2. • The skeletal system provides
structural support and protection to
the human body and its internal
organs, serves as primary home for
blood-forming tissues, and stores
several vital minerals, above all,
calcium.
3. Radiographic examination (X-Ray) is the key to the diagnosis of many
skeletal abnormalities. It is essential that each bone be examined in its
entirety, including the cortex, medullary canal (cancellous bone or
spongiosa), and articular ends. The position and alignment of joints are
determined. In children, the epiphysis and epiphyseal line or physis must be
observed. The adjacent soft tissues are examined. Obliteration of normal
soft-tissue lines and the presence of a joint effusion are of particular
importance. When disease is present, it is important to determine whether
the process is limited to a single bone or joint or whether multiple bones or
joints are involved. The distribution of disease is also a consideration. The
presence and type of bone destruction and bone production, the appearance
of the edges or borders of the lesion, and the presence or absence of cortical
expansion and periosteal reaction are also noted. The radiographic findings
are then correlated with the clinical history and the age and sex of the
patient to arrive at a logical diagnosis. The diagnosis may be firm in some
instances; in other cases, a differential diagnosis is offered since the exact
diagnosis ;cannot be determined.
METODS OF EXAMINATION
4. METODS OF EXAMINATION
• COMPUTED TOMOGRAPHY (PLAIN FILM RADIOGRAPHY,
FLUOROSKOPY): Computed tomography (CT) is advantageous in the
evaluation of the skeletal system. It allows visualization of adjacent soft-tissue
structures and also the marrow in the medullary cavity. The position of
surrounding vascular structures can be determined by the use of contrast
media. CT has the added advantage of being more sensitive to the detection of
bone destruction than plain film radiography or standard tomography. CT
images are displayed in the axial or horizontal plane, and even sagittal and
coronal planes, with image reconstruction. Unfortunately, image reconstruction
degrades the image. Images are displayed with both bone and soft-tissue
windows. The soft-tissue window setting allows visualization of surrounding
soft tissue but is suboptimal for the bony skeleton. The bone window setting
maximizes the visualization of cortical and medullary bone .
5. METODS OF EXAMINATION
• MAGNETIC RESONANCE IMAGING: Magnetic resonance (MR)
imaging is of great value in the evaluation of the skeletal system, particularly
in the detection and evaluation of tumors, infection, bone infarction, and
ischemic necrosis. Because the image is dependent on the presence of
hydrogen, which is abundant in marrow fat, MR imaging visualizes the bone
marrow exquisitely. However, the hydrogen content of cortical bone is very
low, and MR imaging therefore is not as sensitive as CT for the evaluation of
cortical bone. MR imaging has the added advantage of displaying the
anatomy in any plane, including the coronal and sagittal planes, which are
distinctly advantageous in the demonstration or visualization of
abnormalities within bone and their relationship to surrounding soft tissue.
Discrimination between and differentiation of various soft tissues and
pathologic processes may be enhanced by varying the technical parameters
used for the examination. Full the armore, vascular structures are
demonstrated and are clearly visualized without the necessity of contrast
media injection.
6. METODS OF EXAMINATION
• SKELETAL SCINTIGRAPHY:Skeletal scintigraphy or bone scanning is a
valuable adjunct to standard film radiography. Bone-seeking radionuclides
are taken up in areas of increased bone turnover. This occurs normally at the
growth plate in children and at abnormal sites in tumors, infections, and
fractures; in sites of reactive bone formation in arthritis; and in periostitis
regardless of the etiology. Technetium-99m-labeled polyphosphates are the
most common radiopharmaceuticals used, particularly technetium-99m
methyldiphosphonate ("mTc-MDP). Fifteen to 20 millicuries (mCi) is
injected intravenously, and a scan is obtained two hours later. The radiation-
absorbed dose is very low, since the total body dose is 0.009 rad/mCi. The
agent is excreted in the kidneys and collects in the bladder. The target
organ—that is, the organ receiving the highest dose— is the wall of the
bladder, exposed to approximately 0.275 rad/mCi. Bone scanning is more
sensitive to areas of bone turnover and destruction than plain film
radiography or tomography. The bone scan may be positive in the presence
of a normal radiograph, well before the radiograph becomes abnormal.
