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Vol.
159,1892-1897,
June
1998
Printed
in
USA.
ANATOMICAL RELATIONSHIP BETWEEN URETHRA
AND
CLITORIS
HELEN
E.
OCONNELL,
JOHN
M.
HUTSON, COLIN
R.
ANDERSON
AND
ROBERT
J.
PLENTER
From the Department
of
Urology, Royal Melbourne Hospital, and Departments
of
Pediatric
Surgery,
and Anatomy and Cell Biology,
University
of
Melbourne, Victoria, Australia
ABSTRACT
Purpose: We investigated the anatomical relationship between the urethra and the surround-
ing erectile tissue, and reviewed the appropriateness
of
the current nomenclature used
to
describe this anatomy.
Materials and Methods:
A
detailed dissection
was
performed
on
2
fresh and
8
fixed human
female adult cadavers (age range
22
to
88
years). The relationship
of
the urethra
to
the
surrounding erectile tissue was ascertained in each specimen, and the erectile tissue arrange-
ment
was
determined and compared to standard anatomical descriptions. Nerves supplying the
erectile tissue were carefully preserved and their relationship
to
the
soft
tissues and bony pelvis
was noted.
Results: The female urethra, distal vaginal wall and erectile tissue are packed into the
perineum caudal (superficial)
to
the pubic arch, which
is
bounded laterally by the ischiopubic
rami, and superficially by the labia minora and majora.
This
complex is not
flat
against the rami
as
is
commonly depicted but projects from the bony landmarks
for
3
to
6
cm. The perineal urethra
is
embedded in the anterior vaginal wall and
is
surrounded by erectile tissue in all directions
except posteriorly where it relates
to
the vaginal
wall.
The bulbs of the vestibule are inappro-
priately named as they directly relate
to
the other clitoral components and the urethra. Their
association with the vestibule is inconsistent and, thus, we recommend that these structures be
renamed the bulbs
of
the clitoris.
Conclusions:
A
series of detailed dissections suggest that current anatomical descriptions
of
female human urethral and genital anatomy are inaccurate.
KEY
WORDS:
anatomy, clitoris, urethra
The
gross
and histological anatomy of the human female
perineum is oRen described in cursory1 or comparative
terms.2.3
Typically, the human female perineal anatomy is
briefly described only in terms
of
its differences from the
male perineal anatomy. Frequently, descriptions of the neu-
rovascular supply
to
the perineal area are scant or absent.
Female urethral anatomy, with the exception of its sphinc-
ters and surrounding fascia, is usually described without
reference
to
surrounding structures, particularly the clitoris.
The clitoris is said
to
be different from the penis in that the
urethra “does not traverse it.”4
The initial goal of this research was
to
determine the
female anatomy of the cavernosal nerves and whether it was
analogous
to
that of the male anatomy. To begin our inves-
tigation microscopic dissections were performed on fresh tis-
sue from
10
female infant cadavers who had died of sudden
infant death syndrome. They were investigated because com-
parable work had been performed on male infant cadavers.5
While performing these dissections it became apparent that
the end organ erectile tissue was surprisingly different from
the descriptions of it in anatomy publications. To ensure that
such major differences were not age related and to broaden
the
scope
of our research, further investigation of this anat-
omy was performed on adult cadavers. In this study we
determine and describe accurately the
gross
anatomy of the
urethra and its surrounding erectile tissue complex, the cli-
toris. We also review the appropriateness
of
current anatom-
ical terminology used in describing these tissues.
Accepted for publication January
23,
1998.
Supported by the 1997 Bruce Pearson Fellowship, Urological
Trust
of Australia and New Zealand, and the 1994 Victor Hurley Medical
Fund, Royal Melbourne Hospital.
MATERIALS AND METHODS
The perineum and pelvis
of
2
fresh and
8
fixed female
human cadavers were dissected in detail. Fresh tissue was
processed for histology and immunohistochemistry, the find-
ings from which will be published separately. The anatomy
of
the female erectile tissue and its relationship to the urethra
were determined by dissection and documented photograph-
ically. The dissections were compared to anatomy and pelvic
surgery texts, and historical anatomy literature.
