Normal GYN Anatomy

1. SONO 202 OB/GYN
ONLINE REVIEW
Normal Anatomy and Physiology of the
Female Pelvis

2. The bones of the pelvis:
 1. 2 innominate
 2. sacrum
 3. coccyx
 *Iliopectineal line(linea terminalis)
separates the true and false pelvis.
Extends from the sacral prominence to the
pubic symphysis.

4. The muscles of the false pelvis.
 1. psoas major
 2. iliopsoas/iliacus

5. The muscles of the true pelvis.
 1. levator ani and coccygeus
 2. Obturator internus
 3. piriformis

11. Bladder/Ureters
 Bladder is located posterior to the
symphysis pubis and anterior to vagina.
 Ureters are not normally seen
sonographically. May see urine “jets”.

14. Vagina
 The vagina is located posterior to bladder,
anterior to rectum
 Length- 9 cm
 The fornices are potential spaces.
Posterior fornix surrounds the posterior
aspect of the external cervix. Lateral fornix
surround lateral aspect of cervix and
anterior fornix surrounds anterior aspect.

15. Uterus
 The uterus is composed of: fundus, body
(corpus), cervix (isthmus)
 Cervix is composed of:
endocervix, exocervix
 The 3 layers of the uterus:
 1. perimetrium
 2. myometrium
 3. endometrium

16. Uterine Size
 Nulliparous (non pregnant)- Length- 6-8
cm, AP- 3-5 cm
 Parous (past pregnancies) - Length- 8-10
cm, AP- 5-6 cm (fundus to cervix ratio 2:1)
 Postmenopausal (after menopause)-
Length- 3-5 cm, AP- 2-3 cm. (fundus to
cervix ratio 1:1)
 * Size of the uterus depends on age and
number of pregnancies!

17. Pediatric Uterus/Cervix
 Newborn uterus may be enlarged due to
maternal hormones in fetal circulation.
Cervix may be larger than the body of the
uterus.

20. Endometrium
 The 2 layers:
 1. superficial functional (zona functionalis)
 2. basal layer- regenerates new
endometrium
 Endometrial measurement is typically
done in the AP dimension, long
orientation.

21. Uterine Ligaments
 1. Broad Ligament- extend from lateral
aspects of the uterus, attaches to side wall
mesosalpinx, mesovarium, mesometrium
 2. Round ligament-anterior and inferior to
broad ligaments, attach cornua to anterior
wall, keep uterus tilted forward.
 Cardinal and Uterosacral-provides primary
support to uterus

24. Uterine Positions
 The following slides demonstrate the
different uterine positions.
 Version relates to the relationship of the
cervix to vagina.
 Flexion relates to the relationship of the
fundus to the cervix.

25. Most typical position seen.

30. Fallopian Tube
 Length- 7-12 cm
 4 segments of the tube:
 1. intramural (interstitial)- narrowest
segment
 2. isthmus- narrow segment
 3. ampulla – longest portion
 4. infundibulum- trumpet shaped

32. Ovaries
 Ovaries are located anterior to internal
iliac artery/vein, medial to external iliac
artery and vein
2 different layers:
1. cortex- outer layer- source of
eggs/ovulation
2. medulla- center, vessels and connective
tissue
*Ovaries produce 2 hormones: estrogen,
progesterone

33. Ovarian Size
 Ovarian volume- length x width x AP x
0.523
Varies from book to book and with age!

34. TA

35. TV

36.  2 ovarian ligaments:
 1. ovarian- posterior to fallopian tubes
 2. suspensory (infundibulopelvic)- superior
to broad ligament, lateral to fimbria

37. Pelvic Vasculature
 Vessels of the pelvis include:
 1. CIA- off of aorta
 2. EIA- off of CIA
 3. IIA- off of EIA
 4. *Ovarian vein- left into LRV, right into IVC
 5. *uterine artery- off of IIA, supplies most of
blood
 6. Ovarian artery- joins with uterine artery
 7. Arcuate arteries- in myometrium
 8. Radial arteries- feed endometrium

42. Physiology
 Period begins- around 11-13 years
(menarche)
 Ends- 45-55 years (menopause)
 Average cycle- 28 days
 Regulated by the hypothalamus.

43. Menstrual Cycle

44. Ovarian Cycle
 Follicular (Days 1-14)- dominant follicle
reaches size of 2-2.5 cm (graafian follicle)
 Presence of the cumulus oophorus
(nodule within follicle) usually results in
ovulation within 36 hours.
 Ovulatory (Day 14)- surge of LH causes
ovulation
 Luteal (Days 15-28)- formation of corpus
luteum (hypervascular)

45. Follicular Development

48. Endometrial Changes
 The menstrual phases :
 1. Menstrual phase- 1-5 days, 2 mm thick
 2. Proliferative- 6-14 days, estrogen rises
and causes endometrium to thicken, 6-8
mm
 3. Secretory- 15-28 days, corpus luteum
secretes progesterone which causes
further thickening, up to 18 mm thick

50. KNOW THIS!
*Proliferative (3 line sign) Secretory (luteal)

51. Postmenopausal Endometrium
 < 5-8 mm in asymptomatic patient
 4-5 mm is borderline thick if pt. is bleeding
and postmenopausal.
 Hormone Replacement Therapy (HRT)-
> 8 mm is considered thick for unopposed
therapy.
10-12 mm is considered thick for
estrogen phase.

52. Pelvic Recesses
 The pelvic recesses and locations.
 1. vesicouterine recess (pouch) (anterior
cul-de-sac, anterior to uterus, posterior to
bladder.
 2. rectouterine recess (pouch) (posterior
cul-de-sac) (pouch of Douglas)-posterior
to uterus, anterior to rectum.
 3. Space of Retzius- between pubic
symphysis and bladder.