anatomy of female plevis.pptx

Female pelvis, pelvic inlet, outlet,midpelvis, greatest pelvic dimensions,,waste space of Morris, Caldwell Moloy classification, naegele's pelvis, Robert's pelvis , subpubic angle,Gynaecoid pelvis, Android pelvis, anthropoid pelvis, platypelloid pelvis, Sacrosciatic notch, interspinous diameter, inter tuberous diameter

1. Anatomy of Female Pelvis

2. Female pelvis Pelvis may be divided by the linea terminalis into 2 parts Upper part- pelvis major or false pelvis- no Obstetric significance Lower part- pelvis minor or true pelvis Linea terminalis- upper border of Sacral vertebrae, arcuate line of ilium and pectineal line of pubis.

3. True pelvis True pelvis lies below and behind the linea terminals. Walls of true pelvis are partly bony and partly ligamentous Boundaries- Above- Promontory And alae of sacrum, linea terminalis, upper margin of pubic bones Below- pelvic outlet Posterior- anterior surface of sacrum Laterally- inner surface of ischial bones,sacrosciatic notches and ligaments Anterior- pubic bones, ascending superior rami of ischial bones,obturator foramina

4. Pelvic cavity Cylindrical in shape Extends from pelvic brim or inlet from above to outlet below Posterior wall( 10cm)is deeper than anterior wall(5cm) In erect posture, Upper part of the cavity – downwards and backwards Lower part – downward and forwards- curve of Carus

5. Pelvic musculature Boundaries- Sides- pyriformis Posterior- coccygeus muscle Lateral- obturator internus Inferior- levator ani Pelvic diaphragm - musculoaponeurotic part separating the pelvis above from the perineum and vulva below. Formed by levator ani and coccygeus 3 orifices- urinary meatus, vulval outlet, anus.

6. Planes and Diameters of the Pelvis In true pelvis, diameters are taken at different planes. Plane of Pelvic inlet ( superior strait) Plane of pelvic outlet ( inferior strait) Plane of least pelvic dimensions ( midpelvis) Plane of greatest pelvic dimensions ( no obstetrical significance)

7. Pelvic inlet Boundaries- Posterior- sacral Promontory and alae of sacrum Lateral – linea terminalis Anterior- Horizontal rami of pubic bones and pubic symphysis 3 Diameters Anteroposterior diameter Transverse diameter Oblique diameter

8. Anteroposterior diameter of inlet Anatomical conjugate or true conjugate ( 11cm) - distance between sacral Promontory and upper portion of inner surface of pubic symphysis. Obstetrical conjugate ( 10cm)- between sacral Promontory nad nearest point on posterior surface of pubic symphysis. Shortest diameter through which the presenting part of the fetus must pass at the time of delivery. It is indirectly measured by using diagonal conjugate.

9. AP diameter of inlet Diagonal conjugate (11.5-12cm)- sacral Promontory to apex of pubic arch. Clinically measurable, Obstetrical conjugate is calculated by subtracting 1.5- 2cm from the diagonal conjugate, depending on the thickness of pubic arch.

10. Transverse diameter of inlet Greatest distance between the linea terminalis on either side. Measures about 13.5 cm It intersects the diagonal conjugate at a point, 4cm in front of the Promontory Segment posterior to the intersection- Posterior sagittal diameter of inlet- it facilitates the descent of fetal head

11. Oblique diameter of inlet Extends from sacroiliac joint on one side to ilio pectineal eminence on other side. Right oblique diameter- right sacroiliac joint to ilio pectineal eminence on left side Left oblique diameter- left sacroiliac joint to ilio pectineal eminence on right side. Measures about 13cm

12. Pelvic outlet Irregular in outline, resembles 2 triangles in different planes with their bases meeting at the line of inter-ischial spine. Boundaries- Posterior- tip of the coccyx. Lateral- ischial tuberosity Anterior- pubic arch( formed by inferior rami of ischium and pubis as they converge towards pubic symphysis)

13. Diameters of pelvic outlet 3 diameters Anteroposterior diameter( 9.5 – 11.5cm)- inferior border of pubic symphysis to posterior aspect of tip of scrum. Transverse diameter (11cm)- between the inner edges of ischial tuberosities. Posterior sagittal diameter of outlet (7.5cm) – from the midpoint of line between ischial tuberoisties and external surface of the tip of the sacrum.

