Uterus

Ultrasound and uterine orientation: What you need to know

KEY POINTS

  •  Adequate documentation of uterine orientation should be performed on ultrasound reports.
  • Uterine orientation can be important when procedures such as curettage, dilatation and intrauterine device placement are performed.
  • Commonly the terms anteverted, anteflexed, retroverted and retroflexed are used to describe its orientation.
  • The nomenclature is used observing the differences in orientation of the cervix relative to the axis of vagina, when we use the term "verted", and the orientation of the uterine body relative to the axis of the cervix, when we use the term "flexed".

VERSION

    In medicine, version is a term that comes from the latin word vertere which means "to turn". Hereupon, in ginecology the suffix verted describes the turning of the uterine cervix relative to the axis of the vagina (Fig.1 and 2).

 Fig. 1 -  Note the upper left diagram depicting the uterine cervix turned anteriorly, providing more obtuse or acute angles with the vagina axis. This uterine position is called anteverted.The middle diagram shows that the fundus (*) of an anteverted uterus is directed anteriorly pointing toward the transducer. The right picture is the ultrasound image representing the finding as demonstrates the fundus (*) of an anteverted uterus pointing anteriorly. X, vagina axis; Y, cervix axis; A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

Fig. 2 - On the other hand, when the uterine cervix is turned posteriorly (upper left diagram), providing more straight or reflex angles with the vagina axis we have an uterine position called retroverted.The middle diagram shows that the fundus (*) of a retroverted uterus is directed posteriorly pointing away from the transducer. The right picture is the ultrasound image representing the finding as demonstrates the fundus (*) of a retroverted uterus pointing posteriorly. X, vagina axis; Y, cervix axis; A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

    On transvaginal (TV) ultrasound remember that anterior structures appear at the left of the screen, while posterior structures appears to the right of the screen. Said that, an anteverted uterus has its fundus points towards the left side of the image (Fig. 3) while a retroverted uterus has its fundus pointing toward the right side of the image (Fig.4).

Fig. 3 - The left diagram shows the anatomic orientation of an anteverted uterus. Ultrasound image at the right depicts the uterus is it is displayed on the screen. Because the portion of the image closest to the TV transducer is showed at the top of the image by convention, the TV field of view is rotated aproximately 90 degrees counterclockwise in the image displayed in the screen. Thus, the fundus (*) of an anteverted uterus is directed toward the left side of the image displayed on the monitor. A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

 FIg. 4 - On the other hand, the fundus (*) of a retroverted uterus is directed to the right side of the image displayed on the monitor. A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

FLEXION

    The suffix flexed describes the presence of a flexion, curve or bend between the uterine body/fundus and the cervix. 

 FIg. 5 - Observe the upper left diagram depicting the uterine body/fundus axis folded up against the cervix, with its fundus pointing anteriorly. This uterine orientation is called anteflexed.The middle diagram shows that the fundus of an anteflexed uterus is directed anteriorly pointing toward the transducer due to curvature between its body and cervix. The right picture is the ultrasound image representing the finding as demonstrates the fundus  of an anteflexed uterus pointing anteriorly. X, body axis; Y, cervix axis; A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

 Fig. 6 - Note the upper left diagram depicting the uterine body/fundus axis folded up against the cervix, with its fundus pointing posteriorly. This uterine orientation is called retroflexed.The middle diagram shows that the fundus of a retroflexed uterus is directed posteriorly pointing away from the transducer due to curvature between uterine body and cervix. The right picture is the ultrasound image representing the finding as demonstrates the fundus  of a retroflexed uterus pointing posteriorly. X, body axis; Y, cervix axis; A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

 Fig. 7 -  On transvaginal (TV) ultrasound an anteflexed uterus has its fundus points towards the left side of the image with the uterine body folded up (flexed) against the cervix. A, anterior; P, posterior; S, superior; I, inferior; b, bladder.

 Fig. 8 -  A retroflexed uterus can be diagnosed on TV ultrasound when its fundus points to the right side of the image and the uterine body is folded up the cervix pointing posteriorly. A, anterior; P, posterior; S, superior; I, inferior; b, bladder. 

TIP

    If instead there is no significant bend between the uterine body and cervix, we assign the uterine orientation to the angle between the cervix and vagina and the suffix verted is applied.

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Written by Dr. Augusto César
Board certified Brazilian radiologist, co-founder of the Salus Sonography project and Medultra smartphone app. Currently works as an interventional and general radiologist in private practice, São Paulo, Brazil.

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