Female pelvic anatomy can be a conceptual
challenge. Understanding the anatomy helps in
identifi cation, assessment, and management of
pelvic fl oor pathology. To those dealing with
disorders of the pelvic fl oor and to the reconstructive
pelvic surgeon, knowledge of the functional
anatomy is crucial. Apart from the
anatomical dissections, various imaging modalities
particularly magnetic resonance imaging
(MRI) have helped in appreciating the relationships
and supports of the pelvic organs better.
Improved understanding of the pelvic anatomy
should make it possible to align anatomy with
clinical concepts seamlessly.
The pelvic viscera have an integrated anatomical
support with each other due to their orientation
within the pelvis, and at the same time, they
largely function as individual units. The pelvic
fl oor musculature and the pelvic connective tissue
(including fascia and ligaments) form the primary
support for the pelvic organs with the bony pelvis
providing additional support. In general, the
normal anatomical supports of the female pelvic
viscera play a vital role in the reproductive,
storage, and elimination functions of the pelvic
organs, apart from trying to maintain them in their
normal position.
The aim of this chapter is to describe the topographic
or spatial pelvic anatomy, in a practical
aspect to help in optimizing the surgical techniques
in pelvic surgery. Three different anatomic
systems contribute to the support of the
pelvic organs – the bony, muscular, and fascial
support. The clinically relevant bony, muscular,
and fascial supports and the surgically important
spaces in the pelvis are described below along
with a brief mention of their clinical/surgical relevance.
For a more exhaustive anatomy, the
reader is referred to anatomy textbooks cited in
the reference.

Applied Anatomy
The potential safety of the obturator foramen
with the neurovascular bundle occupying only its
superolateral portion, has made it a safe zone for
insertion of the trocars in the transobturator mesh
anchoring techniques.
The Ischial Spine
The ischial spines are bony prominences projecting
from the medial surface of ischium at the
anterior border of greater sciatic notch. The
sacrospinous ligament (SSL) passes medially and
posteriorly from the ischial spine to the lateral
aspect of lower portion of the sacrum and coccyx.
The sacrotuberous ligament extends from the
posterior surface of sacrum to the ischial tuberosity,
and this along with the SSL separates the
greater sciatic foramen from the lesser sciatic
Applied Anatomy
The ischial spines are important surgical reference
points for several pelvic structures (Fig. 1.4 ):
• The pelvic ureter usually leaves the pelvic
sidewall about 1–2 cm from the ischial spine
to pass medially on the pubocervical fascia
before entering the bladder.
• The pudendal nerve and vessel exit the pelvis
through the greater sciatic foramen and course
beneath the ischial spine and sacrospinous
ligament before reentering the lesser sciatic foramen. Identifi cation of ischial spine is
essential when performing sacrospinous
fi xation and planning suture placement to avoid
injury to the pudendal neurovascular bundle.
• The arcus tendineus fascia pelvis (ATFP) and
arcus tendineus levator ani (ATLA) both
extend from the posterior surface of the pubic
bone and end at the ischial spine.
Muscular Support
The levator ani (LA) muscle constitutes the primary
muscular support to the pelvic organs. The
LA muscle consists of three components – the
pubococcygeus, puborectalis, and iliococcygeus,
nomenclatures based on the origin and insertion
of the muscle components (Fig. 1.5 ).
The anterior division of levator ani, the pubococcygeus,
sweeps downward from the inner surface of
the pubic bone along the sides of the urethra, vagina,
rectum, and perineal body. This is further subdivided
into the pubovaginalis, puboperinealis, and
puboanalis. The pubovaginalis portion attaches to
the lateral wall of vagina, the puboperinealis attaches
to the perineal body, and the puboanalis portion
attaches to the anus at intersphincteric groove.
The puborectalis, most caudal part of levator ani,
originates from the inner surface of pubic bone and
forms a U-shaped sling behind the anorectal junction
and contributes to the anorectal angle.
The iliococcygeus portion arises from the
ATLA and ischial spine on both sides and joins
with each other at the iliococcygeal raphe and
coccyx. The iliococcygeal raphe between the anus
and coccyx is referred to as the levator plate and
provides support to the rectum, upper vagina, and
uterus. The openings between the levator ani muscles
through which the urethra, vagina, and rectum
pass is known as the urogenital hiatus. The
whole expansion of the levator ani along with the
coccygeus muscle, perineal membrane, and perineal
body is the pelvic diaphragm.
