Fetal skull is important in obstetrical standpoint as cephalic presentataion is common and a competent midwife must have knowledge about it along with female pelvis.

1. FETAL SKULL
PREPARED BY:
SRUJANI SWETASINA
DASH
NURSING TUTOR
G.N.M.INSTITUTE
A.N.M.M.C.H, GAYA

2. OBJECTIVES
 NEED FOR STUDY ABOUT FETAL SKULL
IN OBSTETRIC
 FUNCTIONS OF SKULL
 BONES OF FETAL SKULL
 SUTURES
 FONTANELLES
 AREAS OF SKULL
 DIAMETERS OF FETAL SKULL
 SUMMARY
 BIBLIOGRAPHY

3. NEED FOR STUDY ABOUT
FETAL SKULL IN OBSTETRIC
The common presentation of fetus is
cephalic during labour and hence it is
the head which first enters the birth
canal. The head or skull is the largest
and least compressible part of fetus.
Once it is born, the rest part of the
fetus comes out smoothly from birth
canal.

4. FUNCTIONS OF FETAL SKULL
 Cranium protects the brain.
 Bony eye sockets protects the eye
against injury
 Temporal bone protects the ear.
 Mandible helps in chewing of food.
 Skull or head is the most common
presenting part which comes out
through the birth canal.

5. BONES OF FETAL
SKULL
 Skull is divided into two parts-
a. CRANIUM
b. FACE

6. BONES OF FETAL SKULL
CRANIUM FACIAL
 Upper bowl shaped part of the
skull which contains the brain.
 9 bones in cranium-
 Anterior portion of skull forms
facial bones.
 14 bones of face-
Bone Name No.
Frontal 2
Parietal 2
Occipital 1
Temporal 2
Sphenoid 1
Ethmoid 1
Total 9
Bones No.
Zygomatic 2
Lacrimal 2
Nasal 2
Inferior nasal Concha 2
Vomer 1
Palatine 2
Maxilla 2
Mandible 1
Total 14

9. SUTURES
Immovable joint between skull bones
• Frontal Suture-
Frontal Bone + Frontal
Bone
• Coronal Suture-
Frontal Bone + Parietal
Bone
• Sagittal Suture
Parietal Bone + Parietal
Bone
• Lambdoid Suture
Parietal Bone + Occipital
Bone
• Squamous Suture

10. FONTANELLES
 Area where two or more sutures join.
 There are 6 fontanelles in skull but only two are of
obstetric importance.
ANTERIOR FONTANELLE POSTERIOR FONTANELLE
Also called as Bregma Also called as Lambda
Located anteriorly at junction of
sagittal, frontal and coronal
sutures.
Located posteriorly at sagittal
and lamdoidal sutures.
Diamond shape Traingle shape
2.5 cm long, 1.5 cm wide 1.2 cm long , 1.2 cm wide
Larger than lambda Smaller than bregma
Ossifies by 18 months after birth Ossifies by 6 weeks after birth

11. CLINICAL SIGNIFICANCE OF
SUTURES AND FONTANELLES
SUTURES
 Helps in moulding
neccessary during
vaginal delivery.
 Digital palpation of
sagittal suture
during p/v
examination gives
an idea of
engagement and
degree of internal
rotation.
FONTANELLES
 Facilitates
moulding
 Palpation denotes
degree of flexion
 Depressed
fontanelle indicates
dehydration
 Elevated fontanelle
indicates raised
ICP
 CSF can be drawn

12. AREAS OF SKULL
 Skull is divided into-
1.Vault
2.Base
3.Face

13. Areas/Landmarks of
Obstetrical Importance
AREA DESCRIPTION
VERTEX Quadrangular area bounded anteriorly by bregma
and coronal sutures and behind by the lambda and
lambdoid sutures and laterally by lines passing
through the pariatal eminences.
BROW Area bounded on one side by bregma and coronal
sutures and on other side by root of nose and supra
orbital ridges of either side.
FACE Area bounded on one side by root of the nose and
supraorbital ridges and on the other by the junction of
the floor of mouth and neck.
OCCIPUT Area of surrounded within occipital bone
SINCIPUT Area lying in front of bregma and corresponds to area
of brow

14. FETAL DIAMETERS
 It has two types of diameters-
a. Anteroposterior Diameters
b. Transverse Diameters

15. ANTERO POSTERIOR
DIAMETERS
Submento Vertical, 11.5
cm

16. Diameter Description Measur
ement
Attitude Present
ation
Suboccipito
Bregmatic
(SOB)
Extends from neck to
centre of bregma
9.5 cm Complete
Flexion
Vertex
Sub Occipito
Frontal
(SOF)
Extends from nape of
neck to centre of sinciput
10 cm Incomplete
Flexion
Vertex
Occipito
Frontal
(OF)
Extends from occipital
eminence to root of nose
11.5 cm Marked
Deflexion
Vertex
Mento
Vertical (MV)
Extends from midpoint of
chin to the highest of
sagittal suture
14 cm Partial
extension
Brow
Sub Mento
Vertical
(SMV)
Extends from junction of
floor of mouth and neck
to the highest point of
sagittal suture
11.5 cm Incomplete
extension
Face
Sub Mento
Bregmatic
(SMB)
Extends from junction of
floor of mouth and neck
to the centre of bregma
9.5 cm Complete
extension
Face

17. TRANSVERSE DIAMETERS

18. Diameter Description Measurement
Biparietal
Diameter
(BPD)
Extends between two parietal
eminences
9.5 cm
Super Sub
Parietal Diameter
(SSPD)
Extends from a point placed
below one parietal eminence to a
point placed above the opposite
side parietal eminence
8.5 cm
Bitemporal
Diameter
(BTD)
Extends from both antero inferior
ends of coronal suture
8 cm
Bi Mastoid
Diameter
(BMD)
Extends from both tip of mastoid
process
7.5 cm

19. SUMMARY
 Fetal skull is significant in obstetrical
standpoint because it is the first part and
hardest part which comes out during
delivery in normal cases and if it is
delivered smoothly then the rest of the
trunk follows smoothly as well.
 A midwife must be competent to
recognise areas, sutures, fontanelles of
fetal skull in order to understand the
attitude, degree of rotation, presentation
& presenting part, status of intracranial
pressure and able to detect deviations
from normal.

20. BIBLIOGRAPHY
 Dutta D.C, “Textbook Of Obstetrics”, Jaypee
Brothers , The Health Science Publishers, 8th
edition, Pg.96-98
 Jacob Annamma, “A Comprehensive
Textbook of Midwifery”, Jaypee Brothers
Medical Publishers(P)LTD, 2nd edition, Pg.43-
51
 Elizabeth Marie, “Midwifery for Nurses”, CBS
Publishers and Distributors Pvt Ltd, 2nd
edition, Pg.90-96
 Kaur Sandeep, “ Midwifery and
Gynaecological Nursing”, CBS Publishers
and Distributors Pvt Ltd, 1st edition, 2019,
Pg.39-40