We were able
to
determine the age range of the cadavers
but not the menopausal status
as
these data were not avail-
able. The ages indicated that
2
were likely premenopausal
(22
and
36
years old, fresh and fxed tissue, respectively).
Of
the remaining cadavers
6
were
70
years old
or
older and
2
were
51
and
55
years old (fresh and fixed tissue, respective-
ly). The appearances of these latter
2
cadavers suggested
that they were postmenopausal. The erectile tissue struc-
tures were more bulky and more easily defined in the
younger specimens.
No
record of previous surgery was ob-
tainable although
3
elderly specimens showed evidence
of
hysterectomy. There was no evidence
of
prior perineal sur-
gery.
Before dissection fixed cadaveric tissue was subjected
to
a
standard embalming regimen of the Department of Anatomy
and Cell Biology, University
of
Melbourne using a mixture
of
40%
formaldehyde, glycerine, ethanol, phenol and saline.
Although the dissection sequence varied somewhat depend-
ing on the goal
of
a specific dissection, a general sequence
was followed. In the fixed cadavers both lower limbs were
amputated and, after section of the abdomen a few cm. above
the pubic symphysis, all pelvic viscera except the uterus,
vagina, bladder and urethra were removed. The perineal
dissection involved excision
of
the adductor muscles at their
1892
ANATOMY
OF FEMALE URETHRA
AND
CLITORIS
1893
origin, taking care to avoid injury to the adjacent erectile
tissue and associated musculature. The suspensory ligament
was dissected in detail in
4
specimens. The labia majora were
dissected and their highly vascular adipose content was
noted. ARer excision of the fat superficial
to
the ischiocaver-
nosus and bulbospongiosus muscles these muscles were re-
moved, exposing the underlying crura and deep perineal
membrane. The bony pelvis was excised unilaterally after
division of the pubic symphysis. Extreme care was taken
to
avoid injury to the neurovascular bundle observed
to
run
adjacent to the lower edge of the ischiopubic ramus. The bone
was separated from the soft tissues progressing from the
lateral edge to the median plane.
This
separation revealed
the clitoral crura and after excising the suspensory ligament
the body
of
the clitoris was also exposed. The flimsy capsule
surrounding the bulbs of the vestibule was removed to expose
the underlying erectile tissue, and the relationship between
the bulbs and the urethra was noted in each specimen. The
internal pudendal and cavernosal neurovascular bundles
were dissected in each specimen and their course was noted.
Exposure of these bundles was facilitated by bilateral exci-
sion of the ischiorectal fossa fat and levator
ani.
The fresh tissue obtained post mortem involved a much
more limited dissection after a standard postmortem exami-
nation had been performed.
An
en bloc dissection of the
uterus, vagina, bladder, urethra, small segment of pubic
symphysis, surrounding erectile tissue, and associated mus-
culature and fat was performed, and a more detailed dissec-
tion was performed using an operating microscope in the
laboratory. All specimens are described according to the
an-
atomical position.
This
research was performed after obtain-
ing appropriate ethics approval from the Victorian Institute
FIG.
2.
Dissection
of
55-year-old cadaver demonstrating same re-
lationships as shown
in
fi
s
1
and
7.
Note
bulbs
(Blb)
flanking
urethra rather than vaginaEstibule
(Vest)
as
in
figure
1.
Cannulas
are present
in
urethra and periurethral plane through which instru-
ments
are
passed for colposuspensions and pubovaginal
slings.
Cr,
crura.
GI,
glans
of
clitoris.
FIG.
1.
Coronal section
of
female erectile tissue
of
76-year-old
fixed
cadaver. Plane
is
ardel
to
superficial surface of pubic rami.