Applied Anatomy
• The normal resting levators maintain a constant
state of contraction and relaxation occurs
only during the elimination process (micturition,
defecation, and parturition). Contraction
of the pubococcygeus elevates the urethra and
the anterior vaginal wall helping in urinary
continence. Pubococcygeus and puborectalis
contraction also elevates the anus and keeps
the urogenital hiatus closed. Contraction of
the levator ani can be assessed on rectovaginal
examination while instructing the patient to
squeeze the muscles as if holding bowels. The
“U-shaped” muscle is felt along the side and
posterior vaginal wall.
• Neuromuscular injury to the levators such as
during childbirth can lead to widening of the
urogenital hiatus and lead to vertical inclination

of the levator plate leading to dysfunction or
prolapse of the pelvic organs (Fig. 1.6a, b ).
• Levator avulsion, a documented injury of
childbirth, was fi rst reported as early as 1907.
Using ultrasound imaging Dietz identifi ed that
levator avulsion involves detachment of the
puborectalis portion from pelvic sidewall and
it occurs in about 36 % after vaginal delivery.
Avulsion can be diagnosed digitally by palpating
the inferior pubic ramus and feeling for
insertion of the puborectalis portion. In the
presence of levator avulsion, 2–3 cm lateral to
the urethra, bony surface of the pubic ramus
can be palpated devoid of the muscle.
Perineal Membrane
A thick fi bromuscular sheet that stretches across
the anterior urogenital triangle of pelvic outlet,
caudal to levator ani, is the perineal membrane
(formerly known as the urogenital diaphragm). It
attaches laterally to the ischiopubic rami and has
a free posterior margin with anchorage at the
perineal body. The urethra and vagina pass
through the hiatus in perineal membrane
(Fig. 1.7 ). The perineal membrane hence fi xes
distal urethra, distal vagina, and the perineal
body to bony pelvis at the ischiopubic rami. The
superfi cial perineal space lies external to the
perineal membrane and contains the superfi cial
perineal muscles, ischiocavernosus, bulbospongiosus
and superfi cial transverse perineal muscles.
The deep perineal pouch lies between the
perineal membrane and levator ani and contains
the external urethral sphincter, compressor urethrae,
urethrovaginalis, and the deep transverse
perineal muscles (Fig. 1.8 ).
Perineal Body
The perineal body situated between distal vagina
and anus is a point of convergence for different
structures. The superfi cial perineal muscles, bulbospongiosus
and superfi cial transverse perineal
muscles, external anal sphincter, perineal membrane,
deep transverse perineal muscles, distal
part of the rectovaginal fascia, pubococcygeus
and puborectalis portion of the levator ani all
insert into this mass of connective tissue (Fig. 1.9 ).
The perineal body plays an important role in the
support of distal vagina and maintaining normal
rectal function. In reconstructive surgeries, it is
therefore important to restore the perineal body
anatomy by proper re-approximation.

Applied Anatomy
Orientation of the superfi cial perineal muscles in
relation to vaginal outlet is important in reconstruction
of the perineum (perineorrhaphy) and in
episiotomy repair. In an ideal reconstruction, the
widened genital hiatus is narrowed, and perineal
body length is maintained.
Connective Tissue Support: Pelvic
Fascia and Ligaments
The pelvic fascia has two components: parietal
and visceral fascia. The parietal fascia covers
the muscles along lateral pelvic wall and on the
superior surface of pelvic diaphragm. The fascia
covering the obturator internus muscle, obturator
fascia, has two thickened portions: arcus tendineus
levator ani (ATLA) and arcus tendineus
fascia pelvis (ATFP), extending from the ischial
spines to posterior surface of pubic bone.
Portions of levator ani originate from ATLA,
while the ATFP provides the lateral point of
endopelvic fascial attachment ( see Fig. 1.4 ).
The existence of the visceral fascia, in certain
areas of pelvis and its various nomenclatures, has
been an area of controversy in pelvic anatomy.
The bladder and vagina are not enclosed in their
own fascial layer, and the vagina appears to be
separated from bladder anteriorly, only by the
adventitial layer of vagina. The existence of a
separate fascial layer between anterior vaginal
wall and bladder has been of dispute on histological
studies, and the nomenclature of pubocervical/
pubovaginal fascia is being questioned. On
the other hand condensation of the visceral fascia
between rectum and vagina, the rectovaginal fascia,
is an identifi able separate layer. This extends
from the perineal body proximally to about
2–3 cm above hymenal ring. Above this level
there is no separate fascial layer, and the endopelvic
fascia attaches posterior vaginal wall laterally
to pelvic side wall.
