1. FETAL SKULL
AND FETAL
CIRCULATION

2. FETAL SKULL
Fetal skull is compressible, and made mainly of thin
pliable tabular(flat) bones forming the vault.
AREAS OF SKULL
 VERTEX
 BROW
 FACE

3.  VERTEX: It is a quadrangular area
bounded anteriorly by the bregma and
coronal suture behind by the lambda and
lambdoidal sutures and laterally by lines
passing thru the parietal eminences.
 BROW :It is an area bounded on one side
by the anterior fontanelle and coronal sutures
and on the other side by the root of the nose
and supra-orbital ridges of either side.

4.  FACE:
It is the area
bounded by the
root of the nose
and supra-
orbital ridges
and on the
other, by the
junction of the
floor of the
mouth with
neck.

5. SINCIPUT: is the
area lying in front of
the anterior fontanelle
and corresponds to
the area of brow.
OCCIPUT: is the
area limited to the
occipital bone.

6. SUTURES
Flat bones of the vault are united together by
the non-osssified membranes attached to the
margins of the bones. These are called
sutures.
THE SAGGITAL SUTURE: lies b/w two
parietal bones.
THE CORONAL SUTURES :run b/w
parietal and frontal bones on either sides.

8. Cont…
THE FRONTAL
SUTURE : lies b/w two
frontal bones.
THE LAMBDOIDAL
SUTURES : separate
the occiput bone and two
parietal bones.

9. IMPORTANCE
 It permits gliding movement of one bone
over the other during moulding of the head.
 Digital palpations of sagittal suture during
internal examination in labour gives an idea
of the manner of engagement of the
head, degree of internal rotation of the head
and degree of moulding of the head.

10. FONTANELLES
Wide gap in the suture line is called fontanelle.
Two obstetrical significance fontanelle are:
 ANTERIOR FONTANELLE:
 Formed by joining four sutures in midplane.
 Anteriorly frontal.
 Posteriorly saggital.
 On either side coronal suture.

11.  Diamond like shape.
 Floor is made by a
membrane.
 Ossified at 18mth
after birth.

12. IMPORTANCE
 Its palpation thru internal examination
denotes the degree of flexion of the head.
 It facilitates the moulding of the head.
 It helps in accomodating the marked brain
growth.
 Palpation reflects intracranial status.

14.  POSTERIOR
FONTANELLE:
 Formed by junction of
three sutures.
 Saggital suture anteriorly.
 Lambdoidal suture on
either side.

15.  Triangular in shape.
 Measures about
1.2 1.2cm.
 Its floor is
membranous but
become bony at 3mth.

16. IMPORTANCE
 It denotes the position of the head in relation
to maternal pelvic.

17. DIAMETERS OF SKULL

18. DIAMETERS ATTITUDE OF THE HEAD PRESENTATION
SUBOCCIPITO-BREGMATIC: 9.5cm COMPLETE FLEXION VERTEX
extends from nape of neck to
centre of bregma.
SUBOCCIPITO-FRONTAL : 10cm INCOMPLETE FLEXION VERTEX
extends from nape of neck to
centre of sinciput.
OCCIPITO-FRONTAL:11.5cm MARKED DEFLEXION VERTEX
extends from the occipital
eminence to the root of the nose.
MENTO -VERTICAL:14cm PARTIAL EXTENSION BROW
extends from the mid point of chin
to the highest pt. on the saggital
suture.
SUBMENTO-VERTICAL: 11.5CM INCOMPLETE FLEXION FACE
extends from junction of floor of
mouth and neck to the highest pt.
on saggital suture.
SUBMENTO-BREGMATIC: 9.5CM COMPLETE FLEXION FACE
extends from junction of floor of
mouth and neck to centre of
bregma.

19. TRANSEVERSE DIAMETERS
 BIPARIETAL DIAMETER:9.5cm
extends b/w two parietal eminences.
 SUPER-SUBPARIETAL:8.5cm
extends from a point placed below one parietal
eminence to a pt. placed above the other parietal
eminence of the opposite side.
 BI-TEMPORAL:8cm dist. b/w antero-
inferior ends of the coronal suture.

20.  BI-MASTOID: 7.5cm dist. b/w tips of
the mastoid process.
MOULDING:
It is the alteration of the shape of the forecoming
head while passing thru the resistant birth
passage during labour.
IMPORTANCE:
 Enables head to pass more easily, thru the
birth canal.
 Shape of the moulding can be an useful
information about the position of head
occupied in the pelvis.

22. Structures in fetal
circulation
 Umbilical vein carries Oxygen & nutrients
to fetus.
 2 umbilical arteries carry deoxygenate blood
and waste product from the fetus.
 Ductus venosus from shunts blood from
umbilical vein to inf. Vena cava, bypassing the
liver and the organs of digestion.

23.  Foramen ovale shunts blood from rt. Atrium to left
atrium.
 Ductus arterioses- Shunts blood from pulmonary
artery to aorta bypassing lungs.

24. FETAL CIRCULATION
Umblical vein carry 80% oxygenated blood
from placenta.
enters
Fetus at umblicus & run along the falciform
ligament of liver.
then
Branches to left lobe of liver & receives
deoxygenated blood from portal vein.

25. More oxygenated blood, mixed with some portal
blood, short circuits liver thru ductus venosus.
enters
Inferior vena cava.
( mean co is inc. in fetus)
Rt. Atrium of heart.
(Superior+inferior Vena cava)
25% of blood pass 75% of bl ood pass thru
Thru tricuspid valve . foraman ovale.

26. Into rt. Ventricle. Into lt.atrium
(blood mixes with venous blood
Pul. trunk returning from lungs thru pul. vein)
(resist in pul.
Artery is high.
So main portion
Of blood) thru mitral opening
pass through ductus
artriosus
lt. ventricle

27. to
ventricular systole
Descending aorta Blood pumped into ascending aorta and
arch of aorta and distribute to,head,
neck, brain arms and heart
by pass (lungs)
leaves the body by the
Way of
2 umbical arteres reach
Placenta (ready for recirculation)

29. CHANGES OF THE FETAL
CIRCULATION AT BIRTH
 CLOSURE OF UMBILICAL ARTERIES:
Obliteration takes place about 2-3 mths. The
distal parts from the lateral umbilical ligaments
and the proximal parts remain open as superior
vesical arteries.
 CLOSURE OF UMBILICAL VEIN: The
Obliteration occurs a little later than the arteries.
After obliteration, the umbilical vein from the
ligamentum teres and the ductus venosus
become ligament venosum.

30.  CLOSURE OF THE DUCTUS
ARTERIOSUS: Functional closure of the
ductus may occur soon after the establishment
of pul. circulation, the anatomical obliteration
takes about 1-3mths and becomes ligamentum
arteriosum.
 CLOSURE OF THE FORAMEN
OVALE: Functional closure occurs soon after
birth but anatomical closure occurs in about 1yr.
(After birth CO is 500ml/min. and
heart rate varies from 120-140 /min.)

32. RECAPTULIZATION
 Posterior fontanelle is of…………….. Shape.
 Anterior fontanelle formed by joining
………., ……….and……….. Sutures.
 Occipito-frontal is ………..cm.
 Longest diameter is………… and of ………cm.
 Saggital suture lies b/w ………… bones.
 …………. carries Oxygen & nutrients
to fetus.

33. BIBLIOGRAPHY
 Dutta D.C. Textbook of obstetrics 6th edition
central publishers.page-83-94,42-44.
 www.blurtit.com/q328911.
 www.tripdatabase.com/doc/226448
 www.purposegames.com/game/fetal-skull-
fontanelles.