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The Vagina

The vagina is a fibromuscular tubular organ running from the vulvar vestibule to the uterine cervix. For the reconstructive pelvic surgeon it is the central corridor of the female pelvis: the plane of dissection for every fistula repair, the scaffold for apical and compartment-based prolapse surgery, the conduit for vaginal access to the bladder / urethra / rectum / ureters, and the target of both reconstructive (neovagina) and ablative (radical colpectomy) operations. This article prioritises the dimensions, relations, three-level support, vascular and nerve supply, and biomechanics that drive those operations, and compresses microbiology, molecular epithelial biology, and developmental detail to the depth a reconstructive surgeon needs.

See also The Vulva for the introital and vestibular anatomy; Female Urethra for the anterior-wall urethral structures; and Perineum for the perineal body and posterior-compartment anchors.

Female reproductive system — sagittal section Blausen Medical — Female reproductive system, sagittal view. (CC BY 3.0)

Dimensions and Shape​

The adult vagina averages ~6–10 cm in length (mean ~6.3 cm, range 6.9–14.8 cm) with substantial individual variation.[1][2] Width tapers distally — ~32 mm proximally, ~27 mm through the pelvic diaphragm, ~26 mm at the introitus.[1] Total mucosal surface area averages ~72 cm².[3]

The vagina is not a straight tube. In the supine pelvis the axis bends predictably:[3]

  • ~90° at the introitus (horizontal axis against the perineum)
  • ~72° in the mid-vagina
  • ~41° at the apex, directed toward the hollow of the sacrum

Three distended zones — useful as an operative shorthand — correspond to the three innervation and support territories:[5]

ZoneLocationKey features
Superficial sphincteric (distal)Surrounded by pelvic-floor muscles and perineal membranePerineal body anchor; bulbospongiosus and superficial transverse perinei
Central transition (mid)Between levator plate and pelvic sidewallLateral attachments to ATFP — the paravaginal territory
Deep forniceal (proximal)Expanded around the cervix; anterior, posterior, lateral fornicesApical support from the cardinal–uterosacral ligament (CUL) complex

Anatomical relations​

AspectRelation
AnteriorUrethra (distal), bladder base and trigone (mid), cervix/vesicocervical space (proximal)
PosteriorPerineal body (distal), rectum (mid), rectouterine pouch of Douglas (proximal, peritoneum)
LateralLevator ani (pubovisceral), pelvic plexus, cardinal ligament, vaginal artery, ureter (~1–2 cm lateral to cervix as it crosses under uterine artery — "water under the bridge")
ApexCervix with anterior, posterior, and lateral fornices
The ureter at the vaginal apex

The ureter crosses inferior to the uterine artery approximately 1.5–2 cm lateral to the cervix, within the cardinal ligament. This is the most common site of iatrogenic ureteral injury in hysterectomy, uterosacral ligament suspension, and deep paravaginal dissection. See The Ureters.

Wall Structure​

Three layers, but only two really matter at the table:[4][7]

LayerCompositionOperative relevance
MucosaNon-keratinised stratified squamous epithelium, hormone-responsive, glycogen-rich with rugae; ~26–28 cell layers in reproductive years[8]Dissection plane for colporrhaphy and fistula repair; atrophies postmenopausally, which is why perioperative topical vaginal estrogen improves tissue quality for native-tissue repair[6]
Muscularis + lamina propria (fibromuscularis)Inner circular + outer longitudinal smooth muscle in a collagen/elastin matrixThe pubocervical fascia anteriorly and rectovaginal (Denonvilliers-analog) fascia posteriorly — the load-bearing layer for prolapse repair and the plane of fascial reconstruction
AdventitiaLoose connective tissue carrying vessels, lymphatics, and nervesThe avascular plane between vaginal wall and bladder/rectum — the plane of vaginal-wall dissection in fistula, prolapse, and hysterectomy procedures

Unlike the cervix, the superficial vaginal epithelium lacks tight junctions and is permeable to macromolecules including IgG.[10] Clinically this underlies the mucosal effectiveness of topical estrogen, antifungals, and microbicides.

Hormone responsiveness. Estrogen thickens the epithelium and loads it with glycogen, which supports lactobacillus colonisation and keeps vaginal pH at ~3.8–4.5.[9] Postmenopausal hypoestrogenism thins the epithelium, reduces glycogen, and raises pH — the substrate of atrophic vaginitis and of the friable tissue that compromises native-tissue prolapse repair.

