Lines

Question 1

Sella Turcica Size normal values

Answer 1

-AP diameter: 5-16mm average of 11mm -Vertical Diameter: 4-12 mm average of 8mm - enlargement = neoplasm, empty sella syndrome, pituitary adenoma or aneurysm

Question 2

when taking a lateral xray of the cervical spine, an enlarged sella turcica is seen, what is the next best step?

a) CT scan
b) MRI
c) xray of lateral skull
d) repeat lateral cervical spine xray

Answer 2

c) xray lateral skull

central beam aimed at EAM, we do this because beam can get distorted in the lateral cervical view causing the illusion of an enarged sella turcica

Question 3

Acromegaly is seen with?

Answer 3

an enlarged sella turcica

an enlarged frontal sinus

Question 4

(Martin’s)Basilar angle

aka Welcker’s

Answer 4

-Projection: Lateral skull
- Landmarks and methods: Draw a line from the
nasion (frontal-nasal junction) to the center of
the sella turcica and one from the center of the
sella turcica to the anterior margin of the
foramen magnum and measure the angle
between them.
-Normal values: Should vary anywhere from 123 ° to 152° with an average of 137°
-Significance: An increased angle is indicative of platybasia, which may or may not be associated with basilar impression.

Question 5

platybasia

Answer 5

skull is long and shallow

Question 6

McGregor’s line (AKA Basal line)

Answer 6

• Most accurate and reproducible method for basilar impression
• Normal values: The odontoid should not lie above this line more than 8mm in males, and 10mm in females. In children younger than 18 years, these values diminish with decreasing age.
• Significance: If odontoid protrudes further than normal, there is suspicion of basilar impression that can be caused by Paget’s, osteomalacia,or fibrous dysplasia.

Question 7

Chamberlain’s line (aka palato-occipital line)

Answer 7

• Normal values: The tip of the odontoid should not project above the line, however there might be a normal variation of 3mm. A projection of 7mm or more is definitely abnormal
• Significance: If odontoid protrudes further than normal, there is suspicion of basilar impression that can be caused by Paget’s, osteomalacia,or fibrous dysplasia.

-Landmarks and methods:Draw a line from the
posterior margin of the hard palate to the
posterior margin of the foramen magnum.
Assess the relationship to the odontoid.

Question 8

Digastric Line (AKA Biventer Line)

Answer 8

• Normal values: The distance from the line to the dens value varies from 1 to 21mm with an average of 11mm. The distance from the line to the Co-C1 joint varies from 4 to 20mm with an average of 4mm.
• Significance: Both measurements decrease with platybasia caused by any of the bone softening disease listed previously.

-Landmarks and methods: Locate the digastric
grooves medial to the base of the mastoid
processes and draw a line between them.
Then measure the vertical distance to the
dens, as well as to the Co-C1 joint.

-dens shouldnt cross the line

Question 9

Atlantodental interspace (ADI) (AKA Atlas- odontoid space, predental space, atlas-dens interval)

Answer 9

• Normal values: The space should be a minimum of 1mm in both children and adults and a maximum of 5 in children and 3 in adults.
• Significance: A decrease in the space is often due to degenerative changes. An increased space can be caused by trauma, occipitalization, Down’s syndrome, pharyngeal infections, inflammatory arthropathies.

-Landmarks and methods: Measure the
distance between the posterior margin of
the anterior tubercle and the anterior
surface of the odontoid.

Question 10

Sagital Dimension of the Cervical Spinal Canal

Answer 10

• Landmarks and methods: Measure the sagital
  diameter from the posterior surface of the
  midvertebral body to the nearest surface of
  the same segmental spinolaminar junction
  line.

-Normal measurements: Average
C1-22mm

C2-20mm

C3-18mm

C4-7-17mm

Question 11

Torg ratio

Answer 11

-Landmarks and methods: Measure the sagital
diameter from the most posterior surface of
endplate to the nearest surface of the same
segmental spinolaminar junction line.
Compare that to the AP dimension of the
midbody.
-Normal measurements: Canal to body ratio
should not be less than 0.80

Question 12

Cervical Gravity Line

Answer 12

-Landmarks and methods: Draw a vertical
line through the apex of the odontoid
process:
-Normal measurements: The line should pass through the body of C7.
-Significance: The line allows the assessment of the location of gravitational stresses at the cervicothoracic junction.

Question 13

Stress line of the C spine (AKA Ruth Jackson’s lines)

Answer 13

-Projection: C spine, neutral, flexion and
extension.

