perineum Flashcards
what are the degrees of the perineal tears?
1st degree —> involves slight tear to the superficial muscles only
2nd degree —> Extend to the deeper muscles of perineum, but anal sphincter is still INTACT
3rd degree —> tear reaches and involves the anal sphincter
4th degree —-> reaches and affects the rectum too
OCCURS IN 5-20% of women having vaginal birth
what happens in cases of injury to the perineal body in vaginal delivery of episiotomy ?
Prolapse of pelvic organs :
urinary bladder, uterus, etc
Episiotomy : cut incision made through the area between the vaginal opening and anus facilitate childbirth
what happens in case of pelvic trauma region?
pelvic region crushed
along with the symphysis pubis and the urethra
then urethra ruptures and urine will go the COLLES FASCIA
recall colles fascia?
membranous layer of superficial fascia of the perineum
the fascia around the superficial perineal space
CONTINUEOUS WITH SCARPAS FASCIA
what is the perineum??
diamond shaped region
located at the medial aspect of the upper thigh
Superomedial to the thigh
what is the anterior boundary of the perineum?
Pubic symphysis
what is the anterolateral boundary of the perineum?
Ischiopubic rami
what is the lateral boundary of the perineum?
ischial tuberosities ( bone structure we sit on )
what is the posterior boundary of perineum?
tip of coccyx
what is the posterior lateral boundary of the perineum?
Sacrotuberous ligament
Extend from the sacrum to the ischial tuberosities
what are the divisions of the perineum?
divided into 2 triangles
by an imaginary line at the ISCHIAL TUBEROSITIES
the 2 triangles :
Urogenital triangle ( ANTERIOR )
ANAL TRIANGLE ( POSTERIOR )
describe the fascias
in the abdomen we have 2 layers of superficial fascia :
Superficial fatty layer ( CAMPER )
Deep membranous layer ( Scarpa )
Scarpa fascia is continuous with COLLES IN THE PERINEUM
what are spaces/pouches we have in the colle’s fascia?
Deep to the colles fascia we have :
Superficial perineal pouch and DEEP perineal pouch
Deeper to the deep one : PELVIC DIAPHRAGM
How do we define demarcate these 2 triangles?
Separated by an imaginary lines passing through
AND BISECTING THE ISCHIAL TUBEROSITY ON EITHER SIDES
What is the deepest muscle that we can see in the triangles?
Levator ani
present both in triangles
what are the external genitalia structure of the female perineum ?
Vaginal opening
Above it —> Urethral opening
Clitoris –> 2 parts ( Prepuce and glans clitoris )
Mons pubis ( Fatty pad )
Labium minus ( Labia minora )—> Inner flaps/folds
what forms the mons pubis?
merging of labia
2 labia majora on either side meet
name the structures from below to above ( Posterior to anterior )
Vaginal opening ( MOST INFERIOR AND POSTERIOR )
Urethral opening
Glans clitoris ( small swelling )
Prepuce of clitoris ( small skin like flap ) ( its superior to the glans clitoris )
Mons pubis ( MERGING OF THE LABIA MAJORA, MOST SUPERIOR AND ANTERIOR )
what are the components of the male perineum ?
Penis :
Glans penis
Corona of the glans
Corpora cavernosum
Corpora spongiosum
Scrotum
scrotum + bulb and attachments of penis
what do you see deep the scrotum?
Root of the penis :
- Bulb of penis, centrally located
- Crus of the penis ( 2 , one of each side )
bulb and crus are not muscles but are made of erectile tissues
what does the ischiocavernosus muscle cover?
Crus of the penis ( the sides )
Beginning of the corpus cavernosum ( sides as well )
what does the bulbospongiosus muscle cover?
bulb of the penis ( center part )
what forms the pelvic diaphragm?
levator ani
what are the layers removed during dissection?
