The fetal skull has an ovoid shape and is larger proportionally than other fetal bones. It is composed of three main parts - the vault, base, and face. The vault contains five bones that are firmly fused together. The base contains five other bones that also fuse together. The face contains 14 bones fused as well. There are five eminences, four important sutures, and two main fontanels that have significance during birth. The sutures and fontanels allow the skull to mold and flex during labor. The skull has six anteroposterior and four transverse diameters that are important measurements.

1. FETAL SKULL
By: Mahibul Saikh

2. Fetal skull:
The fetal skull is ovoid in shape. At term it is larger in proportion to
the other parts of skeleton.
The skull may be divided into three parts : 1.vault
2.Base
3. The face
Vault: The vault is composed of five bones : Two frontal bone ,
two parietal and one occipital bone.
Base: The base of skull is compossed of five bones : two
temporal, one ethmoid, one sphenoid and a part of occipital bone.
They are firmly fused together.
The face: The face is composed of 14 bones and all are fused
together

3. Bones of the skull :
3
• 2 frontal bones
• 2 parital bones
• 2 temporal bones
• 1 occipital bones
Eminence:
The higest point of the bone is called as eminence.
There are total five eminence. those are two frontal ,two
parital and one occipital eminence.

4. Sutures:
It is permits gliding movement of one bone over the other
during molding of fetal head during labour
Importance of
sutures :
Sutures are the area whare two skull bones are joint
together . There are four sutures in the skull those have
obstetrical importance :
1. Frontal suture: Between two frontal bones.
2.Sagittal suture: Between two parietal bones.
3.Coronal suture: Between the frontal and parietal bones.
4. Lambdoid suture: Between the parital and occipital bones .

5. Fontanels:
Fontanels are the area whare two or more sutures are joint
together. there are six fontanels on skull but only two are have
obstetrical importance:
1. Anterior fontanel: It is also known as Bregma. It is diamond
shaped, 2.5 cm long and 1.5 cm wide. It is the largest fontanel . It is
the junction of sagittal, frontal and coronal sutures . It is closes by 18
months of age .
2. Posterior fontanel: It is also known as lamda. It is tringular in
shape and measured about 1.2 * 1.2 cm and smaller than anterior
fontanel. It is located whare the sagital suture meets the lambdoid
suture. it closes by six weeks of age .
Importance:
It facilitates molding of fetal head
Helpful for collection of blood and exchange transfusion
Depressed in dehydration, elivated in case of rise ICP.

6. Diameters of fetal skull:
Fetal skull two type of diameters :
Six anteroposterior
Four transverse
Anteroposterior diameters:
 Suboccipitobregmatic[9.5cm]: Extends from the nape of the neck to center of
the bregma.
 Occipitofrontal[11.5cm]: Extendes from the occipital eminence to the root of
the nose.{Glabella}
 suboccipitofrontal[10cm]: Extendes from the nape of the neck to the anterior
end of the anterior fontanels.
 submentovartical[11.5cm]: Extends from junction of the floor of the mouth to
the highest point of the sagittal suture.
 Mentovartical[14cm]: Extent from midpoint of the chin to the highest poit of the
sagittal suture.
 submentobregmatic[9.5cm]: Extend from junction of floor of the mouth to the
center of the bregma.

7. Transverse diameters:
 Biparietal diameter: Distance between two parietal eminences.
 Bitemporal diameter: Distance between anterioinferior ends of
coronal suture.
 Super subparital diameter: Extend from a point placed below
one parital eminence to a point place above other parital eminence of
opposite side.
 Bimastoid diameter: Distance between the tips of mastoid
process.

8. Thank You