Diagnostic Imaging Final

Nia made fully covers everything

ADI (Atlantodental Interval) normal adult value

< 3mm

Increased ADI suggests

Transverse ligament injury, rheumatoid arthritis, Down syndrome, trauma

C1/C2 ratio indicating possible transverse ligament injury

1.1

C1/C2 ratio highly specific for transverse ligament injury

1.15

Lateral mass displacement suggesting transverse ligament injury

8 mm

Causes of cervical listhesis

Fracture, dislocation, ligamentous laxity, degeneration, anatomic, physiologic

Normal cervical lordosis depth method

8-12 mm

Depth method for cervical lordosis

Line from odontoid tip to posterior C7 body

Hyperlordotic cervical spine (Cobb angle)

45°

Normal cervical lordosis Cobb angle

35-45°

Hypolordotic cervical spine (Cobb angle)

< 35°

Harrison posterior tangent method average cervical curvature

34° ± 9°

Harrison posterior tangent method uses which vertebrae

C2 and C7 posterior body margins

Normal cervical gravity line

Traverses anterior portion of C7 body

Anterior weight bearing cervical gravity line

Falls anterior to C7 body

Posterior weight bearing cervical gravity line

Traverses posterior C7 body

Ruth Jackson stress lines are formed from

Posterior aspects of C2 and C7

Expected Ruth Jackson intersection in extension

C4 disc or C4/C5 facets

Expected Ruth Jackson intersection in flexion

C5 disc or C5/C6 facets

Factors influencing Ruth Jackson stress lines

Muscle spasm, joint fixation, disc degeneration

Normal cervical sagittal canal width

16 mm

Cervical stenosis generally

< 12 mm

Severe cervical stenosis

< 10 mm

Causes of cervical stenosis

Disc degeneration, facet arthrosis, congenital narrowing

Normal lumbar canal diameter

15-27 mm

Lumbar stenosis typically

< 12 mm

Definitely stenotic lumbar canal

< 10 mm

Central lumbar stenosis caused by

Ligamentum flavum hypertrophy, spurs, bony projections

Lateral lumbar stenosis caused by

Superior articular process hypertrophy

Medial lumbar stenosis caused by

Inferior articular process hypertrophy

Fleur-de-lis stenosis caused by

Laminar thickening with posterolateral bulging

Normal retropharyngeal space at C2

< 6 mm

Normal retrotracheal space at C6

< 22 mm

PETB causes of widened prevertebral soft tissues

Pus, edema, tumor, blood

Thoracic kyphosis normal range

20-40°

Thoracic hyperkyphosis

40°

Gold standard for thoracic kyphosis measurement

Cobb angle

Consequences of hyperkyphosis

Falls, fractures, pain, pulmonary dysfunction, decreased quality of life, increased mortality

Pathogenesis of hyperkyphosis

Vertebral fractures, DDD, muscle weakness, genetic predisposition

Most common congenital chest wall deformity

Pectus excavatum

Four features of straight back syndrome

Loss of thoracic kyphosis, reduced AP chest diameter, cardiothoracic ratio <0.5, leftward heart shift

Straight back syndrome AP chest diameter measurement

T8 to sternum <10-11 cm

Lumbar gravity line should intersect

Anterior one-third of sacrum

Lumbar gravity line dropped from

Center of L3

Normal lumbar lordosis

50-60°

Lumbar lordosis measured between

Superior L1 endplate and sacral base

Normal lumbosacral joint angle

5-39°

Average lumbosacral joint angle

18.7°

Normal Ferguson angle

27-57°

Wiltse Type I spondylolisthesis

Dysplastic/congenital

Wiltse Type II spondylolisthesis

Isthmic

Wiltse Type IIA spondylolisthesis

Lytic pars defect

Wiltse Type IIB spondylolisthesis

Elongated pars

Wiltse Type IIC spondylolisthesis

Acute pars fracture

Wiltse Type III spondylolisthesis

Degenerative

Wiltse Type IV spondylolisthesis

Traumatic

Wiltse Type V spondylolisthesis

Pathologic

Wiltse Type VI spondylolisthesis

Iatrogenic

Meyerding Grade I spondylolisthesis

< 25% translation

Meyerding Grade II spondylolisthesis

26-50% translation

Meyerding Grade III spondylolisthesis

51-75% translation

Meyerding Grade IV spondylolisthesis

76-100% translation

Meyerding Grade V spondylolisthesis

100% translation

Another name for Grade V spondylolisthesis

Spondyloptosis

Ulmann line positive finding

L5 crosses perpendicular line

Teardrop distance normal

9-11 mm

Normal teardrop asymmetry between hips

< 2 mm

Widened teardrop causes

Dysplasia, effusion, trauma, infection, inflammation, tumor

Waldenstrom sign

Widened hip joint space

Kohler line another name

Ilioischial line

Coxa profunda finding

Acetabular fossa touches or crosses Kohler line

Protrusio acetabuli finding

Femoral head extends medial to Kohler line

MY PROTRUSIO mnemonic causes

Marfan, Paget, rheumatoid arthritis, osteogenesis imperfecta, trauma/tumor, rickets, unknown, psoriatic arthritis, inflammatory arthritis, osteomalacia

Klein line used to diagnose

SCFE

Normal Klein line

Intersects lateral femoral epiphysis

Trethowan sign

Klein line fails to intersect femoral epiphysis

Best view for Klein line

AP external rotation

Shenton line definition

Smooth arc from superior pubic ramus to femoral neck

Interrupted Shenton line suggests

DDH, femoral neck fracture, severe external rotation

Normal Bohler angle

25-40°

Decreased Bohler angle suggests

Calcaneal fracture

Normal heel pad thickness

< 23 mm

MADCOP causes of thick heel pad

Myxedema, acromegaly, drug (phenytoin), callus, obesity, peripheral edema

Normal glenohumeral joint space

3-6 mm

Normal acromiohumeral interval

7-11 mm

Average acromiohumeral interval

10 mm

Normal AC joint space

1-7 mm

Ulnar variance definition

Relative lengths of distal radius and ulna

Neutral ulnar variance

Radius and ulna at same level

Positive ulnar variance

Ulna projects more distally

Negative ulnar variance

Ulna projects more proximally

Positive ulnar variance associated with

TFCC degeneration and ulnar impaction syndrome

Negative ulnar variance associated with

Kienbock disease

Kienbock disease

Avascular necrosis of the lunate

JDD stands for

Juvenile Discogenic Disease

Another name for JDD

Scheuermann disease

Other names for Scheuermann disease

Juvenile kyphosis, vertebral epiphysitis

Scheuermann disease prevalence

Approximately 5%

Typical age of Scheuermann disease

12-17 years

Sex predominance in Scheuermann disease

Slight male predominance