Does CT Pelvis Cover the Buttocks?
Yes, a standard CT pelvis typically includes the buttocks (gluteal region) in its field of view, as the scan extends from the iliac crests down to below the symphysis pubis, which encompasses the soft tissues of the bilateral gluteal regions.
Anatomic Coverage of CT Pelvis
A CT pelvis scan is designed to image the entire pelvic cavity and surrounding structures. The standard protocol includes:
- Superior extent: Iliac crests
- Inferior extent: Below the symphysis pubis, extending into the perineum
- Lateral extent: Includes the soft tissues of the pelvis, which encompasses the gluteal muscles and subcutaneous tissues of the buttocks bilaterally
Evidence Supporting Perineal and Gluteal Coverage
The importance of scanning below the symphysis pubis to include the perineum and surrounding soft tissues has been established in the radiology literature. Failure to include the perineum and surrounding gluteal region in CT scanning of the pelvis will result in underestimation of disease extent 1. This is particularly critical when evaluating for:
- Pelvic malignancies that may extend into the perineum or gluteal soft tissues
- Abscesses originating from or extending into the perineal space
- Soft tissue pathology involving the buttocks
Important Caveats
Field of View Variations
- The exact inferior extent can vary between institutions and specific clinical indications
- If you need to ensure complete visualization of the lower buttocks or upper thighs, explicitly specify this in your imaging order (e.g., "CT pelvis extended to mid-thighs")
- Some protocols may stop at the ischial tuberosities, which would include most but not all of the gluteal region
When Standard Coverage May Be Insufficient
If you suspect pathology specifically in the lower buttocks or need to evaluate the entire gluteal region comprehensively, consider:
- Requesting "CT pelvis with extended field of view to include entire buttocks"
- Ordering "CT pelvis and proximal thighs" if pathology may extend inferiorly
- Communicating directly with the radiologist about your clinical concern
The standard CT pelvis protocol should capture the buttocks, but when in doubt about coverage for a specific clinical question, communicate your exact anatomic area of concern to the radiology department to ensure appropriate imaging.