Cellular Biology
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Transcript Cellular Biology
Alterations of
Musculoskeletal Function
Chapter 42
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Musculoskeletal Injuries
Fractures
A fracture is a break in the continuity of a bone
Classifications
Complete or incomplete
Closed or open
Comminuted
Linear
Oblique
Spiral
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Fracture Classifications
Transverse
Greenstick
Torus
Bowing
Pathologic
Stress
Fatigue and insufficiency
Transchondral
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Fractures
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Bone Fractures
A broken bone can cause damage to the
surrounding tissue, the periosteum, and the
blood vessels in the cortex and marrow
Hematoma formation
Bone tissue destruction triggers an
inflammatory response
Procallus formation
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Callus Formation
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Bone Fractures
Manifestations
Treatment
Unnatural alignment, swelling, muscle spasm,
tenderness, pain, impaired sensation, and possible
muscle spasms
Closed manipulation, traction, and open reduction
Improper reduction or immobilization
Nonunion, delayed union, and malunion
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Treatment
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Treatment
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Treatment
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Bone Fractures
Dislocation
Subluxation
Temporary displacement of two bones
Loss of contact between articular cartilage
Contact between articular surfaces is only
partially lost
Dislocation and subluxation are associated
with fractures, muscle imbalance, rheumatoid
arthritis, or other forms of joint instability
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Support Structure Injuries
Strain
Sprain
Tear or injury to a tendon
Tear or injury to a ligament
Avulsion
Complete separation of a tendon or ligament from
its bony attachment site
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Tendinopathy and Bursitis
Tendinitis
Tendinosis
Inflammation of a tendon
Painful degradation of collagen fibers
Bursitis
Inflammation of a bursa
Skin over bone, skin over muscle, and muscle and tendon over
bone
Caused by repeated trauma
Septic bursitis is caused by a wound infection
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Tendinopathy and Bursitis
Epicondylitis
Inflammation of a tendon where it attaches to a
bone
Tennis elbow (lateral epicondylitis)
Golfer’s elbow (medial epicondylitis)
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Tendinitis and Epicondylitis
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Tendinitis and Epicondylitis
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Muscle Strain
Sudden, forced motion causing the muscle to
become stretched beyond its normal capacity
Local muscle damage
Muscle strains can also involve the tendons
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Myositis Ossificans
Complication of local muscle injury
Inflammation of muscular tissue with
subsequent calcification and ossification of
the muscle
“Rider’s bone” in equestrians
“Drill bone” in infantry soldiers
Thigh muscles in football players
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Rhabdomyolysis
Rhabdomyolysis (myoglobinuria) is a lifethreatening complication of severe muscle
trauma with muscle cell loss
Crush syndrome
Compartment syndromes
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Osteoporosis
Porous bone
Poorly mineralized bone
Bone density
Normal bone
Osteopenic bone
833 mg/cm2
833 to 648 mg/cm2
Osteoporosis
<648 mg/cm2
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Osteoporosis
Potential causes
Decreased levels of estrogen and testosterone
Decreased activity level
Inadequate levels of vitamins D and C, or Mg++
Demonstrated by reduced bone mass/density and an
imbalance of bone resorption and formation
Bone histology is usually normal but it lacks
structural integrity
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Osteoporosis
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Osteoporosis
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Osteoporosis
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Osteoporosis
Perimenopausal osteoporosis
Iatrogenic osteoporosis
Regional osteoporosis
Postmenopausal osteoporosis
Glucocorticoid-induced osteoporosis
Age-related bone loss
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Osteomalacia
Deficiency of vitamin D lowers the absorption
of calcium from the intestines
Inadequate or delayed mineralization
Bone formation progresses to osteoid
formation but calcification does not occur; the
result is soft bones
Pain, bone fractures, vertebral collapse, bone
malformation
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Paget Disease
Also called osteitis deformans
Excessive resorption of spongy bone and accelerated
formation of softened bone
Disorganized, thickened, but soft bones
Most often affects the axial skeleton
Thickened bones can cause abnormal bone
curvatures, brain compression, impaired motor
function, deafness, atrophy of the optic nerve, etc.