Note
cross section of bulg
(Blb)
and
its
clear relationship
to
crura and
UY
Of
clitoris
(Bd)
as well as
to
urethra
(Ur)
medid
There
is
distinct color difference
&tween
erectile tissue of bult (darker),
ma and corpora (dark), and surrounding tissue.
VW,
of Forensic Pathology and the
Board
of Medical Research,
Royal Melbourne Hospital.
RESULTS
The erectile tissue complex (clitoris) consists of a midline
body (corpora) giving rise
to
bilateral
crura
and separate
bulbs which
sit
posterior
to
the body
as
displayed
in
figures
1
to
3.
The urethra lies surrounded by
this
complex with the
body directly anterior to it, flanked superficially by the bulbs
and deeply by the crura. Thus, the urethra
is
a
pelvic and
perineal conduit embedded in the anterior vaginal wall but in
all other directions
it
is
surrounded by erectile tissue
(figs.
1
and
4).
Figure
1,
a
photograph of
a
section of the erectile
tissue in a coronal plane perpendicular
to
the urethral wall,
reveals the intimate relationship between the urethra and
the bulbs.
In anatomy
texts
the bulbs
are
referred
to
as
the bulbs of
the vestibule and appear
as
if they form an erectile core of the
labia minora (fig.
5).
However, our dissections reveal that the
bulbs relate most closely
to
the clitoris and urethra, and do
not have
a
consistent relationship
to
the vaginal vestibule
(figs.
1
to
4
and
6).
The bulbs lie on the superficial
aspect
of
the vaginal wall and do not form the core of the labia minora.
The arrangement of the erectile tissue complex and its
distribution in
a
young premenopausal woman are clearly
demonstrated in figure
3,
A
and
B.
In
this
dissection the left
labium minora remains
intact
to
demonstrate the position of
the erectile tissue
with
respect
to
the
skin.
The bulbs lie deep
to
the bulbospongiosus muscle and
are
covered with
a
deli-
cate membrane which
is
markedly Merent from the thick
and tough capsule
surrounding
the clitoral
m-m.
In
this
specimen
the
bulbs
are extensive
and almost completely
1894
ANATOMY
OF FEMALE
URETHRA
AND
CLITORIS
found
the
dorsal nerve of the clitoris
to
be noticeably large,
in
most dissections
greater
than
2
mm.
in
diameter. At the
lateral
limit
of the ischiopubic ramus the neurovascular bun-
dle
runs
medially and the dorsal nerve
runs
along the top
surface of the corpora
to
enter the deep
aspect
of
the glans
clitoris (figs.
8
and
9).
In
previous studies
a
cavernosal neurovascular bundle has
been observed
lateral
to
the urethra and lying directly on the
pelvic
aspect
of the anterior vaginal Careful excision of
the endopelvic fascia and bladder facilitates exposure of this
bundle (fig.
9).
DISCUSSION
Since the studies of Masters and Johnson’ there has been
surprisingly little investigation of basic female sexual anat-
omy
or
physiology.
In
Kaplan’s discourse on male and female
sexual structure and function, the clitoris
is
described as
“a
small knob of tissue located below the symphysis pubis.”s
Later, the author states that ”the nerve pathways and spinal
reflex centers have not yet been anatomically delineated with
precision.”
Illustrations of female perineal anatomy from some histor-
ical foreign literature demonstrate diagrams
of
dissections
largely consistent with our
finding~.~-l~
However, modem
anatomy
texts
have reduced descriptions
of
female perineal
anatomy
to
a brief adjunct
after
a
complete description of the
male anatomy. There
are
several
major shortcomings
in
the
anatomy depicted in current literature. The bulbs are either
omitted or, if described, their relationship
to
other cavernous
~~~&&&~$~~
t\gEteF
tissue
is
not observed. The urethra
is
not shown to relate to
the clitoris. The erectile tissue complex
is
displayed
as
if
it
were
flat
against the pubic symphysis and not 3-dimensional
(D).
The
clitoris
is
pictured as minute7.
l3
or not represented
at all, and
its
neurovascular supply
is
rarely described.
FIG.
3.
