anatomy of bony pelvis

1. BONY PELVIS
Dr. Chudamani Pokhrel
Assist. Professor
Dept. Of Human Anatomy
BPKIHS, Dharan

2. BONY PELVIS OR PELVIC GIRDLE
Ilium
Ischium
Pubis
Sacrum
Coccyx
2
Ring of bones made up
of Four Bones :
1. Two hip bones
2. Sacrum
3. Coccyx
Derived from latin word
means Basin
ASIS
AC
OF
Ischial
spine

3. HIP BONE
3

4. ISCHIUM AND PUBIS
4

5. BONY PELVIS OR PELVIC GIRDLE
Pubic symphysis
Sacro-iliac joint
Sacro-coccygeal joint
5
Four Joints :
1. Two sacro-iliac joint
2. Pubic symphysis
3. Sacro-coccygeal joint

6. The Female Pelvis
Anatomy
Pelvic Diameters
Pelvic Types

7. The Female Pelvis
1. False pelvis: Above the pelvic brim and has no obstetric
importance.
2. True pelvis: Below the pelvic brim. It is the bone defined
tunnel that the infant must traverse at birth.
Pelvic brim/Inlet

8. False pelvis:
•Also called greater pelvis
•Contains abdominal organs
True pelvis:
•Also called lesser pelvis
•Contains pelvic organs
•It has inlet, cavity & outlet

9. TRUE PELVIS/LESSER PELVIS
CONTENTS:
A. BONES :
1. Pubic symphysis and
pubic bone
2. Sacrum and coccyx
3. Rami of pubis bone
4. Ischium and its rami
5. Part of ilium
B. Obturator membrane
C. Sacrocrospinous and
sacrotuberous ligaments
D. Muscles
E. Pelvic organs
I
Isch
P
PS
S
C
ASIS
PSIS
Sacrotuberous ligament
Sacrotuberous
ligament

10. or sacral line
PELVIC INLET

12. 12
Anatomical position of pelvis

13. PELVIMETRY
The importance of pelvimetry is mainly obstetrics, but also in
forensic and crime investigations
Helps to figure out whether head of the fetus can fit or not.

14. PELVIMETRY
Methods of Pelvimetry:
1. Skeletonized pelvis
2. Clinical pelvimetry on living subjects
3. Radiological pelvimetry

15. CLINICAL PELVIMETRY

16. Dimensions for External Clinical Pelvimetry
Interspinous distance
•(Between ASIS) : 22-25cm
Intercristal distance
•(Widest distance between Iliac crest) : 25-28cm
External conjugate or Baudeloque’s distance
•Tip of S5 to Pubic sumphysis (Upper border): >19cm
Intertuberous distance:10cm
A-P diameter of pelvic outlet: 13cm

18. Dimensions for Internal Clinical Pelvimetry
 A process used to assess the size of the birth canal by
means of the systematic vaginal palpation of specific bony
landmarks in the pelvis and an estimation of the distances
between them.

19. Dimensions of female pelvis

20. Dimensions of female pelvis : Pelvic Inlet
Oblique diameter : Sacroiliac joint- opposite iliopubic eminence : 12cm

21. Oblique diameter

23. Dimensions of female pelvis : Pelvic cavity
A-P diameter: 12cm
MP of S3 - post. surface of
pubic symphysis
Transverse diameter: 12cm
MP of S3 - post. surface of
pubic symphysis
Oblique diameter: 12cm
SI joint –oppos. Oburator
membrane

24. Dimensions of female pelvis : Pelvic outlet
A-P diameter: 13cm
Tip of coccyx - inf. margin
of pubic symphysis
Largest diameter
Oblique diameter: 12cm
MP of ischiopubic ramus to
MP of oppo. sacrotuberous
ligament
Transverse diameter: 11cm
Between two ischial
tuberosity

25. TYPES OF FEMALE PELVIS

26. Four types of Female Pelvis
The Caldwell-Moloy’s classification
• They differ in:
 Shape of the pelvic inlet
 Shape of the side-walls
 Character of the subpubic arch
• Four types do exist:
1. Gynecoid: 50%.
2. Android: 20%.
3. Anthropoid: 25%.
4. Platypelloid: 5%.
The truth is that the majority of the
pelves are a mixture of all the 4
types.

27. Gynecoid
Android
Anthropoid Platypelloid
Rounded
Trans. Diameter Slightly behind
the centre
Heart shaped
Trans. Diameter Near the
sacrum
AP diameter>Trans.
Wide Trans. diameter

29. Only a Gynecoid and Platyleoid (narrow pelvic cavity)
permits normal delivery without difficulty in deliver, though
gynecoid pelvis permits safe and easier delivery than the
rest.

30. MALE VS FEMALE PELVIS

33. THANK YOU