skeletal system pathology ch4

the skeletal system is composed of 2 tissue types

bone and cartilage

arthro

joint

what are two types of bone?

compact (the outer layer) and cancellous (spongy inner layer)

osteoclasts

cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity.

osteoblasts

 cells that form new bones and grow and heal existing bones. They release bone matrix that turns proteins into new tissue. Bone matrix fills in gaps and spaces in your existing bone tissue. Osteocytes are cells inside mature bone tissue.

what are the 5 functions of bone?

Support, Protect organs, Levers for movement, Blood cell production, Calcium storage

Congenital/Hereditary Diseases of Bone

1. spina bifida
2. vertebral anomalies
3. osteoporosis
4. osteogenesis imperfecta
5. achondroplasia
6. congenital hip displacement

vertebral anomalies

Transitional vertebrae \n Has characteristics of vertebrae on both sides of a major division of the spine. \n It occurs most often at L/S junction.

spina bifida

is a spinal canal defect caused from failure of the posterior elements to fuse properly. \n Large defects have complications of herniations: Meningocele, Myelomeningocele

Meningocele

protrusion of the meninges through the skin

Myelomeningocele

a defect of the backbone (spine) and spinal cord. Before birth, the baby's spine, the spinal cord and the spinal canal do not form or close normally. most serious form of spina bifida.

Spina bifida occulta

a mild, insignificant form, in which there is a splitting of the bony neural canal at the L5 or S1 level.

osteopetrosis

It is a rare hereditary bone dysplasia in which failure of the resorptive mechanism of calcified cartilage interferes with the normal \n replacement by mature bone. results in very brittle bones. Increase in exposure factors required.

osteogenesis imperfecta

\*brittle bones disease”

it is an inherited generalized disorder of connective tissue characterized by multiple fractures and an unusual blue color of normally white sclera.

achondroplasia

most common form of dwarfism. results from diminished proliferation of cartilage in the growth plate (decreased enchondral bone formation)

It is an autosomal dominant condition.

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congenital hip displacement

is known as developmental hip dysplasia. result from incomplete acetabulum formation caused by physiologic and mechanical factors.

inflammatory and Infectious Disorders

reheumatoid arthritis

Osteoarthritis (Degenerative Joint Disease) \n Infectious Arthritis \n Tuberculous Arthritis \n Bursitis \n Rotator Cuff Tears \n Tears of the Menisci of the Knee \n Bacterial Osteomyelitis \n Tuberculous Osteomyelitis

rheumatoid arthritis

a chronic systemic idiopathic disease

appears primarily as a noninfectious inflammatory arthritis of the small joint of the hands and feet.

RA variants: ankylosing spondylitis, reiter’s syndrome, psoriatic arthritis.

ankylosing spondylitis

a variant of rheumatoid arthritis and an inflammatory disease that, over time, can cause some of the bones in the spine, called vertebrae, to fuse. This fusing makes the spine less flexible and can result in a hunched posture. If ribs are affected, it can be difficult to breathe deeply.

Osteoarthritis (degenerative joint disease)

a very common generalized disorder characterized by loss of joint cartilage and ractive new bone formation. Is a part of the wear and tear of the aging process.

infectious arthritis

caused by a pyrogenic organisms. most common type is migratory arthritis from lyme disease. can cause narrowing of the joint space.

tuberculous arthritis

a chronic indolent infectionthat has a gradual onset and a slowly progressive course. Usually involves one joint, commonly the: \n Spine, Hips Knees, Most patients have pulmonary TB.

bursitis

inflamation of the small fluid-filled sac located near the joints that reduce the friction caused by movement. Causses: repeated physical activity (most common), trauma, rheumatoid arthritis, gout, infections.

rotator cuff tears

the rotator cuff of the shoulder is a musculotendinous structure composed of the teres minor, infraspinatus, supraspinatus, and subscapularis muscles. insert mri image

tears of the menisci of the knee

tears of the menisci of the knee are common cause of knee pain. Acute trauma. degeneration due to chronic trauma. MRI is the modality of choice to image menisci tears.

osteomyelitis

an inflammation of the bone and marrow caused by a variety of infectious organisms. infectious organisms reach bone by hematogenous spread, extensioun from an adjacent site of infection, ordirect introduction of organisms (after trauma or surgery).

tuberculous osteomyelitis (pott’s disease)

rare today but usually affects T and L spine.

metabolic bone diseases

Osteoporosis \n Osteomalacia \n Rickets \n Gout \n Paget’s Disease

osteoporosis

generalized or localized deficiency of bone matrix in which the mass of bone per unit volume is decreased in amount butnormal in composition. Causes include aging and postmenopausal hormonal changes. A decrease in kvp is required to obtain quality image.

vertebral plasty

kyphoplasty

are two percutaneous interventional procedures used to treat symptomatic, nonhealing fragility fractures of the spine by injecting polymethyl methacrylate (PMMA) into the vertebral body thereby providing structural support.

osteomalacia

is insufficient mineralization of the adult skeleton. may be caused by inadequate intahe or absorption of calcium, phosphorus, or vitamin D. Other nutritional causes of osteomalacia are chronic kidney failure or kidney diseases that \n cause calcium secretion in the urine.