• Landmarks and methods: Draw a line
  along posterior body of C2and one along
  posterior body of C7. Measure the angles
  in both flexion and extension
• Normal values: In flexion the lines should intersect at the level of C5-6 disc or facets. In extension they should intersect at the level of the C4-5 disc or facets.
• Significance: Muscle spasm, joint fixation and DDD may alter the stress point.

Question 14

Prevertebral soft tissues

Answer 14

• Projection: Lateral C spine
• Landmarks and methods, and normal values:
  Bony landmarks are the anterior arch of C1,
  inferior corners of C2 and 3, superior corner of
  C4 and inferior corners of C5-C7.
• At C2-3 we have the retropharyngeal space,
  which shouldn’t exceed 7mm.
• At C4-5 we have the retrolaryngeal space, which
  shouldn’t exceed 20mm.
• At C5-7 we have the retrotracheal space that
  shouldn’t exceed 22 mm.

-Significance: soft tissue masses may increase the measurements. Examples are posttraumatic hematomas, abscesses, neoplasms.

Question 15

Cobb method for scoliosis (AKA Cobb-Lippman)

Answer 15

-Projection: AP T spine

-Landmarks and methods: Draw lines along the superior and inferior endplates of the two vertebraes that are at the extremes of the scoliosis. Then draw two perpendiculars and measure the angle in betweeen.
YR

-Significance: Curvatures less than 20 ° require no bracing or surgical intervention, however if they are present in a patient between the age of 10 and 15 they should be monitered for a progression of more than 5° in a 3 month period. Curves between 20° and 40° should be braced. Curvatures that excess 40° may require surgical intervention.

Question 16

Risser-Fergusson method

Answer 16

• Projection:AP T spine
• Landmarks and methods: Choose the two end vertebrae like in Cobb’s method and then choose an apical vertebrae. For each of the vertebraes, draw two diagonals that cross each other at the center of the vertebrae. Finally connect the lines going through the centers of the vertebraes and measure the resulting angle at the apex.
• Significance: This method gives values about 25% less than those of Cobb, and its use is discouraged.

Question 17

Thoracic Cage Dimension (AKA Straight Back Syndrome evaluation)

Answer 17

Projection:Lateral chest

• Landmarks and methods: Measure the distance between the posterior sternum and the anterior surface of the 8 thoracic vertebral bodies.
• Normal values: in males the distance should vary between 11 and 18 cm with an average of 14cm. In females it should be between 9 and 15cm with an average of 12.
• Significance: A distance below 13cm in males and below 11 in females may indicate the presence of straight back syndrome. If abnormality is detected, check the heart for murmurs.

Question 18

Lumbar Lordosis

Answer 18

Projection: lateral L spine

• Landmarks and methods: Draw a line along the superior endplate of L1 and one along the superior endplate of S1. Then draw two perpendiculars and measure the angle between them.
• Normal values: There is a wide variation, however an average is between 50 ° and 60°.
• Significance: There is a wide spectrum of opinions. An increase in the angle seems to move the nucleus pulposis anterior, however that is of unclear significance.

Question 19

Lumbosacral angle (AKA Sacral base angle, Ferguson’s angle)

Answer 19

Projection: lateral L or S spine

• Landmarks and methods: Draw a line along the superior endplate of S1 and intersect it with a true horizontal. Measure the angle between them.
• Normal values: there is a wide variation. The minimum angle is 26 °. The maximum 57°. The average is 41°. From recumbent to upright position there is a variation from 8 to 12°. One standard deviation is +/- 7°.
• Significance: There is no consensus on the significance of an decreased or increased angle. An increased angle my put more stress on the lumbosacral posterior joints.

Question 20

Lumbosacral Disc angle

Answer 20

Projection: lateral L or L/S spine

• Landmarks and methods: Draw a line along the inferior endplate of L5 and one along the superior endplate of S1. Measure the angle between them.
• Normal values: the angle should be between 10 and 15°.
• Significance: There is a correlation between an increased angle and LBPn due to facet impaction.There may be a decrease in the value in the presence of acute disc herniation of the 5th lumbar disc.

Question 21

Lumbar gravity line (AKA Ferguson’s weight bearing line, Ferguson’s gravity line)

Answer 21

Projection: Lateral lumbar.

• Landmarks and methods: Find the center of the body of L3 by drawing two diagonals. Then draw a true vertical from this center.
• Normal measurements: The vertical line should intersect S1.
• Significance: If the line is more than 10mm anterior to S1 there may be an increase in shearing stresses in an anterior direction between the lumbosacral apophyseal joints. A posterior shift may increase the stress on the same joints and produce LBPn.