DeLancey's Three-Level Support — the Prolapse Framework​

The mechanical support of the vagina is best understood through DeLancey's three-level model, which drives every compartment-based prolapse operation.[19][21][22]

LevelStructuresClinical failure
Level I — apicalCardinal ligament + uterosacral ligament complex (CUL); suspends the vaginal apex and cervix from the sacrum and pelvic sidewallApical prolapse: uterine descent, vaginal vault prolapse, enterocele
Level II — mid-vaginal / lateralParavaginal attachments to the arcus tendineus fasciae pelvis (ATFP) ("white line") and superior fascia of levator aniAnterior (cystocele) and posterior (rectocele) compartment descent
Level III — distalPerineal membrane, perineal body, and levator–bulbospongiosus complexDistal anterior wall descent, perineal deficiency, gaping introitus

Two operative rules follow:

  • Apical support is the dominant determinant of recurrence. Biomechanical modeling shows that once pubovisceral (levator) impairment crosses a threshold and the genital hiatus opens, anterior-wall prolapse severity is governed by apical support failure.[21] Failing to address a Level-I defect at the time of anterior or posterior repair is a leading cause of recurrence.
  • Paravaginal (Level II) and compartment (Level III) defects can be addressed only after apex is secured.

Vascular Supply and Drainage​

Arterial supply is polysegmental — a major reason vaginal flaps survive — with four paired contributions:[7][12]

ArteryOriginTerritory
Vaginal arteryInternal iliac (anterior division)Dominant middle / lower vagina
Descending vaginal branch of uterine arteryUterine artery (at the point where it crosses the ureter)Upper vagina and cervix
Internal pudendal artery (perineal branches)Internal iliacLower vagina and introitus
Middle rectal arteryInternal iliacPosterior vaginal wall

Microvascular density is richest in the distal anterior wall, both in the lamina propria and muscle layer,[13] which contributes to the tissue's resilience for vaginal-wall flap design and Martius interposition in fistula repair.

Venous drainage parallels the arteries to the vaginal venous plexus and into the internal iliac veins.

Lymphatic drainage split:

  • Upper vagina → internal iliac and external iliac (obturator) nodes.
  • Middle vagina → internal and external iliac nodes.
  • Lower vagina / introitus → superficial inguinal nodes.

This split governs the LN template for vaginal SCC and for gynecologic cancers invading vaginal wall — inguinal evaluation for distal lesions, pelvic LN for proximal.

Innervation​

Two distinct territories:[13][14][15][16]

RegionDominant supplyFunctional notes
Upper vagina (above pelvic diaphragm)Autonomic fibers from the inferior hypogastric (pelvic) plexus — sympathetic T10–L2 and parasympathetic S2–S4Sparse sensory supply; dilation and distension are the main perceived sensations; visceral afferents travel with the pelvic nerve
Lower vagina (below pelvic diaphragm)Pudendal nerve (S2–S4) — perineal branches to introitus and distal vaginal mucosaDense somatic sensation; the introital territory shares its sensory map with the vestibule

Small-nerve-fiber density is highest in the distal anterior vaginal wall[13] — the anatomic substrate for heightened sensitivity in this region and for the post-operative dysesthesia that follows aggressive anterior colporrhaphy / mesh dissection.

Autonomic input drives transudation-based lubrication during arousal, smooth-muscle tone, and vascular engorgement.

Secretion, pH, and the Microbiome (operative level)​

The vagina has no glands. Luminal fluid comes from:

  • Transudate across the permeable superficial epithelium
  • Cervical mucus descending from the endocervix
  • Bartholin and Skene-gland secretions
  • Desquamated epithelial cells

pH ~3.8–4.5 is maintained by estrogen-driven glycogen → lactic acid conversion by lactobacilli (dominantly L. crispatus).[9][17] Practical consequences:

  • Postmenopausal atrophy raises pH, reduces lactobacilli, and predisposes to bacterial vaginosis, candidiasis, and atrophic vaginitis.
  • Preoperative vaginal estrogen improves epithelial thickness, glycogen content, pH, and suture-holding quality before native-tissue prolapse repair and fistula surgery.[6]

