Fetal skull warda

FOR UNDERGRADUATE MEDICAL STUDENTS

1. FETAL SKULL ANATOMY
OSAMA M WARDA MD

2. 2

3. FETAL SKULL
◦The skull is formed of the face , the vault & the base
◦The bones that form the skull are : two frontal bones,
two parietal bones, two temporal bones wings of the
sphenoid & occipital bone
◦The bones of the face & base are heavy & fused
◦The bones of the vault are 2 frontal,2 parietal &
occipital
◦The bones of the vault are not joined thus changes in
the shape of the fetal head during labor can occur due
to molding 3

4. 4

5. FETAL SKULL DEFINITIONS
BregmaÆAnt fontanelle
Brow Ælies between bregma &root of the nose
Face Ælies between root of the nose & suborbital ridges
OcciputÆboney prominence behind post fontanelle
Vertex Ædiamond shaped area between ant & post
fontanelles & parietal eminences
5

6. FETAL SKULL SUTURES
}Frontal sutureÆbetween 2 frontal bones
}Sagittal suture Æbetween 2 parietal bones
}Coronal sutureÆbetween parietal & frontal
}Lambdoid suture Æbetween parietal & occipital
}Temporal sutureÆbetween inferior margin of the
parietal & temporal
6

7. •Fontanelles –fibrous
membranes connecting
the cranial bones
•Allow the brain
to grow
•Convert to bone within 24
months after birth
7

8. FONTANELLS
◦Anterior fontanelle:
-Diamond shaped space between coronal & sagittal suture3 X 3 cm , ossifies at
18 m
◦Post font (lambda):
Triangle shaped space between sagittal & lambdoid suture
8

9. LONGITUDINAL DIAMETERS
9

10. 10

11. Fetal head attitude & Presentation
11
AttitudePresentationDominator*
1.Flexion VertexOcciput
1.Deflexion BrowForehead (frontum)
1.Extention FaceChin (mentum)
1.Side-tilt AsynclitismParietal bone

12. MOULDING OF THE HEAD
}Occurs with descent of the fetal head into the pelvis to
reduce the head circumference
}Frontal bones slip underparietal bones
}Parietal bones override each other
}Parietal bones slip underthe occipital bone
12

13. 13

14. 14
DEGREE OF
HEAD
MOULDING
DESCRIPTION
0suture lines are separate
+1Æsuture lines meet
+2suture lines overlap but can be
reduced by gentle digital pressure
+3overlap irreducible

15. 15
MOULDING

16. 16