However, the bone scan is less specific than the radiograph. Areas of
increased activity are detected, but the cause of the increase often cannot be
stated with certainty, and correlation with plain film radiographs or
computed tomography and magnetic resonance imaging is necessary to
establish a correct diagnosis.
7. SKELETAL GROWTH AND MATURATION
• OSSIFICATION OF THE SKELETON
• The process of bone formation in cartilage is known as endochondral
ossification, which causes bones to grow in length. Some bones are formed in
membrane, known as membranous bone formation. The bones of the cranial
vault are the principal example. Ossification occurs in both cartilage and
membrane in the mandible and clavicle. The tubular bones grow in their
transverse diameters by bone formation within the osteogenic cells of the
inner layer of the periosteum. This could be considered a form of
membranous bone formation.
• At birth, the shafts of the long tubular bones are ossified, but both ends
(epiphyses), with a few exceptions, consist of masses of cartilage. Cartilage is
relatively radiolucent as compared with bone, having the same density as soft
tissue on a conventional radiograph. Thus, at birth the ends of the bones are
separated by radiolucent spaces representing the cartilaginous epiphyses. At
variable times after birth, one or more ossification centers appear in the
epiphyses (the epiphyseal ossification centers). Exceptions occur at the distal
femur and proximal tibia epiphyses, where ossification centers appear during
the last 1 or 2 months of intrauterine life. The short tubular bones are similar
to the long bones except that they have an epiphysis at only one end.
8. SKELETAL GROWTH AND MATURATION
• The distal femur and proximal tibia epiphyseal ossification centers can be
used as indicators of fetal maturity. Formerly, radiographs of the mother's
abdomen were obtained to visualize these centers as evidence of fetal maturity
during the last month of gestation prior to induced labor or cesarean section.
Fetal maturity is now determined by ultrasonographic examination, which is
highly advantageous. Because it does not use ionizing radiation, it can be
employed throughout pregnancy and is safe, accurate, and free of side effects.
The times of appearance of the various epiphyseal ossification centers are
good indicators of skeletal age during infancy and early childhood.
• The flared end of bone is known as the metaphysis, and the tubular
midportion of the shaft the diaphysis. Between the metaphysis and epiphysis
lies the physis or cartilaginous growth plate consisting of four distinct zones—
the resting zone, the proliferating zone, the hypertrophic zone, and the zone of
provisional calcification. In the zone of provisional calcification, mineral salts
are temporarily deposited around the degenerating cartilage cells. Blood
vessels subsequently grow into the lacunae left by the degenerated cartilage
cells, bringing with them osteoblasts, specialized connective tissue cells whose
main function is the production of osteoid. Osteoid is the organic matrix in
which mineral salts are deposited to make bone. Osteoid is relatively
radiolucent and, when present in large amounts, will cause bone to appear
more radiolucent than normal. As osteoid is formed, the zone of provisional
calcification is replaced by trabecular bone.
• It is rather common to see one or more thin opaque lines crossing the shaft
near its ends. These are commonly known as "growth lines" and, while there
may be other causes for them, it is probable that in most cases they indicate a
temporary cessation of orderly ossification brought about by one or more
episodes of systemic illness.
9. SKELETAL GROWTH AND MATURATION
• Epiphysis: The cartilaginous end of a bone.
• Physis: The cartilaginous zone between the epiphysis and
the calcified cartilage, also known as the growth plate or
the epiphyseal plate. When it becomes thin, in late
adolescence, it is sometimes called the epiphyseal line.
• Metaphysis: The flared end of the shaft of a tubular
bone.
• Diaphysis: The tubular shaft of a long bone.
• Epiphyseal ossification center: The ossified portion of an
epiphysis.
• Zone of provisional calcification: The zone of deposition
of mineral salts at the end of the shaft that serves as a
framework for the deposition of osteoid. It is seen in
roentgenograms as a thin white line or narrow zone.
• Osteoid: The organic matrix that is formed by the
osteoblasts and that, when mineralized, becomes bone.
• Endochondral ossification: The process by which bone is
formed from cartilage.
• Intramembranous ossification: The process by which
bone is formed from membrane without a cartilaginous
stage; periosteal and endosteal growth are included.
• Apophysis: An accessory ossification center that forms a
protrusion from the end or near the end of the shaft of a
long bone. Apophyses function as growth centers at
nonarticular margins of bone, i.e., the greater trochanter
of the femur or ischial tuberosity of the pelvis. They
serve as attachments for muscles or ligaments and do not
contribute to the length of a long bone.
