Skip to main content

Female Urethra

The female urethra is a short (~3–5 cm) muscular tube running from the bladder neck to the external meatus, embedded within the anterior vaginal wall and supported by a hammock of endopelvic fascia, paravaginal attachments, and pelvic-floor muscles.[1][9] For the reconstructive pelvic surgeon it is best thought of as the functional center of the anterior compartment — a site whose continence depends on intrinsic sphincteric bulk, hormonally-responsive mucosal coaptation, vascular engorgement ("seal effect"), and a supporting hammock that transmits abdominal pressure to it. Every common reconstructive procedure in this region — midurethral slings, Burch colposuspension, anterior colporrhaphy, urethral diverticulectomy, urethroplasty for stricture, and radical cystectomy with urethral preservation — ultimately turns on one or more of these components.

Segmental Anatomy​

The female urethra is divided into functional zones by percent length rather than by discrete named segments, a convention introduced by DeLancey's paraurethral anatomy work that now drives MRI interpretation and sling-placement decision-making.[4][7]

Zone% of urethral lengthWhat is there
Intramural0–15%Urethra traverses the bladder wall
Midurethra20–60%Striated urethral sphincter (rhabdosphincter); vaginolevator attachments — the target of midurethral slings
Perineal membrane region54–76%Compressor urethrae and urethrovaginal sphincter (external striated muscle continuations); perineal membrane
Distal urethra79–100%Passes between vestibular bulbs and bulbocavernosus muscles
Why the midurethra matters

Midurethral slings (TVT, TOT, single-incision slings) deliberately target the 20–60% zone because that is where the rhabdosphincter lies and where reflex closure against the sling backstop reproduces normal continence on cough. Slings placed too proximal obstruct; too distal, they fail to recruit the sphincter.

Urethral Wall and Histology​

The urethral wall is organized, from lumen outward, into four concentric layers that correspond to the four rings visible on high-resolution MRI.[3][7][8]

Layer (inside → outside)CompositionOperative relevance
MucosaStratified squamous distally; pseudostratified columnar and, occasionally, transitional proximally. Squamous proportion increases with age and estrogen exposure[2]Mucosal coaptation is estrogen-dependent — a mechanism of postmenopausal SUI and a rationale for topical vaginal estrogen
SubmucosaLoose connective tissue with an extensive vascular plexus; urethral interstitial cellsThe engorged submucosal plexus is the "seal" that contributes ~⅓ of resting closure pressure[5][23][24]
Smooth muscleInner longitudinal + outer circular; outermost layer extends anteriorly to pelvic attachments[3][8]The lissosphincter — tonic closure at rest
Striated muscle (rhabdosphincter)Small type I fibers, embedded in the elastic perineal membrane; U-shaped anteriorly, deficient posteriorly where the urethra is continuous with the vagina[6][8]Active phasic closure on cough/Valsalva; the target of AUS cuffs and the structure most affected by vaginal delivery

The rhabdosphincter, compressor urethrae, and urethrovaginal sphincter together constitute the striated urogenital sphincter complex, which extends from midurethra to the perineal membrane.[8][6] Posteriorly the urethra is fused to the anterior vaginal wall; this fusion is the anatomical basis of urethrovaginal fistula and of the "urethral plate" dissection plane during urethral diverticulectomy.

Urethral Support — the Hammock​

Unlike the male urethra, which is structurally tethered to the prostate and perineal membrane, the female urethra depends almost entirely on a dynamic suburethral hammock of vaginal wall, endopelvic fascia, and levator ani for its resting position and for the reflex recruitment that produces stress continence.[1][9][19][20][21][22]

Key support structures​

  • Pubourethral ligaments (three components — proximal, midurethral, distal) run from the pubic bone to the urethra ventrally.[18] Their existence as discrete histologic ligaments has been debated;[1] clinically they are best thought of as thickenings of the endopelvic fascia where it inserts on the urethra.
  • Arcus tendineus fasciae pelvis (ATFP) — the "white line" running from the posterior aspect of the pubic symphysis to the ischial spine. The anterior vaginal wall inserts on the ATFP laterally; detachment of this insertion produces the paravaginal defect.[1][20]
  • Levator ani (pubococcygeus / puborectalis) — the active backstop against which the urethra is compressed on any rise in intra-abdominal pressure. Computational modeling confirms that the puborectalis, pubococcygeus, and the vaginal walls themselves are the dominant individual contributors to urethral support.[19]
  • Perineal membrane — the elastic fiber-rich lamina wrapping the midurethra anteriorly and extending to the perineal body posteriorly.[6]

The hammock mechanism​

Because the urethra is not anchored to a rigid structure, it is the posterior hammock (vaginal wall attached to ATFP and levator) that must supply the "firm backstop" against which a rising abdominal pressure compresses the urethra. This is the mechanical essence of normal stress continence and of the Integral / hammock theories of SUI:[9][22]

  • Detachment of the ATFP insertion produces urethral hypermobility — the urethra rotates downward during Valsalva, escapes the posterior backstop, and fails to coapt. This is the mechanism of most female SUI.
  • Denervation or atrophy of the levator (vaginal birth, age) removes the active component of the backstop. This is the parity-related contribution to SUI.
  • A midurethral sling reintroduces an artificial backstop in the 20–60% zone.

