Download 15-perineum

Urogenital triangle
It is bounded in front by the
pubic arch & laterally by the
ischial tuberosities .
Superficial fascia
Fatty layer
1- The fatty layer is continuous with the fat of
the ischiorectal fossa & the upper part of the
thigh. It is replaced by the dartos muscle in
the scrotum.
2- The membranous layer is attached
posteriorly to the posterior border of the
urogenital diaphragm & laterally to the
margin of the pubic arch & anteriorly it is
continuous with the membranous layer of
the of the anterior abdominal wall . This
fascia is continued over the penis or clitoris
as a tubular sheath . In the scrotum or labia
majora it forms a distinct layer .
Superficial fascia of the thigh
The fatty layer of the fascia extends into the
thigh & continues down over the lower limb
without iterruption.
The membranous layer extends into the
thigh & becomes attached to the deep fascia
after about a fingerbreadth ( 8 cm ) below
the inguinal ligament .
Superficial Perineal Pouch
It is bounded below by the
membranous layer of the
superficial fascia & above by the
urogenital diaphragm.
It is closed behind by the fusion of
its upper & lower walls.
Laterally , it is closed by the
attached membranous layer with
the urogenital diaphragm to the
margins of the pubic arch .
Anteriorly, It communicates with
the space lying between the
superficial fascia & the muscles of
the anterior abdominal wall .
Superficial Perineal Pouch In Male
It contains structures forming the root of the
penis,with the muscles that cover them.
1-The bulbospongiosus Ms.,are situated one on
each side of the midline & cover the bulb of the
penis & the posterior portion of the corpus
spongiosum.
2- Ischiocavernosus Ms., they cover the crus
penis on each side.
Perineal body
Superficial Transverse Perineal Ms.,Each muscle
arises from the ischial tuberosity & inserted into
the perineal body. The function of them is to fix
the perineal body in the center of the perineum.
Small mass of fibrous tissue which is attached
to the center of the posterior margin of the
urogenital giaphragum. The external anal
Nerve Supply : perineal branch of the pudendal
sphincter and 1 ( o ) & 3 ( In) are attached to it .
Penis
It has a fixed root & a body . Its root is made up of 3 masses of erectile tissue called bulb
of penis and R.& L. crura of penis. The bulb is attached to the undersurface of the
urogenital diaphragm and is continued forward into the body to form Corpus Spogiosum
( spongy urethra is present within them ). Each crus is attached to side of pubic arch and
lie side by side in the dorsal part of the body of penis, forming the corpora
cavernosa.
Body Of Penis :It is made up of 2 dorsally placed corpora cavernosa, which communicate with each
other . & a single corpus spongiosum applied to ventral surface. The 3 are erectile tissue. The
corpus spongiosum expands to form the glans penis. On the tip of the glans penis is the external
urethral meatus.
Arteries from internal pudendal &
veins into
internal pudental. The corpora cavernosa by the deep arteries of the penis& the corpus spongiosum
by the artery of the bulb & dorsal artery of the penis.
Nerve supply: pudental N. & pelvic plexuses.
Lymph Drainage: The skin into medial
group of superficial inguinal nodes. The deep structures into internal iliac nodes .
Superficial Perineal Pouch In
Female
It contains the root of the clitoris &
muscles that cover them.
1- Bulbospongiosus muscles : they
surround the orifice of the vagina &
cover the vestibular bulbs. Their
fibers extend forward to gain
attachment to the corpora
cavernosa of the clitoris .
2- The ischiocavernosus muscles :
They cover the crus of the clitoris
Superficial T. perineal muscles :
like male.
Nerve supply : The perineal branch
of the pudendal nerve.
Perineal Body : Is larger than male
. It is a wedge- shaped mass of
fibrous tissue situated between the
lower end of the vagina & anal
canal . It supports the posterior wall
of the vagina.
Female Urogenital Triangle
It contains the external genitalia
and orifice of the urethra & vagina
Clitoris : It corresponds to penis. Is
situated at the apex of the vestibule
anteriorly.
Root of clitoris is made of 3 erectile
masses , the bulb of the vestibule
& R. and L. crura .
The bulb is divided into 2 halves
The crura become the corpora
cavernosa anteriorly.
Body of clitoris :It consists of the 2
corpora cavernosa. The corpus
spongiosum is present by a small
amount of erectile tissue leading
from the vestibular bulbs to the
glans.
Glans of the clitoris It is a small
mass of erectile tissue that caps
the body . The glans is partly
hidden by prepuce.
Blood supply, Lymph drainage ,
Nerve supply are similar to those of
the male penis .
1
2
Vulva ( Female external genitalia )
3-Labia minora : their posterior ends are
united to form the fourchette . Anteriorly,
they enclose the clitoris , forming
prepuse & posterior frenulum.
4-Vestibule : is a triangular area
bounded laterally by the labia minora
Anterior by the clitoris .Posterior by
fourchette.
5- Vaginal Orifice : it is protected by
hymen.
