A 38-year-old woman undergoes a high-resolution CT pelvis for evaluation of chronic pelvic pain. On coronal reformatted images, the radiologist identifies the normal anatomical relationship between the uterus and adjacent structures. Which of the following best describes the normal position of the uterine fundus relative to the pelvic inlet?

Question

Accepted Answer

A. The fundus lies at the level of the pelvic inlet, typically at the level of the iliopectineal line. ## Normal Pelvic Anatomy on Imaging

### Uterine Position and Landmarks

**Key Point:** The normal uterus is an anteverted, anteflexed organ positioned entirely within the true pelvis. The fundus—the superior dome-shaped portion of the uterus—typically lies at or just above the level of the **pelvic inlet** (iliopectineal line / pelvic brim).

### Anatomical Relationships

On coronal and sagittal CT/MRI reformats:

| Structure | Normal Position | Imaging Landmark |
|-----------|-----------------|------------------|
| **Uterine fundus** | At/above pelvic inlet | Iliopectineal line |
| **Uterine body** | Within true pelvis | Between pelvic inlet and pelvic floor |
| **Uterine cervix** | Lower third of uterus | At level of ischial spines |
| **Vagina** | Extends from cervix to perineum | Posterior to pubic symphysis |

### Why This Matters Clinically

**Clinical Pearl:** Fundal position above the pelvic inlet is normal and expected. Descent of the fundus below the pelvic inlet may indicate:
- Uterine prolapse (grade III–IV)
- Pelvic floor dysfunction
- Post-hysterectomy changes

**High-Yield:** On axial imaging, the uterus appears as a triangular or "target" structure at the level of the lower pelvis. On coronal imaging, the characteristic "pear" shape is best appreciated, with the fundus positioned superiorly at or above the pelvic inlet.

### Anteverversion vs. Anteflexion

- **Anteverversion:** The entire uterus (body + cervix) tilts forward relative to the vagina. This is the normal orientation in ~60% of women.
- **Anteflexion:** The uterine body bends forward at the level of the internal cervical os.
- Both are normal variants and do not affect fertility or imaging interpretation.

[cite:Robbins & Cotran 10e Ch 22]

![Normal Pelvic Anatomy diagram](https://mmcphlazjonnzmdysowq.supabase.co/storage/v1/object/public/blog-images/explanation/11911.webp)

Answer

B. The fundus lies superior to the pelvic inlet, typically at the level of the anterior superior iliac spine

Answer

C. The fundus lies posterior to the pelvic inlet, typically at the level of the sacral promontory

Answer

D. The fundus lies anterior to the pelvic inlet, typically at the level of the pubic symphysis

Explanation

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