Dissection of36-year-old fixed premeno ausal cadaver re-
veals extensive erectile tissue
with
bulb
(Blb)
fulpy flanking lateral
vaginal
wall
on
superficial (lateral) as ct. Bulbar neurovascular
&’’$;;.
$:%
cr,
GI,
J-
ofc~to~.
hb
min,
labia
minors.
Vest,
vestibule.
cover the
distal
vaginal wall, which
is
that part of the wall
lying superficial
to
the
bony pelvis. In other specimens from
postmenopausal cadavers the bulbs related more exclusively
to
the clitoris
or
to
the urethra (figs.
1,2
and
6).
The texture
of the erectile tissue of the body and ma was the same but
different &om that of the bulbs, which appeared
to
contain a
dense deep blue vasculature. By comparison, the body and
ma were heavily encapsulated and their vasculature was
deep pink, distinct from the surrounding tissue (fig.
1).
The clitoris
is
a tri-planar complex with the corpora lying
in
the median
sagittal
plane and the crura lying parallel
to
the ischiopubic
rami.
The bulbs then partially
or
completely
fill
the
gap between the labia minora, body and crura
lateral
to
the vaginal wall and urethra. Thus, the clitoris
is
not
flat
against the bone
as
is
shown
in
anatomy and surgery
texts
(fig.
5).
The body of
the
clitoris
is
1
to
2
cm. wide
and
composed of paired corpora
that
are
2
to
4
cm.
long. The crura
extend laterally from the deep aspect of the
body,
and are
5
to 9
cm. long and slightly narrower than the body. The bulbs
are
3
to
7
cm. long, crescentic or triangular
in
shape, and fill
in
the space between the ma, body and urethra, superficial
to
the vaginal wall
(figs.
3
and
6).
The glans and frenulum of the clitoris are usually accu-
rately described in textbooks and are easily demonstrated
because of their superficial position
at
the junction of the
labia minora anterior
to
the urethra. Our dissections re-
vealed no structures consistent with previous descriptions
(fig.
5)
of the greater vestibular (Bartholin’s) glands.3
The internal pudendal neurovascular bundle was observed
to
divide at the most lateral point of the ischiopubic ramus
into the dorsal neurovascular bundle of the clitoris and the
bulbar neurovascular bundle (fig.
7).
The male dorsal neuro-
vascular bundle
is
clearly described in standard textbooks
although the reference
to
corresponding female neuroanat-
OmY
is
usually
absent
Or
inaccurate.
williams
stated
that
“in
the
the
corresPOnding
nerve
(dorsal nerve
Of
the
clitoris)
is
very small and supplies the
~litoris.”~
We have
FIG.
4.
Dissection of fresh tissue from 22-year-old cadaver. Body
of clitoris has been removed revealing that urethra
(Ur)
lies directly
posterior and bulbs,(BZb) are in direct lateral continuity to urethra.
Cr,
crura.
Deep pen
mem,
deep perineal membrane.
Vug,
vapina.
ANATOMY
OF FEMALE
URETHRA
AND
CLITORIS
1895
FIG.
5.
Diagram
shows view of female perineal anatomy typical of standard
textbooks.
Reprinted with
permission3
Vag
mll
FIG.
7.
Clitoris
of
36-year-old cadaver demonstrated
in
relation
to
moved, leavine adiacent deeu fascia.
Cr,
crura.
DV,
dorsal vein.
Pub.
dorsal and pudendal neurovascular bundle
(Neurouasc
B).
Arrow
indicates point
of
origin
of dorsal neurovascular bundle, which
runs
mddy
along
lower
as
t
of ischiopubic ramus, which has
been
removed.
FO~
clarity iscgrectal fat and levator
an^
have
been
re-
6.
Lateral view of cadaver shown
in
figure
2.
Shape
of
bulb
@lb)
is
different from
s
cimen
in
figure
3.
Note
how small bulb is
and
how little of laterrvaginal
Wag)
wall
is
flanked
compared
to
3.
