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Rectovaginal septum (rectovaginal fascia)

The rectovaginal septum is a thin fibromuscular structure that separates the posterior vaginal wall from the anterior rectal wall. It forms part of the pelvic fascia and plays an important role in supporting the pelvic organs. This structure is of high clinical importance in gynecology, colorectal surgery, urogynecology, and imaging, especially in the evaluation of pelvic organ prolapse, rectovaginal fistulas, and deep infiltrating endometriosis.

Synonyms

  • Rectovaginal fascia

  • Denonvilliers’ fascia (in some literature, though this term is more often applied in males)

  • Posterior vaginal fascia

Location and Extent

  • Extends from the posterior fornix of the vagina and cervix superiorly

  • Courses downward between the posterior vaginal wall and the anterior rectal wall

  • Continues inferiorly to blend with connective tissue at the perineal body

Relations

  • Anteriorly: Posterior wall of the vagina

  • Posteriorly: Anterior wall of the rectum (ampulla)

  • Superiorly: Cervix and posterior vaginal fornix

  • Inferiorly: Perineal body and anal canal

Function

  • Provides structural support between the vagina and rectum

  • Helps maintain proper anatomical separation of vaginal and rectal walls

  • Plays a role in pelvic organ support, especially in resisting prolapse

  • Acts as a barrier that can be involved or breached in pathology (e.g., fistula, tumor, or endometriosis)

Clinical Significance

  • Weakening or defects in the rectovaginal septum contribute to rectocele (posterior vaginal wall prolapse)

  • A site of involvement in deep infiltrating endometriosis, often visualized on pelvic MRI

  • May be involved in rectovaginal fistulas, typically secondary to obstetric injury, Crohn’s disease, infection, or surgery

  • Serves as a key surgical landmark in gynecological and colorectal operations

MRI Appearance

T1-weighted images:

  • Septum appears as a thin, low-signal-intensity band between rectum and vagina

  • Fat planes surrounding it provide contrast

T2-weighted images:

  • Septum shows low-to-intermediate signal intensity

  • Endometriosis implants or fibrosis appear as low-signal-intensity thickening

  • Cysts or inflammatory lesions appear with high signal

STIR (Short Tau Inversion Recovery):

  • Normal septum remains low signal

  • Inflammatory or endometriotic lesions appear bright

T1 Fat-Sat Post-Contrast:

  • Normal septum shows little or no enhancement

  • Pathology (endometriosis, tumor, fistula inflammation) demonstrates focal or heterogeneous enhancement

CT Appearance

Non-Contrast CT:

  • Septum is not easily distinguished as a discrete structure

  • Appears as a soft tissue interface between rectum and vagina

  • Thickening or mass may suggest pathology (tumor, abscess, fibrosis)

Post-Contrast CT:

  • Normal septum shows no significant enhancement

  • Pathology (tumor, abscess, inflammatory disease) shows abnormal focal enhancement or rim enhancement in abscesses

MRI image

Rectovaginal Septum MRI axial image image MRI coronal anatomy image

MRI image

Rectovaginal Septum (rectovaginal fascia) MRI sagittal image

CT image

rectovaginal septum CT axial image anatomy image

CT image

rectovaginal septum CT SAGITTAL anatomy image