Anatomy of the bony Anatomy of the bony pel ispel ispelvis pelvis

Lateefa Al DakhyelLateefa Al Dakhyel FRCSC, FACOGFRCSC, FACOGAssistant professor & consultantAssistant professor & consultant

Obstetric &Obstetric & gynecology departmentgynecology departmentCollage of medicineCollage of medicineKi S d U i itKi S d U i itKing Saud UniversityKing Saud University

Q.1- the clinically important important diameter in pelvic inlet is:1-true conjugate2-obesteric conjugate2 obesteric conjugate

3-diagunal conjugate4- all of the above

Q 2 t t f l i i Q.2- most common type of pelvis is1- gynecoid2-anthropoid3-platlypelloidp yp4-android

Q.3-the narrowest diameter in the pelvis is1 interspinous1-interspinous2-anteroposterior of mid pelvis3-oblique diameter4.obestric conjugate

Q.4-Which statement is incorrect1-adequcy of female pelvis for labor can be accurately assessed by CT scan2 progress of labor is the true assessment of female pelvis2. progress of labor is the true assessment of female pelvis3.labor dystocia can caused by android pelvis4.intra labor pelvic assessment can be done

Female bony pelvisFemale bony pelvisy py p False pelvis False pelvis lies above the linea terminalis (pelvic brim)lies above the linea terminalis (pelvic brim)has no obstet ical significancehas no obstet ical significancehas no obstetrical significance.has no obstetrical significance. True pelvis True pelvis Lies below linea terminalis (pelvic brim)Lies below linea terminalis (pelvic brim)has important role in child birthhas important role in child birthIt has inlet, cavity & outletIt has inlet, cavity & outlet

True pelvisTrue pelvisPelvic inletPelvic inlet (superior strait)(superior strait)Pelvic inlet Pelvic inlet (superior strait)(superior strait)boundaries: a. boundaries: a. ramirami of Pubic bone, of Pubic bone, symphysissymphysis pubispubis

p. sacral promontoryp. sacral promontoryp p yp p yl. l. linealinea terminalisterminalis

diameters: diameters: 11 anteroposterior diameteranteroposterior diameter11.anteroposterior diameter .anteroposterior diameter obstetrical conjugate:obstetrical conjugate:shortest distance between the promontory and shortest distance between the promontory and symphysissymphysis pubispubisnormally measuresnormally measures 1010cm or more.cm or more.normally measures normally measures 1010cm or more. cm or more. (others: true conjugate & diagonal conjugate)(others: true conjugate & diagonal conjugate)

22.The transverse diameter .The transverse diameter greatest distance between greatest distance between linealinea terminalisterminalis on either side on either side

33.Rt & Lt oblique diameter .Rt & Lt oblique diameter extend from one of the sacroiliac extend from one of the sacroiliac synchondrosessynchondroses to the to the iliopectinealiliopectineal

eminence on the other sideeminence on the other side

Mid pelvisMid pelvis--at the level of ischial spines at the level of ischial spines

--interspinous diameter usually ~interspinous diameter usually ~1010cm cm

-- Smallest diameter of the pelvisSmallest diameter of the pelvis

Pelvic outletPelvic outlet Pelvic outletPelvic outlet--boundaries a. the area under the pubic archboundaries a. the area under the pubic arch

p. the tip of the sacrump. the tip of the sacruml. l. ischialischial tuberositiestuberosities, , sacrosciaticsacrosciatic ligmentsligments

--diametersdiameters11 Anteroposterior diameter(Anteroposterior diameter(99 55--1111 55))11.Anteroposterior diameter(.Anteroposterior diameter(99..55 1111..55))from the lower margins of the from the lower margins of the symphesissymphesis pubis to the tip of the sacrumpubis to the tip of the sacrum22. The transverse diameter (. The transverse diameter (1111cm)cm)th di t b t th i d f thth di t b t th i d f th i hi li hi l t b itit b itithe distance between the inner edges of the the distance between the inner edges of the ischialischial tuberositistuberositis..33.The posterior .The posterior sagittalsagittal diameter (>diameter (>77..55))from the tip of the sacrum to the line between from the tip of the sacrum to the line between ischialischial tuberositistuberositis

Pelvic shapesPelvic shapesCaldwellCaldwell--Moloy classificationMoloy classification--A line drawn through the greatest diameter of the inlet divides it to ant. A line drawn through the greatest diameter of the inlet divides it to ant. g gg g

& post.& post.