Question 22

Macnab’s Line

Answer 22

Projection: Lateral lumbar

• Landmarks and methods: Draw a line through and parallel to the inferior endplate of the lumbar vertebraes. Look at the relationship with the adjacent tip of the superior articular process (SAP) of the vertebrae above.
• Normal measurements: The line shouldn’t intersect the (SAP).
• Significance: An intersection may be an indication of facet imbrication. However, the reliability of this line has not been documented. Originally it was applied on recumbent radiographs, therefore its validity on upright ones is doubtful.

Question 23

Hadley’s “S” curve

Answer 23

Projection: AP and oblique L spine

• Landmarks and methods: Draw a curvilinear line along the inferior margin of the TP and down along the inferior articular process to the apophyseal joint space. Then go across the joint and along the superior articular process of the vertebrae below.
• Normal measurements: It should look like an S.
• Significance: An interruption indicates facet imbrication. A wide facet joint was linked to disc problems.

Question 24

Van Akkerveeken’s measurement of lumbar instability

Answer 24

• Projection: lateral neutral, flexion, extension of the L spine
• Landmarks and methods: draw two lines along opposing segmental endplates until they intersect posteriorly. Measure the distance from the posterior body margin to the point of intersection.
• Normal values: there should be less than 1.5mm difference in measurements from one posterior body margin to another.
• Significance: If the difference is greater than 1.5mm then there might be disc, or posterior ligament damage. Valuable in flexion and extension.

Question 25

Ulmann’s line (AKA Garland-Thomas line, right-angle test line)

Answer 25

Projection:lateral L and L/S spine - Landmarks and methods: Draw a line along the superior endplate of S1 and then draw a perpendicular to it at the anterior margin of the sacral base. - Normal measurements: the L5 body should lie posterior to, or just at the perpendicular line - Significance: If L5 body crosses the line then there is anterolisthesis.

Question 26

Eisenstein’s Method for Sagittal canal Measurement

Answer 26

Projection: Lateral L spine - Landmarks and methods: Draw a line to connect the tips of the superior and inferior processes at each level. Measure and mark a point at the middle of the posterior body margin. Measure the distance between the posterior body and the line connecting the tips of the SAP and IAP. - Normal measurements: Measurements should not be less than 15 mm. - Significance: A below the norm measurement is indicative of canal stenosis.

Question 27

Canal to body ratio (AKA Spinal index)

Answer 27

Projection: AP and lateral L spine - Landmarks and methods: We need 4 measurements. #1 is the interpedicular distance (A). #2 is the sagittal canal dimension using Eisenstein’s method(B). #3 is the transverse body dimension(C). Finally, measure the sagittal body dimension(D). - Normal measurements: AxB/CxD should be 1/3 to 1/6 at L3 and L4 , and 1/3.2 to 1/6.5 at L5. - Significance: The higher the ratio is the smaller the spinal canal is. This method is unreliable though.

Question 28

intercrestal line

Answer 28

Projection: AP lumbar spine Landmarks and methods: Draw a transverse line connecting the iliac crests. Observe the relationship of L4-5 to the line. Normal measurements: The most stable position appears to be where the line intersects the bottom half of the L4 body or disc. Significance: Useful indicator for predicting the level @ which the most biomechanical stress is occurring. Not a good indicator for LBPn. 4 criteria for probable L4-5 degeneration. -high intercrestal line -long TP L5 -rudimentary rib -transitional vertebra 4 criteria for probable L5-S1 degeneration. -intercrestal line passing through body of L5 -short TP of L5 -no rudimentary rib -no transitional vertebrae

Question 29

Teardrop Distance (AKA Medial joint space of the hip)

Answer 29

- Projection: AP pelvis, hip - Landmarks and methods: measure the distance between the most medial margin of the femoral head and the outer cortex of the pelvic teardrop. - Normal values: the distance should measure a minimum of 6mm and a maximum of 11 with an average of 9mm. - Significance: If the distance is more than 11mm or there is a discrepancy greater than 2mm between both hips then hip disease is most likely present.90% of hip joint effusions will have a more than 1mm discrepancy. A sensitive sign for early Legg-Calve-Perthes disease, septic arthritis, or inflammatory arthritis.

Question 30

Symphysis pubis width

Answer 30

- Projection: AP pelvis - Landmarks and methods: measure the distance between the opposing articular surfaces in the middle of the joint. - Normal values: in the male the average is 6mm and in the female is 5mm. - Significance: widening may be the result of cleidocranial dysplasia, exostrophy of the bladder, hyperparathyroidism, post-traumatic diastasis, inflammatory resorption.