Bd,
body
of clitoris.
Cr,
cma.
GI,
glans of clitoris.
Vest,
vestibule.
symp.,
pubic&nml;hysis.
Our
dissections indicate that the clitoral components are
3-D,
and
this
feature
has
contributed
to
the
poor
documen-
tation of the clitoris hause
it
is
relatively difficult anatomy
to
display.
In
OUT
research the systematic use of photography
throughout the
dissections
enhanced
OUT
understanding of
the
3-D
nature of female perineal anatomy. For example,
demonstrating the anatomy from the
lateral
or
oblique
as-
1896
ANATOMY
OF
FEMALE
URETHRA
AND
CLITORIS
FIG.
9.
Dissection of inside of pelvic floor reveals dorsal vein com-
plex
(DVC),
dorsal neurovascular bundle (Neuro-uusc
B),
vaginal
(Vug!
wall fromrlvic side and edge of endopelvic fascia after careful
excision of blad
er
and endopelvic fascia. Cavernosal neurovascular
bundle is clearly seen lateral
to
urethral
(Ur)
wall.
Cuu
A,
cavernosal
artery.
Cuu
N,
cavernosal nerve.
Cr,
crura. Deep peri
mem,
deep
perineal membrane.
w/
FIG.
8.
Dissection of deep
aspect
of
bod
(Bd)
and right
CNS
(Cr)
of
clitoris, and dorsal neurovascular bunch (Neuru-uusc
B).
Dorsal
vein complex is also seen, including lumen of deep dorsal vein
(DV).
Lab
min,
labia
minora.
Pub.
symp., pubic symphysis.
pect prevents the typical foreshortening usually associated
with illustrations of the body of the clitoris. With photogra-
phy the exact size of
a
structure can
be
displayed and, thus,
the
body is seen
to
be
2
to
4
cm. long.
The bulbar erectile tissue is intimately related
to
the other
components of the clitoris and urethra, and our research
indicates that it
has
been inappropriately named the bulbs of
the vestibule. For clarity and completeness
it
makes more
sense
to
refer
to
the bulbs by their constant relationship
to
the
clitoral components and
to
call them the bulbs of the
clitoris.
While local vasocongestion of the corpora cavernosa and
spongiosum of the
penis
are said
to
produce male erection,
the "bulbs of the vestibule which surround the introitus,
produce vaginal lubrication and the swelling which creates
the
orgasmic platform."s Although there is a paucity of accu-
rate clinical investigation assessing the specific function of
the bulbar erectile tissue, it appears that this tissue is likely
to
have
a
significant sexual role. We hypothesize that the
bulbs add support
to
the distal vaginal wall to enhance its
rigidity during penetration.
The urethra
is
intimately related
to
each component of the
clitoris, but whether
it
has
a
role in sexual activity is uncer-
tain. In
a
feminist account of female perineal anatomy the
bulbar erectile tissue is referred
to
as
the urethral "sponge."14
The authors stated they had no access
to
dissection material
on which
to
base their description of anatomy.
In
a recent
French ultrasonographic study of female sexual sensitivity
the site of the external sphincter of the urethra was identified
as the most sensitive area along the anterior vaginal wall.15
In
that study the urethral sphincter was referred
to
as the
"G
point" and the perineal urogenital tissue referred
to
as the
"ensemble uretro-clitorido-vulvaire." Our study leads
us
to
suspect that the role of the urethra in sexual function is
related to the position of the surrounding erectile tissue
rather than the urethral sphincter.
Whether the urethra has a role in sexual function is
1
issue. Perhaps, of greater concern to the urologist and pelvic
surgeon is whether during operations in the vicinity
of
the
urethra tissues responsible
for
female sexual function are
damaged. Examples of such surgery include partial and total
urethrectomy, urethral and vaginal suspension procedures,
and partial and
total
vaginectomy.
An
extensive review
of
the
literature indicates how seldom sexual function and its pres-
ervation are considered in the outcomes of these operations.
