XI: Transition Zones of the Vertebral Column: Transition Zone Characteristics

Question 1

What is/are the characteristic(s) of occipitalization of C1?

Answer 1

the atlas may be partially or completely fused to the occiput

Question 2

What is another way of implying occipitalization of C1?

Answer 2

atlas assimilation

Question 3

What is the incidence of occipitalization of C1?

Answer 3

0.1 % to 0.8 %

Question 4

When do the bilateral ossification centers for the odontoid process fuse?

Answer 4

at or shortly after birth

Question 5

What joint forms between the odontoid process ossification centers and the centrum of C2?

Answer 5

the subdental synchondrosis

Question 6

Ossification between the odontoid process and centrum joint of C2 first appears at what age?

Answer 6

4 years old

Question 7

A joint between the odontoid process and centrum of C2 is last identified at what age?

Answer 7

7 years old

Question 8

What is the name given to the condition in which the joint formed between the odontoid process and the centrum of C2 persists beyond age 7?

Answer 8

os odontoideum

Question 9

What is the name given to the joint between the odontoid process and the centrym of C2 which is still evident beyond age 7?

Answer 9

persistent subdental synchondrosis

Question 10

What is the name given to the joint formed between the tip of the dens and the odontoid process centers of ossification?

Answer 10

tip of the dens synchondrosis

Question 11

At what age will the tip of the dens center of ossification appear?

Answer 11

sometime in early adolescence

Question 12

Based on the age of appearance, how is the tip of the dens center of ossification classified?

Answer 12

the secondary center of ossification

Question 13

At what age will the tip of the dens fuse with the odontoid process?

Answer 13

before age 12

Question 14

What is a terminal ossicle?

Answer 14

a persistence beyond age 12 of the joint formed between the tip of the dens and the odontoid process centers of ossification

Question 15

What is a basilar impression?

Answer 15

persistence of the nonunion of the basilar and condylar parts of the chondocranium such that the cartilage deforms due to the weight of the brain

Question 16

What is/are the characteristic(s) of dorsalization of C7?

Answer 16

the addition of a rib and changes in superior articular facet orientation are typical

Question 17

What is the incidence of rib-related changes following dorsalization of C7?

Answer 17

from one-half to two and one-half percent of the population

Question 18

What is the gender bias suggested in dorsalization of C7?

Answer 18

female

Question 19

What alteration in C7 facet orientation may accompany dorsalization?

Answer 19

the superior articular facet of C7 may change back, upward, and medial to that of a typical thoracic facet…back, upward, and lateral; the inferior articular facet is unchanged.

Question 20

What percent of the population may demonstrate thoracic-like features at C7?

Answer 20

up to 46%

Question 21

What rib-related changes may accompany cervicalization of T1?

Answer 21

the first rib may decrease in mean relative length or become absent

Question 22

What will result from fusion of a short rib to the T1 transverse process?

Answer 22

the transverse foramen

Question 23

What T1 facet orientation changes may accompany cervicalization?

Answer 23

the superior articular facet may change from back, upward, and lateral to back, upward, and medial; the inferior articular facet is unchanged

Question 24

What is the incidence of cervicalization of T1 in the population?

Answer 24

up to 28% of the population

Question 25

What ribp-related changes may accompany dorsalization of L1?

Answer 25

elongated bones shaped like ribs may appear

Question 26

What is the incidence of lumbar ribs in the population?

Answer 26

over 7% of the population demonstrates lumbar ribs

Question 27

What L1 facet orientation changes may accompany dorsalization?

Answer 27

the superior articular facet may change from concave, back, upward, and medial to flat, back, upward, and lateral; the inferior articular facet is unchanged

Question 28

What is the gender bias associated with dorsalization of L1?

Answer 28

males are two to three times more affected

Question 29

What rib-related changes may accompany lumbarization of T12?

Answer 29

a significant shortening of the mean relative length of 113 mm of the twelfth rib or it becomes absent

Question 30

What T12 facet orientation changes may accompany lumbarization?

Answer 30

the superior articular facet may change from flat, back, upward, and lateral to concave, back, upward, and medial; the inferior articular facet is unchanged

Question 31

What is the usual way to identify the number of cervicals, thoracics and lumbar vertebrae during imaging studies?

Answer 31

Identify the vertebrae with ribs - they will be thoracics; those higher are cervicals, those lower are lumbars

Question 32

What unique characteristics of lumbarization of S1 were stressed in class?

Answer 32

squaring of the vertebral body of S1 and flaring of the sacral ala

Question 33

What is failaure of synostosis between S1 and S2?

Answer 33

the segments do not completely fuse together

Question 34

What is characteristic of sacralization of L5?

Answer 34

L5 may be partially or completely fused to the sacrum

Question 35

What is the incidence of sacralization of L5 in the population?

Answer 35

41% to 85%

Question 36

Which segment demonstrates the greatest morphological variation along the spine?

Answer 36

L5

Question 37

What is the incidence of variation within the sacrococcygeal regions in the population?

Answer 37

up to 14%