the female pelvis embryonic development fetal biometry workshop day 1
TRANSCRIPT
The Female PelvisEmbryonic Development
Fetal Biometry Workshop
Day 1
Expected Learning Outcomes
Describe embryology, anatomy, function of the female pelvis.
Describe sonographic techniques applied in the assessment of the female pelvis.
Describe congenital abnormalities of the female pelvis.
Detection of Genital Anomalies
Fetal period Urinary tract abnormalities – 50% of all congenital
anomalies Hydrometrocolpos of vagina & uterus most common Hydronephrosis or hydroureter
Neonatal period Renal in origin Hydrometrocolpos secondary to an atretic vagina
Premenarche to Adulthood Duplicated uterus with one septated vagina
Expression of Gender in Embryo
Primordial Germ Cells
Inducer Germ Cells
Embryonic Development
Genital Ducts Formation of Fallopian Tubes
Embryonic Development
Formation of the Broad Ligament
Formation of the Vagina
Mullerian Ducts
Embryological ducts fuse together during organogenesis
Form Uterus Upper portion of Vagina Fallopian tubes
Ovaries and lower vagina form from primitive YS Anomalies can lead to infertility Delayed onset of menarche Increased Risk of
IUGR Preterm labor Retained placenta
Wolffian Ducts
Embryologically sits along side with the Mullerian ducts
Male becomes the vas deferens Develops into the trigone of the urinary
bladder and ureters In absence of testosterone these regress Known remnant is Gartner’s duct cyst
Embryonic Development
Formation of the Vagina
Review – embryonic developmentUrinary System Gonads Ducts Mesenteries
3rd Week Pronephros differentiates Primordial cells in allantois
4th Week Pronephros disappears and mesoephros differentiates
Formation of genital ridges
5th Week Metanephros starts to differentiate
Migration of primordial germ cells
6th Week Primitive germ cells invade gonadal ridges
2 sets of ducts exist: wolffian and mullerian
Formation of primitive sex cords: “indifferent stage”
7th Week Primitive sex cords disappear; Cortical cords arise
8th Week Mesonephros disappears, only its duct remains
Mullerian ducts fuse to form uterovaginal canal and fallopian tubes
12th Week Ovary descends Median septum disappears
12th Week to 5th month
Metanephros [3rd stage kidney]
Cortical cords split up and surround primitive germ cells – oogonia
Formation mesosalpinix, mesovarium, broad, proper ovarian & suspensory ligaments
Pelvic Skeleton
Ring of 4 bones Sacrum Coccyx 2 large innominate or hip
bones Principle functions:
1. Weight-bearing bridge between spinal column and bones of lower limbs
2. Directs the pathway of fetal head during childbirth [parturition]
3. Protects the reproductive organs
Pelvic Skeleton
Pelvic Spaces
True Pelvis False Pelvis
Pelvic Muscles
Region Muscle Location
Abdominopelvic Rectus abdominisPsoas major
Anterior wallPosterior wall
False pelvis Iliacus Iliac fossa
True pelvis Obturator internusPiriformisCoccygeusLevator ani
Lateral wallPosterior wallPosterior floorMiddle, anterior floor
Pelvis Muscles
True Pelvis Muscles
Pelvic Organs
Urinary Bladder & urethra Uterus Fallopian tubes Vagina Ovaries Pelvic colon Rectum
Urinary Bladder & urethra
Urinary Bladder Thick-walled Highly distensible
muscular sac Lies between
symphysis pubis & vagina
The Vagina
Uterine Ligaments
Cardinal Round Broad
The Uterus
Uterus Size & Shape Newborns
“adult” contour due to maternal estrogen Infant
Small, high in pelvis, cylindrical, lies along same axis as vagina
Young girls Nearly cylindrical, body more globular
Puberty Characteristic inverted pear shape
Pregnancy Corpus and fundus grow thicker, increasing globularity
Menopause Corpus and fundus shrink and regress to prepubertal state Elderly women – little more than a cap above the cervix
Variants of Uterine Position
Anteflexed forward
Retroflexion backward
Anteverted anterior incline
Retroverted posterior incline
Retroflexed Uterus
Anteflexed Uterus
Anteverted Uterus
Uterine Malformation
Mullerian agenesis Bicornuate Unicornuate Didelphys Septated Arcuate DES exposure High incidence of uterine malformations and
renal abnormalities Abnormalities are always on the same side
Mullerian agenesis
No uterus What would be a symptom Where else should we look
Unicornuate
Only one side of the mullerian duct forms Takes on a penis shape Difficult to tell by US
Didelphys
Both mullerian ducts fail to fuse Double uterus, cervix, and vagina Endometrial cavities are widely separated Partial
Uterus Bicornis Bicollis One vagina 2 cervices 2 uterine horns 1 side has not outlet for menstrual flow
Causes hematometrocolpos Uterus Bicornis Unicollis
One vagina Once cervix 2 uterine horns
Septated Uterus
Arcuate Uterus
DES Exposure
Diethylstilbestrol Synthetic estrogen Used in 40’s-70’s Small, irregular T shaped uterus is the most
common malformation related to drug
The Fallopian Tubes
The Ovaries
Follicular Development
Ovary Location
Bladder empty – ovarian fossa Posterolateral pelvic wall beneath the brim of
pelvis Filling bladder – ovarian fossa at the sides of
uterine fundus Distended bladder – increasing pressure
forces downward in the adnexal space
The Pelvic BowelEcho pattern Shadows
Small Bowel
Variably echogenic content with thin, anechoic ring representing the muscular wall
Shifts with movement of bowel and content
Cecum Same as small bowel Constant except when peristalsis occurs
Sigmoid Echogenic content with thin, anechoic ring representing the muscular wall
Constant except when peristalsis occurs
Rectum Same as Sigmoid Constant and nearly complete; only top surface of fecal boluses can be seen
Pelvic Spaces
Adnexa
Area that is adjacent to uterus
Includes ovaries and fallopian tubes
Arterial System of Pelvis Aorta
Common iliac arteries External and internal or
hypogastric artery Internal courses down into pelvic
cavity Superior gluteal artery is
branch Oburator artery Umbilical artery Uterine-vaginal artery Superior vesical artery Internal pudendal and
inferior gluteal arteries
Venous System of the Pelvis
Inferior vena cava Common iliac veins
External iliac veins – legs
Internal iliac veins – pelvic organs and muscles
Ureter
Courses lateral pelvic wall posterior to the ovary
Enter pelvis at point just caudad to bifurcation of common iliac vessels.
Most anterior and lateral of the 3 tubular structures seen deep to the ovary
Review