Pelvis ppt for nursing student

1. The female pelvis and
fetal skull

‫ا‬
.
‫م‬
.
‫د‬
.
‫المعيني‬ ‫اسراء‬
2016-2017 4th year

2. The bony pelvis is made of four bones :
The sacrum ,coccyx ,and two
innominates(ilium, ischium and pubis).
These bones are held together by symphsis
pubis ,sacroiliac joints and sacrococcygeal
joint.
The sacrum consists of 5 fused vertebrae,the
anterior –superior edge of the first vertebra
is called sacral promontory,which
protrudes slightly into the cavity of the
pelvis.
the anterior surface of the sacrum is usually
concave.it articulates with the illium at its
upper segment ,with coccyx at its lower
segment ,and with the sacrospinous and
sacrotuberous ligaments laterally.
The coccyx is composed of three to five
rudimentary vertebrae. it articulate with the
sacrum.

3. The pelvic brim and
inlet
The pelvic brim is the inlet
of the pelvis and bounded
in front by the symphysis
pubis (the joint separating
the two pubic bones) on
each side by the upper
margin of the pubic bone
the ileopectineal line and
the ala of the sacrum
posteriorly by the
promontory of the sacrum.

4. The pelvic brim
and inlet:
the normal
transverse diameter
in this plane is 13.5
cm and is wider than
the anterior-
posterior diameter
which is normally
11cm ,angle of the
inlet is normally 60
degree to the
horizontal in the
erect position.

5. The cavity is almost
rounded ,as the
transverse and anterior
diameter are similar at
12cm ,the ischial spine
are palpable vaginally
and are used as land
mark to asses the
descent of the head
during vaginal
examination (station)
they are also used as
land marks for providing
an anesthesia block to
the pudendal nerve.
Pudendal nerve passes
behind and below the
ischial spine on each

6. The pelvic midcavity
The pelvic midcavity can be
described as an area bounded in
front by the middle of the
symhysis pubis on each side by
the pubic bone the obturator
fascia and the inner aspect of the
ischial bone and spine
poteriorly by the junction of
the2nd and 3rd section of the
sacrum.

7. The pelvic out let
The pelvic outlet is bounded in front
by the lower margin of the symphysis
pubis
on each side by the descending
ramus of the pubic bone,the ischial
tuberosity and the sacrotuberous
ligment posteriorly by the last piece of
sacrum

8. The pelvic out let
The AP diameter
of the pelvic out let
is 13.5 cm and the
trasverse diameter
is 11cm .

9. Avariety of pelvic shapes has been
described and these may
contributed to difficulties in labor

10. Gynaecoid pelvis
Present in 40%of women
pelvic inlet is rounded
with transverse diameter
larger than antero-
posterior diameter
side wall is straight ,well
rounded sacroscaitic
notch,
well curved sacrum
,spacious sub pubic
angle =90 degree,
average prominence of
spine ,head forced to
occipital anterior
position

11. Anthropoid pelvis
20% of female ,long
narrow oval inlet ,long
antero-posterior diameter
large posterior inclination of
sacrum ,spine not
prominent but close
,narrow subpubic angle
,precipitate occipital-
posterior position and
delivery in such

12. Android pelvis
In 30% of women tringular
inlet with flat post segment
widest diameter closed to
sacrum , side is convergent
,long and narrow
sacrosciatic notch, shallow
sacral curve ,narrow
subpubic arch ,prominent
spine ,forced to be occipit-
trasverse position (funnel
shape) deep trasverse
arrest

13. Platypelloid pelvis
Flattened gynaecoid
pelvis 3%of female
pelvis
oval shape inlet ,straight
or divergent side wall,
round sacrosciatic notch
,posterior inclination of
sacrum ,wide bispinous
diameter ,wide subpubic
angle , fetal head
engage in transverse
diameter increased risk
of obstructed labour.

15. The pelvic floor
This is formed by the two
levator ani muscles which
with their fascia form a
musculofascial gutter
during the 2nd stage of
labour.
The perineal body is a
codensation of fibrous and
muscular tissue lying
between the vagina and the
anus .
It receives attachments of
the posterior ends of the
bulbocavernous muscles
,the medial ends of the
superficial and deep
transverse perineal
muscles and the anterior
fibers of the external anal
sphincter ,it is always
involved in a 2nd degree
perineal tear and an
episiotomy.

16. The FETAL skull
The fetal skull is made up
of the vault ,face ,base.
the sutures are the lines
formed where the individual
bony plates of the skull
meets one another.
At the time of labour ,the
sutures joining the bones of
the face and base of the
skull are firmly united the
vault of the skull is formed
by the parietal bones and
parts of the occipital ,frontal
and temporal bones.
Between these bones
there are four
membaranous sutures,the
sagital ,frontal coronal and
lumbdoidal sutures

17.  The anterior fontanelle or bregma closed at 18 months (diamond
shape)is at the junction of the sagittal ,frontal and coronal sutures
 The posterior fontanelle triangular in shape lies at the junction of
the sagittal and lambdoidal sutures between the two parietal
bones and the occipital bone closed at 6-8 weeks of life.
 It allow these bone to move together and even to overlap the
parietal bones usually tend to slide over the frontal and occipital
bones.
 The bones themselves are compressible together these
characteristics of the fetal skull allow a process called moulding to
occur ,which effectively reduces the diameter of the fetal skull and
encourages progress through the bony pelvis with out harming the
under lying brain.

