• The skeletal system is vital during life.
• Essential role in mineral homeostasis, houses the
hematopoietic elements, provides mechanical
support for movement, protects viscera, and
determines body size and shape.
• Bones are largely made up of an organic matrix
(osteoid) and the mineral calcium hydroxyapatite,
which gives the bones strength and hardness.
• Stony hard structure, bone is a dynamic tissue that
is continuously resorbed, renewed, and
• Parts of a long bones:
• Diaphysis (shaft), physis (growth plate),
• Epiphysis (ends of bone, partially covered by
• Metaphysis (junction of diaphysis and epiphysis,
most common site of primary bone tumors)
• Cross section: Periosteam, cortex (composed of
cortical bone or compact bone),
• Medullary space (composed of cancellous or spongy
• Bone: mineralized osteoid; either lamellar
bone or woven bone.
• Lamellar bone: layered bone with concentric
parallel lamellae; gradually replaces woven
bone; normal type of bone found in adult
skeleton; stronger than woven bone
• Osteoblasts: arise from marrow
mesenchymal cells; when active, are plump
and present on bone surface; eventually are
encased within the collagen they produce.
• Osteoblasts control osteoclast activity via
• Denotes inflammation of bones and marrow
and the common use of the term virtually
always implies infection.
• May be a complication of any systemic
infection but frequently manifests as a primary
solitary focus of disease.
• All types of organisms ,including viruses,
parasites, fungi and bacteria can produce
osteomyelitis, but infections caused by certain
pyogenic bacteria and mycobacteria are the
• Resected femur in a person with draining
• The drainage tract in the sub periosteal shell
of viable new bone (involucrum) reveals the
inner native necrotic cortex (sequestrum).
is almost always caused by bacteria.
1. Hematogenous spread.
2. Extension from a contiguous site.
3. Direct implantation.
• E.coli, Klebsiella and Pseudomonas are more
frequently isolated from patients with
genitourinary tract infections or with
intravenous drug abusers.
• Mixed bacterial infections can be seen in the
setting of direct spread during surgery or
• Salmonella infections for unknown reasons
common in sickle cell patients.
• In 50% of the cases no organisms can be
Sites of involvement:
• Influenced by the vascular circulation, which
varies with age.
• Neonates: the metaphysical vessels
penetrate the growth plate, resulting in
frequent infection of the metaphysis,
epiphysis or both.
• In children: metaphysical.
• Adults: epiphyses and subchondral regions.
• Sub acute
• Chronic , On clinical duration of disease
SEQUENCE OF INFECTION:
Once localized in bone, the bacteria proliferate
and induce an acute inflammatory reactions and
causes cell death.
• Necrosis of the bone within first 48hrs.
• Spread of bacteria and inflammation within
the shaft of the bone and may percolate
through the haversian systems to reach the
• In children ,the periosteum is loosely
attached to the cortex; therefore sizable sub
periosteal abscess formation occurs.
• Further ischemia and bone necrosis occurs.
• Dead pieces of bone are known as the
• Rupture of the periosteum→soft tissue
abscess formation→draining sinuses.
• In infants epiphyseal infection may spread to
the adjacent joint and causes septic or
suppurative arthritis.; may lead to permanent
• After the first week chronic inflammatory
cells become more numerous with the
release of cytokines and deposition of new
bone formation at the periphery.
• New bone may be deposited as a sleeve of
living tissue known as the Involucrum.
• Brodies abscess:
• Small intraosseus abscess that frequently
involves the cortex and is walled off reactive
• Sclerosing osteomyelitis of Garre typically
• develops in the jaw.
• Clinical Course:
• Fever ,chills, malaise, marked to intense
throbbing pain over the affected region.
• Blood cultures
• Acute bacterial arthritis.
• Pathologic fracture.
• Secondary amyloidosis
• Squamous cell carcinoma.
• Rarely sarcoma in the affected bone
Routes of entry;
• Usually blood borne and originate from a
focus of active visceral disease.
• Direct extension (e.g. from a pulmonary focus
into a rib or from tracheobronchial nodes into
adjacent vertebrae) or spread via draining
• In patients with AIDS frequently multifocal.
