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Topic

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Fundus of uterus in pregnancy

The fundus of the uterus is the rounded superior portion of the uterus, located above the openings of the uterine (fallopian) tubes. It represents the uppermost convex part of the uterine cavity and forms an important anatomical landmark in gynecology and obstetrics.

It plays a central role in pregnancy, being the site where the placenta often implants, and its position and height are used clinically to estimate gestational age during antenatal care. In gynecology, the fundus is a landmark for uterine orientation (anteverted vs retroverted) and pathology such as fibroids or congenital anomalies.

Synonyms

  • Uterine fundus

  • Fundal portion of uterus

  • Superior uterine dome

Structure

  • Myometrium: Thick muscular wall forming the bulk of the fundus, capable of powerful contractions during labor

  • Endometrium: Lining mucosa, continuous with uterine cavity, responsive to hormonal changes

  • Serosa (peritoneum): Outer covering, continuous with peritoneum of abdominal cavity

Relations

  • Superiorly: Covered by peritoneum and related to small intestine and sigmoid colon

  • Laterally: Continuous with uterine tubes at cornua (tubal openings)

  • Inferiorly: Continuous with uterine body

  • Posteriorly: Related to loops of small intestine or sigmoid colon

  • Anteriorly: Related to urinary bladder when full

Function

  • Acts as the superior pole of the uterine cavity

  • Provides implantation site for fertilized ovum and placental attachment in pregnancy

  • Contracts strongly during labor to help expel fetus and placenta

  • Used clinically to measure fundal height in obstetrics, estimating fetal growth and gestational age

Clinical Significance

  • Pregnancy monitoring: Fundal height correlates with gestational age

  • Placental location: Common site of implantation; fundal placenta considered normal

  • Fibroids: Subserosal or intramural fibroids commonly arise in fundal region

  • Congenital anomalies: Bicornuate or septate uterus affects shape of fundus

  • Uterine rupture: Fundal rupture is rare but serious, often associated with previous cesarean scar extension

MRI Appearance

T2 HASTE (T2 GRE):

  • Myometrium of fundus: intermediate signal intensity

  • Endometrium lining: bright hyperintense stripe

  • Junctional zone (inner myometrium): low hypointense band

  • Pathology (fibroids, adenomyosis): appears as focal low or heterogeneous signal within fundus

T1 GRE:

  • Fundal myometrium: isointense to slightly hypointense compared to pelvic muscles

  • Endometrium: thin isointense or slightly higher signal line

  • Hemorrhagic or pathological lesions (e.g., fibroid degeneration, endometrial changes): bright hyperintense foci

MRI image

fundus of uterus in pregnancy