2. Q.3)DESCRIBED THE FETAL SKULL (MARKS:5/8)
• The skull is divided into the vault, the base and the face.
• The vault is the large dome shaped part above the imaginary line
drowns between the orbital ridges and the nape of the neck.
• The base is composed of bones which are firmly united to protect the
vital centres in the medulla.
• The face is composed of 14 small bones which are also firmly
united and non- compressible.
3. Bones of the Vault
-- There are five main bones in the vault of the fetal skull.
A. The occipital bone lies
at the back of the head
and forms the region of
the occiput.
B. The two parietal bones lie
on either side of the skull.
C. The two frontal bones from
the forehead or sinciput.
D. The two temporal bones from
the both side of skull.
4. Sutures and fontanelles
Sutures are cranial joints and are formed where two bones
adjoin.
Where two or more sutures meet, a fontanell is formed.
Types of sutures
A. The lambdoidal suture is shped like the Greek letter lambda and
separates the occipital bone from the two parital bones.
B. The sagital suture lies between the parital bones.
C. The coronal suture separetes the frontal bones from the parital
bones, passing from one temple to the other.
D. The frontal suture runs between the two haves of the frontal bone.
5. Types of fontanelle
A. The posterior fontanelle or lambda is situated at the junction
of the lambdiodal and sagital sutures. It is small triangular in shape
and can be recogonized vaginally.
B. The anterior fontanelle or bregma is found at the junction of
the sagittal, coronal and frontal sutures and recognized vaginally.
• The sutures and fontanelles, because they consist of memberanous
spaces, allow for a degree of overlapping of the skull bones during
labour and delivery.
7. Land Marks of the Fetal Skull :-
- Sinciput
- Occiput
- Glabella
- Anterior fontanelle
- The vertex
- Posterior fontanelle
- Occuputal protuberunse
- The mentum
Sinciput
Anterior Fontanelle
Posterior Fontanelle
Occiput protuburance
Vertex
Glabela
Mentum
Occiput
8. Diameters of the Fetal Skull
The measurement of the skulls are transverse,
anteropositerior or longitudinal.
- Transverse diameters
- Biparietal diameter 9.5 cm between the parietal eminence
- Bitemporal diameter 8.2cm between the furthers points of
the coronal suture at the temples.
- Anteroposterior or longitudinal diameters
- Suboccipitobregmatic 9.5 cm from below the occipital
protuberance to the center of the anterior fontanelle or
bregma.
9. - Suboccipitofrontal 10cm from below occipital protuberance to the
center of the frontal suture.
- Occipitofrontal 11.5 cm from the occipital protuberance to the
glabella.
- Mentovertical 13.5cm from the point of the chin to the highest
point on the vertex sightly nearer to the posterior than to the
anterior fontanelle.
- Submentovertical 11.5 cm from the point where the chin joins the
neck to the highest point on the vertex.
- Submentobregmatic 9.5cm from the point where the chin joins
the neck to the center of the bregma.
