Transition Zones Flashcards

1
Q

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

A

the atlas may be partially or completely fused to the occiput

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2
Q

What is another way of implying occipitalization of C1?

A

atlas assimilation

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3
Q

What is the incidence of occipitalization of C1?

A

0.1% to 0.8%

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4
Q

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

A

during the last trimester in utero

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5
Q

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

A

at or shortly after birth

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6
Q

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

A

the subdental sunchondrosis

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7
Q

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

A

4 years old

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8
Q

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

A

7 years old

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9
Q

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?

A

os odontoideum

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10
Q

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

A

persistent subdental synchondrosis

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11
Q

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

A

tip of the dens synchondrosis

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12
Q

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

A

sometime in early adolescence

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13
Q

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

A

before age 12

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14
Q

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?

A

terminal ossicle

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15
Q

What is a basilar impression?

A

persistence of the nonunion of the basilar and condylar parts of the chondrocraniom such that the cartilage deforems due to the weight of the brain

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16
Q

What is a basilar invagination?

A

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

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17
Q

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

A

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

18
Q

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

A

no, they are typically asymptomatic

19
Q

What is the gender bias suggested in dorsalization of C7?

A

female

20
Q

What alteration in C7 facet orientation may accompany dorsalization?

A

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.

21
Q

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

A

up to 46%

22
Q

What T1 facet orientation changes may accompany cervicalization?

A

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

23
Q

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

A

up to 28% of the population

24
Q

What is the incidence of lumbar ribs in the population?

A

over 7% of the population demostrates lumbar ribs

25
Q

What L1 facet orientation changes may accompany dorsalization?

A

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

26
Q

What is the gender bias associated with dorsalization of L1?

A

males are two to three times more affected

27
Q

What T12 facet orientation changes mar accompanr lumbarization?

A

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

28
Q

What T11 facet orientation changes may accompany lumbarization?

A

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

29
Q

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

A

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

30
Q

What is characteristic of lumbarization of S1?

A

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

31
Q

What is failure of synostosis between S1 and S2?

A

the segments do not completely fuse together

32
Q

What is squaring of the vertebral body of S1?

A

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

33
Q

What is flaring of the sacral ala?

A

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

34
Q

What articular facet changes accompany lumbarization of S1?

A

none

35
Q

What is characteristic of sacralization of L5?

A

L5 may be partially or completely fused to the sacrum

36
Q

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

A

41% to 85%

37
Q

Which segment demostrates the greatest morphological variation along the spine?

A

L5

38
Q

What articular facet changes accompany sacralization of L5?

A

none

39
Q

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

A

up to 14%

40
Q

What is characteristic of sacralization of Co1?

A

the premature fusion of Co1 to the sacrum

41
Q

What is characteristic of coccygealization of S5?

A

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