Chapter 21 - Bones & Joints Flashcards
what are the 5 functions of the skeletal system?
-reservoir of minerals (calcium and phosphorus)
-protection of organs
-production of blood cells
-movement
-shape
what is bone made of?
connective tissue
outer most layer of compact bone
cortex
inner spongy layer of bone
trabeculae
what is bone marrow
spaces between trabeculae that consist of fat and blood-forming tissue
osteoblast
build bones
osteoclasts
break down bones
osteocytes
bone cells
Wolff’s Law
muscle pulls on bone and strengthens it – strength of bone depends on activity level
endochondral ossification
lay down cartilage
bone replaces cartilage
ossification at epiphyseal plate
females don’t grow as tall because their epiphyseal plate closes sooner
intramembranous ossification
no cartilage phase occurs — usually in flat bones
bone mineral density
amount of mineral per cm of bone
what is an indicator of fracture risk?
bone mineral density
what factors influence bone mineral density
diet
physical activity
hormones
ethnicity (caucasian and asian)
age
sex
what is the most common affliction of bone?
fracture
causes of fractures
trauma OR
pathologic (diseases like cancer or osteoporosis)
what is osteopenia?
generalized loss of bone
what can osteopenia be caused by?
osteoporosis
osteomalasia (vitamin D deficiency)
what is the most common malignancy of bone?
metastatic cancer
what are the most common cancers of bone in children and adolescents?
osteosarcoma and Ewing sarcomewhat
what bone cancer is most common in adults?
multiple myeloma
most common symptoms associated with bone
pain
decreased mobility
deformity
symptoms associated with arthritis include
joint stiffness and decreased mobility
pain and inflammation
tests for bones
X-rays and CT scans (tumors)
serum tests
-calcium, phosphorus, and alkaline phosphatase (measure BMD)
-erythrocyte sedimentation rate (how fast RBC settle to measure inflammation)
-rheumatoid factor (arthritis) and uric acid levels (gout)
what are used to diagnose arthritis and osteomyelitis
cultures
how to diagnose bone tumor or confirm infection
biopsy
achondroplasia
dwarfism = mutation in fibroblast growth factor 3 (Fgfr3)
-faulty bone formation in extremities and skull bones
what type of genetic disease is achondroplasia?
autosomal dominant (one copy from one parent)
what are the majority of mutations in achondroplasia?
de novo (in sperm or egg cell)
osteogenesis imperfecta
imperfect creation of bone because of insufficient collagen formation; they become thin and delicate and break easily “brittle bone”
what type of genetic disease is osteogenesis imperfecta?
autosomal dominant
what does osteogenesis imperfecta increase susceptibility for?
bone fractures
how many types of osteogenesis imperfecta are there?
8
symptoms/manifestations of osteogenesis imperfecta
malformation of fingers and toes
spinal curvature
brittle teeth and bones
blue sclera
clubfoot (talipes)
foots grow inward toward one another
what is the most common congenital disorder of the legs
clubfoot talipes
cause of clubfoot
multifactorial inheritance (many genes)
how do you treat clubfoot?
manipulation and casts
fracture definition
any disruption in continuity of bone
what are fractures most often caused by?
trauma or pathologic fracture (underlying disease of bone)
why does breaking a bone hurt?
because you tear the periosteum where pain receptors are
simple fracture
bone broken in only two pieces
comminuted fracture
bone is shattered
compound fracture
fracture that breaks skin - potential for infection
pathologic fracture
fracture through a diseased area of the bone
greenstick fracture
bent bone – adolescence only because bones aren’t fully matured
What two things must happen for a bone to heal properly?
broken fragments have to be close to each other and the fracture must be stabilized (cast or splint)
healing process of a fracture
proliferation of osteoblasts from site of fracture and vascular channels from periosteum; immature bone and cartilage gradually remodel into mature bone
how long does it take for a bone to heal?