The endopelvic fascia is not a true fascia on
histology and correct terminology would be endopelvic
connective tissue. The term endopelvic fascia,
however, is commonly used. Condensations
of these fascia termed as ligaments include the
uterosacral, cardinal, pubovesical, and pubourethral
ligaments. The endopelvic tissue is a continuous
layer extending from the uterosacral
ligaments proximally to the pelvic portion of levator
ani muscle distally, up to the level of urethra
(Fig. 1.10 ).
The endopelvic fascia also extends laterally
across the pelvis, with its medial attachments to the
lateral wall of cervix and vagina and lateral attachments
to pelvic sidewall along the ATFP. This
attachment stretches the vagina transversely
between bladder and rectum and divides pelvis into
an anterior and posterior compartment. The bladder
and urethra occupy the anterior compartment.

the rectum and anal canal, posterior compartment
and the uterus and cervix, the middle or apical
The three integrated levels of pelvic support
projected by DeLancey to explain pelvic organ
prolapse are defi ned by the endopelvic connective
tissue attachments.
Level I Support
The cervix and upper vagina are suspended by
the endopelvic fascia (parametria, paracolpium)
and condensations of the connective tissue, uterosacral
and cardinal ligaments. Uterosacral ligaments
pass posteriorly from cervix and upper
vagina, form lateral boundaries of pouch of
Douglas, and attach to the front surface of sacrum
from sacrococcygeal joint up to the level of S3.
The cardinal ligaments (transverse cervical)
extends from the cervix and lateral vaginal fornix
to the posterolateral pelvic wall. These attachments
are referred to as the level I or suspensory
support. Failure of level I support leads to uterine
or vaginal vault prolapse (apical prolapse).
Level II Support
The fascial attachment in mid-vagina extends
from lateral vaginal walls to the ATFP and medial
surface of levator ani. It prevents descent of the
anterior and posterior vaginal walls with increase
in abdominal pressure. This is referred as level II
support or attachment axis. The differentiation
between a “central cystocele” and a “paravaginal
defect” in anterior compartment prolapse is based
on the type of endopelvic fascia defi ciency at this
level. In central cystocele (distension cystocele),
there is weakening of the connective tissue in
midline, resulting in loss of midline rugosity of
the vaginal wall. Lateral cystocele or paravaginal
defect results from lateral detachment of fascia
from the ATFP, and central rugosity are preserved
in these. Prior to surgical intervention, it would
be helpful to identify the type of anterior wall
prolapse, lateral detachment or central failure to
plan the optimal surgical technique.
The endopelvic connective tissue also extends
as pubourethral ligaments, from the urethra to
posterior surface of pubic bone, providing urethral
support and maintenance of bladder neck closure
during Valsalva maneuvers. The bladder neck in
addition, through its relation to the anterior vaginal
wall is indirectly supported by the attachment
axis. Hence failure of level II support results not
only in anterior and posterior vaginal wall prolapse
but also to stress urinary incontinence.
Level III Support
The lower one-third of vagina is fused with the
surrounding structures; through the endopelvic
fascia anteriorly to distal urethra, posteriorly to
perineal body, and laterally to pubovaginalis
muscle and perineal membrane. This is referred
to as the level III support or fusion axis. Level III
disruption anteriorly can result in stress urinary
incontinence from urethral hypermobility and
posterior disruption can result in distal rectocele
or perineal descent.
Ligaments Used in Reconstructive
Sacrospinous Ligaments (SSL)
The sacrospinous ligament with its lateral attachment
at ischial spines has a close relationship
with pudendal neurovascular bundle and to sciatic
nerve (Fig. 1.11 ). The anterior surface of the
SSL is muscular and forms the coccygeus muscle
and is referred to as the coccygeus–sacrospinous
ligament complex (C-SSL). The average length
of the SSL is 5.43 cm and the position of the
pudendal complex is about 0.9–3 cm medial to
ischial spine behind the SSL. Suture placement
for SSL fi xation ideally should be 1.5–2 cm
medial to ischial spine. It should never be across
the entire thickness of the ligament to prevent
damage to underlying structures. The sciatic
nerve lies 2.5 +/− 0.4 cm lateral to the ischial
spine posterior to SSL. On cadaver dissections,
either the third sacral nerve or the pudendal nerve
is found to course on the superior border of
C-SSL complex at its midpoint in a signifi cant
proportion. The diligence in trying not to enclose
the whole width of the ligament at SSL fi xation is
important for this reason.