• Pott disease is the involvement of
• Thoracic and lumber vertebrae followed by
the knees and hips are the most common
sites of skeletal involvement.
• The infection breaks through the invertebral
discs and extends into the soft tissues
Clinical features and complications:
• Fever , Weight loss
• May form an inguinal mass ‘which represents a
cold fluctuant psoas abscess.
• Bone destruction.
• Tuberculous arthritis.
• Sinus tract formation
• Femoral head with a subchondral, wedge-
shaped pale yellow area of osteonecrosis.
• The space between the overlying articular
cartilage and bone is caused by trabecular
compression fractures without repair.
• Autosomal dominant disorder of synthesis of
type 1 collagen that constitutes to 90-95% of
• Sclera,eyes,joints,ligaments, teeth, skin.
• Too little bone.
• Type-1. 2, 3, 4.
• Skeletal radiogram of a fetus with lethal type
II osteogenesis imperfecta.
• Note the numerous fractures of virtually all
bones, resulting in accordion-like shortening
of the limbs.
• Marble bone disease.
• Autosomal disorder, characterised by
increased skeletal mass or osteosclerosis
caused by hereditary defect in osteoclast
• Failure of normal osteoclast dysfunction of
bone resorption coupled with continued
bone formation and endochondral
ossification results in net overgrowth of
calcified dense bone.
• Too much bone
• Radiogram of the upper extremity in an
individual with osteopetrosis.
• The bones are diffusely sclerotic, and the
distal metaphyses of the ulna and radius are
poorly formed (Erlenmeyer flask deformity).
• Section of proximal tibial diaphysis from a
fetus with osteopetrosis.
• The cortex (1) is present, but the medullary
cavity (2) is filled with primary spongiosa,
which replaces the hematopoietic elements.
Metabolic and Endocrine bone diseases.
• Osteomalacia and rickets
• Hyper parathyroidism
• Thyroid dysfunction
• Renal osteodystropy
• Skeletal fluorosis.
• COMMOM CLINICAL SYNDROME, involving
multiple bones in which quantitative reduction
of bone tissue mass but the bone tissue mass
is otherwise normal.
• Elderly, post menopausal women.
• Backache .
• Radiologicaly 30% of bone mass.
• Osteoporotic vertebral body (right)
shortened by compression fractures
compared with a normal vertebral body.
• Note that the osteoporotic vertebra has a
characteristic loss of horizontal trabeculae
and thickened vertical trabeculae.
• Many diseases and disorders have been
associated with osteoporosis
• In general, immobilization causes bone loss
(following the 'use it or lose it' rule).
• Hypo gonadal states can cause secondary
• These include Turner syndrome, Klinefelter
syndrome, Kallmann syndrome, anorexia
nervosa, hypothalamic amenorrhea
• A bilateral oophorectomy (surgical removal
of the ovaries) or a premature ovarian failure
• Endocrine disorders that can induce bone
loss include Endocrine disorders that can
induce bone loss include Cushing's syndrome,
hypothyroidism, diabetes mellitus type 1 and
Is a term that denotes increased porosity of the
skeleton resulting from reduction in the bone
It may be localized →disuse osteoporosis of a
may involve the entire skeleton, as a
metabolic bone disease.
• The two main biochemical markers for bone
• serum alkaline phosphatase and serum
• Markers for bone resorbtion include urinary
calcium and urinary hydroxyproline
• The best long-term approach to osteoporosis is
• Children and young adults, particularly women,
with a good diet (with enough calcium and
vitamin D) and get plenty of exercise, will
build up and maintain bone mass.
• This will provide a good reserve against bone loss
later in life. Exercise places stress on bones that
builds up bone mass
Osteitis fibrosa cystica
• Skeletal manifestation of
• Hyper calcaemia.
• Brown tumour or reparative gaint cell
granuloma of hyperparathyroidism.
• Demineralization, bone resorption.
• Hyperparathyroidism with osteoclasts boring
into the center of the trabeculum (dissecting
• High sodium fluoride content in soil and
• Endemic fluorosis: Panjab , Andhra Pradesh.
