Reproductive health and medicine

1. FETAL SKULL AND MATERNAL PELVIS
DR.Anne Ngoiri

2. FETAL SKULL

3. • Vertex : It is a quadrangular area bounded anteriorly by the
bregma and coronal sutures behind by the lambda and
lambdoid sutures and laterally by lines passing through the
parietal eminences.
• Brow : It is an area bounded on one side by the anterior
fontanel and coronal sutures and on the other side by the
root of the nose and supraorbital ridges of either side.
• Face : It is an area bounded on one side by root of the
nose and supraorbital ridges and on the other, by the
junction of the floor of the mouth with neck.
• Sinciput is the area lying in front of the anterior fontanel
and corresponds to the area of brow
• occiput is limited to the occipital bone.

4. SUTURES:
 The sagittal or longitudinal
suture lies between two
parietal bones.
 The coronal sutures run
between parietal and frontal
bones on either side.
The frontal suture lies
between two frontal bones.
The lambdoid sutures
separate the occipital bone
and the two parietal bones.

5. IMPORTANCE OF SUTURES
1) It permits gliding movement of one bone over the
other during molding of the head, a phenomenon of
significance while the head passes through the pelvis
during labor.
2) Digital palpation of sagittal suture during internal
examination in labor gives an idea of the manner of
engagement of the head , degree of internal rotation of
the head and degree of molding of the head.

6. FONTANELS:
• Wide gap in the suture line is called fontanel.
• two are of obstetric significance:
• (1) Anterior fontanel or bregma and
• (2) Posterior fontanel or lambda.
• Anterior fontanel
– It is formed by joining of the four sutures in the midplane. anteriorly
frontal, posteriorly sagittal and on either side, coronal.
– The shape is like a diamond.
– Its anteroposterior and transverse diameters measure approximately 3
cm each.
– The floor is formed by a membrane and it becomes ossified 18 months
after birth. It becomes pathological, if it fails to ossify even after 24
months.

7. Importance: ANTERIOR FONTANELLE
• Its palpation through internal examination denotes the
degree of flexion of the head.
• It facilitates molding 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 the first year of life.
• Palpation of the floor reflects intracranial status—
depressed in dehydration, elevated in raised intracranial
tension.

8. Posterior fontanel
• It is formed by junction of three suture lines — sagittal
suture anteriorly and lambdoid suture on either side.
• It is triangular in shape and measures about 1.2 × 1.2
cm .
• Its floor is membranous but becomes bony at term.
Thus, truly its nomenclature as fontanel is misnomer.
• It denotes the position of the head in relation to
maternal pelvis.

9. DIAMETERS OF SKULL

11. MOLDING:
• It is the alteration of the shape of the fore-coming
head while passing through the resistant birth passage
during labor
• Molding disappears within few hours after birth.
• Grading: There are three gradings.
– Grade-1—the bones touching but not overlapping,
– Grade-2—overlapping but easily separated and
– Grade-3—fixed overlapping.

12. Importance:
• Slight molding is inevitable and
beneficial. It enables the head to
pass more easily, through the birth
canal.
• Extreme molding as met in
disproportion can cause severe
intracranial disturbance in the
form of tearing of tentorium
cerebelli or subdural hemorrhage.
• Shape of the molding can be a
useful information about the
position of the head occupied in
the pelvis

13. CAPUT SUCCEDANEUM
• It is theformation of swelling due to stagnation of fluid
in the layers of the scalp beneaththe girdle of contact.
• The girdle of contact is either bony or the dilating
cervix or vulval ring.
• The swelling is diffuse, boggy and is not limited by the
suture line
• It may be confused with cephalhematoma
• It disappears spontaneously within 24 hours after
birth.
• Caput usually occurs after rupture of the membranes

14. IMPORTANCE
• It signifies static position of the head for a long period
of time.
• Location of the caput gives an idea about the position
of the head occupied in the pelvis and thedegree of
flexion achieved.