for graduate and undergraduate students

1. FEMALE PELVIS
By: Maj Saminder Malik
MSc (N) Obs & Gyn

3. INTRODUCTION
 important from obstetric point of view
 Forms passage for fetus to pass through the birth canal

5. PELVIC BONES
Female pelvis is formed by 04 pelvic bones
1. Innominate bones- 2
2. sacrum – 1
3. Coccyx - 1

7. INNOMINATE BONES
Consists of 3 parts
Ilium
Ischium
pubis

10. ILIUM
o Large flared outer part
o Iliac crest: it is the upper border of ilium and when we place
hand on the hip it rest on the iliac crest
o Iliac spine: the anterior side and posterior side of ilium consists
of two bony projections each namely
1. anterior superior iliac spine
2. anterior inferior iliac spine
1. posterior superior iliac spine
2. posterior inferior iliac spine
o Iliac fossa: The concave anterior surface of the ilium is the iliac
fossa

11. ISHCHIUM
It is the thick lower part of innominate bone
Ishchial tuberosity: large prominence on which body rest while
sitting
Ishchial spine: an inward projection behind and above ishchial
tuberosity. During labor station of head is estimated in relation to
ishchial spine

12. PUBIC BONE
Forms the anterior part of innominate bone
Body of pubis: thick and flat part of pubic bone
Ramii: two arm like projection - superior & inferior
Symphysis pubis: the joint between two pubic bones
Pubic arch: formed by the infusion of inferior ramii
Obturator foramen: space enclosed by pubic ramii, pubic bone and
ishchium
Sciatic notch: curves on the lower border of innominate bones., for
passage of great vessels
Greater sciatic notch: extends from posterior inferior iliac spine to the
ishchial spine
Lesser sciatic notch: between ishchial spine and ishchial tuberosity
Acetabulum: deep cup like structure to receive head of femur

14. SACRUM
Wedge shaped bone consisting 05 fused vertebrae
Sacral promontory: Upper border of 1st sacral vertebra is known
as sacral promontory
Ala of sacrum: Lateral side of sacral promontory is known as ala
of sacrum or wing of sacrum
Halo of sacrum: There are two pairs of holes through which
nerves are entering into the pelvic organs

15. COCCYX
Vestigial tail
Consists of 04 fused vertebral
Forms a triangular bone

16. PELVIC JOINTS
Sacroiliac Joints= 02 , strongest joints in body , connects sacrum
with ilium
Sacrococcygeal= 1, base of coccyx articulates with tip of sacrum.
Movement of this joint during labor facilitates smooth passage of
the baby
Symphysis pubis: form at the junction of two pubic bones, united
by a pad of cartilage

18. PELVIC LIGAMENTS
Each joint is held by the ligaments
Sacroiliac ligament: medial surface of ilium to sacrum
Sacrospinous ligament: Lateral aspect of the sacrum to ishchial
spines
Sacrotuberous ligament: Lateral aspect of sacrum to inner
aspect of ishchial tuberosity
Interpubic ligament: Between two pubic bones
Iliolumbar ligament: iliac crest to lumbar vertebrae

20. TYPE OF PELVIS
False pelvis
True pelvis

21. FALSE PELVIS
No obstetric importance
Above the pelvic brim / true pelvis
Anterior: abdominal wall
Posterior: lumbar vertebrae
Lateral: iliac crest

22. TRUE PELVIS
Bone defined tunnel through which baby has to pass during birth
- pelvic brim
- pelvic cavity
- pelvic outlets

24. PELVIC BRIM
Almost round in shape except at the side of sacral promontory
Poste: Ala or wings of sacrum, sacral promontory
Lateral: iliac bones and its lateral borders
Anterior : pubic bones
Plane of brim is 55 to 60⁰ above the horizontal plane

25. LANDMARKS OF INLET OR BRIM
1. Sacral promontory
2. Ala of sacrum
3. Sacroiliac joint
4. Iliopectineal line
5. Iliopubic eminence
6. Pectineal line
7. Pubic tubercle
8. Pubic crest
9. Symphysis pubis

26. PELVIC CAVITY
Above: brim
Below: outlet
Anterior: pubic bone & pubic symphysis
Posterior: curve of sacrum
Measurement: 12 cm diameter

27. PELVIC OUTLET
Lower part of true pelvis
1. anatomical outlet: Lower borders of each of the bone together
with sacrotuberous ligament
2. Obstetrical outlet: diamond shaped
AP diameter – sacrococcygeal joint to lower border of symphysis
pubis
Transverse : between two ishchial spine and two ischial
tuberosities

28. PELVIC MUSCLES
Inner aspect of bony pelvis is covered with muscle
Above the brim: iliac & psoas
Side walls: obturator internus and its fascia
Posterior: Pyriformis
Pelvic floor: Levator Anii & Coccygenous

30. PELVIC DIAMETERS (INLET)
ANTEROPOSTERIOR
True Conjugate: from tip of sacral promontory to upper border of
symphysis pubis12cm
Obstetric conjugate: from tip of sacral promontory to the most
bulging point on the back of symphysis pubis (1cm below its upper
border)10.5 cm
Diagonal Conjugate: from tip of sacral promontory to lower
border of symphysis pubis 12-12.5cm
TRANSVERSE DIAMETER
Two farthest points on iliopectineal lines (4cm from promontory &
7cm from symphysis pubis) largest diameter in pelvis 13cm
OBLIQUE DIAMETER
sacroiliac joint to iliopectineal eminence 12 cm (Rt and Lt)

31. PELVIC CAVITY
Round
All diameters are same 12 cm

33. PELVIC OUTLET
Obstetric
AP: from tip of sacrum to lower border of symphysis pubis as coccyx
moves backwards in 2nd stage of labor (13cm)
Transverse: between ishchial spines (10.5 cm)
Anatomical
AP: from tip of coccyx to lower border of symphysis pubis
Transverse: inner aspect of ishchial tuberosities

34. CLASSIFICATION OF PELVIS
Gynecoid pelvis
Android pelvis
Anthropoid pelvis
Platypelloid pelvis

36. GYNAECOID PELVIS
Female pelvis
50% females
Rounded – slightly oval inlet
Straight pelvic sidewalls with roomy pelvic cavity
Good sacral curve
Ishchial spine not prominent
Pubic arch is wide

37. ANDROID PELVIS
Male pelvis
Pelvic brim is heart shaped convergent sidewalls
Narrow pubic arch
Prominent spines

38. ANTHROPOID & PLATYPELLOID
ANTHROPID
Long and narrow pelvic canal AP diameter is more than
transverse diameter
Straight pelvis side walls
PLATYPELLOID
3% women
TD is much more than AP diameter
Sacral promontory pushed forward

39. IDEAL OBSTETRIC PELVIS
Brim: round or oval transversely
No undue projection of sacral promontory
AP: 12 cm
TD: 13cm
Plane of pelvic inlet 55degree
Cavity: shallow with straight side walls, no great projections of ischial
spines and smooth sacral curve
Outlet: rounded pubic arch with suprapubic angle more than 80⁰
Intertuberous diameter more than 10cm

40. FAVOURABLE PELVIS
Sacral promontory cannot be felt
Ischial spine not prominent
Suprapubic arch accept 2 fingers
Intertuberous diameter accepts 4 knuckles on pelvic exam

41. PELVIC DEFORMITIES

42. PELVIC DEFORMITIES