Rickets

is a systemic disease of infancy and childhood that is the equivalent of osteomalacia in adults. Calcification of growing skeletal elements is defective because of a deficiency of vitamin D in the diet or a lack of exposure to ultraviolet radiation (sunshine), which converts sterols in the skin into vitamin D

Gout

a disorder in the metabolism of purine (a component of nucleic acids). Creates increases uric acid in the blood, which leads to the deposition of uric acid crystals in the joints, cartilage, and kidney. A very painful arthritis that initially attacks a single joint, primarily the first metatarsophalangeal joint.

paget’s disease

Paget’s disease is also known as osteitis deformans. It is one of the most common chronic metabolic diseases of the skeleton. There is associated increased risk of osteosarcoma later in life. There is no known cure.

Lead poisoning

Lead poisoning results from the ingestion of lead-containing materials (especially paint) or from the occupational inhalation of lead fumes. Environmental exposure occurs when drinking water (contaminated pipes) and eating food that is processed, preserved, or stored in \\n containers made with lead. Currently, it is the number one major environmental pollutant worldwide.

chronic lead poisoning causes

mental retardation, seizures, behavioral disorders, or delayed development. Children are more susceptible to lower doses. Lead’s affects on CNS are more severe

fibrous dysplasia

is characterized by the proliferation of fibrous tissue within the medullary cavity. It causes loss of trabecular markings and widening of the bone.

Ischemic necrosis of bone

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Occurs due to a loss of blood supply \n • Causes \n Thrombosis \n Vasculitis \n Disease of surrounding bone \n Single or repeated trauma \n Steroid therapy \n Cushing’s disease \n Hemolytic anemia (especially sickle cell disease) \n Chronic alcoholism \n Chronic pancreatitis \n Gaucher’s disease \n Radiation therapy \n Caisson disease (a complication of underwater diving, the “bends”)

benign bone tumors

 Osteochondroma \n  Enchondroma \n  Giant Cell Tumor \n (Osteoclastoma) \n  Osteoma \n  Osteoid Osteoma \n  Simple Bone Cyst \n  Aneurysmal Bone Cyst \n  Bone Island

malignant bone tumors

Osteogenic sarcoma \n Chondrosarcoma \n Ewing’s sarcoma \n Multiple myeloma \n Bone metastases

Osteochondroma (exostosis)

it is a benign projection of bone with a cartilaginouus cap that arises in childhood or the teen years. It is common near the knee. Characteristics: long axis of tumor runs parallel to the bone shaft. Points away from the nearest joint

osteo-

of the bone

\-chrondro

cartilage

enchondroma

slow growing benign neoplasm. cartilaginous tumors arising in the medullary canal. they are primarily in the small bones of the hands and feet. They are often found when a fracture occurs with minimal force.

giant cell tumor(osteoclastoma)

giant cell tumor typically arises at the end of the distal femur or proximal tibia of a young adult after epiphyseal closure (20- to 40-year olds). does not affect the joint.

osteoma

often arise in the outer table of the skull, the paranasal sinuses (especially frontal and ethmoid), and the mandible. cause pain. appear radiographically as well- circumscribed, extremely dense, round lesions that are rarely larger than 2 cm in \n diameter.

osteoid ostoma

is typically imaged as a small, round or oval, lucent center (the nidus), less than 1 cm in diameter, that is surrounded \n by a large, dense sclerotic zone of cortical thickening. \n  It is most common in teenagers or young adults. \n  Symptoms are local pain, which increases at night and is easily relieved by aspirin.

simple bone cyst

is a true fluid-filled cyst with a wall of fibrous tissue, which most often occurs in the proximal humerus or femur at \n the metaphysis. \n It is asymptomatic. \n It is often discovered either incidentally or after pathologic fracture.

aneurysmal bone cyst

An aneurysmal bone cyst is not a true neoplasm or cyst. \n consists of numerous blood-filled, arteriovenous communications thought to be caused by trauma.

bone island

Bone islands are solitary, sharply demarcated areas of dense compact bone that occur most commonly in the pelvis and upper femur. appear in every bone except the skull.

osteogenic sarcoma

Osteogenic sarcoma generally occurs in the end of a long bone in the metaphysis \n (especially about the knee). It is a malignant tumor of osteoblasts, which produce osteoid and spicules of calcified \n bone. It is most common in persons between 10 to 25 years old. \n Smaller peak incidence is seen in older persons who have a preexisting bone disorder, particularly Paget’s disease.

chondrosarcoma

a malignant tumor of cartilaginous origin that may originate anew or within a preexisting cartilaginous lesion Commonly occurs in long bones, but often originates in a rib, scapula, or vertebra. It is about half as common as osteogenic sarcoma. \n  It develops at a later age (peak incidence in 35-to-60-year-olds), grows more slowly, and metastasizes later.

