Transition Zones

Question 1

What is/are the characteristics of occipitization of C1?

Answer 1

the atlas may be partially or completely fused to the occiput

Question 2

What is another way of implying occipitization of C1?

Answer 2

atlas assimilation

Question 3

What is the incidence of occipitization of C1?

Answer 3

0.1% - 0.8%

Question 4

When do the centers of ossification for the odontoid process first appear?

Answer 4

during the last trimester in utero

Question 5

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

Answer 5

at or shortly after birth

Question 6

What joint is formed between the odontoid process osssification centers and the centrum of C2?

Answer 6

subdental synchrondosis

Question 7

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

Answer 7

4 years old

Question 8

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

Answer 8

7 years old

Question 9

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

Answer 9

os odontoideum

Question 10

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

Answer 10

persistent subdental synchondrosis

Question 11

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

Answer 11

tip of the dens synchondrosis

Question 12

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

Answer 12

sometime in early adolescence

Question 13

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

Answer 13

before age 12

Question 14

If the joint formed between the tip of the dens and odontoid process centers of ossifcation persists beyond age 12, what is the condition called?

Answer 14

terminal ossicle

Question 15

What is a basilar impression?

Answer 15

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

Question 16

What is basilar invagination?

Answer 16

the upper cervical spine appears to be invaginated into the skull on X-ray analysis

Question 17

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

Answer 17

from .5 - 2.5% of the population

Question 18

Do patients typically present with symptoms specific for dorsalization of C7?

Answer 18

no, they are typically asymptomatic

Question 19

What is the gender bias suggested in dorsalization of C7?

Answer 19

female

Question 20

What is the alteration in C7 facet orientation may accompany dorsalization?

Answer 20

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

Question 21

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

Answer 21

up to 46%

Question 22

What T1 facet orientation changes may accompany cervicalization?

Answer 22

superior articular facet may change from back, upward, and lateral (BUL) to back, upward, and medial (BUM);
inferior articular facet is unchanged

Question 23

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

Answer 23

up to 28% of the population

Question 24

What is the incidence of lumbar ribs in the population?

Answer 24

over 7%

Question 25

What L1 facet orientation changes may accompany dorsalization?

Answer 25

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

Question 26

What is the gender bias associated with the dorsalization of L1?

Answer 26

males are 2-3 times more affected

Question 27

What T12 facet orientation changes may accompany lumbarization?

Answer 27

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

Question 28

What T11 facet orientation changes may accompany lumbarization?

Answer 28

inferior articular facet may change from flat, forward, medial and downward to
convex, forward, lateral, and downwards;
superior articular facet remains unchanged

Question 29

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

Answer 29

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

Question 30

What is characteristic of lumbarization of S1?

Answer 30

the failure of synostosis between S1 and S2, squaring of the vertebral body of S1 and flaring of the sacral ala

Question 31

What is failure of synosotosis between S1 and S2?

Answer 31

the segments do not completely fuse together

Question 32

What is squaring of the vertebral body of S1?

Answer 32

the S1 vertebral body has similar anterior and posterior heights, hence a lack of wedging

Question 33

What is flaring of sacral ala?

Answer 33

the transverse process of the ala appears to elevate as though separating from the rest of the sacral ala

Question 34

What articular facet changes accompany lumbarization of S1?

Answer 34

none

Question 35

Which segment demonstrates the greatest morphological variation along the spine?

Answer 35

L5

Question 36

What articular facet changes accompany sacralization of S5?

Answer 36

none

Question 37

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

Answer 37

up to 14%

Question 38

What is the characteristic of sacralization of Co1

Answer 38

the premature fusion of Co1 to sacrum

Question 39

What is the characteristic of coccygealization of S5?

Answer 39

the separation of S5 from sacrum and its’ premature fusion to Co1