2 - Congenital Anomalies

Question 1

What is nonsegmentation of C0 from C1

Answer 1

Occipitalization

Question 2

Four examples of occipital vertebrae

Answer 2

Third condyle
Epitransverse process
Paracondylar process
Paramastoid process

Question 3

What is a third condyle?

Answer 3

Occipitalization vertebrae from the front of forament magnum to anterior tubercle

Question 4

What is epitransverse process?

Answer 4

Occipitalization vertebrae off TP of C1 that articulates with C0.

Question 5

What is paracondylar process?

Answer 5

Occipital vertebrae off C0 next to condyle to TP of C1

Question 6

What is paramastoid process?

Answer 6

Occipital vertebrae adjacent to mastoid to TP of C1

Question 7

Basilar impression

Answer 7

When dens is pushed up into foremen magnum

Question 8

What 2 measurements are used to see if there is basilar impression?

Answer 8

McGregor’s line: palate to inferior occiput

Chamberlain’s line: palate to posterior foramen magnum

Question 9

What is abnormal measurement for McGregors Line

Answer 9

If dens is >8-10 mm above line it means there is occipitalization

If dens is >4.5 mm above line it means there is basilar invagination

Question 10

What is abnormal measurement for Chamberlain Line

Answer 10

If dens is >3 mm above the line, basilar invagination

Question 11

What are primary and secondary reasons for basilar impression?

Answer 11

1˚ : occipitalization, C1 posterior arch agenesis - spina bifida occulta

2˚ : bone softening d/t Pagets, osteomalacia, fibrous dysplasia

Question 12

What is Arnold-Chiari malformation

Answer 12

Downward displacement and elongation of brain stem and cerebellar tonsils

Question 13

Sx of Arnold-Chiari malformation

Answer 13

Mild HA, neck pain, stridor, apnea, nystagmus, CN palsies

Many are asymptomatic

Question 14

stridor

Answer 14

High-pitched breath sound resulting from turbulent air flow in larynx or lower in bronchial tree

Question 15

Other findings associated with Arnold-Chiari malformation

Answer 15

Syringomyelia and hydrocephalus

Question 16

Arnold-Chiari malformations greater than ____ are concerning

Answer 16

3mm

<3mm is not concerning

Question 17

In an MRI how can you tell the difference between T1 and T2 weighted

Answer 17

T1 CSF is dark

T2 CSF is bright

Question 18

What is syringomyelia

Answer 18

Spinal cord cavity (syrinx)

Question 19

Etiology of syringomyelia

Answer 19

Pressure, tumor, congenital, Arnold-Chiari malformation (2˚ to pathologically CSF dynamics)

Question 20

What is spina bifida occulta, is it significant?

Answer 20

Failure of fusion of 2 posterior arch ossification centers that produce midline defect

Usually NOT significant. Though some authors disagree and say increased posterior disc herniation and isthmic spondy

Question 21

How does spina bifida appear on xray?

Answer 21

No spinolaminar junction

Question 22

What are the things you need for stability between C1-C2? (4)

Answer 22

Intact dens,
Anterior arch,
Lateral masses,
Transverse ligaments

Question 23

What are signs seen on xray of posterior arch agenesis?

Answer 23

Hypertrophy and sclerosis of anterior arch, megaspinous of C2

Question 24

Etiology of posterior arch agenesis

Answer 24

Congenital
SOL
Infection (e.g. osteomyelitis) though unlikely because there is no vertebral body (vertebral bodies contain blood vessels, desirable to infection to spread more easily)

Question 25

What is posterior ponticle of C1?

Answer 25

Partial or complete ossification of oblique portion of atlanto-occipital membrane So it looks like a bony arch from posterior arch to lateral masses

Question 26

What is characteristic of Trisomy 21 (Down Syndrome) ?

Answer 26

Atlanta-axial instability due to lax transverse ligament and therefore that can cause increased ADI (atlanto-dental interspace) Prone to cervical spondylitis and myelopathy

Question 27

What is ossiculum terminale and what does it look like?

Answer 27

Non-fusion of 2˚ growth center of the dens Looks like a little bone at the tip of the dens. Also called Persistens of Bergman

Question 28

How do you DDX ossiculum terminale/persistens of Bergman from acute fracture?

Answer 28

Congenital ossiculum terminale would be sclerotic and not have a clean line

Question 29

What is os odontoideum?

Answer 29

2 halves of odontoid unite and do not fuse to C2

Question 30

Is os odontoideum considered stable or unstable?

Answer 30

Unstable. The transverse ligament is intact but unstable because dens is unattached to C2 body

Question 31

What is a hypoplastic/agenesis odontoid

Answer 31

Odontoid halves do not develop fully or at all

Question 32

Should you manipulate hypoplastic/agenesis odontoid?

Answer 32

Not if its unstable. Obviously. Do flexion/extension films.

Question 33

What is block vertebra/synostosis?

Answer 33

Non segmentation of 2 adjacent segments.

Question 34

What are the radiographic findings for block vertebra/synostosis? (triad)

Answer 34

Wasp waist appearance Rudimentary disc Fused posterior elements

Question 35

Surgical vs congenital block vertebra/synostosis

Answer 35

SPs separated

Question 36

Most common vertebral levels for congenital block vertebra?

Answer 36

C2/3 C5/6 L4/5

Question 37

What is klippel-feil syndrome?

Answer 37

``` Multiple block vertebra, Spina bifida occulta, Scoliosis, Sprengel’s deformity (1 scap undescended), and Platybasia ``` Rule #3 applies here: look for soft tissue anomalies. May have GU anomalies especially kidneys (e.g. horseshoe kidney, 2 ureters from 1 kidney, etc)

Question 38

What is the classic triad for klippel-feil syndrome?

Answer 38

Short, webbed neck (pterygium colli) Lowered hairline Reduced cervical ROM

Question 39

What is sprengel’s deformity?

Answer 39

Congenitally undescended scapula

Question 40

What chunk of bone may be present in Sprengel’s deformity?

Answer 40

Omovertebral bone: a chuck of bone that fixes scapula to spine

Question 41

What is cervical spondylolisthesis?

Answer 41

Congenital form caused by bilateral agenesis of pedicles and dysplasia of articulation processes

Question 42

What cervical level is most commonly involve in spondylolisthesis? What sex is more common?

Answer 42

C6 M>F Spina Bifida Occulta (SBO) is commonly at this level too

Question 43

What level is a cervical rib most common at?

Answer 43

C7, 6, 5. If rib is at C5 pt will have ribs at C6, C7 too.