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Osteomyelitis
Osteomyelitis is most often caused by a
staphylococcal infection
Most common cause is open wound (exogenous); also
can be from a blood-borne (endogenous) infection
Manifestations
Acute and chronic inflammation, fever, pain, necrotic bone
Treatment
Antibiotics, débridement, surgery, hyperbaric oxygen
therapy
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Osteomyelitis
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Bone Tumors
May originate from bone cells, cartilage,
fibrous tissue, marrow, or vascular tissue
Osteogenic, chrondrogenic, collagenic, and
myelogenic
Malignant bone tumors
Increased nuclear/cytoplasmic ratio, irregular
borders, excess chromatin, a prominent nucleolus,
and an increase in the mitotic rate
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Bone Tumors
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Bone Tumors
Patterns of bone destruction
Geographic pattern
Moth-eaten pattern
Permeative pattern
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Bone Tumors
Osteosarcoma
38% of bone tumors
Predominant in adolescents and young adults;
occurs in seniors if they have a history of
radiation therapy
Contain masses of osteoid
“Streamers”: noncalcified bone matrix and callus
Located in the metaphyses of long bones
50% occur around the knees
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Osteosarcoma
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Bone Tumors
Chondrosarcoma
Tumor of middle-aged and older adults
Infiltrates trabeculae in spongy bone; frequent in
the metaphyses or diaphysis of long bones
The tumor contains lobules of hyaline cartilage
that expand and enlarge the bone
Causes erosion of the cortex and can expand into
the neighboring soft tissues
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Chondrosarcoma
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Bone Tumors
Fibrosarcoma
Firm, fibrous mass of collagen, malignant
fibroblasts, and osteoclast-like cells
Usually affects metaphyses of the femur or tibia
Metastasis to the lungs is common
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Bone Tumors
Myelogenic tumors
Giant cell tumor
Causes extensive bone resorption due to the
osteoclastic origin of the giant cells
Located in the epiphyses of the femur, tibia, radius, or
humerus
The tumor has a slow, relentless growth rate
Myeloma
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Giant Cell Tumor
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Inflammatory vs. Noninflammatory
Joint Disease
Differentiated by:
Absence of synovial membrane inflammation
Lack of systemic signs and symptoms
Normal synovial fluid analysis
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Osteoarthritis
Degeneration and loss of articular cartilage,
sclerosis of bone underneath cartilage, and
formation of bone spurs (osteophytes)
Also referred to as degenerative joint disease
Incidence increases with age
Primary disease is idiopathic
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Osteoarthritis
Osteoarthritis is characterized by local areas
of damage and loss of articular cartilage, new
bone formation of joint margins, subchondral
bone changes, and variable degrees of mild
synovitus and thickening of the joint capsule
Manifestations
Pain, stiffness, enlargement of the joint,
tenderness, limited motion, and deformity
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Osteoarthritis
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Osteoarthritis
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Inflammatory Joint Disease
Commonly called arthritis
Characterized by inflammatory damage or
destruction in the synovial membrane or
articular cartilage and by systemic signs of
inflammation
Fever, leukocytosis, malaise, anorexia, and
hyperfibrinogenemia
Infectious or noninfectious
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Rheumatoid Arthritis (RA)
Inflammatory joint disease
Systemic autoimmune damage to connective tissue,
primarily in the joints (synovial membrane)
Similar symptoms to osteoarthritis
Presence of rheumatoid factors (RA or RF test)
Antibodies (IgG and IgM) against antibodies
Joint fluid presents with inflammatory exudate
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Rheumatoid Arthritis (RA)
Pathogenesis
CD4 T helper cells and other cells in the synovial fluid
become activated and release cytokines
Recruitment and retention of inflammatory cells in the
joint sublining region
Viscous cycle of altered cytokine and signal transduction
pathways
Possible immune complex deposition and inflammatory
cytokine release
RANKL release and osteoclast activation
Angiogenesis in the synovium
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Rheumatoid Arthritis (RA)
Evaluation (4 or more of the following)
Morning joint stiffness lasting at least 1 hour
