M1.1 — 5 Lx, sacrum, coccyx 0-4

Question 1

The typical L spine has ___ shaped vertebral bodies, _____ shaped central canal

Answer 1

kidney shape vertebral bodies
triangular central canal

Question 2

What are the atypical Lx vertebrae?

Answer 2

L5

Question 3

T/F? In children, disc are vascularized?

Answer 3

T

vessels cross the cartilaginous plate and into the disc

Question 4

what age does the disc vascularization disappear?

Answer 4

begins to disappear after 8 yo, completely gone by 30 yo

Question 5

When does the lumbar lordosis curve form?

Answer 5

forms during the first 3 years commencing before children start to sit, stand or walk

May increase until 14-16yo

Question 6

how is the Lx lordosis curve formed?

Answer 6

formed by wedging of the Lx vertebral bodies and intervertebral disc

Question 7

the sacrum is the result of __(#) fused sacral vertebral and ____ segments

Answer 7

5 fused sacral vertebral and costal segments

Question 8

the sacrum central canal is _____ shaped

Answer 8

triangular shaped

Question 9

How many primary ossification centers occur in the sacrum? where?

Answer 9

35

5 per segment (5 segments)
- 1 for the body
- 2 halves of the neural arch
- 2 costal processes

Question 10

How are the sacral alae formed? when?

Answer 10

the first 3 sacral segments have a pair of costal elements that project anterolaterally to form the alae around the 2nd year of life

Question 11

what do the 5 sacrum segments look like at birth?

Answer 11

resemble developing Lx vertebra and are separated by discs

Question 12

when does the sacrum fuse?

Answer 12

does not begin until puberty, commences until the end of 2nd decade, generally complete around 22yo

S1-2 may not fuse until 4th decade of life or later

Question 13

how many segments form the coccyx?

Answer 13

4 vertebrae, may have 3-5

Question 14

when and how is the coccyx formed?

Answer 14

arises from caudal eminence at 4-8 weeks of gestation

the eminence regresses at birth leaving 4 precursor vertebrae

Question 15

when does the primary ossification take place for each segment of the coccyx? when do they unite and fuse

Answer 15

cornua ossify from separate centers
1st segment = 1-4yo
2nd segment = 5-10yo
3rd segment = 10-15yo
4th segment = 14-20 yo

segments unite at 25-30yo

may fuse to the sacrum later in life (F>M)

Question 16

what is the most common type of coccyx position?

Answer 16

Type I >50% of population

gentle ventral curvature as a continuation of the natural curvature of the sacrum

Question 17

how common is type II coccyx position? how is it positioned?

Answer 17

8-32%

more prominent ventral curvature with apex pointed anteriorly

Question 18

how common is type III coccyx position? how is it positioned?

Answer 18

4-16%

acute anterior angulation but not subluxated

Question 19

how common is type IV coccyx position? how is it positioned?

Answer 19

1-9%

focal anterior angulation with anterior subluxation

Question 20

how common is type V coccyx position? how is it positioned?

Answer 20

1-11%

posterior angulation

Question 21

how common is type VI coccyx position? how is it positioned?

Answer 21

1-6% (least common)

scoliotic deformity or lateral deviation

Question 22

how common is spina bifida occulta?

Answer 22

10-20% of population

most common in the lower Lx spine

Question 23

how common are lumbosacral transition segments (aka “lumbarization” or “sacralization”?

Answer 23

25% of population

Question 24

what radiographic view is best to see lumbosacral transitional vertebrae?

Answer 24

Ferguson’s view

Question 25

How are lumbosacral transitional vertebrae categorized?

Answer 25

Castellvi system

Question 26

what is the Castellvi system Type Ia and Ib lumbosacral transitional vertebrae?

Answer 26

enlarged and dysplastic TP (at least 19mm) unilateral (Ia) or bilateral (Ib) no clinical significance

Question 27

what is the Castellvi system Type IIa and IIb lumbosacral transitional vertebrae?

