Transition Zones

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

.1% to .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

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

Answer 5

the subdental synchondrosis

Question 6

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

Answer 6

amphiarthrosis synchondrosis

Question 7

Ossification between the odontoid process and centrum joint of C2 first appears 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

persistant subdental synchondrosis

Question 11

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

Answer 11

tip of the dens of synchondrosis

Question 12

What is the classification of the joint formed between the tip of the dens and odontoid process centers of ossification?

Answer 12

amphiarthrosis synchondrosis

Question 13

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

Answer 13

sometime in early adolescence

Question 14

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

Answer 14

secondary center of ossification

Question 15

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

Answer 15

before age 12

Question 16

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

Answer 16

terminal ossicle

Question 17

What is a basilar impression?

Answer 17

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 18

What is a basilar invagination?

Answer 18

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

Question 19

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

Answer 19

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

Question 20

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

Answer 20

no, they are typically asymptomatic

Question 21

What is the gender bias suggested in dorslaization of C7?

Answer 21

female

Question 22

What alteration in C7 facet orientation may accompany dorsalization?

Answer 22

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

Question 23

What alteration in C6 facet orientation may accompany dorsalization?

Answer 23

C6 demonstrates a change in inferior articular facet orientation from forward, lateral, and downward to forward, medial, and downward; the superior articular facet unchanged

Question 24

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

Answer 24

up to 46%

Question 25

What rib related chnages may accompany cervicalization of T1?

Answer 25

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

Question 26

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

Answer 26

up to 28% of the population

Question 27

What is the incidence of lumbar ribs in the population?

Answer 27

over 7% of the population demonstrates lumbar ribs

Question 28

What T12 facet orientation changes may accompany dorsalization?

Answer 28

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

Question 29

What is the gender bias associated with dorslaization of L1?

Answer 29

males are two to three times more affected

Question 30

What rib related changes may accompany lumbarization of T12?

Answer 30

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

Question 31

What T12 facet orientation changes may accompany lumbarization?

Answer 31

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

Question 32

What T11 facet orientation changes may accompany lumbarization?

Answer 32

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 33

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

Answer 33

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

Question 34

What is the charactistic of lumbarization of S1?

Answer 34

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

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 articular facet changes accompany sacralization of L5?

Answer 37

none

Question 38

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

Answer 38

up to 14%

Question 39

What is the characteristics of sacralization of Co1?

Answer 39

the premature fusion of Co1 to the sacrum

Question 40

What is the characteristic of coccygealization of S5?

Answer 40

the seperation of S5 from sacrum and it's premature fusion to Co1

Question 41

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

Answer 41

at or shortly after birth