6Orifices of the ducts of the greater
vestibular glands are found in the
groove between the hymen & the
posterior part of the labium minus.
Blood supply : external & internal
pudendal arteries .
Nerve supply : Anterior parts are
supplied by ilioinguinal & genital branch
of genitofemoral . The posterior parts
are supplied by branches of the perineal
nerves & posterior cutaneous nerves of
the thigh .
Lymph drainage : into medial group of
superficial inguinal nodes .
Urogenital Diaphragm
It is a triangular musculofascial
diaphragm. It fills the gap of the pubic
arch .It is formed by the sphincter
urethrae & the deep transverse perineal
ms.These muscles are enclosed between
a superior & inferior layers of fascia of
this diaphragm.
The inferior fascia is called perineal
membrane.
The closed space that is between the 2
layers of the fascia is known as the deep
perineal pouch
Anteriorly , the 2 layers of fascia fuse ,
leaving a small gap beneath the symphysis
pubis . They form the anterior transverse
perineal ligament.
Posteriorly , the 2 layers of fascia fuse with
each other & with the membranous layer of
the superficial fascia & the perineal body .
Deep perineal pouch in Male
It contains the membranous part of the
urethra; sphincter urethra; bulbourethral
glands; the deep transverse perineal
muscles; the internal pudendal vessels &
their branches and the dorsal nerves of the
penis.
Membranous part of the urethra:
It is about 1.3 cm long & lies within the
urogenital diaphragm & is surrounded by the
sphincter urethra muscle. It continuous
above with the prostatic urethra & below with
the penile urethra . It is the shortest & least
dilatable part of the urethra.
Bulbourethral Glands: they lie beneath the
sphincter urethrae muscle. Their ducts pierce
the perineal membrane & enter the penile
Sphincter Urethae Muscle : It surrounds the urethra portion of the urethra. Their secretion is as a
in the deep perineal pouch. It arises from the pubic result of erection.
arch on the 2 sides & passes medially to encircle the Deep transverse perineal muscles: They lie
P. to sphincter urethrae. It arises from the
urethra. Its nerve supply is the perineal branch of
pudendal nerve. It is the means by which micturition ischial ramus & passes medially to be
inserted into the perineal body.
can be voluntary stopped.
Dorsal Nerve of Penis: It arises from pudendal N. It Internal Pudendal Artery : It enters the deep
pass forward through deep perineal pouch to skin of perineal pouch & gives rise to the As. Of bulb
penis.
Deep Perineal Pouch in Female
It contains part of the urethra & part of
vagina .
The sphincter urethrae, which is pierced
by the urethra & vagina. ( like male ).
The deep transverse perineal muscles(like
male ) .
Internal pudendal vessesls & their
branches and the dorsal nerves of the
clitoris ( their arrangement similar to male)
Urethra : it opens into the vestibule about
2.5 cm below the clitoris. It traverses the
sphincter urethrae & lies immediately
infront of the vagina. At the sides of the
external urethral meatus are small
openings of the ducts of the paraurethral
glands .
The cause of pelvic deformities may
be due to:
1- congenital
2- required due to
a. disease
b. poor posture
c. fractures
d. rickets
Deformities of the pelvis may be responsible for
dystocia ( difficult labor )
Some of differences between the
male & female pelvis
Female pelves are classified
into 4 groups
1- Normal
3
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1
2- The inlet is ovale , long; narrow.
3- Contracted outlet .
2
4
4-Promontary is pushed forward & the
inlet is flattened .
Estimation of the transverse diamerter
( width ) of the pelvic outlet by means of
a closed fist
Injury to the pelvic floor
It results in the loss of support for the pelvis viscera leading to
1- Utrine & Vaginal prolapse.
2- Herniation of the bladder ( cystocele )
3- Alteration in the position of the bladder neck & urethra ( the normal angle between the
urethra & the posterior wall of the bladder is lost ) leading to stress incontinence ( the
patient dribbles urine as in coughing ).
4- Prolapse of the rectum.
Fascial ligaments of the uterine cervix
They assist to prevent uterine prolapse .
The visceral pelvic fascia around the uterine cervix & vagina is referred as the
parametrium .
Primary Megacolon
It is more common in male than in female .The child fails to pass meconium; the
abdomen becomes distended due to distention of the sigmoid colon which is hyper
trophied while the rectum & anal canal are constricted the cause is due to complete
failure of development of the parasympathetic ganglion cells in this region . Excision of
the aganglionic segment of the bowel.
Tubal Ligation
It is used to obtain permanent birth control . If
the ova is discharged from the ovarian follicles it
will degenerate in the tube proximal to the
obstruction. Fertilization can occur again in
about 20 % of women .
Pelvic Inflammatory Disease
Ascending infection from the cervix can occur &
is followed by infection of the tubes ( Salpingitis)
Leakage of pus into the peritoneal cavity causes
pelvic peritonitis & pelvic abscess or general
peritonitis .
Cysts of the Ovary
Follicular cysts : are common & originate in
unrupture graafian follicles.It does not exceed to
1.5 cm.
