skeletal System….cont  There are 206 bones in the human body, divided into four categories: 1) long bones (eg, femur) 2) short bones (eg, metacarpals) 3) flat bones (eg, sternum) 4) and irregular bones (eg, vertebrae). The shape and construction of a specific bone are determined by its function and the forces exerted on it. The structure of the bone : Bones are constructed of cancellous (trabecular) and cortical (compact) bone tissue. Long bones are shaped like rods or shafts with rounded ends. The shaft, known as the diaphysis, is primarily cortical bone. The ends of the long bones, called epiphyses, are primarily cancellous bones. The epiphyseal plate separates the epiphyses from the diaphysis and is the center for longitudinal growth in children. It is calcified in adults. The ends of long bones are covered at the joints by articular cartilage, which is tough ,elastic, avascular tissue. Long bones are designed for weight bearing and movement.  The structure of the bone:  Short bones consist of cancellous,bone covered by a layer of compact bone  Flat bones are important sites of hematopoiesis and frequently protect vital organs. They are made of cancellous bone layered between compact bone  Irregular bones have unique shapes related to their function. Generally, irregular bone structure is similar to that of flat bones. The microscopic structure of the bone :  Bone is composed of cells, protein matrix, and mineral de-posits. The cells are of three basic types:  Osteoblasts: Osteoblasts function in bone formation by secreting bone matrix. The matrix consists of collagen and ground substances (glycoproteins and proteoglycans) that provide a framework in which inorganic mineral salts are deposited. These minerals are primarily composed of calcium and phosphorus.  Osteocytes: Osteocytes are mature bone cells involved in bone maintenance; they are located in lacunae (bone matrix units).  Osteoclasts: located in shallow Howship’s lacunae (small pits in bones), are multinuclear cells involved in dissolving and resorbing bone The microscopic structure ….cont  The microscopic functioning unit of mature cortical bone is the osteon (Haversian system). The center of the osteon, the Haversian canal, contains a capillary. Around the capillary are circles of mineralized bone matrix called lamellae. Within the lamellae are lacunae that contain osteocytes.  These are nourished through tiny structures, canaliculi (canals), which communicate with adjacent blood vessels within the Haversian system. Lacunae in cancellous bone are layered in an irregular lattice network (trabeculae). Red bone marrow fills the lattice network. Capillaries nourish the osteocytes located in the lacunae  Covering the bone is a dense, fibrous membrane known as the periosteum. This membranous structure nourishes bone and facilitates its growth. The periosteum contains nerves, blood vessels, and lymphatics. It also provides for the attachment of tendons and ligaments (Porth & Matfin, 2009).  The endosteum is a thin, vascular membrane that covers the marrow cavity of long bones and the spaces in cancellous bone. Osteoclasts, which dissolve bone matrix to maintain the marrow cavity, are located near the endosteum in Howship’s lacunae (Porth & Matfin, 2009).  Cancellous bone receives a rich blood supply through metaphyseal and epiphyseal vessels. Periosteal vessels carry blood to compact bone through Volkmann’s canals. In addition, nutrient arteries penetrate the periosteum and enter the medullary cavity through foramina (small openings). Arteries supply blood to the marrow and bone. The venous system may accompany arteries or may exit independently (Porth &Matfin, 2009).  Bone marrow is a vascular tissue located in the medullary (shaft) cavity of long bones and in flat bones.  Red bone marrow, located mainly in the sternum, ilium, vertebrae,and ribs in adults, is responsible for producing red blood cells, white blood cells, and platelets through a process called hematopoiesis.  In adults, the long bone is filled with fatty, yellow marrow (Porth & Matfin, 2009). Bone tissue is well vascularized. Bone Formation  Osteogenesis (bone formation) begins long before birth.  Ossification is the process by which the bone matrix is formed and hard mineral crystals composed of calcium and phosphorus (eg, hydroxyapatite) are bound to the collagen fibers. These mineral components give bone its characteristic strength, whereas the protein and collagen gives bone its resilience (Porth & Matfin, 2009). Bone Maintenance  During childhood, bones grow and form by a process called modeling.  By early adulthood (early 20s), remodeling is the primary process that occurs. Remodeling maintains bone structure and function through simultaneous resorption and osteogenesis, and as a result, complete skeletal turnover occurs every 10 years (U.S. Department of Health and Human Services [DHHS], 2004). The factors that affect the balance between bone resorption and formation:  The balance between bone resorption and formation is influenced by the following factors:  physical activity:particularly weight-bearing activity, acts to stimulate bone formation and remodeling. Bones subjected to continued weight bearing tend to be thick and strong. Conversely, people who are unable to engage in regular weight-bearing activities, such as those on prolonged bed rest or those with some physical disabilities, have increased bone resorption from calcium loss, and their bones become osteopenic and weak. These weakened bones may fracture easily.  