Scanning Ovaries and the Non-Pregnant Uterus

Jun 5, 2024

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Scanning Ovaries and the Non-Pregnant Uterus

Topics Covered

  • Mare reproductive anatomy
  • How ultrasound works
  • Basic scanning procedure
  • The equine estrus cycle
  • Follicles
  • Ovulation and uterine edema
  • CHS and CLS
  • Uterine fluid and endometrial cysts

Anatomy Overview

  • Reproductive Tract Location: Sits on top of the digestive system, near the spine.
    • Elevation near the rectum due to digestive system's position.
  • Ovaries: Located near the kidney/hip.
  • Bladder: Found directly below the vagina on ultrasound.
  • Uterine Body: In front of the bladder.
  • Uterine Horns: Connected to the uterine body; near the rectum.
  • Oviduct: Too small to be seen by ultrasound.
  • Broad Ligament: Suspends the reproductive tract.

Scanning Procedure

  1. Initial Insertion
    • Insert an arm into the rectum.
    • First structure: Bladder (appears gray; variable in tone).
  2. Orienting the Probe
    • Point the probe downward (6 o'clock, or 5/7 o'clock positions).
  3. Locating the Uterine Body
    • Rotate probe left/right, move forward slightly.
    • Boundaries indicated with red arrows on ultrasound.
  4. Tracing Uterine Horns
    • Rotate to pick up the horn; follow it to the ovary.
    • Uterine horn appears smaller and disappears as you move.
    • Continue to rotate and insert deeper to find the ovary.
  5. Identifying and Measuring the Ovary
    • Ovary will include gray ovarian tissue between follicles.
    • Rotate up/down on the ovary to ensure complete view.
    • Measure the largest follicle.
  6. Scanning the Second Ovary
    • Trace back to uterine body, rotate to other horn.
    • Follow horn up to second ovary.
    • Use same up/down rotation to identify largest follicle.

Tips

  • Bladder Appearance: Mare urine can vary in color (dark gray to light gray).
  • Depth Adjustment: Often need to go several inches further to locate the ovary.
  • Red Arrows: Utilize on ultrasound images to understand boundaries.

By following the uterus as a guide and effectively using rotation and depth adjustments, accurate scanning and identification of ovaries and their follicles can be achieved.