Question 31

Presacral space

Answer 31

- Landmarks: the gray soft tissue density located between the anterior surface of the sacrum and the posterior wall of the rectum is assessed. - Normal measurements: In children the average thickness is 3mm (1-5). In adults it is 7mm (2-20). - Significance: Increase in thickness may indicate soft tissue mass such as tumor, fracture, IBD.

Question 32

Shenton’s line (AKA Makka’s line, Menard’s line)

Answer 32

Projection: AP pelvis and hip - Landmarks and methods: draw a line along undersurface of femoral neck and continue it along the inferior margin of the superior pubic ramus. - Normal measurements: it should be smooth - Significance: hip dislocation, femoral neck fracture, SCFE (Slipped femoral capital epiphysis).

Question 33

Iliofemoral Line

Answer 33

- Projection: AP pelvis and hip. - Landmarks and methods: draw a curvilinear line along the outer surface of the ilium, across the joint and onto the femoral neck. - Normal measurements: a bilateral and smooth line with a small convexity at the superior part of the femoral head. - Significance: congenital dysplasia, SCFE, dislocation and fracture.

Question 34

Femoral angle (AKA Mikulicz angle)

Answer 34

Projection: AP pelvis and hip - Landmarks and methods: draw a parallel line through the midaxis of the femoral shaft and one through the femoral neck. Measure the angle in between. - Normal measurements: the angle should be between 120 ° and 130°. - Significance: a decreased angle is indicative of coxa vara and an increased angle is indicative of coxa valga.

Question 35

Skinners Line

Answer 35

Projection: AP pelvis and hip - Landmarks and methods: draw a line parallel to the axis of the femoral shaft. Then draw one that is at a straight angle and that is perpendicular to the tip of the greater trochanter. - Normal measurements: the fovea capitis should lie above or at the level of the trochanteric line. - Significance: fractures are the most common cause for superior displacement and they lead to coxa vara.

Question 36

Klien's line

Answer 36

Projection: AP and frog leg hip or pelvis - Landmarks and methods: draw a line along the outer margin of the femoral neck. - Normal measurements: compare to the opposite side. There should be the same degree of overlap of the femoral head. - Significance: SCFE

Question 37

SCFE

Answer 37

Question 38

Patellar positions (AKA Patella alta evaluation)

Answer 38

- Projection: lateral knee - Landmarks and methods: The patellar length (PL) is the greatest diagonal dimension between superior and inferior poles. The patellar tendon (PT) is the distance between the insertion of the posterior tendon surface at the inferior patellar pole and notch at the tibial tubercle. - Normal measurements: the two line should be equal to each other within 20%. - Significance: If the patellar tendon is longer, patella alta is present. This can be found in association with chondromalacia patellae or tendon tears. A low riding patella may be seen in polio, achondroplasia, juvenile RA.

Question 39

Heel pad measurement Acromegaly (heel pad sign)

Answer 39

- Projection: Lateral foot, lateral calcaneous. - Landmarks and methods: measure the shortest distance between the plantar surface of the calcaneous and the skin contour. - Normal measurements: in both males and females the minimum is 19mm. The maximum in males is 25mm and in females 23mm. It may be slightly increased in African Americans. -Significance: If increased it could indicate acromegaly. The achilles tendon thickness may also be assessed 1 to 2 cm above the calcaneous. It should be about 4-8mm. Inflammatory arthritis edema can thicken it.

Question 40

Boehler’s angle (AKA !xial relationship of the calcaneous, Tuber angle)

Answer 40

- Projection: Lateral foot, or calcaneous - Landmarks and methods: connect the three highest points on the superior surface of the calcaneous and connect them with 2 tangential lines. Measure the angle. - Normal measurements: angle should vary from 28-40 °. - Significance: if the angle is decreased there might be a fracture with a displacement of the calcaneous.

Question 41

Acromiohumeral joint space

Answer 41

- Normal measurements: the distance should be about 9mm (7-10mm) - Significance: a decreased value is indicative of rotator cuff tear, degenerative tendinitis (nothing opposes the deltoid that pulls the humeral head superiorly). If increased, there is possible subluxation, dislocation, joint effusion, brachial plexus injury.

Question 42

Radiolunate angle (AKA Lunate tilt)

Answer 42

- Projection: Lateral wrist - Landmarks and measurements: draw two lines to approximate the long axes of the radius and lunate so that they are parallel. - Normal measurements: the lines should be parallel. - Significance: If the lunate is flexed more than 15 degrees, volar intercalated segment instability (VISI) is suggested. If the angle is greater than 10 degrees in extension, dorsal intercalated segment instability(DISI) is suggested. Occasionally VISI and usually DISI occur with scapholunate dissociation; VISI is also related to triquetrolunate dissociation.