Transition Zones

Question 1

What are the transition zones of the vertebral column?

Answer 1

Occipitocervical, cervicothoracic, thoracolumbar, lumbosacral, and sacrococcygeal zones

Question 2

What are the possible transition zone - segment combinations?

Answer 2

Cervicalization of the occiput, occipitalization of C1
Dorsalization of C7, cervicalization of T1
Lumbarization of T12, dorsalization of L1
Sacralization of L5, lumbarization of S1
Coccygealization of S5, sacralization of Co1

Question 3

What is/are the characteristic(s) of cervicalization of occiput?

Answer 3

An increase in occipital bone size, formation of new or larger lines, on the occipital bone

Question 4

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

Answer 4

The atlas may be partially or completely fused to the occiput

Question 5

What is another way of implying occipitalization of C1?

Answer 5

Atlas assimilation

Question 6

What is the incidence of occipitalization of C1?

Answer 6

0.1-0.8%

Question 7

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

Answer 7

During the last trimester in utero

Question 8

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

Answer 8

At or shortly after birth

Question 9

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

Answer 9

The sub dental synchondrosis

Question 10

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

Answer 10

4 years old

Question 11

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

Answer 11

7 years old

Question 12

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 12

Os odontoideum

Question 13

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

Answer 13

Persistent subdental synchondrosis

Question 14

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

Answer 14

Tip of dens synchondrosis

Question 15

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

Answer 15

Sometime in early adolescence

Question 16

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

Answer 16

Secondary center of ossification

Question 17

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

Answer 17

Before age 12

Question 18

What is a terminal ossicle?

Answer 18

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

Question 19

What is a basilar impression?

Answer 19

Persistence of the nonunion of the basilar and condylar parts of the chondrocranium such that the cartilage deforms due to the wight of the brain

Question 20

What is basilar invagination?

Answer 20

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

Question 21

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

Answer 21

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

Question 22

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

Answer 22

From 0.5-2.5% of the population

Question 23

Do patients typically present with symptoms specific for dorsalization C7?

Answer 23

No, they are typically asymptomatic

Question 24

What is the gender bias suggested in dorsalization of C7?

Answer 24

Female

Question 25

What alteration in C7 facet orientation may accompany dorsalization?

Answer 25

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

Question 26

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

Answer 26

Up to 46%

Question 27

What rib-related changes may accompany cervicalization of T1?

Answer 27

The fist rib may decrease in mean relative length or become absent

Question 28

What will result form fusion of a shot rib to the T1 TVP?

Answer 28

The transverse Foramen

Question 29

What T1 facet orientation change may accompany cervicalization?

Answer 29

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

Question 30

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

Answer 30

Up to 28% of the population

Question 31

What rib-related changes may accompany dorsalization of L1?

Answer 31

Elongated bones shaped like ribs may appear

Question 32

What is the incidence of lumbar ribs in the population?

Answer 32

Over 7% of the population

Question 33

What L1 facet orientation changes may accompany dorsalization?

Answer 33

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

Question 34

What T12 facet orientation changes may accompany dorsalization?

Answer 34

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

Question 35

What is the gender bias associated with dorsalization of L1?

Answer 35

Males are 2-3x more affected

Question 36

What rib-related changes may accompany lumbarization of T12?

Answer 36

A significant shortening of the mean relative length of 113mm of the 12th rib or it becomes absent

Question 37

What T12 facet orientation changes may accompany lumbarization?

Answer 37

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 38

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

Answer 38

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

Question 39

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

Answer 39

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

Question 40

What is failure of synostosis between S1 and S2?

Answer 40

The segments don't completely fuse together

Question 41

What is characteristic of sacralization of L5?

Answer 41

L5 may be partially or completely fuse to the sacrum

Question 42

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

Answer 42

41-85%

Question 43

Which segment demonstrates the greatest morphological variation along the spine?

Answer 43

L5

Question 44

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

Answer 44

Up to 14%

Question 45

What is the characteristic of sacralization of Co1?

Answer 45

The premature fusion of Co1 to the Sacrum

Question 46

What alteration in C6 facet orientation may accompany dorsalization?

Answer 46

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 47

What C7 facet orientation changes may accompany cericalization?

Answer 47

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

Question 48

What T11 facet orientation changes may accompany lumbarization?

Answer 48

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 49

What is squaring of the vertebral body of S1?

Answer 49

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

Question 50

What is flaring of the sacral ala?

Answer 50

The TVP of the ala appears to elevate as though separating form the rest of the sacral ala