10. • Normal long bones in (a) child and
(b) adult. Increase in length takes
place at the cartilagenous
epiphyseal plate. In the growing
child, calcification of cartilage
occurs at the interface between the
radiolucent growing cartilage and
the bone to give the zone of
provisional calcification, which is
seen as a dense white line forming
the ends of the shaft and
surrounding the bony epiphyses.
This calcified cartilage becomes
converted to bone. (If there is
temporary cessation of growth
then the zone of provisional
calcification may persist as a thin
white line, known as a 'growth
line', extending across the shaft of
the bone.) As the child grows older
the epiphyseal plate becomes
thinner until, eventually, there is
bony fusion of the epiphysis with
the shaft. a b
11. • The radiological responses of bone to
pathological process are limited; thus similar x-
ray signs occur in widely different conditions. It
should be noted that it takes time for the various
signs to develop; for example, in adults, it takes
several weeks for a periosteal reaction to be
visible after trauma and, in a child with
osteomyelitis, the clinical features are present
from seven to ten days before the first sign is
visible on the radiograph. In general, the signs
take longer to develop in adults than they do in
children. The signs of bone disease are :
12. - Decrease in bone density which may be focal or generalized.
Focal reduction in density is usually referred to as a lytic
area' or an area of 'bone destruction'. When generalized,
decrease in bone density is best referred to as 'osteopenia'
until a specific diagnosis such as osteomalacia or
osteoporosis can be made.
- Increase in bone density (sclerosis) which may also be focal
or generalized.
- Periosteal reaction. The periosteum is not normally visible
on a radiograph. The term 'periosteal reaction' refers to
excess bone produced by the periosteum, which occurs in
response to such conditions as neoplasm, inflammation or
trauma. Several patterns of periosteal reaction do not
correlate with specific diagnoses. At the edge of a very
active periosteal reaction there may be acuff of new bone
known as a Codman's triangle. Although often seen in
highly malignant primary bone tumours, e.g. osteosarcoma,
a Codman's triangle is also found in other aggressive
conditions.
13. Different types of periosteal
reactions, (a) Smooth
lamellar periosteal reaction
on the radius and ulna in a
case of non-accidental
injury, (b) Spiculated
(sunray) periosteal reaction
in a case of osteogenic
sarcoma (arrows), (c) Onion
skin periosteal reaction in a
case of Ewing's sarcoma
(arrows). Here the periosteal
new bone consists of several
distinct layers, (d) Codman's
triangle in a case of
osteogenic sarcoma. At the
edge of the lesion the
periosteal new bone is lifted
up to form a cuff (arrow).
a
b
c d
14. • Cortical thickening also involves the laying down of new
bone by the periosteum , but here the process is very
slow. The result is that the new bone, although it may
be thick and irregular, shows the same homogeneous
density as does the normal cortex. There are no
separate lines or spicules of calcification as seen in a
periosteal reaction. The causes are many, including
chronic osteomyelitis, healed trauma, response to
chronic stress or benign neoplasm. The feature common
to all these conditions is that the process is either very
slowly progressive or has healed.
15. • Cortical thickening.
Note the thickened
cortex in the midshaft
of the tibia from old,
healed osteomyelitis.
16. • Alteration in trabecular pattern is a complex response
usually involving a reduction in the number of
trabeculae with an alteration in the remaining
trabeculae, e.g. in osteoporosis and Paget's disease. In
osteoporosis the cortex is thin and the trabeculae that
remain are more prominent than usual, whereas in
Paget's disease the trabeculae are thickened and
trabeculation is seen in the normal compact bone of the
cortex.
• Alteration in the shape of a bone is another complex
response with many causes. Many cases are congenital
in origin; some are acquired, e.g. acromegaly and
expanding bone tumours.
• Alteration in bone age. The time of appearance of the
various epiphyseal centres and their time of fusion
depend on the age of the child.
17. Bone Trauma.
Imaging techniques.
Plain bone radiographs
Plain radiography in bone trauma is invaluable in
order to:
• diagnose the presence of a fracture or
dislocation;
• determine whether the underlying bone is
normal or whether the fracture has occurred
through abnormal bone (pathological fracture);
• show the position of bone ends before and after
treatment of a fracture;
• assess healing and complications of fractures.