Gynaecoid pelvis:Gynaecoid pelvis:

1.1.It is the commonest type (It is the commonest type (5050%)%)2.2.Inlet is slightly oval or round (TD~APD)Inlet is slightly oval or round (TD~APD)3.3.Sacrum is wide with average concavity and Sacrum is wide with average concavity and g yg y

inclination. inclination. 4.4.ischial spines not prominent (transverse ischial spines not prominent (transverse

diameter is = >diameter is = >1010cm) cm) 5.5.SacroSacro--sciatic notch is wide.sciatic notch is wide.6.6. wide pubic archwide pubic arch

Anthropoid pelvis:Anthropoid pelvis:1.1.It makes It makes 2525% of white & ~ % of white & ~ 5050% of nonwhite % of nonwhite

womenwomenwomen.women.2.2.All anteroposterior diameters are more than All anteroposterior diameters are more than

transverse diameters (Oval anteroposteriorly)transverse diameters (Oval anteroposteriorly)transverse diameters (Oval anteroposteriorly)transverse diameters (Oval anteroposteriorly)3.3.Ischial spines mostly prominent.Ischial spines mostly prominent.44 Sacrum is long and narrowSacrum is long and narrow4.4.Sacrum is long and narrow. Sacrum is long and narrow. 5.5.SacroSacro--sciatic notch is wide. sciatic notch is wide.

66 S b bi l iS b bi l i6.6.Subpubic angle is narrow.Subpubic angle is narrow.

Android pelvis :Android pelvis :Android pelvis :Android pelvis :1.1.It is~ It is~ 3030% of white & ~% of white & ~1515% % 00f nonwhite women. f nonwhite women. 22 Inlet is triangular or heartInlet is triangular or heart--shaped with anterior narrowshaped with anterior narrow2.2.Inlet is triangular or heartInlet is triangular or heart--shaped with anterior narrow shaped with anterior narrow

apex. apex. 3.3.Side walls are converging (funnel pelvis) with projecting Side walls are converging (funnel pelvis) with projecting

ischial spines. ischial spines. 4.4.SacroSacro--sciatic notch is narrow. sciatic notch is narrow.

5.5.Subpubic angle is narrow

PlatypelloidPlatypelloid pelvis :pelvis : PlatypelloidPlatypelloid pelvis :pelvis :

11 It is a flat female type it is rarest ~It is a flat female type it is rarest ~33% of% of1.1.It is a flat female type, it is rarest ~It is a flat female type, it is rarest ~33% of % of women only.women only.

2.2.All All anteroposterioranteroposterior diameters are short. diameters are short. pp3.3.All transverse diameters are long (oval All transverse diameters are long (oval

transverse)transverse)4.4.SacroSacro--sciatic notch is narrow. sciatic notch is narrow. 5.5.SubpubicSubpubic angle is wide.angle is wide.6.6.The sacrum usually is well curved and rotated The sacrum usually is well curved and rotated

backward.backward.

IntermediateIntermediate--type pelvistype pelvisyp pyp pmixed types are much more frequent than pure types.mixed types are much more frequent than pure types.

significant clinical points significant clinical points --obstructed labor caused narrowing of midpelvis or pelvic obstructed labor caused narrowing of midpelvis or pelvic

outletoutletoutletoutlet--obstetric conjugate obstetric conjugate can be measured radiological only, can be measured radiological only,

diagonal conjugate can be estimated clinicallydiagonal conjugate can be estimated clinicallyg j gg j g--ischial spins can be felt with vaginal examischial spins can be felt with vaginal exam--most important test for pelvic adequacy is labor progress it most important test for pelvic adequacy is labor progress it

lflfselfself

Clinical estimation of pelvic sizeClinical estimation of pelvic sizeClinical estimation of pelvic sizeClinical estimation of pelvic size

Best test of pelvic adequacy is progress of labor it self

History of vaginal delivery of average weight fetus means the pelvic is

adequate. Pelvic inadequacy: -big baby

-small pelvis-abnormal positionabnormal position