The Fetus in Relation to the Bony Pelvis

Question 1

_________ is important because an essential feature of labor is the adaptation between the head and the maternal bony pelvis.

Answer 1

Fetal head size

Question 2

The firm skull is composed of____________________

Answer 2

two frontal, two parietal, and two temporal bones, along with the upper portion of the occipital bone and the wings of the sphenoid.

Question 3

The fetal skull bones are separated by membranous spaces termed ________________

Answer 3

sutures

Question 4

The most important sutures are the_______, between the two frontal bones; the_________, between the two parietal bones; the _________ between the frontal and parietal bones; and the____________, between the posterior margins of the parietal bones and upper margin of the occipital bone.

Answer 4

two frontal

sagittal

two coronal,

two lambdoid

Question 5

The term _______ describes the irregular space enclosed by a membrane at the junction of several sutures (see Fig. 7-11).

Answer 5

fontanel

Question 6

The___________________ is a lozenge-shaped space situated at the junction of the sagittal and the coronal sutures.

Answer 6

greater, or anterior, fontanel

Question 7

​ The__________________ is a small triangular area at the intersection of the sagittal and lambdoid sutures. The localization of these fontanels gives important information concerning the presentation and position of the fetus during labor.

Answer 7

lesser, or posterior, fontanel

Question 8

It is customary to measure certain critical diameters and circumferences of the newborn head (Fig. 7-12).

These include:

Answer 8

1. The occipitofrontal (11.5 cm)
2. The biparietal (9.5 cm),
3. The bitemporal (8.0 cm).
4. The occipitomental
5. The suboccipitobregmatic (9.5 cm)

Question 9

The ___________ which follows a line extending
from a point just above the root of the nose to the most
prominent portion of the occipital bone.

Answer 9

occipitofrontal (11.5 cm),

Question 11

The _____________ the greatest transverse diameter of the head, which extends from one parietal boss to the other.

Answer 11

biparietal (9.5 cm),

Question 12

The _____________ which is the greatest distance
between the two temporal sutures.

Answer 12

bitemporal (8.0 cm),

Question 13

The ___________, which extends from the chin
to the most prominent portion of the occiput.

Answer 13

occipitomental (12.5 cm)

Question 14

The ________________, which follows a line
drawn from the middle of the large fontanel to the undersurface
of the occipital bone where it joins the neck.

Answer 14

suboccipitobregmatic (9.5 cm)

Question 16

The greatest circumference of the head, which corresponds to the plane of the occipitofrontal diameter averages _____, a size too large to fit through the pelvis.

Answer 16

**34.5 cm **

Question 17

The smallest circumference, corresponding to the plane of the suboccipitobregmatic diameter, is ___________.

Answer 17

32 cm

Question 18

The cranial bones are normally connected only by a thin fibrous tissue layer. This allows considerable shifting or sliding of each bone to accommodate the size and shape of the maternal pelvis. This process is termed ____________. The head position and degree of skull ossification result in a spectrum of cranial plasticity. In some cases, this contributes to fetopelvic disproportion, a leading indication for cesarean delivery (Chap. 23, p. 463).

Answer 18

molding