dietary intake of certain nutrients, especially calcium.Good dietary habits are integral to bone health. In particular, absorption of approximately 1000–1200 mg of calcium daily is essential to maintaining adult bone mass. This may be achieved through ingesting calcium-rich foods on a daily basis (eg, through drinking 16 to 24 ounces of milk daily). The factors that affect the balance between bone resorption and formation: cont  several hormones, including calcitriol ( activated vitamin D), parathyroid hormone (PTH), calcitonin, thyroid hormone, cortisol, growth hormone, and the sex hormones estrogen and testosterone (DHHS, 2004).  Several hormones are vital in ensuring that calcium is properly absorbed and available for bone mineralization and matrix formation. Calcitriol functions to increase the amount of calcium in the blood by promoting absorption of calcium from the gastrointestinal tract. It also facilitates mineralization of osteoid tissue. A deficiency of vitamin D results in bone mineralization deficit, deformity, and fracture (DHHS, 2004). The factors that affect the balance between bone resorption and formation: cont.  PTH and calcitonin are the major hormonal regulators of calcium homeostasis. PTH regulates the concentration of calcium in the blood, in part by promoting movement of calcium from the bone. In response to low calcium levels in the blood, increased levels of PTH prompt the mobilization of calcium, the demineralization of bone, and the formation of bone cysts.  Calcitonin, secreted by the thyroid gland in response to elevated blood calcium levels, inhibits bone reasorption and increases the deposit of calcium in bone (DHHS, 2004). Both thyroid hormone and cortisol have multiple systemic effects with specific effects on bones. Excessive thyroid hormone production in adults (eg, Graves’ disease) can result in increased bone resorption and decreased bone formation.  Increased levels of cortisol have these same effects. Patients receiving long-term synthetic cortisol or corticosteroids (ie, prednisone) are act increased risk for steroid induced osteopenia and fractures.  Growth hormone has direct and indirect effects on skeletal growth and remodeling. It stimulates the liver and to alesser degree the bones to produce insulin like growth factor- 1(IGF-I), which accelerates bone modeling in children and adolescents. Growth hormone also directly stimulates skeletal growth in children and adolescents. The factors that affect the balance between bone resorption and formation: cont  It is believed that the low levels of both growth hormone and IGF-I that occur with aging may be partly responsible for decreased bone formation and resultant osteopenia (DHHS, 2004).  The sex hormones testosterone and estrogen have important effects on bone remodeling. Estrogen stimulates osteoblasts and inhibits osteoclasts; therefore, bone formation is enhanced and resorption is inhibited. Testosterone has both direct and indirect effects on bone growth and formation. It directly causes skeletal growth in adolescence and has continued effects on skeletal muscle growth throughout the lifespan.  Increased muscle mass results in greater weight-bearing stress on bones, resulting in increased bone formation. In addition, testosterone converts to estrogen in adipose tissue, providing an additional source of bone-preserving estrogen for aging men.  During the process of bone remodeling, osteoblasts produce a receptor for activated nuclear factor-kappa B ligand (RANKL) that binds to the receptor for activated nuclear factor-kappa B (RANK) present on the cell membranes of osteoclast precursors, causing them to differentiate and mature into osteoclasts, which causes bone resorption. Conversely, osteoblasts may produce osteoprogerin (OPG), which blocks the effects of RANKL, thereby turning off the process of bone resorption.  T cells that may become activated as a result of the inflammatory process may also produce RANKL, overriding the effects of OPG and causing continued bone resorption during times of stress and injury,which can lead to loss of bone matrix and fractures.  Research is currently focused on developing medications that block the effects of RANKL and on developing useful laboratory tests of RANKL levels that may guide therapy aimed at reducing the risk of fractures (McCormick, 2007).  Blood supply to the bone also affects bone formation.With diminished blood supply or hyperemia (congestion), osteogenesis and bone density decrease. Bone necrosis occurs when the bone is deprived of blood.  Bone Healing  Most fractures heal through a combination of intramembranous and endochondral ossification processes. When a bone is fractured, the bone fragments are not patched together with scar tissue. Instead, the bone regenerates itself.  Fracture healing occurs in the bone marrow, where endothelial cells rapidly differentiate into osteoblasts; in the bone cortex, where new osteons are formed; in the periosteum, where a hard callus (fibrous tissue) is formed through intramembranous ossification peripheral to the fracture, and where cartilage is formed through endochondral ossification adjacent to the fracture site; and in adjacent soft tissue, where a bridging callus forms that provides stability to the fractured bones.  Bone Healing….cont  The process of fracture healing occurs over three phases.  These include the following: Phase 1: Reactive phase: When a fracture occurs, the body’s response is similar to that after injury else-where in the body. There is bleeding into the injured tissue and formation of a hematoma at the site of the fracture. Cytokines are released that initiate the fracture healing processes by causing the proliferation of fibroblasts and that cause angiogenesis to occur ( the growth of new blood vessels). Granulation tissue begins to form within the clot and becomes dense. Phase II: Reparative phase: During this phase, the granulation tissue is initially replaced with a callus precursor, called procallus. Fibroblasts invade the procallus and produce a denser type of callus that is composed mostly of fibrocartilage. This fibrocartilaginous callus is replaced with denser bony callus within approximately 3 to 4 weeks post injury. Lamellar bone then forms as the bony callus calcifies months post injury.  