Variation

Question 1

define anatomical variation

Answer 1

anatomical change to a structure, whether negative, positive or neutral in effect

Question 2

what is hemivertebrae

Answer 2

variation in which only part of the vertebral body develops

Question 3

what causes of hemivertebrae have been presented

Answer 3

nutritional deficiencies
chondrification
membranous stage
ossification centres affected

Question 4

what 4 classification of hemivertebrae exist

Answer 4

fully segmented
semi-segmented
incarcerated
non-segmented

Question 5

what are the implications of hemivertebrae

Answer 5

rotation and curvature anomalies
developmental delay
missing rib
butterfly vertebra

Question 6

define lumbosacral transition vertebrae

Answer 6

appearance of unexpected vertebrae in segment

Question 7

what is the incidence of lumbosacral transitional vertebrae

Answer 7

4-30% reported

Question 8

what gene may be involved in LSTV development

Answer 8

Hox gene

Question 9

describe the 4 types of LSTV

Answer 9

I - dysplastic T process
II - increased growth of T process with diarthroidal joint formation
III - fusion of process and sacrum
IV - mix of type II and III

Question 10

define block vertebrae

Answer 10

fusion of adjacent vertebrae

Question 11

why do block vertebrae occur developmentally

Answer 11

failure of somite segmentation

Question 12

what two scores are used for block vertebrae

Answer 12

Degree-of-fusion score
Bruckl classification

Question 13

what syndrome are block vertebrae associated with

Answer 13

Klippel-feil syndrome

Question 14

describe some implications of block vertebrae

Answer 14

increased degeneration risk
increased risk of adjacent segment disease
decreased IV foramen diameter
spinal canal stenosis

Question 15

what is ponticulus posticus

Answer 15

bony arch creates foramen over vertebral artery groove

Question 16

what is the IR of ponticulus posticus

Answer 16

7-21%

Question 17

how does ponticulus posticus develop

Answer 17

ossification of posterior AO membrane

Question 18

Describe ponticulus posticus classifications

Answer 18

complete - foramen extends from superior articular facet to posterior arch
incomplete/partial - does not extend to posterior arch
mix

Question 19

describe the implication of ponticulus posticus

Answer 19

headache
vertigo
neck pain
visual issues

Question 20

what may be compressed in ponticulus posticus

Answer 20

vertebral artery and 1st spinal nerve

Question 21

when is surgical removal of the arch in ponticulus posticus required

Answer 21

severe symptoms

Question 22

what surgical procedure may ponticulus posticus affect

Answer 22

lateral mass screw fixation