introduction to OBGYN part 2

Uterus Anatomy and Surrounding Structures

• Uterus subdivisions (outline in blue): fundus (superior), body (middle), cervix or neck of the uterus (inferior, opens to the vagina).

• Uterine cavity (also called the endometrial cavity): a potential space within the uterus, lined by the endometrium (mucous membrane).

• The cervix has its own canal and mucous membrane that is not lined with endometrium and is not shared with the menstrual cycle.

• The uterus connects laterally to hollow tubes called the fallopian (uterine) tubes; the fallopian tubes lie just anterior to the ovaries (the gonads).

• The cervix of the uterus extends into the hollow tube called the vagina. The vagina is an internal hollow tube and is not part of the external genitalia.

• Internal reproductive organs overview: for more information about surrounding structures, refer to the next module.

• Basic anatomical relationships in the uterus:

  • Cervix is the most inferior portion of the uterus and opens to the vagina.
  • Body is the mid portion of the uterus.
  • Fundus is the superior portion of the uterus.
  • In a midsagittal view, the uterus appears roughly in the center of the pelvis and tinted blue in diagrams.
  • The uterine cavity (lined by endometrium) sits in the center of the uterus.
  • Laterally, the uterus is flanked by the fallopian tubes and ovaries on both sides.
  • The vagina lies inferior to the uterus and extends toward the outside of the body.
  • Anterior relationships: the urinary bladder sits anterior to the uterus; the urethra is visible in imaging but not labeled in the provided view.
  • Anterior to the urinary bladder lies the symphysis pubis.

• Symphysis pubis: anatomical definition and imaging terminology

  • The symphysis pubis is a fibrous disc-like joint that joins the left and right pubic bones at the midline.
  • In imaging, sonographers may refer to either the superior ramus of the pubis or the symphysis itself as the "symphysis pubis" when describing echoes along the midline.
  • The term can also be used more generally to indicate the echo along the midline near the pubic region.

• Imaging and anatomical context in a midsagittal slice

  • The uterus sits in the center of the pelvis.
  • The uterine cavity is in the center of the uterus and lined by endometrium.
  • The fallopian tubes and ovaries lie laterally to the uterus (left and right sides).
  • The vagina is inferior to the uterus and continues to the external genitalia.
  • The bladder is anterior to the uterus; the urethra is in the region but not labeled in the diagram.
  • The symphysis pubis lies anterior to the bladder.

• Internal exam considerations and department protocol

  • Some departments prohibit sonographers from performing internal pelvic exams unless the patient has had an internal pelvic exam previously.
  • Always know your department's protocol before attempting an internal exam.
  • If internal exam cannot be performed due to policy, plan to keep the bladder full so the radiologist can perform a transabdominal scan (TAS) if needed.
  • If internal exam is possible, proceed accordingly per protocol and patient safety considerations.

• Preparation pitfalls and practical notes

  • A humorous but memorable aside from the transcript: there is mention of crumbs in the bed during patient preparation, highlighting the importance of cleanliness and proper setup for imaging sessions.
  • Practical implication: ensure the bed and surrounding area are clean and free of debris to avoid distractions and maintain professionalism during imaging.

• Quick recap of key definitions and relationships

  • Fundus = superior portion of the uterus
  • Body = middle portion of the uterus
  • Cervix = inferior portion; opens to the vagina
  • Endometrium = mucous membrane lining the uterine cavity
  • Endometrium is not the same as the mucous membrane lining the cervical canal
  • Fallopian tubes lie laterally and are anterior to the ovaries
  • Ovaries = gonads, located laterally
  • Vagina = internal hollow tube connected to the cervix; not part of external genitalia
  • Bladder lies anterior to the uterus; symphysis pubis lies anterior to the bladder
  • Symphysis pubis synonyms in imaging include the superior ramus or the symphysis itself

• Note on further study

  • If you want more information about internal reproductive organs and surrounding structures, refer to the next module in the course.