Vascular Supply and the "Seal Effect"​

Arterial supply is from branches of the internal pudendal and vaginal arteries; venous drainage parallels the arteries into the vesical and pudendal plexuses. The submucosal venous plexus is longitudinally oriented (not plexiform in the usual sense) and highly responsive to estrogen.[14][15][16]

Quantitative Doppler studies show regional variation:

  • Highest perfusion intensity in the distal urethra (rich venous vascularization).
  • Greatest resistance index in the anterior proximal urethra.
  • Midurethral vascularity differs between external and internal sub-layers.[14][15]

The contribution of this engorged submucosal plexus to resting closure pressure is substantial — approximately one-third of maximal urethral closure pressure (MUCP) in classical studies[23][24] — and is the "seal" that allows the mucosa to coapt so completely. Impaired urethral blood flow is a common risk factor for urinary dysfunction, which is part of why menopause, vascular disease, and pelvic radiation degrade continence.

Lymphatic drainage follows the vessels:

  • Proximal two-thirds → pelvic nodes (obturator, internal/external iliac).
  • Distal third → superficial inguinal nodes.[17]

Innervation​

The urethra has dual somatic and autonomic innervation, with the somatic supply arriving through two distinct routes — a clinically critical detail for any radical pelvic or vaginal surgery.[10][11][12][13]

Somatic​

  • Pudendal nerve (S2–S4) — from Onuf's nucleus, supplies the rhabdosphincter, compressor urethrae, and urethrovaginal sphincter.
  • Intrapelvic somatic branch — a separate pathway from S2–S4 sacral roots, running beneath the endopelvic fascia in close relation to the inferior vascular pedicle of the bladder and the lateral/anterior vaginal wall.[11] This branch is at risk during radical pelvic surgery (hysterectomy, colpectomy, radical anterior exenteration) and during vaginal dissections carried lateral to the urethra.

Autonomic​

  • Sympathetic (T10–L2, hypogastric) — α₁-adrenergic closure at bladder neck and proximal urethra; β at dome.
  • Parasympathetic (S2–S4, pelvic) — nitrergic and cholinergic; opens the urethra at the start of voiding.
  • Dual nitrergic/non-nitrergic innervation — nNOS-positive branches from the vaginal nervous plexus and nNOS-negative fibers from the pudendal nerve enter the sphincter complex at different points.[10]

Sensory​

Dense sensory innervation of the urothelium and lamina propria.[5] The precise contribution of urethral afferents to continence remains incompletely understood but likely supports the guarding and voiding reflexes.

Continence Physiology​

Resting maximal urethral closure pressure (MUCP) in continent nulliparous women is typically 60–100 cmH₂O, reliably exceeding intravesical pressure during storage and rising promptly during stress. Landmark studies that selectively ablated each component of urethral wall integrity report approximately equal contributions from three components:[23][24]

ComponentContribution to MUCPFailure mode
Striated + smooth muscle~⅓Vaginal delivery, pudendal injury, denervation with age, pelvic floor disuse
Submucosal vascular plexus ("seal")~⅓Menopause, vascular disease, pelvic radiation
Connective tissue / mucosal coaptation~⅓Estrogen deficiency, age-related collagen change

Dynamic behavior adds two further mechanisms:

  • Reflex closure. The distal two-thirds of the urethra contains an active closure mechanism that depends on preserved midurethral support.[25] Loss of support (paravaginal defect, levator injury) abolishes this reflex despite intact nerves — which is why re-establishing support alone with a midurethral sling often restores continence.
  • Passive pressure transmission. The proximal abdominal third of the urethra transmits intra-abdominal pressure passively; the distal segments require active reflex recruitment.[25]

Life-course and hormonal effects​

  • MUCP declines ~15% per decade even in nulliparous women.[23][24]
  • MUCP is ~40% lower in women with SUI compared with age-matched continent controls.[24]
  • Vaginal birth reduces striated sphincter fiber number and is associated with ~25% lower MUCP in women with persistent postpartum SUI.[22][24]
  • Estrogen decline at menopause affects mucosal coaptation, vascular engorgement, and connective-tissue turnover — the pharmacologic rationale for topical vaginal estrogen in postmenopausal urogenital atrophy and SUI symptoms.[5][23]

