sacral promontory superiormost portion of the sacrumsacrum border of the pelvic inletpelvic inlet can be touched bone marker Bones sacral promontory Sacrum : 5 fused vertebrae Coccyx : 4 fused cartilaginous bones
Ischium (3#) Coxae : ilium (2#) pubis (4#) Bones tuberosity ischial tuberosity --- marks the lateral boundary of the pelvic outlet.
Joints Symphysis pubis Greek word “growing together” Absorb shock during walking. Delivery of baby. gap of the symphysis pubis non-pregnant: 4-5mm Pregnant: less than 9mm
Joints Diastasis of the symphysis pubis result from: rapid birth; forceps delivery; prenatal; symptom: pelvic girdle pain --- involving 45% of all pregnant women and 25% of all women postpartum symphysiotomy
Ligaments 1.Extend from the lateral border of the sacrum and coccyx to the ischial spine 2.A thin, triangular ligament 3.With sacrotuberous ligament, Closes off the greater sciatic notch to form the greater sciatic foramen and closes off the lesser sciatic notch to form the lesser sciatic foramen Sacrospinous ligament
Ligaments Function -to prevent posterior rotation of the ilium with respect to the sacrum -Fixation site for pelvic organ prolapse Sacrospinous ligament sacrospinous ligament suspension the vaginal apex is suspended posteriorly and laterally to the ligament on either side or both sides
- Extend from the posterior aspect of the lower 3 sacral vertebrae to the ischial tuberosity - It is flat, and triangular in form; narrower in the middle than at the ends. Ligaments Sacrotuberous ligament
Boundary of pelvis Border line posterior upper border of sacral promontory lateral iliopectineal line anterior upper border of pubis
False pelvis ( pelvis major ) ---above the border line and has no obstetric importance. True pelvis ( pelvis minor ) ---below the border line and related to the child -birth The bone delivery canal of childbirth Boundary of pelvis The female bony pelvis is divided into:
Planes of True Pelvis pelvic inlet is heart-shape, bounded by. posteriorly upper border of sacral promontory. laterally: iliopectineal line. anteriorly: upper border of pubis anteroposterior about 11cm. transverse about 13cm oblique about 12.75cm
Mid-cavity It is a segment, the boundaries of which are: the roof is the plane of pelvic inlet, the floor is the plane of the plane of pelvic outlet, anterior - the shorter symphysis pubis, posterior - the longer sacrum. o Interspinous diameter = 10 cm between the tips of ischial spines. Planes of True Pelvis
Pelvic outlet: 2 triangular planes with 1 base which is the intertuberous diameter Planes of True Pelvis Anterior sagittal plane: apex - the lower border of the symphysis pubis. laterally: the ischiopubic arch Posterior sagittal plane: apex - the tip of the coccyx. Laterally - sacrotuberous ligament
Diameters of pelvic outlet Planes of True Pelvis Antero-posterior diameter =11.5cm from Sacro-coccygeal joint to the lower border of symphysis pubis. Transverse diameters (Bituberous diameter) = 9 cm between the inner aspects of the ischial tuberosities. Anterior sagittal diameter = 6 cm from the lower border of the symphysis pubis to the centre of the bituberous diameter. Posterior sagittal diameter = 8.5 cm from Sacro-coccygeal joint to the centre of the bituberous diameter.
Caldwell- Moloy Classification of Pelvic Types (1933) Four types of female pelves were described. Actually, the majority of pelvis are mixed types.
Gynaecoid pelvis Ideal shape, best chances for normal vaginal delivery. 1.It is the normal female type. 2.Inlet is slightly transverse oval. 3.Sacrum is wide with average concavity and inclination. 4.Side walls are straight with blunt ischial spines. 5.Sacro-sciatic notch is wide. 6.Subpubic angle is 90-100 o.
Anthropoid pelvis 1.It is ape-like type. 2.All anteroposterior diameters are long. 3.All transverse diameters are short. 4.Sacrum is long and narrow. 5.Sacro-sciatic notch is wide. 6.Subpubic angle is narrow (<90 0 ) 7.prominent ischial spines
Android pelvis 1.It is a male type. 2.Inlet is triangular or heart-shaped with anterior narrow apex. 3.Side walls are converging (funnel pelvis) 4.Projecting ischial spines. 5.Sacro-sciatic notch is narrow. 6.Subpubic angle is narrow <90o
Platypelloid pelvis 1.It is a flat female type. 2.All anteroposterior diameters are short. 3.All transverse diameters are long. 4.Sacro-sciatic notch is narrow. 5.Subpubic angle is wide
The tissues closing down the pelvic outlet (muscles and fasciae) Function - providing support for pelvic organs, e.g. the bladder, rectum, the uterus. - maintenance of continence Anterior part (urogenital triangle) urethra and vagina pass through Posterior part (anal triangle) rectum pass through
Pelvic floor Inner layer (pelvic diaphragm 盆膈 ) the main support of the pelvic floor formed by the levator ani and coccygenus muscles and covering fasciae. Levator ani: （肛提肌 ) pubococcygenus ( 耻尾肌 ), iliococcygenus ( 髂尾肌 ), puborectalis ( 坐尾肌 )
Levator ani Pubococcygenus (PC ) -a hammock-like muscle -stretches from the pubic bone to the coccyx (tail bone) -controls urine flow and position the baby's head during childbirth. Iliococcygenus (IC) - arises from the ischial spine, super ramus of the pubis, and is attached to the coccyx - Help for vaginal contraction Puborectalis (PR) sphincter ani externus sphincter ani externus - arise from the lower part of the symphysis pubis,and the superior fascia of the urogenital diaphragm, meet with the corresponding fibers of the opposite side around the lower part of the rectum, and form for it a strong sling. - Relaxation reduces the angle between rectum and anus, allowing defecation in conjunction with relaxation of the internal and external sphincters.
Pelvic floor Perineum general conception: the tissues closing down the pelvic outlet Clinical conception: the tissues between vaginal and anus. - thickness: 3-4cm - the outlayer support for pelvic floor
SUMMARY Bones Joints Ligaments planes of the pelvis Types of the female pelvis Pelvice floor