18. Defenitions:
Vertex the area of the
fetal skull bounded by
the two parietal
eminences and the
anterior and posterior
fontanelle.
Attitude of the fetal
head refers to the
degree of flexion and
extension at the upper
cervical spine.
Different longitudinal
diameters are presented
to the pelvis in labor
depending on the
attitude of the fetal
head.

19. Engagment
occurs when the widest
diameter of the fetal
presenting part has
passed through the
pelvic inlet .
In vertex –biparietal ,
breech-intertrochanteric
.

20. Station:
of the presenting part in the
pelvis canal is define as its level
above or below the plane of the
ischial spines.
Ischial spine level =zero station
eacn 1 cm above or below the level
of ischial spine, given -1 and +1

21. Synclitic:
when the biparietal diameter is
parallel to the pelvic plane
and the sagital suture is mid
way between the anterior and
posterior planes of the pelvis
when this relationship not
present the head is
considered to be asynclitic

22. The diameter of fetal skull:
 Vertex presentation
 Well flexed head the longitudinal
diameter ,is the suboccipito –
bregmatic diameter 9.5 cm and
measured from the sub occipital
to the anterior fontanelle

.
 longitudinal diameter that
present in a less well flexed head
such as is found in the occipito-
posterior position is the Sub-
occipito-frontal diameter and is
measured from the suboccipital
region to the prominence of the
forehead 10 cm .

23.  Further extension of the head
Occipito-frontal daimeter
present this is measured from
the root of the nose to the
posterior fontanelle and is
11.5 cm.

24. 
The largest longitudinal
daimeter that may present is
the Mentvertical which is
taken from the chin to the
furthest point of the vertex and
measure 13 cm known as Brow
presentation and it is usually
too large to pass through the
normal pelvis.

25.  Extension of the fetal
head beyond this point
result in a smaller
daimeter,submentobreg
matic daimeter is
measured below the chin
to the anterior fontanelle
and is 9.5cm this is
clinically a face
presentation.

27.  Transverse diameters of
fetal skull are:
 Biparietal (9.5 cm)this is
largest
transverse,diameter
(between two parietal
bones).
 Bitemporal 8 cm shortest
transverse diameter
,between two temporal
bones.

28. Clinical pelvimetry:
The clinical evaluation is started by assessing the pelvis inlet.
Pelvic inlet:
can be assess clinically for its anteroposterior diameter .
The obstetric conjugate can be estimated from the diagonal
conjugate ,which is obtained on clinical examination .
The diagonal conjugate is approximated by measuring from the lower
border of pubis to the sacral promontory using the tip of the
second figure and the point where the base of the index figure
meets the pubis

30. The obstetric conjugate is then estimated by subtracting 1.5 to 2 cm,
depending on the height and inclination of the pubis.
Often the middle figure of the examining hand cannot reach the
sacral promontory, thus the obstetric conjugate is considered
adequate .If the diagonal conjugate is greater than or equal to
11.5 cm the anteroposterior diameter of the inlet is considered to
be adequate.
The anterior surface of the sacrum is then palpated to assess its
curvature. The usual shape is concave .
Aflat or convex shape may indicate anteroposterior constriction
throughout the pelvis

.

31. Diagonal conjugate

33. The midpelvis

cannot accurately be measured clinically in either the
anteropoterior or transverse diameter .
A reasonable estimate of the size of the mid pelvis ,however ,can be
obtained as follows. the pelvis side walls can be assessed to
determine whether they are convergent rather than having the
normal ,almost parallel,configuration.
The ischial spines are palpated carefully to assess their prominance
and several passes are made between the spines to approximate
the bispinous diameter .

34. The lenghth of the sacrospinous
ligment is assessed by placing
one fingure on the ischial spine
and on the sacrum in the
midline.
The average length is 3 fingure
breadths.
If the sacrospinous notch that is
located lateral to the ligament
can accommodate two-and half
fingure tips,the posterior mid
pelvis is most likely of
adequate dimensions. short
ligament suggests a forward
inclination of the sacrum and a
narrwed sacrospinous notch.

35. pelvic outlet is assessed.
This is done by first placing a fist
between the ischial tuberosities.
An 8.5cm distance is considered an
adequate transverse diameter.
The posterior sagittal measurement
should also be greater than8cm.
The infrapubic angle is assessed by
placing thumb next to each
inferior pubic ramus and then
estimating the angle at which
they meet.An angle of less than
90 degree is associated with a
contracted transverse diameter in
the midplane and out let.

36. Radiological assessment
of the pelvis:

When an accurate measurement of the pelvis is indicated nuclear
magnetic resonance may be used .The advantage of MRI over the
X-Ray or CT for the pelvic assessment is the lack of ionizing
radiation exposure.
Indications:
1-Clinical evidence or obstetric history suggestive of pelvic
abnormalities.
2-Ahistory of pelvic trauma.