MATERNAL PELVIS Flashcards
Pelvic brim / lamina terminalis
Public symphysis
Public crest
Public tubercle
Illeopectineal eminence
Illeopectineal line
Sacroilliac joint
Ala of sacral bone
Sacral promontory
Pelvic inlet
Pelvic brim is inlet
Cavity level vertebral
Lies at S2-S3
Pelvic outlet
Obs - at ischial spine ( mid pelvis )
Anatomical - at ischial tuberosity
AP dia of pelvis
True conj - tip of pubic symphysis to sacral promontory= 11 cm
OBSTETRICS CONJUGATE - mid of pubic symphysis to promontory = 10-10.5 cm
DIAGONAL CONJUGATE - lower border of pubic symphysis to sacral promontory = 12 cm
Longest AP diameter
DIAGONAL CONJUGATE
12 cm or more is ideal
Finger can’t touch sacral promontory on P/V examination
Formula for :
OC = DC - 1.5 to 2 cm
TC = DC - 1 cm
Smallest AP dia
Obstetric conjugate
If less than 10 cm - CONTRACTED PELVIS , VAGINAL DELIVERY NOT POSSIBLE
Transverse diameter of Pelvic inlet
2 fartherest points on illeopectineal line - 13 cm
OBLIQUE DIA
distance between one side sacroilliac joint to other side illeopectineal eminence
12 cm
Plane of Greatest pelvic dimension , significance
Mid of pubic symphysis to junction of S2 -3
Laterally - Obturator foramen
it is the roomiest part of pelvic cavity 🌟
All diameter 12 cm
Plane of least pelvic dimension , significance
Lower border of pubis symphysis to junc of S4-5
Laterally - Ischial spine
Mid pelvis lies at this dimension
Narrowest plane of pelvis
AP diameter 11.5-12 cm
Transverse dua of pelvic cavity , Significance
Interischial or Bispinous dia - b/w both ischial spines
10 cm
Most imp diameter in labour
Measure by touching both ischial spines simulateouly with 2 fingers of same hand
If touched = 8 cm , CONTRACTED PELVIS
bBoundaries of anatomical outlet
ANT - END of pubic symphysis
POST - TIP OF sacrum or coccyx
Laterally - Ischial tuberosity
Clinical pelvimetry
Primigravida - 38 to 39 weeks
Multigravida - at onset of labour
Contracted pelvis definition
Any essential diameter shortened by 0.5 cm
Contracted inlet - obstetric conjugate <10 cm
Contracted mid pelvis - IID <= 8 CM
CONTRACTED OUTLET - bituberoud dia <=8 cm
Mgt contracted pelvis
Diagnosed by Clinical pelvimetry
Delivery by C section
No role of trial of labour
Normal varieties of pelvis , Criteria, name of classification
Gynecoid - M/C 50%
ANDROID
ANTHROPOID
PLATYPELLOID / FLAT BOWL SHAPED / FLAT GYNECOID PELVIS
CRITERIA USED TO IDENTIFY :
shape of inlet
Transverse vs AP dia
Ischieal spine
Side walls
Subpubic angles
Caldwell - Mohoy classification
CPD
Cephalo pelvic disproportion
Pelvis small for baby
Normal pelvis
Normal baby
Relative finding
May occur at inlet / mid pelvis / outlet
Diagnosis of CPD
Trial of labour > MRI > Clinical pelvimetry
CPD INDICATORS DURING LABOUR
Moulding + slow progression of labour
Caput succedaneum + slow progress of labour