ewing’s sarcoma

primary malignant tumor arising in the bone marrow of long bones. Occurs in children and you adults. Rare over the age of 30.

multiple myeloma

a widespread malignancy of plasma cells. associated with bone destruction, bone marrow failure, hypercalcemia, renal failure, and recurrent infection. the disease affects primarily persons between 40 and 70 years of age. most die within 3-5 years of diagnosis.

bone matastases

are the most common malignant bone tumors. Are more common than primary neoplasms. Spread rom primary tumors by means of the bloodstream or lymphatic vessels or by direct extension. The most common primary tumors are carcinomas of \n the breast, lung, prostate, kidney, and thyroid. Favorite sites of metastatic spread are bones containing red marrow, such as the spine, pelvis, ribs, skull, and the upper ends of the humerus and femur.

complete fracture

results in 2 bone fragments

incomplete fracture

one side of bone cortex intact

open fracture (compound)

Fracture with associated skin wound

closed fracture

Fracture with skin intact

transverse fracture

fracture line is horixontal to long axis of bone

oblique

fracture line extends at an angle to long axis of bone

spiral

fracture line encircles the shaft

avulsion

small fragments pulled from bone by attached ligaments or tendons

comminuted

more than 2 bone fragments

types of fractures

butterfly

triangular fragment separated from 2 larger fragments

segmental

a piece of the shaft is separated by proximal and distal fracture lines

compression

compacts the trabeculae

depressed

fragment driven inward, e.g., skull fragment pushed into brain

green stick

occurs in immature bone; one side of cortex remains intact

torus (buckle)

compaction of one side of the cortex

bowing

plastic deformity of bone

fracture healing

Radiographic evidence is a continuous external bridge of callus (calcium deposition)that unites the fracture fragment

pathologic fractures

occur in diseased bones. Stress or force is usually not significant enough to cause a fracture in healthy bone.

stress fractures

are the response of bone to repeated stressors, none of which alone would cause a fracture.

battered-child syndrome

 Battered-child syndrome refers to multiple, repeated, physically induced injuries in young \n children caused by parents or guardians. \n  It is also known as suspected nonaccidental trauma (SNAT). \n  Imaging professionals have a legal responsibility to report suspicious cases to their supervisors. \n  The facility is legally obligated to notify authorities

location of fractures

Undisplaced – fragments not angled or separated \n  Displacement - described by direction of distal fragment in relation to proximal fragment \n  Angulation – angular deformity of the axes of the major fracture fragments

colles’ fracure

Transverse fracture through the distal radius with dorsal (posterior) angulation. Common for ulnar styloid to fracture, too

boxer’s fracture

Transverse fracture of the neck of the 5th metacarpal with palmar angulation of the distal fragment Often caused by hitting an object with a closed fist

monteggia fracture

Ulnar shaft fracture associated with anterior dislocation of the radius at the elbow

galeazzi fracture

Radial shaft fracture and a dorsal (posterior) dislocation of the ulna at the wrist

Pott’s fracture

Fracture of both malleoli with ankle dislocation \n  Trimalleolar \n  Fracture of both malleoli and the posterior lip of the tibia ; usually represent fracture-dislocations

bimalleolar fracture

Fracture of both malleoli One side is usually spiral or oblique and the other transverse

Trimalleolar

Fracture of both malleoli and the posterior lip of the tibia ; usually represent fracture-dislocations

Jones fractures

transvere facture of the 5th metatarsal base.

___ is the most commoly dislocated joint and most are dislocated ____

Shoulder is the most commonly dislocated joint.

fractures of the spine are classified

 Stable \n  Unstable

jefferson

communited fracture of c1. most do not survive this fracture.

odontoid fractures

Most occur at base of dens

hangman’s fracture

fracture of C2 arch with subluxation of C2-C3.

Clay shoveler’s

An avulsion fracture of a spinous process in the lower C-spine or upper T-spine.

Seat-belt fracture

Transverse fracture of lumbar vertebral body. Associated with severe visceral injuries

herniated of intervertebral disks

protrusion of a portion of the disk. most common sites are: l4-l5, l5-S1, C5-C6, C6-C7, T9-T12. Can cause issues to the nerve roots which can cause pain and loss of motor function.

HNP (Herniation of Intervertebral Disks) myelogram

 a diagnostic imaging test generally done by a radiologist. It uses a contrast dye and X-rays (fluoroscopy) or computed tomography (CT) to look for problems in the spinal canal. Problems can develop in the spinal cord, nerve roots, and other tissues. 

HNP MRI

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Scoliosis

is a twisting and curvature of the vertebral column in the lateral perspective. It is generally shaped somewhat like an “S.” \n The most common types of scoliosis: \n  Idiopathic \n  Functional \n  Neuromuscular \n  Degenerative

spondylolysis

cleft in the pars interarticularis without displacement. Usually bilateral. most common at L5.

spondylolisthesis

forward displacement of one vertebra on another. Causes chronic back pain. May be caused by spondylolysis.

\-listhesis

 means to slip forward