The document discusses the fetal skull, its parts, diameters, and importance during labor and birth. The fetal skull is made of thin, pliable bones that allow the head to mold and pass through the birth canal. It has three main parts: the vault, face, and base. Key diameters that facilitate birth include the biparietal diameter and suboccipitobregmatic diameter. Fontanels and sutures between the skull bones also aid molding and rotation of the fetal head. Palpation of the skull landmarks provides information about engagement and positioning during delivery.

1. FETAL SKULL
Kshyanaprava Behera
Assistant Professor
SUM Nursing College, SOA University

2. INTRODUCTION
 The fetal head is large in relation to the fetal
body compared with adult.
Adaptation between the skull and the pelvis is
necessary to allow the head to pass through the
pelvis during labour without complication.

4. FETAL SKULL
 The skull bones encases and protect the brain.
Fetal skull is compressible, and made mainly of
thin pliable tabular(flat) bones forming the
vault.
 The fetal skull has three major parts :
1. Vault of the cranium (Roof)
2. Face
3. Base

7. 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 through 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.

8. FACE
• It is the area bounded by the root of the nose and
supraorbital ridges and on the other, by the
junction of the floor of the mouth with neck.
SINCIPUT
• It is the area lying in front of the anterior
fontanell and corresponds to the area of brow.
OCCIPUT
• It is the area limited to the occipital bone.

10. SUTURES
• Flat bones of the vault are united together by the
non-ossified 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.
• THE FRONTAL SUTURE : Lies b/w two frontal
bones.
• THE LAMBDOIDAL SUTURES : Separate the
occiput bone and two parietal bones.

12. 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.

13. FONTANELLS
• Wide gap in the suture line is called fontanell.
ANTERIOR FONTANELL:
Formed by joining four sutures in midplane.
Anteriorly frontal bone-.
Posteriorly saggittal.
On either side coronal suture. Diamond like
shape.
Floor is made by a membrane.
Ossified at 18 months after birth.

14. IMPORTANCE
 Its palpation through internal examination denotes the
degree of flexion of the head.
 It facilitates moulding of the head.
 As it remains membranous long after birth, it helps in
accommodating the marked brain growth, the brain
becoming almost double its size during first year of life.
 Palpation of the floor reflects intracranial statusdepressed
in dehydration, elevated in raised intracranial tension.
 Collection of blood and exchange transfusion, on rare
occasion, can be performed through it via the superior
longitudinal sinus.
 Cerebrospinal fluid can be drawn, although rare, through
the lateral angle of the anterior fontanelle from the lateral
ventricle.

16. POSTERIOR FONTANELL:
• Formed by junction of three sutures.
• Saggittal suture anteriorly.
• suture on either side.
• Triangular in shape.
• Measure about 1.2 x1.2cm.
• Its floor is membranous but become bony at 3months.
SAGGITTAL FONTANELL:-
• It is inconsistent in its presence.
• It is situated on the saggittal suture at the junction of
anterior to two-third and posterior one-third.
• It has got no clinical importance.

19. LANDMARKS
 Occiput- is the occipital bone/external occipital
protuberance.
 Sinciput- is the forehead region of fetal head.
 Parietal eminences- are the eminences of parietal on either
side.
 Mentum- it is the chin.
 Vertical point- it is the center of saggital suture.
 Frontal point- is the root of nose.
 Sub occiput- is the junction fetal neck and occiput.
 Sub mentum- it is the junction between neck and chin.
 Bi parietal- is the transverse distance between two parietal
eminences.
 Bi temporal- is the distance between two lower end of
coronal suture.

21. DIAMETER OF SKULL
• TRANSVERSE DIAMETER:-
Bi parietal Diameter-
 Measure about 9.5cm.
 It extends between two parietal eminences.
Bi-temporal diameter-
 Measure about 8cm.
 It is the distance between anterio-inferior ends
of the coronal suture.

23. • LONGITUIDNAL DIAMETER
Sub-occipitobregmatic- (9.5cm).
 The diameter from below the occipital
protuberance to the center of the anterior
fontanelle.
Sub-occipitofrontal- (10cm).
 The diameter from below the occipital
protuberance to the center of the frontal suture.
Occipitofrontal-(11.5cm).
 The diameter from the occipital protuberance to
the glabella.

24. Continued…..
Mentovertical- (13.5cm).
 The diameter from the point of the chin to the
highest point on the vertex, slightly nearer to the
posterior than to the anterior fontanelle.
Submentovertical- (11.5cm).
 The diameter from the point where the chin joins
the neck to the highest point where the chin joins
the neck to the highest point on the vertex.
Submentobregmatic- (9.5cm).
 The diameter from the point where the chin joins
the neck to the center of bregma.

28. BIBLIOGRAPHY
1. Shirish S Sheth,“Essential of Obstetrics”, 1st
Edition, Jaypee Brothers Medical Publishers,
New Delhi,2004, page no.: 102 - 104.
2. Diane M, “Myles textbook for Midwives”, 14th
edition, Elsevier Publisher, London, 2008, page
no: 157-160
3. Dutta D.C, “Textbook of obstetrics” 7thedition
Published By New Central Book Agency, page
86-89