Female Pelvis

1. KANCHAN MEHRA
NURSING LECTURER
NCON
FEMALE PELVIS

2. INTRODUCTION
Pelvis is a basin shaped structure that connects the trunk and the legs ,
supports and balance the trunk .
The pelvis is important from the obstetrics points of view , as it forms
passage through which the fetus has to pass.

4. BONE
 Bones forming the female pelvis –
4 bones :
1. Innominate bone(Coxal bone) – 2
2. Sacrum – 1
3. Pubis – 1

5.  2 Innominate bone consists of three parts:
- Illium
- Ischium
- Pubis

6. Illium
Illium is a large flared outer part.
- Illiac crest: it is upper border of illium and when we place hand on hip it
rest on the illiac crest
- Illiac fossa: the concave anterior surface of the illium is the illiac fossa.
- Illiac spine : anterior and posterior side of illium consist of 2 bony
projection.
 Anterior superior illiac spine
 Anterior inferior illiac spine
 Posterior superior illiac spine
 Posterior inferior illiac spine

7. ISCHIUM
Ischium is the thick lower part of innominate bone.
 Ischial tubersity: Ischial tubersity has a large prominence on which
body rest while sitting.
 Ischial spine: Behind and little above the ischial tubersity is an
inward projection known as ischal spine .
- In labor, the station of the head is estimated in relation to the ischial
spine.

8. PUBIC BONE
Pubic bone forms the anterior part of the two innominate bone
 Body of Pubis: thick and flat part of the pubis.
 Superior and inferior rami: Two arms like projections.
 Pubic arch: inferior rami fused to form pubic arch.
 Obturator formane : created by ischium and pubic bone through
which nerves and blood supply pass.
 Acetabulam: Deep cup like structure that receive the hand of the
femur.

10. SACRUM
Sacrum is made of five flattened and fused sacral vertebrae.
 Sacral Promontory: Upper border of 1st sacral vertebrae is known
as Sacral Promontory
 Ala of sacrum: lateral side of Sacral Promontory is known as Ala/
wing of sacrum

11. COCCYX
Four coccygeal vertebrae are fused together and forming a small
triangular bone.
 Uper end of this bone joins with the lower end of the sacrum and the
lower end is free.
 It can move backward during labour which allow the fetus head to
pass through it

13. JOINTS
There are four pelvic joints -
 One symphysis pubis: it formed at the junction of two pelvic bones
which are united by a pad of cartilage.
 Two sacroilliac joint: These are the strongest joints in the body.
They join sacrum to the illium bone.
 One sacrococcygeal joint: Between the sacrum and coccyx

15. PELVIC LIGAMENT
Each of the pelvic joints is healed together by the ligaments.
 Interpubic ligament: Lies between the 2 pubic bone.
 Sacroilliac ligament: Ligament lies between the sacrum and Illium.
 Sacrococcgeal ligament: Between the sacrum and coccyx.
 Sacrospinous ligament: Lateral aspect of the sacrum to ischial
spine.
 Sacrotuberous ligament: Runs from sacrum to the ischial tuberosity.

17. PELVIC LANDMARKS
1. Symphysis pubis
2. Pubic crest (upper border of the symphysis pubis)
3. Pubic tubercle (superior ramus of the pubic bone)
4. Pectinal line of pubis
5. Illiopubic eminence
6. Illiopectinal line
7. Sacroilliac joint
8. Ala of sacrum/ sacral wing
9. Sacral promontory

20. PELVIC DEVISION
1) False pelvis
2) True pelvis
False pelvis : The false pelvis is formed by the iliac portions of the
innominate bones and is limited above by the iliac crests. It has got little
obstetric significance.
 Its only obstetric function is to support the enlarged uterus during pregnancy.
True Pelvis : It forms the canal through which the fetus has to pass. it is
divided into inlet, cavity (Brim) and outlet.

22. DIAMETER OF PELVIS
 INLET: As the inlet is the brim of the pelvis, the circumference of
the inlet is formed by the bony landmarks.
Diameters:
 Anteroposterior(11cm):
ANATOMICAL: It is the distance between the midpoint of the
sacral promontory to the inner margin of the upper border of
symphysis pubis It measures 11 cm

23.  Obstetric conjugate: It is the distance between the midpoint of
the sacral promontory to prominent bony projection in the midline
on the inner surface of the symphysis pubis.It measures 10 cm.
 Diagonal conjugate: It is the distance between the midpoint on
the sacral promontory to lower border of symphysis pubis. It
measures 12 cm.

24.  Oblique diameters: There are two oblique diameters— right and left.
Each one extends from one sacroiliac joint to the opposite iliopubic
eminence and measures 12 cm
 Transverse diameter: It is the distance between the two farthest points
on the pelvic brim over the iliopectineal lines. It measures 13 cm

25. CAVITY
 It is almost round, it is difficult to measure the diameters. All
diameters are same. It measures abour 12 cm

26. OUTLET
 Obstetrical outlet:
 Anteroroposterior - from the tip of the sacrum to the lower border
of symphysis pubis. It measures abour 13 cm
Oblique- it extends from right and left sacrospinous ligament to
obturator foramen. It measures abour 12 cm
Transverse- It is the distance between the tip of two ischial spines. it
is smallest diameter of pelvis. It measures abour 11 cm

27. DIAMETER OF PELVIS