Skin
Superficial fatty layer and deep membranous layer ( COLLES FASCIA / Superficial perineal fascia )
Superficial perineal pouch
Deep fascia of the perineum
Perineal membrane ( INFERIOR LAYER O UROGENITAL DIAPHRAGM )
Deep perineal pouch
Superior layer of the urogenital diaphragm ( inferior pelvic fascia / inferior layer of pelvic diaphragm )
Levator ani ( diaphragm )
Superior layer of pelvic diaphragm ( Superior pelvic fascia )
what does the deep fascia of the perineum encloses?
muscles in the superficial perineal pouch
SO the deep fascia of the perineum needs to be removed first to access the muscles of the superficial perineal pouch
what does the superior layer of urogenital diaphragm / inferior pelvic fascia / inferior layer of pelvic diaphragm COVER?
pelvic diaphragm ( levator ani )
what does the perineal membrane separates ?
Superficial and deep perineal pouches
where is the superifical perineal pouch opened?
anteriorly
but the rest is closed
where is the urogenital diaphragm seen?
Deep perineal pouch
which is enclosed by the superior and inferior fascia of the urogenital diaphragm
Superior urogenital diaphragm fascia = inferior pelvic fascia
Inferior urogenital diaphragm fascia = Perineal membrane
why is it called inferior pelvic fascia?
because the pelvic diaphragm is above it
describe the continuousity of the colles fascia?
Colle’s fascia is continuous with the SCARPA fascia in the abdomen
extend downwards to be continuous with the fascia of the penis
further inferiorly to be continuous with the dartos fascia of the scrotum
what covers the muscles in the superficial perineal pouch?
deep fascia of the perineum
what do you have to remove to access the muscles in the superficial perineal pouch?
Fatty layer
membranous layer ( colle’s fascia )
deep fascia of the perineum ( cuz it covers the muscles in the superficial pouch )
what are the layers of the superficial fascia of the perineum ?
Fatty layer
Deep membranous layer ( colle’s fascia / superficial perineal fascia )
Deep perineal fascia
why does the urine accumulates only in the superficial perineal pouch ?
the deep membranous layer ( colles )
folds after attaching to holdens line on the sides
forming pocket in the anterior abdominal wall
Since this splitting is at the level of the ASIS
in cases of urethral rupture urine will accumulate only in the superficial perineal pouch ( scrotum and penis )
up to the junction between the umbilicus and pubic symphysis
WHY NOT GO TO THE THIGH? CUZ HOLDENS LINE
what are the layers of the deep fascia?
Perineal membranes ( aka inferior fascia of urogenital diaphragm )
Inferior pelvic fascia / Inferior fascia of the pelvic diaphragm / endopelvic fascia ( Superior fascia of urogenital diaphragm )
what are points to consider?
Colle’s fascia is the inferior most –> aka SUPERFICIAL PERINEAL FASCIA
Perineal membrane is called inferior fascia of the urogenital diaphragm is because it forms the floor of the deep perineal pouch
we have to remove the deep fascia of perineum to access the muscle in the superficial perineal pouch
superficial perineal pouch is found between?
Colles fascia ( superficial perineum fascia ) —> inferiorly )
and
Deep perineum fascia and PERINEAL MEMBRANE ( Inferior urogenital diaphragm fascia ) —> SUPERIORLY
deep perineal pouch is found between?
perineal membrane ( inferior urogenital diaphragm fascia )
and
Inferior pelvic fascia/endopelvic fascia ( Superior urogenital diaphragm fascia )
what muscle is found in the deep perineal pouch?
deep transverse perineal muscle which forms the urogenital diaphragm
what is the floor of the superficial perineal pouch?
Colle’s fascia / superficial perineal fascia —> INFERIOR
what is the roof of the superficial perineal pouch?
Deep perineum fascia + PERINEAL MEMBRANE ( inferior urogenital )—–> SUPERIORLY
what is the lateral boundary of the superficial perineal pouch?
Pubic arch / ischiopubic rami
what forms the posterior boundary of the superficial perineal pouch?
Closed by the fusion of the colle’s fascia and perineal membrane
what is the anterior boundary of the superficial perineal pouch?
it is open :
Continuous upwards with : SCARPA’S FASCIA ( at the ASIS is where superficial layer arise )
Continuous downward with the penis fascia and dartos fascia of the scrotum
LIMITED BY PUBIC SYMPHYSIS
what is the lateral attachment of the perineal membrane?