6-8 weeks
osteomyelitis
bacterial infection of bone and marrow
etiology of osteomyelitis
organisms gain access to bone via:
-spread of infection from somewhere else in the body
-following trauma or surgery to bone itself
manifestations of osteomyelitis
-fever
-local pain and tenderness
how to diagnose osteomyelitis
X-ray
how to treat osteomyelitis
antibiotics
surgery if needed
complications of osteomyelitis
spread of infection (endocarditis or sepsis)
amputation of limb
osteoporosis
absolute reduction of total bone mass – histology is normal but lacks structural integrity
is osteoporosis age related?
yes; one third of the population over 85 have it
who is more at risk for osteoporosis?
women; especially after menopause due to decreased estrogen levels
symptoms of osteoporosis
none
what can result from osteoporosis
increased mortality
loss of independent living
decreased mobility
causes of osteoporosis
primary: age, declining estrogen
secondary: excess cortisol, increased PTH
at what age does your bone mass peak?
25-30
risk factors of osteoporosis
age
ethnicity (caucasian and asian)
genetics
skeletal frame size (smaller)
decreased estrogen/testosterone
decreased physical activity
excess intake of phosphorus, alcohol, nicotine
inadequate vitamin D, calcium, potassium, magnesium
manifestations of osteoporosis
vertebral fractures
lumbar lordosis and kyphoscoliosis (hunchback)
pulmonary embolism (fractures of the neck, pelvis, spine)
how to diagnose osteoporosis
DEXA (dual-energy x-ray absorptiometry)
can osteoporosis be reversed?
no - once the bone is gone, it’s gone (osteocytes cannot regenerate themselves)
treatment for osteoporosis
medication:
-osteoclast inhibitory
-estrogen mimetic
-synthetic PTH
osteopenia
lower than normal bone mineral density (precursor to osteoporosis)
osteomalacia
softening of bone from poor mineralization
cause of osteomalacia?
vitamin D deficiency
what is osteomalacia called in children?
rickets
complications of osteomalacia
deformity, increased fracture risk
scoliosis
abnormal S-shaped curvature of sping
kyphosis
abnormal forward bending of upper spine (hunchback)
potential causes of spine deformities
arthritis
congenital
osteoporosis
idiopathic
complications of spine deformities
impairment of activity
breathing problems
back pain
hematopoeitic cancer is what percentage of bone cancers?
40% - most common
what are benign cysts and tumors of the bone called?
osteomas
what are primary malignant bone tumors called?
osteosarcomas
what is the most common malignant tumor of the bone in children?
osteosarcoma
symptoms of osteosarcoma
bone pain
progressive enlargement of mass
pathologic fracture
is osteosarcoma more common in males or females?
males
where do osteosarcomas usually occur
the ends of long bones
is metastases common in osteosarcomas
yes
arthritis
degeneration of synovial joints
arthroscopy
tool with a lighted camera to visualize joint space
osteoarthritis
degenerative joint disease – “wear and tear” of joints from old age
what joints does osteoarthritis affect?
weight-bearing big joints, small joints of hands and feet
primary classification of osteoarthritis
unknown or multifactorial
secondary classification of osteoarthritis
related to another disease
etiology of osteoarthritis
cartilage becomes thin and the bone surfaces rub together producing bone cysts
treatment of osteoarthritis
replace the joint
risk factors for osteoarthritis
increased age
joint trauma; long-term stress
endocrine disorders
drugs
obesity
rheumatoid arthritis
systemic autoimmune disease affecting the joints; produces chronic inflammation and thickening synovial membrane
what is often associated with rheumatoid arthritis
rheumatoid factor; an autoantibody in blood and synovial tissues (attacks immune system)
is rheumatoid arthritis age associated?
no
clinical course of rheumatoid arthritis
malaise, fatigue, and generalized joint pain
-joints then become swollen, warm, painful and stiff
treatment for RA
immunosuppressants or NSAIDs
Gout/gouty arthritis
too much uric acid in the blood and other body fluids; crystals made of uric acid deposit in tissues throughout the body
where does gouty arthritis usually occur
big toe (50%), heel, ankle, inside of foot, knee, wrist, elbow
contributing factors of gout
age
male
obesity
high intake of alcohol and red meat
genetic predisposition
