Exam 1, Ch. 4, Skeletal Pathologies

Question 1

Spina Bifida (definition and cause)

Answer 1

• posterior defect of the spinal cord in which posterior elements do not fuse properly
• moderate and severe forms have herniation of meninges (meningocele) or meninges and spinal cord (myelomengingocele)
• associated neurological deficits

Question 2

Spina Bifida (on an image)

Answer 2

• herniated spinal column seen as soft tissue mass
• large bony defects
• absence of laminae

Question 3

Osteogenesis Imperfecta (definition and cause)

Answer 3

• inherited
• connective tissue disorder
• bones break easily

Question 4

Osteogenesis Imperfecta (on an image)

Answer 4

• because of multiple fractures and defective cortices, the bones heal with exuberant callus formations
• bones may appear deformed due to amount of fractures

Question 5

Achondroplasia (definition and cause)

Answer 5

• hereditary
• most common form of dwarfism
• diminished perforation of cartilage in the growth plates

Question 6

Achondroplasia (on an image)

Answer 6

• progressive narrowing of interpedicular distances from above downward
• long bones appear short and thick

Question 7

Congenital Hip Dysplasia (definition and cause)

Answer 7

• incomplete acetabulum formation due to mechanical and hormonal reasons
• more common in females
• tendons and ligaments responsible for proper femoral head alignment are affected

Question 8

Congenital Hip Dysplasia (on an image)

Answer 8

• both AP and Cleaves (bilateral frog-leg) required for diagnosis
• AP: shows slightly wider joint space
• Cleaves: shows hip dislocation (usually superiorly and posteriorly)

Question 9

Reiter’s Syndrome (definition and cause)

Answer 9

• form of rheumatoid arthritis
• primarily affects young adult men
• normally occurring after venereal or GI infections
• affects SI joints, heels, and toes

Question 10

Reiter’s Syndrome (on an image)

Answer 10

• ankylosing (fusing) of SI joints bilateral but asymmetric
• ankylosing usually affects feet (not hands)
• only minimal changes to spine

Question 11

Osteoarthritis (definition and cause)

Answer 11

• also called degenerative bone disease
• loss of joint cartilage and reactive new bone formation
• 2 causes: (1) part of normal wear and tear process of aging; (2) a repeatedly traumatized or abnormal stress on a joint due to deformity

Question 12

Osteoarthritis (on an image)

Answer 12

• weight-bearing joints (spine, hip, knee, ankle) and IP joints of fingers
• narrowing of joint space
• periarticular sclerosis (articular ends of bones become more dense)
• cystlike lesions with sclerotic margins on articular surfaces
• spurs with well-defined bony protuberances

Question 13

Infectious Osteoarthritis (definition and cause)

Answer 13

• also called pyogenic osteoarthritis
• pyogenic organisms gain entry into joints by way of hematogenous route, trauma, or adjacent osteomyelitis
• often caused by migratory Lyme Disease

Question 14

Infectious Osteoarthritis (on an image)

Answer 14

• soft tissue swelling
• periarticular edema displaces or obliterates adjacent tissue fat planes
• severe infections: extensive destruction and loss of cortical outline

Question 15

Osteomalacia (definition and cause)

Answer 15

• excessive osteoid formation (less common) or insufficient mineralization of osteoids (more common)
• due to lack of absorption or intake of calcium, phosphorus, or vitamin D
• renal disease may be cause too (calcium gets excreted in urine)

Question 16

Osteomalacia (on an image)

Answer 16

• loss of bone density
• bone cortex appears more dense in contrast to the deossified medullary
• bowing deformities in pelvis, vertebral column, thorax, and/or prox. extremities

Question 17

Rickets (definition and cause)

Answer 17

• infant (or early childhood) equivalent to Osteomalacia
• deficient in vitamin D due to diet or lack of exposure to UV radiation (sunshine which converts sterols in skin to vitamin D)

Question 18

Rickets (on an image)

Answer 18

• best seen on the fastest growing bones (radius/ulna, sternal end of ribs, prox. tibia/humerus)
• more distance between ossified epiphysis and shaft
• metaphyseal ends of bone appear “cupped” or “frayed”

Question 19

Gout (definition and cause)

Answer 19

• disorder in the metabolism of purine
• increase in blood level of uric acid leads to deposition of uric acid crystals in the joints, cartilage, and kidney
• caused by overproduction in uric acid (primary gout)
• or by drugs, increased turnover of nucleic acids, or decrease in excretion of uric acids

Question 20

Gout (on an image)

