Pelvimetry, a process of measurement of pelvis area.

1. Obstetrical Anatomy
M. Zakria Rehman

2. The bony structures of the pelvis is comprised
of
Sacrum
• First to third coccygeal vertebra, and
The two os-coxae, each formed by
the
• Ilium
• Ischium
• Pubis

4. 1. SACROILIAC LIGAMENTS
2. SACROSCIATIC LIGAMENTS

5. PELVIMETRY
Is the technique of measuring the dimensions of the
osseous pelvis from which the approximate pelvic area
is calculated.

6. Indications
• To select heifers at the time of joining breeding programme.
• Pregnancy testing for dystocia-free calving.
• To predict a possible dystocia due to feto-pelvic disproportion.

7. Types of pelvimetry
External or indirect pelvimetry
Internal or direct pelvimetry

8. Pelvic Caliber
External Type Internal Type

9. EXTERNAL PELVIMETRY
• This is arrived at by determining the diameters of pelvis from
certain body measurements.
• The following external pelvic measurements are taken
A = Distance between the external angle of the ilium (cm)
B = Distance between the ischial tuberosity (cm)
C = Distance between the summit of the croup and the hip joint
(cm)

10. Distance between the external angle of the ilium (cm) = A

11. Distance between the ischial tuberosity (cm) = B

12. Distance between the summit of the croup and the hip joint (cm) : C

13. S.No. Measurement Formula
1. Transverse diameter of pelvic outlet : ¼ (A+B)
2. Vertical diameter of pelvic outlet : ¾ x C
3. Transverse diameter of pelvic inlet : 12.2/10 x (Transverse diameter of pelvic
outlet)
4. Vertical diameter of pelvic inlet : 13/10 x (vertical diameter of pelvic
outlet).
Based on the measurements the pelvic area is calculated as follows

14. VERTICAL DIAMETER

15. HORIZONTAL DIAMETER

16. PELVIC INLET

17. Formulae for Pelvis Area (cm2)

18. SHAPE AND BIOMETRY OF BONY PELVIS
Species Shape of pelvic
inlet
Sacro-pubic
(Cm)
Bisiliac
(Cm)
Cow Elliptical 19.0 – 24.1 14.6 – 19.0
Mare Round 20.3 – 25.4 19.0 – 24.1
Sheep Elliptical 7.6 – 10.8 5.7 – 8.9
Sow Elliptical 9.5 – 15.2 6.3 – 10.2
Bitch Round 3.3 – 6.3 2.8 – 5.7

19. Calculate the weight of calf considering the pelvic
area…