Our dissections demonstrated considerable age related
variation in the dimensions of the erectile tissue between
specimens. The specimens derived from premenopausal ca-
davers revealed substantially more extensive erectile tissue
than those of the elderly cadavers.
It
is possible that typical
dissections of female genital anatomy are performed on ca-
davers of more advanced age than those dissections per-
formed on male subjects. Certainly the size
of
the erectile
tissues uncovered by our dissections was greater than ex-
pected based on anatomy textbook diagrams. While male
urogenital anatomy is easier to investigate because of its
more external or superficial position, except
for
the labia,
glans clitoris and vaginal introitus, the female urogenital
tissues are internal and relatively obscured by overlying
subcutaneous fat.
CONCLUSIONS
A
dissection based study
of
female cadavers suggests that
current anatomy texts do not accurately display female per-
ANATOMY OF FEMALE URETHRA AND CLITORIS
1897
4.
Ramanes,
G.
J.:
Cunningham’s Textbook of Anatomy,
12th
4.
Oxford: Oxford
University
Press,
1981.
5.
Walsh,
P.
C. and Donker, P.
J.:
Impotence
following
radical
prostatectomy: insight into etiology and prevention.
J.
Urol.,
128:
492,1982.
6.
Hautmann, R. E., Phs, T. and de Petrimni, R.: The ileal neo-
bladder
in
women:
9
years of experience
with
18
patients.
J.
Urol.,
1%
76,
1996.
7.
~~te~,
w.
H.
and
Jobson,
v.
E.:
H~~
bsponse.
Boston: Little, Brown
&
Co,
1966.
1974.
9.
Rauber,
Arthur
Georgi,
1897.
organes
gbnito-
urinaires.
Edited by
P.
Poirier and
A.
Charpy.
Paris:
Masson
et Cie, p.
578, 1901.
ineal anatomy. Cadaveric dissection
has
facilitated an in-
creased understanding of the gross anatomy of the urethra
and surrounding erectile tissue as well
as
its
neurovascular
supply. We found the clitoris
to
be intimately related
to
the
perineal urethra and more extensive
than
typical diagrams
indicate.
me
bulbs
of
the
vestibule
appear
to
be
inappropri-
ately named because of their constant relationship to
the
urethra and clitoris, and we recommend they be referred to
as the bulbs of
the
clitoris.
erence material, the
staff
at
the Victorian
Institute
of Foren-
sic Pathology, particularly Ms. %cia O’Brien, facilitated
the
postmortem studies, and Prof. Lorraine Dennerstein, Prof.
F.
Douglas Stephens,
MI-.
Warren
F.
Johnson,
Prof. G.D.
Clunie, Dr.
Norm
Eizenberg and Dr. Edward
J.
McGuire
provided guidance and inspiration.
as.
J~~
cleeve provided
assistance
with
historical
ref-
8.
&plan, H.
s.:
The New sex Therapy. London: Bdhh Tindall,
Anatomic
des
Menschen.
10.
~~ff~l,
H.:
~~~fi
gbni~ de la
femme.
11.
Rauvibre, H.: Anatomie
Humaine.
Park
Masson
et Cie,
1943.
12.
Testut, L. and
Latarjet,
A:
Trait4
D’anatomie
Humaine. Paris:
G.
Doin
et
Cie,
1949.
13.
Pescatori, E.
S.,
Engelman,
J.
C., Davis,
G.
and Goldstein,
I.:
Priapism of the clitork a
case
report
following
trazodone
use.
J.
Urol.,
149:
1557, 1993.
14.
A New
View
of a Woman’s Body. Edited by C. Dawner and R.
Chalker. New York
Simon
and Schuster,
1980.
15.
Len&
L. C.,
Vanneuville,
G.,
Monnet,
J.
P. and Harmand,
Y.:
Sphincter
ur6tral
(point
G).
Codlations anatomcAiniques.
Rev.
FT.
Gynec.
Obst.,
87:
65,1992.
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1.
McMinn, R.
M.
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