Biomechanics — What Fails in Prolapse​

The vagina is a viscoelastic, anisotropic fibromuscular organ: stiffer longitudinally than circumferentially, with time-dependent creep under load and a pressure-dependent stress response.[11][18][20]

Prolapse develops when three supports fail sequentially:

  1. Levator ani (pubovisceral) impairment → genital hiatus opens
  2. Apical (Level I) support failure → proximal descent
  3. Paravaginal (Level II) + distal (Level III) failure → compartment-specific bulge

This sequence is the reason prolapse operations anchor at Level I first (sacrocolpopexy, uterosacral suspension, sacrospinous fixation) and add compartment repair only after apex is restored.

Developmental Origin​

Contemporary lineage-tracing studies (PAX2 for Müllerian, FOXA1 for urogenital-sinus epithelium) demonstrate that the entire vaginal epithelium is urogenital-sinus (UGS)-derived, not Müllerian.[23][24][25] Müllerian epithelium is progressively replaced by UGS epithelium in a caudal-to-cranial direction during weeks 9–21.

Clinical consequences:

  • Müllerian anomalies (vaginal agenesis, transverse septum, duplicated vagina) reflect disordered Müllerian-duct fusion and descent but not UGS development.
  • DES-exposed offspring develop clear cell adenocarcinoma of the vagina from remnant Müllerian epithelium — the clinically most important reason to appreciate the mixed embryologic lineage.
  • Neovaginal reconstruction in Müllerian agenesis (MRKH) uses non-genital tissues (dilator therapy, skin graft [McIndoe], peritoneum [Davydov], buccal mucosa, bowel segment [sigmoid / ileum], or tissue-engineered scaffolds) because the patient lacks the vaginal primordium entirely.

Clinical Correlations for the Reconstructive Surgeon​

  • Apical prolapse reconstruction. Sacrocolpopexy (mesh to sacral promontory) is the gold-standard restoration of Level-I support. Uterosacral ligament suspension (USLS) and sacrospinous ligament fixation (SSLF) are vaginal-route alternatives. All three require concurrent paravaginal/anterior/posterior compartment repair for the Level-II/III defects that coexist.
  • Paravaginal defect repair. A Level-II defect (detached ATFP) produces a lateral cystocele that does not respond to anterior colporrhaphy. Paravaginal repair reattaches the pubocervical fascia to the ATFP via retropubic or vaginal approach.
  • Anterior colporrhaphy. Addresses a central (distension) Level-II defect; outcomes are better when apical support is simultaneously restored. Mesh-augmented anterior repair has been curtailed by the FDA-mandated transvaginal-mesh limitations.
  • Posterior colporrhaphy and rectocele repair. Plicates the rectovaginal fascia; the perineal body is reconstructed at the distal (Level-III) terminus. A weakness in the perineal body alone accounts for many "recurrent rectoceles" after apparently successful posterior colporrhaphy.
  • Vaginal hysterectomy. Uses the vaginal fornices as the access route; the apex is anchored to the uterosacral-cardinal complex at closure to prevent subsequent vault prolapse.
  • Vesicovaginal fistula (VVF). Almost all non-obstetric VVF in high-resource settings is post-hysterectomy, at the vaginal cuff just above the trigone. Latzko partial colpocleisis (intact fistula, wide mobilisation, multilayer tension-free closure) and standard transvaginal layered repair with Martius interposition are the mainstay techniques; transabdominal repair is reserved for complex, high-lying, radiation-related, or ureteric-involvement fistulae.
  • Rectovaginal fistula (RVF). Obstetric (OASIS-related), inflammatory (Crohn's), or post-radiation. Repair depends on etiology, location, and sphincter status: transvaginal advancement flap, transperineal rectovaginal septum repair, gracilis interposition, or definitive diversion.
  • Urethrovaginal fistula (UVF). Most commonly iatrogenic (anti-incontinence surgery, diverticulectomy). Layered vaginal-flap repair with interposition flap (Martius, peritoneal, gracilis) and catheter drainage.
  • Vaginal stenosis and reconstruction. Post-radiation, post-LS, post-FGM, post-radical cystectomy, or congenital (MRKH). Options: dilator therapy, vaginal-wall flaps, buccal-graft neovagina, sigmoid / ileal neovagina, peritoneal (Davydov) neovagina.
  • Vaginoplasty.
    • Primary neovagina (MRKH / DSD / gender-affirming): McIndoe (split-thickness graft on stent), Davydov (peritoneum), Vecchietti (traction-dilation), sigmoid (excellent length, self-lubricating but colitis risk, rare adenocarcinoma), ileum (adequate length, less mucus output).
    • Gender-affirming vaginoplasty: penile skin inversion, scrotal graft, or pedicled bowel as the neovaginal lining; the canal is dissected in the plane between urethra/prostate (anterior) and rectum (posterior) — a plane where the peritoneal reflection defines the superior limit.
  • Vaginal cuff dehiscence. A complication of hysterectomy (particularly total laparoscopic hysterectomy); presents as post-coital bleeding, evisceration, or acute abdomen with bowel through the cuff. Emergent repair transvaginally or abdominally, with dehiscence-prevention strategies including tissue-preserving colpotomy closure and estrogen support.
  • Clear-cell adenocarcinoma of the vagina. A DES-exposure sequela arising from residual Müllerian vaginal epithelium; historically seen in the upper anterior vagina of women exposed in utero.
  • Vaginal SCC. Rare, usually upper vagina, HPV-associated. Treatment depends on stage: radiation for most, surgery for small, superficial, or distal tumors (partial or radical vaginectomy with LND dictated by site).
  • Pessary fitting. Success depends on vaginal length, genital hiatus size, introital tone, and estrogenic status of the mucosa. Perioperative topical vaginal estrogen improves retention and comfort.
  • Perioperative vaginal estrogen. In postmenopausal women undergoing native-tissue apical prolapse repair, perioperative topical estrogen improves tissue-handling quality — the Rahn 2023 JAMA trial supports this adjunct.[6]
  • Vaginal packing. A staple of postoperative care after vaginal surgery — provides hemostasis, supports flaps, and splints grafts. Typically removed at 24 h with Foley catheter drainage maintained as needed.

