Craniosynostosis

Question 1

When does skull development start?

Answer 1

23-26 days gestation

Question 2

How do the cranial vault and skull base form?

Answer 2

Cranial vault - forms from intramembranous ossification of the memebranous neocranium

Skull base - forms from endochondral ossification of the cartilaginous neocranium

Question 3

Embryology of facial bones

Answer 3

From viscerocranium
First pharyngeal arch - maxillary process forms maxilla, zygoma, squamous temporal bone
Mandibular process forms mandible, malleus, and incus

Second pharyngeal arch - stapes, styloid process of temporal bone, lesser horn and superior body of hyoid

Question 4

When is brain adult size? Trajectory?

Answer 4

25% at birth, 50% at 6 months, 75% at one year, full adult volume by 2.5 years

Question 5

When do the fontanelles close

Answer 5

Anterior closes at 2 years of age

Posterior closes at 2 months of age

Question 6

Sinus development

Answer 6

Maxillary 3 months gestation - childhood
Sphenoid 5 months gestation - childhood
Ethmoid 5 months gestation - puberty
Frontal 5 years (only one to appear postnatally) - adolescence

Question 7

When do the sutures fuse?

Answer 7

Metopic - 3 to 9 months
Sagittal - 20 to 22 years
Coronal - 23 to 24 years
Lambdoid - 26 years

Question 8

Virchows law

Answer 8

Growth restriction occurs perpendicular to the affected suture, compensatory skull growth occurs parallel to the affected suture

Question 9

Most common craniosynostosis

Answer 9

Sagittal (>50%) followed by unilateral coronal (20%)

Question 10

Findings associated with metopic synostosis

Answer 10

Trigonocephaly
Pointed forehead
Frontal bossing
Bitemporal narrowing
Hypotelorism
Recessed superior orbital rims

Question 11

Harlequin deformity

Answer 11

Lack of ipsilateral descent of sphenoid during development with unicoronal synostosis

Question 12

Most common syndromic synostosis

Answer 12

Bicoronal

Question 13

Kleebattschadel deformity

Answer 13

Syndromic pancraniosynostosis with cloverleaf deformity

Question 14

Aperts syndrome

Answer 14

Craniosynostosis 
Hypertelorism, parrot beak nose, mid face hypoplasia 
Severe syndactyly of hands and feet
Mental status variable 
FGFR2 mutation

Question 15

Crouzons syndrome

Answer 15

Autosomal dominant FGFR2 mutation 
Coronal and lambdoidal synostosis
Exorbitism/proposis
Midface hypoplasia
Conductive hearing loss
Normal extremities 
Mental status variable

Question 16

Saethre Chotzen syndrome

Answer 16

Autosomal dominant TWIST 1 mutation
Asymmetric coronal synostosis 
Shallow orbits, eyelid ptosis 
Low hairline
Midface hypoplasia
Partial syndactyly
Normal extremities

Question 17

Pfieffers syndrome

Answer 17

Autosomal dominant FGFR1, 2, 3 mutations
Coronal and/or sagittal synostosis 
Hypertelorism, midface hypoplasia 
***Broad thumbs and great toes***
Mental status variable

Question 18

Which craniofacial syndrome is autosomal recessive

Answer 18

Carpenter

Question 19

Carpenter syndrome

Answer 19

Autosomal recessive 
Variable synostosis
Flat nasal bridge
Low set eyes, abnormal globes and canthi
Brachydactyly, syndactyly of hands and feet
Short stature 
Impaired mental status

Question 20

Boston type craniosynostosis

Answer 20

Autosomal dominant MSX2 mutation
Craniosynostosis, soft palate cleft
Short first metatarsal head, triphalangeal thumb

Question 21

Craniosynostosis syndrome with joint problems

Answer 21

Muenke syndrome

Question 22

Craniosynostosis with white forelock of hair

Answer 22

Waardenburg syndrome