18. Fracture Terminology
Frequently, a fracture is very obvious but in some cases the
changes are more subtle. Fractures may be recognized or
suspected by the following signs:
• Fracture line. The fracture usually appears as a lucent line. This
may be very thin and easily overlooked. Occasionally, the fracture
appears as a dense line from overlap of the fragments.
• A step in the cortex may be the only evidence of a fracture.
• Interruption of bony trabeculae is of use in impacted fractures
where there is no visible lucent line. This is, however,
a difficult sign to evaluate.
• Bulging or buckling of the cortex is a particularly important
sign in children, where fractures are frequently of the green-stick
type.
• Soft tissue swelling may be a valuable guide to the presence of an
underlying fracture.
• A joint effusion may become visible following trauma. In
the elbow, where an effusion often indicates a fracture, fat pads
lie adjacent to the joint capsule and, if there is an effusion, they
will be displaced away from the shaft of the humerus on the
lateral view.
19. • Fracture of forearm showing the value of
two views. (a) The fractures of the radius
and ulna show little displacement on the
frontal projection, (b) The lateral view,
however, shows a marked angulation.
Fracture of the ulna appearing as
a sclerotic line (arrow).
20. Dislocation
• The joint surfaces no longer maintain their normal relationship to each
other. An associated fracture should be carefully looked for.
Colles' fracture showing the bony
trabeculae are interrupted across the
fracture site (arrow). There is also a
step in the cortex.
Fracture of neck of humerus
appearing as a step in the cortex
(arrow).
21. Greenstick fracture of lower end of radius in a
child. There is buckling of the cortex (arrows).
22.
23. SPECIFIC INJURIES
Stress fracture
• Stress fractures are due to repeated, often minor,
trauma. They occur in athletes, particularly in the
tibia and fibula. Another example is the so-called
march fracture occurring in the shafts of the
metatarsals. Initially, despite the presence of pain,
a radiograph will show no evidence of a fracture
but if a further film is taken after 10-14 days a
periosteal reaction may draw attention to the
fracture site, where a thin crack may be visible. A
stress fracture may appear as a sclerotic band
across the bone and a fracture line may not
necessarily be visible. Radionuclide bone
scanning can be helpful in distinguishing stress
fractures from other causes of pain, because a
stress fracture will appear as an area of increased
uptake before any changes are visible on the
radiographs.
Insufficiency fracture
• An insufficiency fracture results from normal
activity or minimal trauma in weakened bone
commonly from osteoporosis or osteomalacia.
Compression fractures of the vertebral bodies are
the commonest insufficiency fractures but they
also characteristically occur in the sacrum, pubic
rami and femoral necks though other bones may
be involved.
Stress fracture.
This film was taken
two weeks after the
onset of pain. It
shows a periosteal
reaction (arrow)
around the
metatarsal shaft
although a fracture
cannot be seen.
Stress fracture, (a) Fracture appearing
as a sclerotic band (vertical arrows)
across the tibia accompanied by a
periosteal reaction (horizontal arrow),
(b) In this calcaneum there is a
sclerosis adjacent to the fracture
(arrow).
a b
Stress fracture. Radionuclide
bone scan showing increased
uptake in the tibia (arrow) of
this athlete with pain in the leg.
The radiographs at the time of
the scan were normal.
24. BONE DISEASE
When considering the diagnosis and differential
diagnosis of bone diseases, it is convenient to
divide disorders into those that:
• cause solitary lytic or sclerotic lesions;
• produce multiple focal lesions, i.e. several
discrete lytic or sclerotic lesions in one or more
bones;
• cause generalized lesions where all the bones
show diffuse increase or decrease in bone
density;
• alter the trabecular pattern;
• change the shape of the bone.
25. BONE DISEASE
Solitary areas of lysis, sclerosis or a combination of the two, are usually one of the
following:
• bone tumors
a) malignant (primary or secondary)
b) benign
• osteomyelitis
• bone cysts, fibrous dysplasia or other non-neoplastic defects of bone
• conditions of uncertain nature such as Langerhans histiocytosis and osteoid osteoma.
`Primary malignant bone tumors and osteomyelitis are usually accompanied by periosteal
reaction. Pathological fractures may be seen through benign and malignant bone
tumors and through bone cysts.