14. Plane of least pelvic dimensions ( Midpelvis) Boundaries- Anterior- lower margin of pubic symphysis Lateral- ischial spines Posterior- tip of the sacrum. 3 diameters Anteroposterior diameter (11.5cm) – midsymphysis to fused S2,S3 Transverse or interspinous diameter (10cm)- between the base of ischial spines. Smallest diameter of pelvis. Posterior sagittal diameter (4.5cm)- midpoint of the line between the ischial spines and sacrum.

15. Plane of greatest pelvic dimensions No obstetrical significance Boundaries- Posterior-junction of S2 ,S3, Lateral- ischial spines over the middle of acetabulum. 2 diameter Anteroposterior diameter (12.5cm) Transverse diameter (12.75cm)

16. Planes and diameters of pelvis Diameters Pelvic inlet Pelvic outlet Least pelvic dimensions Greatest pelvic dimensions AP diameter True conjugate- 11cm Obst. conjugate- 10cm Diagonal conjugate- 11.5-12cm 9.5- 11.5 cm 11.5cm 12.5 cm Transverse diameter 13.5cm 11cm 10cm 12.75cm Oblique diameter 13cm - - - Posterior sagittal diameter 4cm 7.5cm 4.5cm

17. Waste space of Morris Normally, the distance between the pubic symphysis and the edge of round disc diameter 9.3cm( approximately fetal head ) placed under sub pubic arch. Normally, the subpubic angle is well rounded and the distance between the pubic symphysis and edge of the disc should not be more than 1cm. If it is more than 1cm, AP diameter of outlet is reduced.

18. Waste space of Morris

19. Caldwell and Moloy’s classification Morphological classification of pelvis. Intermediate or Mixed type of Pelvis Most common Type of pelvis can be determined by posterior segment, while anterior segment determines the tendency. Eg- pelvis with gyneacoid posterior segment with android type of anterior segment- gynecoid pelvis with android tendency

20. Caldwell and Moloy’s classification Gynecoid pelvis Android pelvis Anthropoid pelvis Platypelloid pelvis Shape Heart shaped Funnel shaped Anteroposteriorly oval Transversely oval Inlet TD vs AP PSD vs ASD Sides of posterior segment- >/= </= Wide / well rounded < , restricts the posterior space Not rounded, anterior pelvis- narrow, triangular < Anterior segment- narrow, pointed >> Wide , flat Midpelvis Sidewalls Spines TD Straight Not prominent >/= 10cm Convergent Prominent Convergent Prominent Straight Outlet Pubic arch Wide Narrow Narrow, well shaped Very wide Sacrum Inclination Sacrosciatic notch Neither anterior nor posterior well rounded, never narrow Straight +/- curvature Narrow ,highly arched Straight Large Average Narrow

21. Clinical significance Gynecoid pelvis Android pelvis Anthropoid pelvis Platypelloid pelvis Small gynecoid pelvis Proportionately reduced diameter, with normal shape Delay at every stage of labour Occipito posterior position- m/c Incomplete rotation Deep transverse arrest Persistent Occipito posterior position Difficulty in engagement of fetal head

22. Abnormalities of pelvis Rachitic flat pelvis Nagele’s pelvis Robert’s pelvis Kyphoscoliosis Rickets Arrested development of one alae of sacrum Arrested development of both alae of sacrum Tuberculosis Rickets

23. Rachitic type of pelvis

24. Naegele’s pelvis vs Robert’s pelvis