Clinical Correlations for the Reconstructive Surgeon​

  • Stress urinary incontinence — support vs sphincter. SUI clinically bins into "hypermobility" (loss of backstop) and "intrinsic sphincter deficiency (ISD)" (loss of MUCP). Midurethral slings address the support component; ISD with fixed urethra favors AUS, bulking agents, or autologous fascial sling at the bladder neck.
  • Midurethral sling placement. Target the 20–60% zone of the urethra (the rhabdosphincter); confirm by the two-thirds / one-third landmark from the meatus. Retropubic (TVT) slings pass through the retropubic space and risk bladder and vascular injury; transobturator slings (TOT) traverse the obturator foramen and risk groin pain and obturator nerve injury; single-incision slings minimize passage but have tradeoffs in long-term efficacy.
  • Burch colposuspension. Anchors the paravaginal fascia to Cooper's (pectineal) ligament, re-establishing ATFP-level support for the proximal urethra and bladder neck. Best suited to hypermobility-dominant SUI in women undergoing concurrent laparotomy for another indication.
  • Urethral diverticulum. Arises from periurethral glandular obstruction and rupture into the urethral lumen, typically along the posterolateral midurethra. Diverticulectomy requires a flap-based anterior vaginal wall approach, complete sac excision, multilayer closure (including a Martius flap when tissue quality or fistula risk is high), and protection of the urethra from secondary stricture.
  • Female urethral stricture. Uncommon but underdiagnosed. Treated by dorsal or ventral onlay buccal-graft urethroplasty; stricture patterns differ from male urethra because of the short length, lack of a corpus spongiosum, and vaginal-wall continuity.
  • Urethrovaginal fistula. Typically iatrogenic (anti-incontinence surgery, anterior colporrhaphy, urethral diverticulectomy) or obstetric. Repair principles: wide mobilization, tension-free multilayer closure, interposition flap (Martius, gracilis, or peritoneal) to separate urethra from vagina, and catheter drainage.
  • Radical cystectomy with urethral preservation for orthotopic neobladder. Urethral continence after cystectomy-neobladder in women depends on sparing the midurethral and distal rhabdosphincter and the intrapelvic somatic nerves, which run close to the lateral vaginal wall and the inferior vascular pedicle.[6][11] Frozen-section clearance of the proximal urethra + preservation of the midurethral nerves and vessels is standard.
  • Radical pelvic surgery and pudendal sparing. Pudendal and intrapelvic somatic branches run lateral to the vagina and beneath the endopelvic fascia; lateral vaginal dissections and wide radical colpectomy predictably injure them and produce sphincter denervation.
  • Cystocele repair. A large anterior compartment defect can displace the urethrovesical junction and cause occult or de novo SUI after repair. Concurrent anti-incontinence procedures are considered when preoperative testing (stress test with prolapse reduction) suggests risk.

Videos​

Lecture series by Dr. Divakar Dalela (Dalela Academy of Urology):

Female urethra — Part 1
Dr. Divakar Dalela
Female urethra — Part 2
Dr. Divakar Dalela
Female urethra — Part 3
Dr. Divakar Dalela
Female urethra — Part 4
Dr. Divakar Dalela
Female urethra — Part 5
Dr. Divakar Dalela
Female urethra — Part 6
Dr. Divakar Dalela
Female urethra — Part 7
Dr. Divakar Dalela

References​

1. Hamner JJ, Carrick KS, Ramirez DMO, Corton MM. "Gross and Histologic Relationships of the Retropubic Urethra to Lateral Pelvic Sidewall and Anterior Vaginal Wall in Female Cadavers: Clinical Applications to Retropubic Surgery." Am J Obstet Gynecol. 2018;219(6):597.e1–597.e8. doi:10.1016/j.ajog.2018.09.037

2. Carlile A, Davies I, Faragher E, Brocklehurst JC. "The Epithelium in the Female Urethra: A Quantitative Study." J Urol. 1987;138(4):775–777. doi:10.1016/s0022-5347(17)43369-6

3. Liu T, Muro S, Tharnmanularp S, Akita K. "Three-Dimensional Analysis of the Distribution of Smooth and Skeletal Muscle Tissue Around the Female Urethra." Int Urogynecol J. 2025;36(3):647–654. doi:10.1007/s00192-025-06045-w

4. DeLancey JO. "Correlative Study of Paraurethral Anatomy." Obstet Gynecol. 1986;68(1):91–97.

5. Mueller M, Drumm BT, Hannan JL, Ruetten H. "Advancing Our Understanding of the Urothelium and Lamina Propria, Hormone Receptors, Vascular Supply, and Sensory Aspects of the Female Human Urethra." Neurourol Urodyn. 2025;44(4):935–943. doi:10.1002/nau.70003