Phase III: Remodeling phase: The final phase of fracture healing results in remodeling the new bone into its former structural arrangement. Remodeling may take months to years, depending on the extent of bone modification needed, the function of the bone, and the functional stresses on the bone. Bone healing phases:  Serial x-rays are used to monitor the progress of bone healing. The type of bone fractured, the adequacy of blood supply, the surface contact of the fragments, the immobility of the fracture site, and the age and general health of the person influence the rate of fracture healing. Adequate immobilization is essential until there is x-ray evidence of bone formation with ossification.  Immature bone develops from the endosteum. There is an intensive regeneration of new osteons, which develop in the fracture line by aprocess similar to normal bone maintenance. Fracture strength is obtained when the new osteons have become established. Structure and Function of the Articular System:  The junction of two or more bones is called a joint (articulation). There are three basic kinds of joints: synarthrosis, amphiarthrosis, and diarthrosis joints.  Synarthrosis joints: are immovable (eg, the skull sutures).  Amphiarthrosis joints: (eg, the vertebral joints and the symphysis pubis) allow limited motion; the bones of amphiarthrosis joints are joined by fibrous cartilage.  Diarthrosis joints: are freely movable joints.  There are several types of diarthrosis joints: Ball-and-socket joints (eg, the hip and the shoulder) permit full freedom of movement. Hinge joints permit bending in one direction only (eg, the elbow and the knee). Saddle joints allow movement in two planes at right angles to each other. The joint at the base of the thumb is a saddle, biaxial joint. Pivot joints are characterized by the articulation between the radius and the ulna. Gliding joints allow for limited movement in all directions and are represented by the joints of the carpal bones in the wrist.  Articular System structure :  The ends of the articulating bones of a typical movable  joint are covered with smooth hyaline cartilage. A tough, fibrous sheath called the joint capsule surrounds the articulating bones. The capsule is lined with a membrane, the synovium, which secretes the lubricating and shock- absorbing synovial fluid into the joint capsule. Therefore, the bone surfaces are not in direct contact. In some synovial joints (eg, the knee), fibrocartilage disks (eg, medial meniscus) are located between the articular cartilage surfaces.These disks provide shock absorption (Porth & Matfin, 2009).  Ligaments (fibrous connective tissue bands) bind the articulating bones together. Ligaments and muscle tendons, which pass over the joint, provide joint stability. In some joints, interosseous ligaments (eg, the cruciate ligaments of the knee) are found within the capsule and add anterior and posterior stability to the joint.  A bursa is a sac filled with synovial fluid that cushions the movement of tendons, ligaments, and bones at a point of friction. Bursae can be found in the joints of the elbow, shoulder, hip, and knee. Structure and Function of the Skeletal Muscle System:  The muscles of the body are composed of parallel groups of muscle cells (fasciculi) encased in fibrous tissue called fascia (epimysium). The more fasciculi contained in a muscle, the more precise the movements. Muscles vary in shape and size. Skeletal Muscle Contraction:  Each muscle cell (also referred to as a muscle fiber) contains myofibrils, which in turn are composed of a series of sarcomeres, the actual contractile units of skeletal muscle. Sarcomeres contain thick myosin and thin actin filaments. Skeletal Muscle Contraction: cont  Muscle cells contract in response to electrical stimulation delivered by an effector nerve cell at the motor end plate. When stimulated, the muscle cell depolarizes and generates an action potential in a manner similar to that described for nerve cells.  These action potentials propagate along the muscle cell membrane and lead to the release of calcium ions that are stored in specialized organelles called sarcoplasmic reticula.  When there is a local increase in calcium ion concentration, the myosin and actin filaments slide across one another. Shortly after the muscle cell membrane is depolarized, it recovers its resting membrane voltage.  Calcium is rapidly removed from the sarcomeres by active reaccumulation in the sarcoplasmic reticulum. When the calcium concentration in the sarcomere decreases, the myosin and actin filaments cease to interact, and the sarcomere returns to its original resting length (relaxation). Actin and myosin do not interact in the absence of calcium (Porth & Matfin, 2009).  Energy is consumed during muscle contraction and relaxation. The primary source of energy for the muscle cells is adenosine triphosphate (ATP), which is generated through cellular oxidative metabolism.  At low levels of activity (ie, sedentary activity), the skeletal muscle synthesizes ATP from the oxidation of glucose to water and carbon dioxide.  During periods of strenuous activity, when sufficient oxygen may not be available, glucose is metabolized primarily to lactic acid, an inefficient process compared with that of oxidative pathways. Stored muscle glycogen is used to supply glucose during periods of activity.  Muscle fatigue is thought to be caused by depletion of glycogen and accumulation of lactic acid. As a result, the cycle of muscle contraction and relaxation cannot continue.  