M1.1 — 6 skull and Cx 5-11

Question 1

By age __, skull measurements should be closely approaching maturation

Answer 1

5

Question 2

head length reaches full maturation at __ years in F, __ years in M? Head width? head height?

Answer 2

length = 10 F, 14 M
width = 14 F, 15 M
height = 13 F+M

Question 3

what is a posterior ponticle?

Answer 3

aka arcuate foramen
- partial of complete ossification of the inferior/oblique fibers of the the posterior atlanto-occipital membrane - where the vertbral artery passes on the atlas

Question 4

how common is a posterior ponticle?

Answer 4

8-26.2%
- prevalence increases with age
- may occur as early as 5yo but increases with puberty

Question 5

what are symptoms of a posterior ponticle?

Answer 5

HA, Cx P

Question 6

what causes Os Odontoideum?

Answer 6

may be secondary to ununited ossification center OR unrecognized fracture before the age of 5 or 6

Question 7

what’s the clinical significance of Os Odontoideum?

Answer 7

instability and chronic symptoms - atlantoaxial instabiltiy

Question 8

what does it look like radiographically?

Answer 8

smooth, well-corticosteroids ossicle

1/2 the size of normal dense - cephalic

hypertrophy of anterior arch of atlas

Question 9

what are radiographic findings of a dens fracture?

Answer 9

lucent margins
normal size dens
severe hyperflexion or extension

Question 10

what is ossiculum terminate?

Answer 10

“persistent ossiculum terminale”, “bergmann’s ossicle”

failure of fusion

Question 11

when does ossiculum terminale appear?

Answer 11

appears at 5-8 yo, fuses by 12 yo (same as secondary ossification timeline)

cannot diagnose until 12yo

Question 12

what is the radiographic appearance of ossiculum terminale?

Answer 12

well-corticated, midline, dens is normal in height

Question 13

what is the atlantodental interval? what is the measurement?

Answer 13

space between the anterior aspect of dens and posterior aspect of atlas

<5mm in children, <3mm in adults
d/t more cartilage and ligamentous laxity in children

Question 14

what measurement of the space for the cord is abnormal?

Answer 14

distance between the posterior aspect of dens and anterior aspect of posterior tubercle

if <13mm, indicates neurological problems

Question 15

what is the plane of Cx articular facets in children?

Answer 15

horizontal in young children - results in physiological subluxation

the lower Cx become more vertical in adults

Question 16

What is the posterior line of Swischuk?

Answer 16

spinolaminar line extending from C1-C3

normal = within 1mm of C2 spinolaminar line

Question 17

what is normal prevertebral space in 0-6yo, 7-15 yo and adults at C2? C6?

Answer 17

0-6 C2 = <8mm
C6 = <10mm

7-15 C2 = <7mm
C6 = <14mm

adults C2 = <7mm
C6 = <21mm