The radiological diagnosis of a localized bone lesion can be a problem. Some conditions are
readily diagnosed but, in others, even establishing which broad category of disease is
present can be difficult. The initial radiological decision is usually to try and decide
whether the lesion is benign, i.e. stable or very slow growing, or whether it is
aggressive, i.e. a malignant tumor or an infection. It is also important to know the age
of the patient, since certain lesions tend to occur in a specific age range.
The precise diagnosis of a bone tumor can be notoriously difficult both for the radiologist
and the pathologist. Accurate histological diagnosis is essential for all malignant lesions
and it is important to realize that separate portions of a tumor may show different
histological appearances. In general, plain film radiography is the best imaging
technique for making a diagnosis, whereas CT and/or MRI often show the full extent of
a tumours to advantage. The main role for radionuclide bone scanning is to diagnose
metastatic bone disease. Metastatic malignant tumors are by far the commonest bone
neoplasm, outnumbering many times primary malignant tumors.
26. Joints
• The plain film examination remains important for
imaging joint disease, but MRI is being used with
increasing frequency to show meniscal and
ligamentous tears in the knee, rotator cuff tears
of the shoulder and avascular necrosis of the
hip. Arthrography involves injecting contrast
medium into the joint space directly and taking
plain films or CT scans. The main use of
arthrography is to demonstrate meniscal tears of
the knee and occasionally rotator cuff tears of
the shoulder, but it has been largely replaced by
MRI.
27. Plain film signs of joint disease
• Synovial joints have articular surfaces covered
by hyaline cartilage. Both articular and
intraarticular cartilage (such as the menisci in
the knee) are of the same radiodensity on plain
films as the soft tissues and therefore are not
visualized as such; only the space between the
adjacent articular cortices can be appreciated .
The synovium, synovial fluid and capsule also
have the same radiodensity as the surrounding
soft tissues and, unless outlined by a plane of
fat, cannot be identified as discrete structures.
The articular cortex forms a thin, well-defined
line which merges smoothly with the remainder
of the cortex of the bone.
28. Signs indicating the presence of
an arthritis.
Joint space narrowing is due to destruction of articular cartilage. It occurs in
practically all forms of joint disease, except avascular necrosis.
Swelling of the soft tissues around a joint may be seen in any arthritis
accompanied by a joint effusion and whenever periarticular inflammation is
present. It is, therefore, a feature of inflammatory, and particularly infective,
arthritis. Discrete soft tissue swelling around the joints can be seen in gout
due to gouty tophi.
Osteoporosis of the bones adjacent to joints occurs in many painful conditions.
Underuse of the bones seems to be an important mechanism, but is not the
only factor. Osteoporosis is particularly severe in rheumatoid and
tuberculous arthritis.
-Response to the deposition of urate crystals in gout.
-Destruction caused by infection:
-pyogenic arthritis.
-tuberculosis.
-Synovial overgrowth caused by repeated haemorrhage in haemophilia and
related bleeding disorders.
-Neoplastic overgrowth of synovium, e.g. Synovial sarcoma.
29. Signs that point to the cause of
an arthritis
• Articular erosions
• Osteophytes, subchondral
sclerosis and cysts
• Alteration in the shape of the joint
30. Advanced rheumatoid arthritis
(arthritis mutilans). There is
extensive destruction of the
articular cortex of the
metacarpophalangeal joints with
ulnar deviation of the fingers.
Fusion of the carpal bones and
wrist joint has occurred.
Early rheumatoid arthritis. Small erosions
are present in the articular cortex (arrows)
and there is soft tissue swelling around the
proximal interphalangeal joints.
31. Osteoarthritis is the commonest form of arthritis. It is
due to degenerative changes resulting from wear and
tear of the articular cartilage. The hip and the knee are
frequently involved but, despite being a weight-bearing
joint, the ankle is infrequently affected. The wrist, joints
of the hand and the metatarsophalangeal joint of the big
toe are also frequently involved.
32. In osteoarthritis can usually be seen:
Joint space narrowing. The loss of joint space is maximal in the
weight-bearing portion of the joint; for example, in the hip it is
often maximal in the superior part of the joint, whereas in the
knee it is the medial compartment that usually narrows the most.
Even when the joint space is very narrow it is usually possible to
trace out the articular cortex.
Osteophytes are bony spurs, often quite large, which occur
at the articular margins.