During muscle contraction, the energy released from ATP is not completely used. The excess energy is dissipated in the form of heat. During isometric contraction, almost all of the energy is released in the form of heat; during isotonic contraction, some of the energy is expended in mechanical work. In some situations (eg, shivering), the need to generate heat is the primary stimulus for muscle contraction.  The contraction of muscle fibers can result in either isotonic or isometric contraction of the muscle. In isometric contraction, the length of the muscles remains constant but the force generated by the muscles is increased; an example of this is pushing against an immovable wall.  Isotonic contraction, on the other hand, is characterized by shortening of the muscle with no increase in tension within the muscle; an example of this is flexing the forearm. In normal activities, many muscle movements are a combination of isometric and isotonic contraction. For example, during walking, isotonic contraction results in shortening of the leg, and isometric contraction causes the stiff leg to push against the floor.  The speed of the muscle contraction is variable. Myoglobulin is a hemoglobin like protein pigment present in striated muscle cells that transports oxygen. Muscles containing large quantities of myoglobulin (red muscles) have been observed to contract slowly and powerfully (eg, respiratory and postural muscles).  Muscles containing little myoglobulin (white muscles) contract quickly (eg, extraocular eye muscles). Most muscles contain both red and white muscle fibers (Porth & Matfin, 2009). Muscle Tone:  Relaxed muscles demonstrate a state of readiness to respond to contraction stimuli. This state of readiness, known as muscle tone (tonus), is produced by the maintenance of some of the muscle fibers in a contracted state.  Muscle spindles, which are sense organs in the muscles, monitor muscle tone. Muscle tone is minimal during sleep and is increased when the person is anxious. A muscle that is limp and without tone is described as flaccid; a muscle with greater-than-normal tone is described as spastic. In conditions characterized by lower motor neuron destruction (eg, polio), denervated muscle becomes atonic (soft and flabby) and atrophies. Muscle Actions:  Muscles accomplish movement by contraction. Through the coordination of muscle groups, the body is able to perform a wide variety of movements.The prime mover is the muscle that causes a particular motion. The muscles assisting the prime mover are known as synergists.  The muscles causing movement opposite to that of the prime mover are known as antagonists. An antagonist must relax to allow the prime mover to contract, producing motion. For example, when contraction of the biceps causes flexion of the elbow joint, the biceps are the prime movers, and the triceps are the antagonists. A person with muscle paralysis (a loss of movement, possibly from nerve damage) may be able to retrain functioning muscles within the synergistic group to produce the needed movement. Muscles of the synergistic group then become the prime movers.  Muscles need to be exercised to maintain function and strength. When a muscle repeatedly develops maximum or close to maximum tension over a long time, as in regular exercise with weights, the cross-sectional area of the muscle increases. This enlargement, known as hypertrophy, results from an increase in the size of individual muscle fibers without an increase in their number.  Hypertrophy persists only if the exercise is continued. The opposite phenomenon occurs with disuse of muscle over a long period of time. Age and disuse cause loss of muscular function as fibrotic tissue replaces the contractile muscle tissue. The decrease in the size of a muscle is called atrophy.  Bed rest and immobility cause loss of muscle mass and strength. When immobility is the result of a treatment modality (eg, casting, traction, or bedrest), the patient can decrease the effects of immobility by isometric exercise of the muscles of the immobilized part.  Quadriceps contraction exercises(tightening the muscles of the thigh) and gluteal setting exercises (tightening of the muscles of the buttocks) help maintain the larger muscle groups that are important in ambulation. Active and weight- resistance exercises of uninjured parts of the body maintain muscle strength.  When muscles are injured, they need rest and immobilization until tissue repair occurs. The healed muscle then needs progressive exercise to resume its preinjury strength and functional ability. Gerontologic Considerations:  Multiple changes in the musculoskeletal system occur with aging  There is a loss of height due to osteoporosis (abnormal excessive bone loss),  kyphosis, thinned intervertebral disks, compressed vertebral bodies, and flexion of the knees and hips.  Numerous metabolic changes, including menopausal withdrawal of estrogen and decreased activity, contribute to osteoporosis (DHHS, 2004;McCormick, 2007). Women lose more bone mass than men. In addition, bones change in shape and have reduced strength. Fractures are common. Collagen structures are less able to absorb energy.  Increased inactivity, diminished neuron stimulation, and nutritional deficiencies contribute to loss of muscle strength.  In addition, remote musculoskeletal problems for which the patient has compensated may become new problems with age-related changes. For example, people who have had polio and who have been able to function normally by using synergistic muscle groups may discover increasing incapacity because of a reduced compensatory ability.  