Bone Disorders and
Abnormalities
Miss Peale
Human A&P – November 13, 2007
Rickets
Definition: disorder primarily caused by lack of
vitamin D, calcium, or phosphate, which leads to
softening and weakening of the bones
Causes:
•Mostly dietary: lactose
intolerance, vegetarian diets
•Hereditary effects
•Sunlight
Treatments:
•Address underlying cause
(liver, kidney, absorption
problems)
•Supplements of Vitamin D,
phosphate and calcium
•Exposure to sunlight
Abnormal Spinal Curvatures
Kyphosis: Exaggerated thoracic curvature
• Also referred to as roundback or hunchback
• Causes: posture, congenital, osteoporosis
Lordosis: Exaggerated lumbar curvature
•Also referred to as swayback
•Causes: Obesity, osteoporosis, kyphosis
Scoliosis: Lateral curvature of the spine
•Affects 2% of population
•Causes are unknown
•Develops in childhood, can worsen with age
Abnormal Spinal Curvatures (Cont)
Treatments (Depends on cause!):
Kyphosis:
• Exercise
• Anti-inflammatory injections
• Back brace worn through skeletal maturity
• Surgery to reduce curvature when over 75 degrees
Lordosis:
• Observation
• Exercise
• Back brace worn through skeletal maturity
Scoliosis:
• Observation
• Back brace to prevent progression
• Surgery in severe cases
Name the curvature
Osteoporosis
Definition: Osteoporosis, or porous bone, is a disease characterized by
low bone mass and structural deterioration of bone tissue, leading to
bone fragility and an increased susceptibility to fractures, especially
of the hip, spine and wrist, although any bone can be affected.
• Affects 44million Americans = 55% of 50+ year olds
• 80% affected are women; 20% are men
• Responsible for 1.5 million fractures
Causes/Risk Factors:
•Low bone mass
•Being thin/underweight/having small frame; anorexia
•Estrogen deficiency (result of menopause or absence of periods) or low
levels of testosterone (men)
•Low LIFETIME calcium intake
•Vitamin D deficiency
•Unhealthy lifestyles: smoking, excessive drinking, little or no exercise
Osteoporosis (cont)
Symptoms/Detection:
• Bone mineral density (BMD) test – measures fracture
risk and rate of bone loss
• Bone fractures (esp. hip, spine, and wrist)
Treatments/Prevention:
•Prevention is key!!!
•98% skeletal mass developed by age 20 in young women
•Diet w/ Vitamin D and calcium, weight and resistance training, no
smoking and limited alcohol intake
•Antiresorptive medications: prevents resorption of Vitamin D, calcium
and phosphate back into body
•Hormone therapy/Estrogen replacement
Bone Fractures
Definition: Damage to bone resulting from
extreme loads, sudden impact, or stress from
unusual directions
Types of Fractures:
•Closed = simple fracture: completely internal and
does not break the skin
•Open = compound fracture: fracture projects
through skin; higher risk of infection and/or
uncontrolled bleeding
Fracture Classification
Pott’s Fracture: fracture at
ankle that affects both tibia
and fibula
Comminuted fractures:
shatter affected area into
bony fragments
Transverse fracture: break
on shaft of a bone across
its long axis
Fracture Classification (cont)
Displaced fracture: produce
new and abnormal bone
arrangements
Spiral fracture:
produced by twisting
stress along length
of the bone
Greenstick fracture: one
side of shaft is broken
while other side is bent;
occur in children whose
bones have not ossified
yet
Fracture Classification (cont)
Epiphyseal fracture: occur at
growthplate where bone is
undergoing ossification
Compression
fracture: extreme
stress (landing on
rear end after falling)
Colle’s fracture: distal
radius, usual the result of
catching oneself from a fall
Fracture Classification (cont)
Stress fracture: result of
continual stress and or
pressure (ex: runners)
Dislocation: displacement
of bones at an articulation
Fracture Repair
Step 1:
• Blood vessels are broken and extensive
bleeding occurs
• Fracture hematoma (large blood clot)
seals off vessels
• Lack of blood flow results in death of
osteocytes = death of bone surrounding
fracture and along shaft in either direction
Step 2:
•Cell of intact endosteum and periosteum undergo rapid
mitosis & daughter cells migrate to fracture zone
•External callus (enlarged collar of cartilage and bone) forms
around the bone and the fracture site
•Internal callus forms with bone marrow cavity and between
broken ends of the shaft
•Cells at external callus differentiate into chondrocytes and
form block of cartilage
•Cells at both calluses differentiate into osteoblasts that
create a bridge between bone fragments
Fracture Repair (cont)
Step 3:
• Osteoblasts replace central cartilage of external
callus with spongy bone
• Struts of spongy bone unite broken ends
• If fragments are present, body begins resorption
Step 4:
•Osteoclasts and osteoblasts continue to
remodel region of fraction for 4 months-1+years
•Bony calluses are remodeled & no longer exist
•Only living compact bone remains (osteocytes)
Sources
Rickets:
http://www.nlm.nih.gov/medlineplus/ency/article/000344.htm
Abnormal spinal curvatures:
http://orthoinfo.aaos.org/topic.cfm?topic=A00423
Osteoporosis:
http://www.nof.org/osteoporosis/diseasefacts.htm
Bone fractures:
http://www.Medscape.com