Subchondral sclerosis usually occurs on both sides of the joint; it is
often worse on one side. Subchondral cysts may be seen beneath
the articular cortex often in association with subchondral
sclerosis. Normally, the cysts are easily distinguished from an
erosion as they are beneath the intact cortex and have a sclerotic
rim but occasionally, if there is crumbling of the joint surfaces,
the differentiation becomes difficult.
Loose bodies are discrete pieces of calcified cartilage or bone lying
free within the joint, most frequently seen in the knee. It is
important not to call the fabella, a sesamoid bone in the
gastrocnemius, a loose body in the knee joint.
Osteoarthritis and rheumatoid arthritis are the two types of
arthritis most commonly encountered.
33. METABOLIC BONE DISEASES
• Metabolic bone diseases include diseases of increased bone resorption,
such as osteoporosis, and of calcium metabolism, such as rickets,
osteomalacia, hyperparathyroidism, and renal osteodystrophy. Primary
osteoporosis is an age-related disorder preferentially affecting women
that ultimately may cause a loss oi 35% to 50% of cortical or trabecular
bone mass. It is related to hormonal influences (e.g., estrogen deficiency),
reduced physical activity, and nutritional and genetic factors. Secondary
osteoporosis follows a large variety of diseases, including malabsorption
or malnutrition, endocrine disorders (e.g., hyperparathyroidism or
hypoparathyroidism, hypogonadism, and type 1 diabetes) and neoplastic
diseases, such as multiple myeloma and bony metastases. Disorders in
calcium homeostasis cause reduced matrix mineralization with
osteopenia. Primary and secondary hyperparathyroidism (with the latter
related to renal insufficiency) are characterized by increased osteoclastic
bone resorption with features of dissecting osteitis and osteitis fibrosa
cystica (von Recklinghausen disease of the bone)
34. Rickets and Osteomalacia
• In rickets and osteomalacia, mineralization of osteoid is reduced while
bone mass remains normal. Rickets affects the growing bones of
children, and osteomalacia affects the newly formed bone matrix in
adults. Responsible metabolic disturbances are vitamin D deficiency,
phosphate deficiency, and mineralization defects. Growing bone is
severely changed in children with rickets because inadequate
mineralization of osteoid matrix leads to overgrowth and distortion of
epiphyseal cartilage projecting into the
medullary space, disruption of osteoid/cartilage replacement, and
reactive proliferation of capillaries and fibroblasts. Loss of structural
stability causes skeletal bone deformations (thoracic kyphosis, lumbar
lordosis, coxa vara, genu varum). Osteocartilaginous thickening of
ribs produces characteristic rachitic rosary. Adults with osteomalacia
experience only mild bowing of long bones; however, stress resistance
of bones is reduced, and gross or microscopic fractures
35. Renal Osteodystrophy
• Renal osteodystrophy, which is most common in
patients undergoing long-term dialysis tor chronic
renal failure, combines the changes of osteomalacia
with focal soft tissue, bone resorption, and vascular
calcifications are observed (metastatic calcification)
tumorlike calcium deposits in some cases. While
osteomalacic changes suggest renal tubular damage,
additional focal osteoclastic bone resorption is caused
by secondary hyperparathyroidism. Therapeutic
planning must focus on treating the chronic renal
disease, replacing 1,25(OH),-D, substituting for
hypophosphatemia, and partially resecting
hyperplastic parathyroid glands.
36. Primary Hyperparathyroidism
• Primary hyperparathyroidism causes generalized bone resorption
by focal osteoclastic activities (as described in osteitis fibrosa
cystica) combined with an increased incidence of stone formation
(e.g., nephrolithiasis). Osteoclastic hyperactivity starts at
subperiosteal and endosteal surfaces, cutting into the bone and
replacing respective splits and holes by connective tissue (dissecting
osteitis). Areas of hemorrhage and microfracture may occur. Larger
cystic spaces occur eventually, hemorrhage expands, and resorptive
giant cell granulomas develop ("brown tumors" in osteitis fibrosa
cystica). These must be distinguished from aneurysmal bone cysts
(ABCs), giant cell tumor (GCT) of bone, and telangiectatic OS.