However, many of the effects of aging can be slowed if the body is kept healthy and active through positive lifestyle behaviors. Assessment of musculoskeletal system:  Health History: The nursing assessment of the patient with musculoskeletal dysfunction includes an evaluation of the effects of the musculoskeletal disorder on the patient. Common Symptoms: During the interview and physical assessment, the patient with a musculoskeletal disorder may report pain, tenderness, tightness, and abnormal sensations. The nurse assesses and documents this information. Common Symptoms:  Pain: Most patients with diseases and traumatic conditions or disorders of the muscles, bones, and joints experience pain.  Bone pain is characteristically described as a dull, deep ache that is “boring” in nature, whereas muscular pain is described as soreness or aching and is referred to as “muscle cramps.” Fracture pain is sharp and piercing and is relieved by immobilization. Sharp pain may also result from bone infection with muscle spasm or pressure on a sensory nerve.  Rest relieves most musculoskeletal pain. Pain that increases with activity may indicate joint sprain, muscle strain, or compartment syndrome, whereas steadily increasing pain points to the progression of an infectious process (osteomyelitis), a malignant tumor, or neurovascular complications. Radiating pain occurs in conditions in which pressure is exerted on a nerve root.  Pain is variable, and its assessment and nursing management must be individualized.  Altered Sensations:  Sensory disturbances are frequently associated with musculoskeletal problems. The patient may describe paresthesias, which are burning, tingling sensations or numbness. These sensations may be caused by pressure on nerves or by circulatory impairment. Soft tissue swelling or direct trauma to these structures can impair their function. The nurse assesses the neurovascular status of the involved musculoskeletal area.  Questions that the nurse should ask regarding altered sensations include the following:  Is the patient experiencing any abnormal sensations or numbness?  If the abnormal sensation or feeling of numbness involves an extremity, how does this feeling compare to sensation in the unaffected extremity?  When did the condition begin? Is it getting worse?  Does the patient also have pain? (If the patient has pain, then the questions and assessments for pain discussed previously should be followed.)  Assessments that the nurse should make regarding the altered sensations include the following:  If the affected part is an extremity, how does its over-all appearance compare to the unaffected extremity?  Can the patient move the affected part? If an extremity is involved, does each toe/finger have normal sensation and motion (flexion and extension), and is the skin warm or cool?  What is the color of the part distal to the affected area? Is it pale? Mottled? Cyanotic?  Does rapid capillary refill occur?  Is a pulse distal to the affected area palpable? If the affected area is an extremity, how does the pulse compare to the pulse of the unaffected extremity?  Is edema present?  Is any constrictive device or clothing causing nerve or vascular compression?  Does elevating the affected part or modifying its position affect the symptoms? Past Health, Social, and Family History: When assessing the musculoskeletal system, the nurse should gather pertinent data to include in the patient’s health history, such as occupation (eg, does the patient’s work require physical activity or heavy lifting?), exercise patterns, and dietary intake (eg, calcium and vitamin D). Concurrent health conditions (eg, diabetes, heart disease, chronic obstructive pulmonary disease, infection, pre-existing disability) and related problems, such as familial or genetic abnormalities. Physical Assessment:  An examination of the musculoskeletal system ranges from a basic assessment of functional capabilities to sophisticated physical examination maneuvers that facilitate diagnosis of specific bone, muscle, and joint disorders. The extent of assessment depends on the patient’s physical complaints.  health history, and physical clues that warrant further exploration. The nursing assessment is primarily a functional evaluation, focusing on the patient’s ability to perform activities of daily living.  Posture  The normal curvature of the spine is convex through the thoracic portion and concave through the cervical and lumbar portions. Common deformities of the spine include  Kyphosis: an increased forward curvature of the thoracic spine.  lordosis, or swayback, an exaggerated curvature of the lumbar spine.  and scoliosis: a lateral curving deviation of the spine.  Kyphosis : is frequently seen in elderly patients with osteoporosis and in some patients with neuromuscular diseases. Scoliosis may be congenital, idiopathic (without an identifiable cause), or the result of damage to the paraspinal muscles, as in polio.  Lordosis: is frequently seen during pregnancy as the woman adjusts her posture in response to changes in her center of gravity.  During inspection of the spine, the entire back, buttocks, and legs are exposed. The examiner inspects the spinal curves and trunk symmetry from posterior and lateral views.  Standing behind the patient, the examiner notes any differences in the height of the shoulders or iliac crests. Shoulder and hip symmetry, as well as the line of the vertebral column, are inspected with the patient erect and with the patient bending forward (flexion).  Scoliosis is evidenced by an abnormal lateral curve in the spine, shoulders that are not level, an asymmetric waistline, and a prominent scapula, accentuated by bending forward.  Older adults experience a loss in height due to loss of vertebral cartilage and osteoporosis-related vertebral compression fractures. Therefore, an adult’s height should be measured during health screenings.  Gait:  Gait is assessed by having the patient walk away from the examiner for a short distance.  