References​

1. Barnhart KT, Izquierdo A, Pretorius ES, et al. "Baseline Dimensions of the Human Vagina." Hum Reprod. 2006;21(6):1618–1622. doi:10.1093/humrep/del022

2. Pendergrass PB, Reeves CA, Belovicz MW, Molter DJ, White JH. "The Shape and Dimensions of the Human Vagina as Seen in Three-Dimensional Vinyl Polysiloxane Casts." Gynecol Obstet Invest. 1996;42(3):178–182. doi:10.1159/000291946

3. Luo J, Betschart C, Ashton-Miller JA, DeLancey JO. "Quantitative Analyses of Variability in Normal Vaginal Shape and Dimension on MR Images." Int Urogynecol J. 2016;27(7):1087–1095. doi:10.1007/s00192-016-2949-0

4. Haylen BT, Vu D, Wong A, Livingstone S. "Surgical Anatomy of the Mid-Vagina." Neurourol Urodyn. 2022;41(6):1293–1304. doi:10.1002/nau.24994

5. Appelbaum AH, Zuber JK, Levi-D'Ancona R, Cohen HL. "Vaginal Anatomy on MRI: New Information Obtained Using Distention." South Med J. 2018;111(11):691–697. doi:10.14423/SMJ.0000000000000889

6. Rahn DD, Richter HE, Sung VW, Pruszynski JE, Hynan LS. "Perioperative Vaginal Estrogen as Adjunct to Native Tissue Vaginal Apical Prolapse Repair: A Randomized Clinical Trial." JAMA. 2023;330(7):615–625. doi:10.1001/jama.2023.12317

7. Zulfiqar M, Shetty A, Yano M, et al. "Imaging of the Vagina: Spectrum of Disease With Emphasis on MRI Appearance." Radiographics. 2021;41(5):1549–1568. doi:10.1148/rg.2021210018

8. Patton DL, Thwin SS, Meier A, et al. "Epithelial Cell Layer Thickness and Immune Cell Populations in the Normal Human Vagina at Different Stages of the Menstrual Cycle." Am J Obstet Gynecol. 2000;183(4):967–973. doi:10.1067/mob.2000.108857

9. American College of Obstetricians and Gynecologists. "Vaginitis in Nonpregnant Patients: ACOG Practice Bulletin, Number 215." Obstet Gynecol. 2020;135(1):e1–e17. doi:10.1097/AOG.0000000000003604