Luteal cysts : Fluid is retained in the corpus
luteum which cannot become fibrosed. It does
not exceed to 3 cm .
The Rectouterine Pouch & Disease
The pouch lies directly behind the posterior fornix of the vagina.
It becomes the site for the accumulation of blood ( from a ruptured ectopic
pregnancy ). Or pus from a ruptured pelvic appendicitis or in gonococcal
peritonitis .
Culdocentesis is a passage of a needle into the pouch through the posterior
fornix .
The interior of the female pelvic peritoneal cavity can be viewed by using an
endoscope through a small colpotomy incision.
Internal Hemorrhoids ( piles )
They are varicosities of the tributaries of the
superior rectal vein and are covered by mucous
membrane & the submucosa .
These tributaries lie in the anal canal columns at
the 3, 7, and 11 o’clock positions when the patient
is viewed in the lithotomy position. Also, it may
contain a terminal branch of the superior rectal
artery.
The first degree is within the anal canal
If they extrude from the anal canal on defecation
then return at the end of the act ( 2nd degree) .
If they elongate & prolapse on defecation and
remain outside the anus ( 3rd degree) .
They occur in the upper half of the anal canal
which is innervated by autonomic afferent nerves,
so they are painless but may give rise to an aching
sensation. They are sensitive to stretch.
The causes are : 1- The vein is valveless
2- A congenital weakness of the vein wall
3Chronic constipation
4- Pregnancy due to
pressure on the vein.
5-Portal hypertension .
N.B. The possibility that cancer of rectum is
External Hemorrhoids
They are varicosities of the tributaries of the
inferior rectal vein.
They are covered by mucous membrane or skin.
They are sensitive to pain ,temperature, touch and
pessure & are innervated by the inferior rectal
nerves. So , they are painful .
Thrombosis of an external hemorrhoid is common .
Anal Fissure
The anal columns are connected by anal
valves ( folds). In chronic constipation ,
these valves can torn down to the anus ( as
a result of catching on the fold of the
mucous membrane by the edges of the
fecal mass.
The elongated ulcer known as an anal
fissure . It occurs mostly in the midline
posteriorly or ,less anteriorly.
The cause is due to sweep of the superficial
part of the external sphincter in the lateral
sides of the anal canal and not encircle it .
This means that there is lack in the support
The site of the anal fissure in the sensitive
lower half of the anal canal , which is
innervated by the inferior rectal nerve,
results in reflex spasm of the external anal
sphincter .
For this pain the fissure must examine
under local anethesia.
The Ischiorectal Fossae & Infection
They are filled with fat that is poorly vascularized
.
1-Infection commonly tracks laterally from the
anal mucosa through the external anal sphincter .
2-Infection of the perianal hair follicles or sweat
glands can cause infection in the fossae.
Rarely, a perirectal abscess bursts downward
through the levator ani muscle.
An ischiorectal abscess may involve the opposite
fossa by spread of infection across the midline
behind the anal canal .
Rectal examination
The following structures can be palpated
by the gloved index finger inserted into the
anal canal & rectum .
Anteriorly : In the female
In the male
Opposite Rectouterine
Terminal vagina
Phalanx
cervix
Rectovesical
vas deference
P. surface of bl
seminal vesicle
Opposite urogenital
Middle
diaphragm
Phalanx
vagina
Rectoprostatic
fascia
prostate
Opposite
Proximal
Phalanx
perineal
body
lower part
of vagina
perineal body
urogenital diaph
bulb of penis
Posteriorly: the sacrum, coccyx and
anococcygeal body
Laterally : ischiorectal fossa & ischial
spines.
Injury To Perineum During Childbirth
During childbirth, the perineal body can
be damaged by laceration causing
permanent weakness of the pelvic floor .
Also, tear of the lower third of the
posterior wall of the vagina and the
overlying perineal skin.
In sever tears the lacerations may extend
backward into the anal canal & damage
the external sphincter. In this case an
accurate repair of the walls of the anal
canal, vagina and perineal body must
done .
During second stage of labor , when the
baby’s head is presenting at the vaginal
orifice episiotomy is done.
Episiotomy may be median or
mediolateral which is performed usually .
The incision is made through the perineal
skin. It is a median incision that turns
laterally as it proceeds posteriorly.
Episiotomy is used in breech & forceps
Vaginal examination
This examination is used to know
the health of the vaginal walls ,
the uterus, and thesurroundin g
structures
The upper half of the vagina lies
above pelvic floor between the
bladder anteriorly & the rectum
posteriorly.
The lower half lie within the
perineum between the urethra
anteriorly & the anal canal
posteriorly.
Pudental Nerve Block
Area of Anesthesia: Is the skin of perineum.It
abolish sensation from the posterior part of
perineum that is because the anterior part is
innervated by the ilioinguinal & genitofemoral
nerves. So, it does not abolish pain from
uterine contractions that ascend to spinal
cord via the sympathetic afferent nerves
Indications : Forceps delivery & episiotomy.