Arthritis of three or more joint areas
Arthritis of the hand joints
Symmetric arthritis
Rheumatoid nodules
Abnormal amounts of serum rheumatoid factor
Radiographic changes
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Rheumatoid Arthritis (RA)
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Rheumatoid Arthritis (RA)
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Ankylosing Spondylitis (AS)
Inflammatory joint disease of the spine or sacroiliac
joints causing stiffening and fusion of the joints
Systemic, immune inflammatory disease
Primary proposed site is the enthesis
Site where ligaments, tendons, and the joint capsule are
inserted into bone
Cause unknown, but there is a strong association
with HLA-B27 antigen
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Ankylosing Spondylitis (AS)
Begins with the inflammation of fibrocartilage,
particularly in the vertebrae and sacroiliac joint
Inflammatory cells infiltrate and erode fibrocartilage
As repair begins, the scar tissue ossifies and calcifies;
the joint eventually fuses
Early symptoms
Low back pain, stiffness, pain, and restricted motion
Patient demonstrates loss of normal lumbar curvature
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Ankylosing Spondylitis (AS)
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Gout
Metabolic disorder that disrupts the body’s control of
uric acid production or excretion
Gout manifests high levels of uric acid in the blood
and other body fluids
Occurs when the uric acid concentration increases to
high enough levels to crystallize
Crystals deposit in connective tissues throughout the
body
When these crystals occur in the synovial fluid, the
inflammation is known as “gouty arthritis”
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Gout
Gout is related to purine (adenine and
guanine) metabolism
Affected patients can have accelerated purine
synthesis, breakdown, or poor uric acid
secretion in the kidneys
Mechanisms for crystal deposition
Lower body temperatures, decreased albumin or
glycosaminoglycan levels, changes in ion
concentration and pH, and trauma
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Gout
Clinical stages
Asymptomatic hyperuricemia
Acute gouty arthritis
Tophaceous gout
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Gout
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Gout
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Disorders of Skeletal Muscle
Contracture
Muscle fiber shortening without an action
potential
Caused by failure of the sarcoplasmic reticulum
(calcium pump) even with available ATP
Stress-induced muscle tension
Neck stiffness, back pain, clenching teeth, hand
grip, and headache
Associated with chronic anxiety
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Fibromyalgia
Chronic widespread joint and muscle pain
Vague symptoms
Possible factors
Increased sensitivity to touch, absence of
inflammation, fatigue, and sleep disturbances
Flulike viral illness, chronic fatigue syndrome,
HIV infection, Lyme disease, medications,
physical or emotional trauma
Scientific studies are unclear
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Fibromyalgia
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Disuse Atrophy
Reduction in the normal size of muscle cells
due to prolonged inactivity
Bed rest, trauma, casting, or nerve damage
Treatment
Isometric movements and passive lengthening
exercises
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Muscle Membrane Abnormalities
Myotonia
Periodic paralysis
Hypokalemic periodic paralysis
Hyperkalemic periodic paralysis
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Diseases of Energy Metabolism
McArdle disease
Acid maltase deficiency
Myophosphorylase deficiency
Pompe disease
Myoadenylate deaminase deficiency (MDD)
Lipid deficiencies
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Polymyositis and Dermatomyositis
Collectively described by the term myositis
Viral, bacterial, and parasitic myositis
Staphylococcus aureus infections
Trichinosis
Trichinella infection
Toxoplasmosis
Polymyositis and dermatomyositis
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Polymyositis and Dermatomyositis
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Toxic Myopathies
The most common cause of toxic myopathy is
alcohol abuse
Acute attack of muscle weakness, pain, and
swelling
Chronic weakness in a drinker of long duration
Necrosis of individual muscle fibers
Disturbance of energy turnover, gene dysregulation,
and initiation of apoptosis
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Muscle Tumors
Rhabdomyosarcoma
Malignant tumor of striated muscle
Usually muscles of the tongue, neck, larynx,
nasal cavity, axilla, vulva, and heart
Highly malignant with rapid metastasis
Types
Pleomorphic, embryonal, and alveolar
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