Answer 20

• acute gout primarily affects first metatarsophalangeal joint
• joint effusion and periarticular swelling
• erosions on articular surface appear as cystlike lesions; often look like a “rat bite”

Question 21

Osteoporosis (definition and cause)

Answer 21

• generalized or localized deficiency of bone matrix; bone mass is decreased but normal in composition
• caused by accelerated resorption of bone or, in some cases, decreased bone formation
• caused by aging and postmenopausal hormone changes
• to visualize on x-ray, use lowest practical kVp
• DEXA is used more often

Question 22

Osteoporosis (on an image)

Answer 22

• 50-70% of bone loss needs to be present before radiolucencies are seen on radiographs
• because of endosteal resorption, cortex appears thin and dense; causing “picture frame” appearance
• commonly seen on spine and pelvis; and sella turcica and dorsum sellae

Question 23

Paget’s Disease (definition and cause)

Answer 23

• also called osteitis deformans
• one of most common chronic metabolic diseases of skeleton
• destruction and reparation of bone causes thickened bony structures that fracture easily
• usually starting at middle age, affects men twice as often as women

Question 24

Paget’s Disease (on an image)

Answer 24

• coarsening of trabeculae of pelvic iliac margins which causes thickening of pelvic brim
• in lone bones: cortical thickening, destruction of bony trabeculae, and accentuation of secondary trabeculae

Question 25

Bacterial Osteomyelitis (definition and cause)

Answer 25

• inflammation of bone and bone marrow
• caused by infectious organisms by route of hematogenous spread, adjacent infection site, or by direct introduction (thru trauma or surgery)

Question 26

Bacterial Osteomyelitis (on an image)

Answer 26

• begins as abscess of bone
• in long bones: deep, soft tissue swelling adjacent to metaphysis
• after acute infection, bone appears thickened and sclerotic with irregular outer margin

Question 27

Osteochondroma (definition and cause)

Answer 27

• benign growth of bone with a cartilaginous cap (called exostosis); usually in knee
• usually forms in childhood or teen years
• exostosis grows laterally from epiphysis

Question 28

Osteochondroma (on an image)

Answer 28

exostosis characteristically runs parallel to long bone and away from parent bone

Question 29

Giant Cell Tumor (definition and cause)

Answer 29

• also called osteoclastoma
• usually benign
• tumor arising from distal femur or proximal tibia in young adults after epiphyseal closure (20-40 years old)

Question 30

Giant Cell Tumor (on an image)

Answer 30

• begins as radiolucent lesion

- as tumor extends into shaft, characteristic appearance a of large bubble separated by thin strips of bone

Question 31

Osteoid Osteoma (on an image)

Answer 31

• small, round or oval, lucent center
• less than 1 cm in diameter
• surrounded by a large, dense sclerotic zone of cortical thickening

Question 32

Osteogenic Sarcoma (definition and cause)

Answer 32

• malignant tumor consisting of osteoblasts
• generally occurs in metaphysis of long bone, usually the knee
• primarily affects people between ages 10-25
• can affect older people esp. with a history of Paget’s

Question 33

Osteogenic Sarcoma (on an image)

Answer 33

• mixed destructive and sclerotic lesion
• with a soft tissue mass
• elevation of periosteum with subsequent new bone formation called Codman’s Triangle

Question 34

Chondrosarcoma (definition and cause)

Answer 34

• malignant tumor of cartilaginous lesion
• may form from preexisting cart. lesion or form anew
• develops at later age than Osteogenic Sarcoma (35-60)

Question 35

Chondrosarcoma (on an image)

Answer 35

• bone destruction
• amorphous calcification within cartilaginous matrix. layman’s terms: looks like random spotting of calcifications in tumor

Question 36

Ewing’s Sarcoma (definition and cause)

Answer 36

• malignant tumor arising in bone marrow of long bones

- primarily affects young adults (rare after 30)

Question 37

Ewing’s Sarcoma (on an image)

Answer 37

• ill-defined permeative area of bone destruction (underlying medullary destruction)
• in central portion of shaft
• runs parallel to shaft

Question 38

Scoliosis (definition, cause, on an image)

Answer 38

• abnormal twisting and curving of spine
• twists vertebral bodes laterally/horizontally
• cause unknown
• S curve appearance
• should include entire spine down to hips

Question 39

Spondylolithesis (definition and image)

Answer 39

• defect in pars interarticularis WITH displacement of vertebra
• commonly affects L5
• displacement demonstrated well on lateral L-spine
• cleft (separation) of pars interarticularis seen well on oblique L-spine
• neck of Scottie dog appears detached from body