TRANSITION ZONES OF THE VERTEBRAL COLUMN - Transition zone characteristics

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 - segmental combinations?

Answer 2

cervicalization of 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 characteristics 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 of occipitalization of 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% to 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 subdental 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 identified 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 the 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

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

Answer 16

before age 12

Question 17

What is the terminal ossicle?

Answer 17

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

Question 18

What is a basilar impression?

Answer 18

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 19

What is a basilar invagination?

Answer 19

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

Question 20

What is/are the characteristics of dorsalization of C7?

Answer 20

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

Question 21

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

Answer 21

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

Question 22

What is the gender bias suggested in dorsalization of C7?

Answer 22

female

Question 23

What alteration in C7 facet orientation may accompany dorsalization?

Answer 23

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 24

What alteration in C6 facet orientation may accompany dorsalization?

Answer 24

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

Question 25

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

Answer 25

up to 46%

Question 26

What rib-related changes may accompany cervicalization of T1?

Answer 26

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

Question 27

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

Answer 27

the transverse foramen

Question 28

What T1 facet orientation changes may accompany cervicalization?

Answer 28

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

Question 29

What C7 facet orientation changes may accompany cervicalization?

Answer 29

the inferior articular facet may change from forward, medial, and downward (ForMeD) to forward, lateral, and downward (FoLD) ; the superior articular facet is unchanged

Question 30

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

Answer 30

up to 28%

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 demonstrates lumbar ribs

Question 33

What L1 facet orientation changes may accompany dorsalization?

Answer 33

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 34

What T12 facet orientation changes may accompany dorsalization?

Answer 34

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

Question 35

What is the gender bias associated with dorsalization of L1?

Answer 35

males are two to three times 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 twelfth rib or it becomes absent

Question 37

What T12 facet orientation may accompany lumbarization?

Answer 37

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

Question 38

What T11 facet orientation changes may accompany lumbarization?

Answer 38

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

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 squaring of the vertebral body of S1?

Answer 40

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

Question 41

What is flaring of the sacral ala?

Answer 41

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

Question 42

What is characteristic of sacralization of L5?

Answer 42

L5 may be partially or completely fused to the sacrum

Question 43

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

Answer 43

41% to 85%

Question 44

Which segment demonstrates the greatest morphological variation along the spine?

Answer 44

L5

Question 45

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

Answer 45

up to 14%

Question 46

What is characteristic of sacralization of Co1?

Answer 46

the premature fusion of Co1 to the sacrum