The examiner observes the patient’s gait for smoothness and rhythm. Any unsteadiness or irregular movements (frequently noted in elderly patients) are considered abnormal.  Limping motion is most frequently caused by painful weight bearing. In such instances, the patient can usually pinpoint the area of discomfort, thus guiding further examination. If one extremity is shorter than another, a limp may also be observed as the patient’s pelvis drops downward on the affected side with each step.  Limited joint motion may affect gait and a knee may be implicated. Evaluation of the knee involves the joints, bones, ligaments, tendons, and cartilage, and may include tests for the anterior and collateral ligaments, medial and lateral ligaments, and medical meniscus.  In addition, avariety of neurologic conditions are associated with abnormal gaits, such as a spastic hemiparesis gait (stroke), step-page gait (lower motor neuron disease), and shuffling gait (Parkinson’s disease). Bone Integrity:  The bony skeleton is assessed for deformities and alignment. Symmetric parts of the body, such as extremities, are compared. Abnormal bony growths due to bone tumors may be observed. Shortened extremities, amputations, and body parts that are not in anatomic alignment are noted. Fracture findings may include abnormal angulation of long bones, motion at points other than joints, and crepitus (a grating sound) at the point of abnormal motion. Movement of fracture fragments must be minimized to avoid additional injury.  Joint Function:  The articular system is evaluated by noting range of motion, deformity, stability, and nodular formation. Range of motion is evaluated both actively (the joint is moved by the muscles surrounding the joint) and passively (the joint is moved by the examiner). The examiner is familiar with the normal range of motion of major joints.  Precise measurement of range of motion can be made by a goniometer (a protractor designed for evaluating joint motion). Limited range of motion may be the result of skeletal deformity, joint pathology, or contracture (shortening of surrounding joint structures) of the surrounding muscles, tendons, and joint capsule. In elderly patients, limitations of range of motion associated with osteoarthritis may reduce their ability to perform activities of daily living.  If joint motion is compromised or the joint is painful, the joint is examined for effusion (excessive fluid within the capsule), swelling, and increased temperature that may reflect active inflammation. An effusion is suspected if the joint is swollen and the normal bony landmarks are obscured. The most common site for joint effusion is the knee.  If large amounts of fluid are present in the joint spaces beneath the patella, it may be identified by assessing for the balloon sign and for ballottement of the knee (Fig. 66-5). If inflammation or fluid is suspected in a joint, consultation with a physician is indicated.  Joint deformity may be caused by contracture, dislocation (complete separation of joint surfaces), subluxation (partial separation of articular surfaces), or disruption of structures surrounding the joint. Weakness or disruption of joint-supporting structures may result in a weak joint that requires an external supporting appliance (eg, brace).  Palpation of the joint, while it is passively moved, provides information about the integrity of the joint. Normally, the joint moves smoothly. A snap or crack may indicate that a ligament is slipping over a bony prominence. Slightly roughened surfaces, as in arthritic conditions, result increpitus (grating, crackling sound or sensation) as the irregular joint surfaces move across one another.  The tissues surrounding joints are examined for nodule formation. Rheumatoid arthritis, gout, and osteoarthritis may produce characteristic nodules. The subcutaneous nodules of rheumatoid arthritis are soft and occur within and along tendons that provide extensor function to the joints.  The nodules of gout are hard and lie within and immediately adjacent to the joint capsule itself. They may rupture, exuding white uric acid crystals onto the skin surface. Osteoarthritic nodules are hard and painless and represent bony overgrowth that has resulted from destruction of the cartilaginous surface of bone within the joint capsule. They are frequently seen in older adults.  Often, the size of the joint is exaggerated by atrophy of the muscles proximal and distal to that joint. This is seen in rheumatoid arthritis of the knees, in which the quadriceps muscle may atrophy dramatically. In rheumatoid arthritis, joint involvement assumes a symmetric pattern  Muscle Strength and Size:  The muscular system is assessed by noting muscular strength and coordination, the size of individual muscles, and the patient’s ability to change position.  Weakness of a group of muscles might indicate a variety of conditions, such as polyneuropathy, electrolyte disturbances (particularly potassium and calcium), myasthenia gravis, poliomyelitis, and muscular dystrophy. By palpating the muscle while passively moving the relaxed extremity, the nurse can determine the muscle tone. The nurse assesses muscle strength by having the patient perform certain maneuvers with and without added resistance. For example, when the biceps are tested, the patient is asked to extend the arm fully and then to flex it against resistance applied by the nurse. sustained dorsiflexion of the foot or extension of the wrist. Fasciculation (involuntary twitching of muscle fiber groups) may be observed.The nurse measures the girth of an extremity to monitor increased size due to exercise, edema, or bleeding into the muscle. Girth may decrease due to muscle atrophy. The unaffected extremity is measured and used as the reference standard for the affected extremity. Measurements are taken at the maximum