Characteristic radiographic changes in hyperparathyroidism are found
preferentially in the hands (radial phalanges of the second and third
fingers), with signs of focal calcinosis in the spine and the cartilage of
major joints
37. Infectious Arthritis
• Infectious arthritis is an acute or chronic inflammation of a
joint or joints, usually caused directly or indirectly by specific
infectious organisms. Infectious arthritis is caused directly by
seeding of such pyogenic organisms as gonococci,
staphylococci, meningococci, and pneumococci. Infection
results in a characteristic edematous and neutrophilic
infiltration of the synovialis with hemorrhage or necrosis
(according to endotoxin or exotoxin activities) and with
subsequent lymphoplasmacytic infiltration, capillary
proliferation, and fibrosis, depending on the duration of the
process. Destruction of ( artilage and fibrous adhesions may
cause final joint dysfunction and ankylosis.
38. Tuberculous Arthritis
• Tuberculous arthritis is characterized by granulomatous reaction and
runs a primary chronic course. It is the consequence of hematogenous
spread of organisms, usually during early or later phases of stage II
tuberculosis (early or late postprimary tuberculosis). Infection usually
affects only one joint, most frequently the spine, the hip, the knee, the
elbow, or the ankle. The onset of symptoms is insidious; frequent local
muscle spasms at night may be the first suspicious sign of the disease.
Walking may be problematic if the spine is involved (Pott disease).
Radiographic changes and strong positive tuberculin skin test results
are helpful in establishing the diagnosis. Diagnostic proof is given by
tissue biopsy and the demonstration of acid-fast bacilli in the
granulomatous inflammation as well as by culture or polymerase
chain amplification reaction (PCR) techniques
39. Rheumatoid Arthritis
• Rheumatoid arthritis (RA) is a systemic chronic progressive
inflammatory disease with symmetric involvement of small
joints. Variants are Still disease in children (juvenile arthritis)
and ankylosing spondylitis (Bechterew disease) preferentially
involving the vertebral column and the sacroiliacal joints. RA
is representative of a group of autoimmune disorders referred
to as collagen-vascular diseases, which include lupus
erythematosus, primary systemic sclerosis, polymyositis, and
dermatomyositis. The etiology of RA is unknown; however, its
pathogenesis includes genetic factors (prevalence of HLA-
DR4 and HLA-DR1 genes and others), autoimmune reactions
(possibly postinfectious), and local factors such as mechanical
stress and specifics of tissue reactivity.
40. Rheumatoid Arthritis: Clinical
Manifestations
• Microscopic features of rheumatoid arthritis (RA) are
progressive villous hypertrophy of the synovialis secondary to
fibrinous swelling, proliferation of synovial lining cells, and
lymphoplasmacytic infiltration. With increasing chronicity,
acute inflammatory reactions are replaced by granulation
tissue and fibrosis covering and eroding the cartilaginous
surface of the joints (pannus formation). Joint mobility is
severely inhibited with grossly impressive deviations
(subluxation) of joints. End-stage disease is characterized by
complete fibrous obliteration of the joints. Adjacent soft
tissues may contain focal granulomas with binucleated giant
cells (Aschoff cells) surrounding soft tissue fibrinoid necrosis
(rheumatic nodule). Although 25% of patients with RA may
recover completely, 50% experience terminal severe
incapacitation. Death usually occurs from complications such
as infections, gastrointestinal hemorrhage, or cardiovascular or
pulmonary involvement.
41. Fibrous Dysplasia
• Fibrous dysplasia (FD) is a tumorimitating developmental
abnormality of bone that consists of circumscribed mixed fibrous
and osseus lesions. FD may be associated with endocrine
abnormalities and skin pigmentation such as precocious puberty
and cafe au lait spots (McCune-Albright syndrome),
acromegaly, Cushing syndrome. Monostotic and polyostotic
forms frequently occur in the proximal femur, the tibia, the ribs,
and the mandible. Polyostotic forms (25%) also may involve the
pelvis, the hands, or the feet. Growing lesions cause pain,
deformation of bones, and pathologic fractures. Characteristic
radiographic findings show a ground-glass, slightly
"multivesiqular" ("soap bubble") appearance with distinct
borders. Microscopy shows a dense whorled fibrous tissue
containing spicules of woven bone. The prognosis of FD is good,
and management should prevent complications such as fractures.
Rarely, malignant sarcomas may complicate the course of FD.
42. The localized lesion, (a) A well-defined
sclerotic edge indicating a benign lesion
- a fibrous cortical defect. Fibrous dysplasia.