Answer 27

accessory articulation unilaterally (IIa) or bilateral (IIb) most clinically significant type

Question 28

what is Bertolotti’s syndrome? symptoms? increased risk of ___?

Answer 28

Type IIa or IIb accessory articulation of L5-S1 may be painful - Lx and glute P increased risk of disc herniation

Question 29

what is the Castellvi system Type IIIa and IIIb lumbosacral transitional vertebrae? increased risk of ___?

Answer 29

fusion of the TP/sacrum unilateral (IIIa) or bilateral (IIIb) may have increased risk of disc herniation

Question 30

what is the Castellvi system Type IV lumbosacral transitional vertebrae? symptoms?

Answer 30

type IIa on one side and IIIa on the other articulation may be painful

Question 31

what is caudal regression syndrome?

Answer 31

isolated partial agenesis of the coccyx to lumbosacral agenesis

Question 32

what causes caudal regression syndrome?

Answer 32

- often sporadic - maternal diabetes predisposes (20% of cases are associated with Type I or II maternal DM) - insult in early pregnancy (<4th week of gestation) (hyperglycemia, infection, toxic and ischemic insults)

Question 33

what are symptoms of caudal regression syndrome?

Answer 33

- neurogenic bladder - sensorimotor paresis - narrow hips, hypoplastic gluteal muscles, shallow intergluteal cleft - club feet - normal intelligence

Question 34

Why are symptoms of tethered cord syndrome worse during times of rapid growth?

Answer 34

the spine grows faster than the cord - leads to neuronal dysfunction

Question 35

what are symptoms of tethered cord syndrome? when do they occur?

Answer 35

occur during times of rapid growth (2 years, 7-8 years, puberty) occasionally undiagnosed until adulthood - progressive led weakness/sensory loss - bowel or bladder dysfunction - LBP/sciatica - scoliosis symptoms are progressive if left untreated

Question 36

What level should the spinal cord terminate? what level is abnormal?

Answer 36

conus should terminate at T12/L1 in adults L2-3 in children around 5 yo - abnormal if L2 or below in adults

Question 37

What is the most common congenital CNS malformation? where in the spine is it located

Answer 37

spina bifida manifestations LS region (90%)

Question 38

what is the cause of spina bifida manifesta?

Answer 38

multi factorial with both genetic and environmental factors - inadequate intake of folic acid

Question 39

what is the difference between meningocele, myelomeningocele, myeloschisis, and raschischisis

Answer 39

- meningocele - meninges protrude - myelomeningocele - meninges + nervous tissue protrude - myeloschisis - cord is exposed to the environment - no meninges/skin covering - rachischisis- very severe

Question 40

what is diastematomyelia?

Answer 40

split cord malformation - longitudinal split in the spinal cord

Question 41

what level(s) is common for diastematomyelia?

Answer 41

L1-2 (50%), T7-T12 (25%)

Question 42

what is the embryological cause of diastematomyelia?

Answer 42

gastrulation stage - abnormal movement and separation of precursor cells - persistent or abnormal adhesion between the ectoderm and endoderm - creates additional neuroenteric canal, notochord develops 2 hemicords

Question 43

what is type I diastematomyelia?

Answer 43

duplicated sac with midline spur (osseous or fibrous)

Question 44

what are causes of type I diastematomyelia?

Answer 44

vertebral anomalies - hemivertebrae, butterfly, spina bifida, fusion of laminae

Question 45

what are signs of type I diastematomyelia?

Answer 45

- skin pigmentation, hemangioma, hypertrichosis

Question 46

what are signs of type I diastematomyelia?

Answer 46

scoliosis and tethered cord, leg weakness, LBP, incontinence

Question 47

what is type II diastematomyelia?

Answer 47

single rural sac containing both hemicords - may have hydromyelia (syrinx), may have spina bifida but spinal anomalies are less common than type I

Question 48

what are symptoms of type I diastematomyelia?

Answer 48

may be asymptomatic

Question 49

what is type I diastematomyelia?