circumference of the extremity. It is important that the measurements be taken at the same location on the extremity, and with the extremity in the same position, with the muscle at rest. Distance from a specific anatomic landmark (eg, 10 cm below the medial aspect of the knee for measurement of the calf muscle) should be indicated in the patient’s record so that subsequent measurements can be made at the same point. For ease of serial assessment, the nurse may indicate the point of measurement by marking the skin. Variations in size greater than 1 cm are considered significant. Skin  In addition to assessing the musculoskeletal system, the nurse inspects the skin for edema, temperature, and color. Palpation of the skin can reveal whether any areas are warmer, suggesting increased perfusion or inflammation, or cooler, suggesting decreased perfusion, and whether edema is present. Cuts, bruises, skin color, and evidence of decreased circulation or inflammation can influence nursing management of musculoskeletal conditions.  Neurovascular Status  It is important for the nurse to perform frequent neurovascular assessments of patients with musculoskeletal disorders (especially of those with fractures) because of the risk for tissue and nerve damage.  One complication that the nurse needs to be alert for when assessing the patient is compartment syndrome, which is described in detail later in this unit. This major neurovascular problem is caused by pressure within a muscle compartment that increases to such an extent that microcirculation diminishes, leading to nerve and muscle anoxia and necrosis. Function can be permanently lost if the anoxic situation continues for longer than 6 hours. Diagnostic Evaluation Imaging Procedures:  X-Ray Studies: X-ray studies are important in evaluating patients with musculoskeletal disorders. Bone x-rays determine bone density, texture, erosion, and changes in bone relationships. X-ray study of the cortex of the bone reveals any widening, narrowing, or signs of irregularity. Joint x-rays reveal fluid, irregularity, spur formation, narrowing, and changes in the joint structure. Multiple x-rays, with multiple views (eg, anterior-posterior, lateral), are needed for full assessment of the structure being examined. Serial x-rays may be indicated to determine the status of the healing process. After being positioned for the study, the patient must remain still while the x-rays are obtained.  Computed Tomography :A computed tomography (CT) scan, which may be performed with or without the use of contrast agents, shows in detail a specific plane of involved bone and can reveal tumors of the soft tissue or injuries to the ligaments or tendons. It is used to identify the location and extent of fractures in areas that are difficult to evaluate (eg, acetabulum).  Magnetic Resonance Imaging: Magnetic resonance imaging (MRI) is a noninvasive imaging technique that uses magnetic fields, radiowaves, and computers to demonstrate abnormalities (ie, tumors or narrowing of tissue pathways through bone) of soft tissues such as muscle, tendon, cartilage, nerve, and fat. Because an electromagnet is used, patients with any metal implants, clips, or pacemakers are not candidates for MRI.  To enhance visualization of anatomic structures, intravenous (IV) contrast agent may be used. During the MRI, the patient must lie still and will hear a rhythmic knocking sound. Patients who experience claustrophobia may be unable to tolerate the confinement of closed MRI equipment without sedation. Open MRI systems are available, but they use lower-intensity magnetic fields, which produce lower-quality images. Advantages of open MRI include increased patient comfort, reduced problems with claustrophobic reactions, and reduced noise.  Arthrography  Arthrography is useful in identifying acute or chronic tears of the joint capsule or supporting ligaments of the knee, shoulder, ankle, hip, or wrist. A radiopaque contrast agent or air is injected into the joint cavity to visualize irregular surfaces. The joint is put through its range of motion to distribute the contrast agent while a series of x-rays is obtained. If a tear is present, the contrast agent leaks out of the joint and is evident on the x-ray image.  After an arthrogram, a compression elastic bandage is applied as prescribed and the joint is usually rested for 12 hours. The nurse provides additional comfort measures (mild analgesia, ice) as appropriate and explains to the patient that it is normal to experience clicking or crackling in the joint for a day or two after the procedure, until the contrast agent or air is absorbed. Nursing Interventions for Imaging Studies:  Before the patient undergoes an imaging study, the nurse assesses for conditions that may require special consideration during the study or that may be contraindications to the study (eg, pregnancy; claustrophobia; inability to tolerate required positioning due to age, or disability; metal implants). If contrast agents will be used for CT scan, MRI, or arthrography, the patient is assessed for possible allergies. Bone Densitometry:  Bone densitometry is used to estimate bone mineral density (BMD). This can be performed through the use of x-rays or ultrasound. The most common modalities used include dual energy x-ray absorptiometry, quantitative computed tomography (QCT), and quantitative ultrasound  (QUS). DXA BMD measures of the hip and spine are very accurate in estimating the extent of osteoporosis and monitoring a patient’s response to treatment for osteoporosis.  BMD of the forearm, finger, or heel, though its ability to project hip or spine fracture risk is less accurate than DXA. While the BMD of the heel can be used to diagnose and monitor osteoporosis, predicting hip fracture risk related to osteoporosis is best achieved through DXA of the hip; hence, it is the most commonly prescribed diagnostic test for determining BMD.  