• Nonendemic fluorosis:
JAMES PAGET IN 1877
• Pagets diseases of bone or osteitis
• Osteolytic and osteosclerotic disease of bone
of uncertain aetiology involving one bone or
• Age 50 yrs.
• Fibrous dysplasia is a common benign fibro-osseous lesion,
• occurs sporadically during the period of skeletal growth (ages 10
• It is a hamartoma and is characterized by the intramedullary
• There are two forms of the disease: monostotic (80% of cases)
• Polyostotic involvement may be a part of
• McCune-Albright syndrome (fibrous dysplasia, patchy cutaneous
• pigmentation, and precocious puberty), or Mazabraud's
• (fibrous dysplastic lesions in close proximity to soft tissue
• Most common locations include the long
bones (femur, tibia andhumerus), the ribs,
cranio-facial bones and pelvis.
• In the long bones, the lesion is found in the
metaphysis or diaphysis.
• The hallmark of fibrous dysplasia is inability
of tissue at the affected site to produce
mature lamellar bone
• Typical Clinical Picture:
• A 22-year-old female was seen in consultation
for a lesion in the proximal femur.
• She complained of chronic mild to moderate
pain in her right hip and was walking with a
• Physical examination revealed hip deformity
and minimal limb length discrepancy.
• There were no other abnormal findings.
• A very characteristic feature is "ground glass"
• Remember that when this disorder involves
the long bone, it commonly produces what is
called "long lesion in the long bone"
• Three key features:
• lucency, sclerotic rim and cortical expansion.
• Three characteristic histologic features of this
• a) thin, wavy spicules of woven bone
• b) lack of osteoblastic rimming or osteoclastic
• c) moderately cellular bland fibrous
• In children, stromal mitoses may be frequent,
1 to 5 per hpf
• Non-Ossifying Fibroma (NOF)
• (Fibrous cortical defect, or Metaphysical
• NOF is a common, non-neoplastic, self-healing lesion
occurring in skeletally immature individuals, usually
between the ages of 5 and 20 years.
• Small lesions are usually incidental radiological
• The larger lesions occupying more than a half of the
bone diameter may present with a pathologic
• l Location.
• In most cases, NOF presents as a solitary lesion in the
metaphysis or meta-diaphysis of the long bone at the
knee (distal femur, proximal tibia or fibula), distal tibia
and proximal humerus.
• Typical Clinical Presentation:
• An incidental finding of a bone lesion in the
distal tibial meta-diaphysis of an 13-year-old
• The lesion was totally asymptomatic.
• l As always, pay attention to the patient's age.
The fact that the lesion did not produce
symptoms and was found incidentally suggests
• Plain radiograph shows
a sharply demarcated,
lucent, loculated, metadiaphyseal
lesion surrounded by a rim of
Note the eccentric location along the long axis
of the bone.
Plain radiograph demonstrates a well-
defined ,symmetric ,expansile,
intramedullary lytic lesion of the proximal
• Solitary bone cyst is relatively common, non-
neoplastic lesion, typically occurs in the skeletally
immature patients, in the first and second
decades of life (80% of cases).
• It is usually a unicameral cyst, which does not
have an epithelial lining (hence not a true cyst)
and is filled with serous fluid.
About 80% of cases are diagnosed in two locations:
humerus and proximal femur.
In the long bone, SBC characteristically involves
the metaphysis and diaphysis.
• Other possible skeletal sites are the ilium, talus,
and calcaneus. 10020-08-2014
Aneurysmal Bone Cyst (ABC)
• Aneurysmal Bone Cyst (ABC) is a rapidly growing, locally
aggressive, intramedullary, vascular lesion, which
characteristically produces blowout expansion of the
affected portion of the bone.
ABC can be primary (de novo) or secondary.
• Secondary ABC may develop in a pre-existing benign
• as chondroblastoma, chondromyxoid fibroma, giant cell
tumour, and fibrous dysplasia, or be superimposed on a
malignant tumor (osteosarcoma).
• Although ABC can occur at any age, the majority of
patients are younger than 25. 10220-08-2014
• Typical Clinical Presentation:
• A 17-year-old male presented with a slowly
enlarging, painful lesion of the right