6. Hinata N, Murakami G, Abe S, et al. "Detailed Histological Investigation of the Female Urethra: Application to Radical Cystectomy." J Urol. 2012;187(2):451–456. doi:10.1016/j.juro.2011.10.037

7. Strohbehn K, Quint LE, Prince MR, Wojno KJ, DeLancey JO. "Magnetic Resonance Imaging Anatomy of the Female Urethra: A Direct Histologic Comparison." Obstet Gynecol. 1996;88(5):750–756. doi:10.1016/0029-7844(96)00323-7

8. Colleselli K, Stenzl A, Eder R, et al. "The Female Urethral Sphincter: A Morphological and Topographical Study." J Urol. 1998;160(1):49–54. doi:10.1016/s0022-5347(01)63025-8

9. Norton P, Brubaker L. "Urinary Incontinence in Women." Lancet. 2006;367(9504):57–67. doi:10.1016/S0140-6736(06)67925-7

10. Yucel S, De Souza A, Baskin LS. "Neuroanatomy of the Human Female Lower Urogenital Tract." J Urol. 2004;172(1):191–195. doi:10.1097/01.ju.0000128704.51870.87

11. Borirakchanyavat S, Aboseif SR, Carroll PR, Tanagho EA, Lue TF. "Continence Mechanism of the Isolated Female Urethra: An Anatomical Study of the Intrapelvic Somatic Nerves." J Urol. 1997;158(3 Pt 1):822–826. doi:10.1097/00005392-199709000-00035

12. 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

13. Panicker JN, Fowler CJ, Kessler TM. "Lower Urinary Tract Dysfunction in the Neurological Patient: Clinical Assessment and Management." Lancet Neurol. 2015;14(7):720–732. doi:10.1016/S1474-4422(15)00070-8

14. Siracusano S, Bertolotto M, d'Aloia G, Silvestre G, Stener S. "Colour Doppler Ultrasonography of Female Urethral Vascularization in Normal Young Volunteers: A Preliminary Report." BJU Int. 2001;88(4):378–381. doi:10.1046/j.1464-410x.2001.02233.x

15. Wieczorek AP, Woźniak MM, Stankiewicz A, et al. "Quantitative Assessment of Urethral Vascularity in Nulliparous Females Using High-Frequency Endovaginal Ultrasonography." World J Urol. 2011;29(5):625–632. doi:10.1007/s00345-011-0732-x

16. Sery FG, Wolfram-Gabel R, Sick H. "Microvascularization of the Female Urethra in Fetuses, Neonates and Infants." Surg Radiol Anat. 2002;24(5):271–276. doi:10.1007/s00276-002-0062-1

17. Carroll PR, Dixon CM. "Surgical Anatomy of the Male and Female Urethra." Urol Clin North Am. 1992;19(2):339–346.

18. El-Sayed RF, Morsy MM, El-Mashed SM, Abdel-Azim MS. "Anatomy of the Urethral Supporting Ligaments Defined by Dissection, Histology, and MRI of Female Cadavers and MRI of Healthy Nulliparous Women." AJR Am J Roentgenol. 2007;189(5):1145–1157. doi:10.2214/AJR.07.2215

19. Peng Y, Khavari R, Nakib NA, Boone TB, Zhang Y. "Assessment of Urethral Support Using MRI-derived Computational Modeling of the Female Pelvis." Int Urogynecol J. 2016;27(2):205–212. doi:10.1007/s00192-015-2804-8

20. DeLancey JO. "Structural Aspects of the Extrinsic Continence Mechanism." Obstet Gynecol. 1988;72(3 Pt 1):296–301.

21. Chermansky CJ, Moalli PA. "Role of Pelvic Floor in Lower Urinary Tract Function." Auton Neurosci. 2016;200:43–48. doi:10.1016/j.autneu.2015.06.003

22. Ashton-Miller JA, DeLancey JO. "Functional Anatomy of the Female Pelvic Floor." Ann N Y Acad Sci. 2007;1101:266–296. doi:10.1196/annals.1389.034

23. van Geelen H, Sand PK. "The Female Urethra: Urethral Function Throughout a Woman's Lifetime." Int Urogynecol J. 2023;34(6):1175–1186. doi:10.1007/s00192-023-05469-6

24. Pipitone F, Sadeghi Z, DeLancey JOL. "Urethral Function and Failure: A Review of Current Knowledge of Urethral Closure Mechanisms, How They Vary, and How They Are Affected by Life Events." Neurourol Urodyn. 2021;40(8):1869–1879. doi:10.1002/nau.24760

25. de Vries AM, Venema PL, Heesakkers JPFA. "Midurethral Support Is Also Necessary for Reflex Closure of the Urethra." Neurourol Urodyn. 2018;37(8):2965–2972. doi:10.1002/nau.23807