Transitional Zones

Question 1

What is/are the characteristics 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%-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 ossification centers for odontoid process fuse?

Answer 5

at or shortly after birth

Question 6

what joint is formed between the odontoid process ossification centers and the centrum of C2

Answer 6

the subdental synchondrosis

Question 7

ossification between the odontoid process and centrum joint of C2 first appear at what age?

Answer 7

4 years old

Question 8

A joint between the odontoid process and the 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 the 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 of the joint formed between the tip of the dens and the odontoid process centers of ossification?

Answer 11

tip of 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 withe the odontoid process?

Answer 13

before age 12

Question 14

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

Answer 14

terminal ossicle

Question 15

What is basilar impression?

Answer 15

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

Question 16

What is the 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 rib related changes following dorsalization of C7?

Answer 17

from one half to two and one half percent of the population 0.5-2.5%

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 alteration in C7 facet orientation may accompany dorsalization?

Answer 20

the 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

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

Question 23

What is the incidence of cervicalization of 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 % of the population demonstrates lumbar ribs

Question 25

What L1 facet orientation changes may accompany dorsalization?

Answer 25

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

Question 26

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

Answer 26

males are two to three times more affected

Question 27

What T12 facet orientation changes may accompany lumbarization?

Answer 27

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 28

What T11 facet orientation changes may accompany lumbarization?

Answer 28

the inferior articular facet may change from flat, forward medial and downward to convex, forward lateral and downward; the superior articular facet is 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 the failure of synostosis between S1 and S2?

Answer 31

the segments do not completely fuse together

Question 32

What is the 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 the flaring of the 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

What is the characteristic of sacralization of L5?

Answer 35

L5 may be partially or completely fused to the sacrum

Question 36

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

Answer 36

41% to 85%

Question 37

Which segments demonstrates the greatest morphological variation along the spine?

Answer 37

L5

Question 38

what articular facet changes accompany sacralization of L5?

Answer 38

none

Question 39

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

Answer 39

up to 14%

Question 40

What is the characteristic of sacralization of Co1?

Answer 40

the premature fusion of Co1 to the sacrum

Question 41

What is the characteristic of coccygealization of S5?

Answer 41

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