What are the implications of a pelvis ultrasound (USS) showing a relationship between the uterus and the bladder?

Pelvic Ultrasound: Relationship Between the Uterus and Bladder

The relationship between the uterus and bladder on pelvic ultrasound is a normal anatomical finding that serves as an important landmark for proper imaging technique and evaluation of pelvic structures. 1

Normal Anatomical Relationship

• For transabdominal pelvic ultrasound, the bladder serves as an acoustic window that allows visualization of the uterus and other pelvic organs 1
• Optimal bladder filling occurs when the bladder dome is positioned just above the uterine fundus, creating an ideal imaging window 1
• The bladder and uterus have a direct anatomical relationship with the bladder located anteriorly to the uterus in the pelvis 1
• This relationship is important for assessing uterine position (anteverted vs. retroverted) and mobility 2

Imaging Technique Considerations

• Transabdominal ultrasound requires a distended bladder to create an acoustic window for visualizing the uterus and adnexa 1
• Underdistention of the bladder limits visualization of pelvic structures 1
• Transvaginal ultrasound, conversely, is best performed with an empty bladder 1
• A combined approach (transabdominal and transvaginal) provides the most comprehensive evaluation of pelvic structures 1

Clinical Implications

• The relationship between the bladder and uterus helps identify:

  • Uterine position (anteverted, retroverted, or midline) 2
  • Uterine mobility 1
  • Presence of adhesions (when normal mobility is restricted) 1
  • Potential space-occupying lesions between these structures 1

• Changes in this relationship may indicate:

  • Pelvic organ prolapse 1, 3
  • Adhesions from previous surgery or inflammation 1
  • Mass effect from fibroids, adenomyosis, or other pathology 1

Practical Considerations

• For transabdominal scanning, images should be obtained in both sagittal and transverse planes 1
• To optimally image the uterus, the transducer should be aligned with the long axis of the uterus, which may be angled right or left of the midline cervix 1
• The bladder-uterine interface is an important landmark for identifying the anterior uterine wall 1
• While traditionally a full bladder was required for all pelvic ultrasounds, modern practice shows that transvaginal scanning with adjunctive transabdominal empty bladder approach can replace the full bladder technique for most routine pelvic sonography 4

Common Pitfalls

• Overdistention of the bladder can compress and displace pelvic organs, altering their apparent position and relationship 2
• Underdistention limits visualization during transabdominal scanning 1
• Bladder filling status affects the assessment of uterovaginal prolapse (increased bladder volume reduces the extent of prolapse) 2
• Failure to recognize that a retroverted uterus may appear differently in relation to the bladder compared to an anteverted uterus 2
• Misinterpreting normal anatomical variations as pathology 1