10. Blaskewicz CD, Pudney J, Anderson DJ. "Structure and Function of Intercellular Junctions in Human Cervical and Vaginal Mucosal Epithelia." Biol Reprod. 2011;85(1):97–104. doi:10.1095/biolreprod.110.090423

11. White SE, Conway CK, Clark GL, et al. "Biaxial Basal Tone and Passive Testing of the Murine Reproductive System Using a Pressure Myograph." J Vis Exp. 2019;(150). doi:10.3791/60125

12. Höckel M, Horn LC, Fritsch H. "Association Between the Mesenchymal Compartment of Uterovaginal Organogenesis and Local Tumour Spread in Stage IB-IIB Cervical Carcinoma." Lancet Oncol. 2005;6(10):751–756. doi:10.1016/S1470-2045(05)70324-7

13. Li T, Liao Q, Zhang H, et al. "Anatomic Distribution of Nerves and Microvascular Density in the Human Anterior Vaginal Wall: Prospective Study." PLoS One. 2014;9(11):e110239. doi:10.1371/journal.pone.0110239

14. Barry CM, Ji E, Sharma H, et al. "Morphological and Neurochemical Differences in Peptidergic Nerve Fibers of the Mouse Vagina." J Comp Neurol. 2017;525(10):2394–2410. doi:10.1002/cne.24214

15. Wecht JM, Krassioukov AV, Alexander M, et al. "International Standards to Document Autonomic Function Following SCI (ISAFSCI): Second Edition." Top Spinal Cord Inj Rehabil. 2021;27(2):23–49. doi:10.46292/sci2702-23

16. Hoyle CH, Stones RW, Robson T, Whitley K, Burnstock G. "Innervation of Vasculature and Microvasculature of the Human Vagina by NOS and Neuropeptide-Containing Nerves." J Anat. 1996;188(Pt 3):633–644.

17. Paavonen J, Brunham RC. "Bacterial Vaginosis and Desquamative Inflammatory Vaginitis." N Engl J Med. 2018;379(23):2246–2254. doi:10.1056/NEJMra1808418

18. Clark-Patterson GL, McGuire JA, Desrosiers L, et al. "Investigation of Murine Vaginal Creep Response to Altered Mechanical Loads." J Biomech Eng. 2021;143(12):121008. doi:10.1115/1.4052365

19. Kieserman-Shmokler C, Swenson CW, Chen L, et al. "From Molecular to Macro: The Key Role of the Apical Ligaments in Uterovaginal Support." Am J Obstet Gynecol. 2020;222(5):427–436. doi:10.1016/j.ajog.2019.10.006

20. Xu Z, Chen N, Wang B, et al. "Creation of the Biomechanical Finite Element Model of Female Pelvic Floor Supporting Structure Based on Thin-Sectional High-Resolution Anatomical Images." J Biomech. 2023;146:111399. doi:10.1016/j.jbiomech.2022.111399

21. Chen L, Ashton-Miller JA, Hsu Y, DeLancey JO. "Interaction Among Apical Support, Levator Ani Impairment, and Anterior Vaginal Wall Prolapse." Obstet Gynecol. 2006;108(2):324–332. doi:10.1097/01.AOG.0000227786.69257.a8

22. Lamblin G, Delorme E, Cosson M, Rubod C. "Cystocele and Functional Anatomy of the Pelvic Floor: Review and Update of the Various Theories." Int Urogynecol J. 2016;27(9):1297–1305. doi:10.1007/s00192-015-2832-4

23. Hülsman CJM, Köhler SE, Morosan-Puopolo G, Hikspoors JPJM, Lamers WH. "The Development of the Human Female Reproductive Tract: Part 2 — Vagina." Clin Anat. 2025. doi:10.1002/ca.70015

24. Robboy SJ, Kurita T, Baskin L, Cunha GR. "New Insights Into Human Female Reproductive Tract Development." Differentiation. 2017;97:9–22. doi:10.1016/j.diff.2017.08.002

25. Fritsch H, Hoermann R, Bitsche M, Pechriggl E, Reich O. "Development of Epithelial and Mesenchymal Regionalization of the Human Fetal Utero-Vaginal Anlagen." J Anat. 2013;222(4):462–472. doi:10.1111/joa.12029