Bone Scan  A bone scan is performed to detect metastatic and primary bone tumors, osteomyelitis, some fractures, and aseptic necrosis.  A bone-seeking radioisotope is injected IV. The scan is performed 2 to 3 hours after the injection.  At this point, distribution and concentration of the isotope in the bone are measured. The degree of nuclide uptake is related to the metabolism of the bone. An increased uptake of isotope is seen in primary skeletal disease (osteosarcoma), metastatic bone disease, inflammatory skeletal disease (osteomyelitis), and fractures that do not heal as expected.  Nursing Interventions  Before the patient undergoes a bone scan, the nurse inquires about possible allergies to the radioisotope and assesses for any condition that would contraindicate performing the procedure (eg, pregnancy).  In addition, the patient is encouraged to drink plenty of fluids to help distribute and eliminate the isotope. Before the scan, the nurse asks the patient to empty the bladder, because a full bladder interferes with accurate scanning of the pelvic bones.  Arthroscopy:  Arthroscopy is a procedure that allows direct visualization of a joint to diagnose joint disorders. Treatment of tears, defects, and disease processes may be performed through the arthroscopy.  The procedure is performed in the operating room under sterile conditions; injection of a local anesthetic agent into the joint or general anesthesia is used. A large-bore needle is inserted, and the joint is distended with saline.  The arthroscopy is introduced, and joint structures, synovium, and articular surfaces are visualized. After the procedure, the puncture wound is closed with adhesive strips or sutures and covered with a sterile dressing. Complications are rare but may include infection, hemarthrosis, neurovascular compromise, thrombophlebitis, stiffness, effusion, adhesions, and delayed wound healing. Nursing Interventions:  After the arthroscopic procedure, the joint is wrapped with a compression dressing to control swelling. In addition, ice may be applied to control edema and enhance comfort.  Frequently, the joint is kept extended and elevated to reduce swelling. It is important to monitor and document the neurovascular status.  Analgesic agents are administered as needed. The patient is instructed about activities and exercises that may be performed. The patient and family are informed of the symptoms (eg, swelling, numbness, cool skin) to watch for in order to determine whether complications are occurring and of the importance of notifying the physician of these observations. Arthrocentesis  Arthrocentesis (joint aspiration) is carried out to obtain synovial fluid for purposes of examination or to relieve pain due to effusion.  Examination of synovial fluid is helpful in the diagnosis of septic arthritis and other inflammatory arthropathies and reveals the presence of hemarthrosis (bleeding into the joint cavity), which suggests trauma or a bleeding disorder.  Normally, synovial fluid is clear, pale, straw colored, and scanty in volume. Using aseptic technique, the physician inserts a needle into the joint and aspirates fluid. Anti-inflammatory medications may be in-jected into the joint. A sterile dressing is applied after aspiration. There is a risk of infection after this procedure. Electromyography:  Electromyography (EMG) provides information about the electrical potential of the muscles and the nerves leading to them.  The test is performed to evaluate muscle weakness, pain, and disability. The purpose of the procedure is to determine any abnormality of function and to differentiate muscle and nerve problems. Needle electrodes are inserted into selected muscles, and responses to electrical stimuli are recorded on an oscilloscope.  Biopsy:  Biopsy may be performed to determine the structure and composition of bone marrow, bone, muscle, or synovium to help diagnose specific diseases.  The nurse teaches the patient about the procedure and assures the patient that analgesic agents will be provided. The nurse monitors the biopsy site for edema, bleeding, pain, and infection. Ice is applied as prescribed to control bleeding and edema. In addition, analgesic agents are administered as prescribed for comfort.  Laboratory Studies  Serum calcium levels are altered in patients with osteomalacia, parathyroid dysfunction, Paget’s disease, metastatic bone tumors, or prolonged immobilization. Serum phosphorus levels are inversely related to calcium levels and are diminished in osteomalacia associated with malabsorption syndrome. Acid phosphatase is elevated in Paget’s disease and metastatic cancer. Alkaline phosphatase is elevated during early fracture healing and in diseases with increased osteoblastic activity (eg, metastatic bone tumors).  Bone metabolism may be evaluated through thyroid studies and determination of calcitonin, PTH, and vitamin D levels. Serum enzyme levels of creatine kinase and aspartate aminotransferase become elevated with muscle damage. Serum osteocalcin (bone GLA protein) indicates the rate of bone destruction. Urine calcium levels increase with bone destruction (eg, parathyroid dysfunction, metastatic bone tumors, multiple myeloma)  Specific urine and serum biochemical markers can be used to provide information about bone formation. These include urinary N-telopeptide of type 1 collagen (N-Tx) and deoxypyridinoline (Dpd), both of which reflect increased osteoclast activity and increased bone resorption.  Conversely, elevated serum levels of bone-specific alkalinephosphatase (ALP), osteocalcin, and intact N-terminal propeptide of type 1 collagen (P1NP) reflect increased activity of osteoblasts and enhanced bone remodeling activity