Periosteum of the ischiopubic rami like the superficial perineum pouch
what is the anteriorly/apex attachment of the perineal membrane?
arcuate pubic ligament / inferior pubic ligament between the pubic symphysis
thickened to form TRANSVERSE PERINEAL LIGAMENT
the perineal membrane is fully attached anteriorly BUT THE SUPERIFICAL PERINEAL POUCH AS OPENED
what is the posterior attachment of the perineal membrane?
Continuous and fuses with :
Inferior pelvic fascia ( superior urogenital ) —> SUPERIORLY
Colle’s fascia —> inferiorly
Attached to perineal body
what forms floor boundary of the deep perineal pouch?
Perineal membrane ( Inferior urogenital fascia )
what forms the roof boundary of the deep perineal pouch?
Inferior pelvic fascia ( Superior urogenital fascia )
what forms the lateral boundary of the deep perineal pouch?
pubic arch / ischiopubic rami
what forms the posterior boundary of the deep perineal pouch?
Fuses with the perineal membrane to pelvic fascia
what forms the anterior boundary of the deep perineal pouch?
fuses with the perineal membrane to pelvic fascia
what is the content of the superficial perineal pouch in males?
1- ROOT OF THE PENIS :
Bulb
Crus ( 2 crura )
2- 3 MUSCLES :
Bublospongiosus ( covers the bulb ) —> closest to the ischiopubic ramus
Ischiocavernosus ( covers the crus ) —> located in the middle
Superficial transversus perineal ( runs transversally )
3- vessels and nerves :
2 scrotal nerves ( posterior scrotal/labial nerve)
2 scrotal vessels ( posterior scrotal/labial )
the muscles in the superficial perineal pouch run over what?
over the erectile tissue
erectile tissue = bulb and crus = both form the root of the penis
These muscles should be removed to see the erectile tissue
what is perineal body?
important fibromuscular point where multiple muscles insert
what inserts in the perineal body?
anal sphincter
Deeper to it , levator ani also attaches
Superficial transverse perineal muscle
bublospongiosus muscles
Deep to it, deep transverse perineal muscle in the deep perineal pouch also attach
if the perineal body is torn all of these muscles can be affected , in episiotomy during childbirth, where small incision is made, cutting too deep may damage the perineal body and muscles attaches it
what is the blood supply of the superficial perineal pouch?
Internal pudendal artery
what does internal pudendal artery divide to?
Inferior rectal
Dorsal artery of penis/ clitoris
Perineal artery
what does the perineal artery divide into?
Muscular
Posterior scrotal/labial
So :
Internal —> perineal —> scrotal
what is the nerve supply of superficial perineal pouch?
Same concept as the blood supply :
Pudendal nerve :
Inferior rectal
Dorsal nerve of penis/clitoris
Perineal :
Muscular
Posterior scrotal/labial
how does the pudendal nerve supply and enter the region?
Supply most of the muscles in the perineal region as well as the skin around it
Passes through a canal known as :
Pudendal canal and it is related to the piriformis muscle
describe the course of the pudendal nerve?
Enter the perineal region , gives off 3 main branches :
First branch moves anteriorly and it is called the dorsal nerve of the penis/clitoris
Second branch moves posteriorly towards the rectum ( INFERIOR RECTAL NERVE )
Third branch supplies the perineal muscle and it is called PERINEAL NERVE—> give raise to muscular and posterior scrotal/labia
describe the course of muscular branch of perineal nerve?
Muscular branch of the perineal nerve enters the DEEP PERINEAL POUCH
supplies the deep perineal muscle
pierces the perineal membrane where it enters the superficial pouch and supply the muscle there
HENCE THE PERINEAL NERVE IS CONTENT OF THE DEEP PERINEAL POUCH
and
THE POSTERIOR SCROTAL/LABIAL BRANCHES OF THE PERINEAL IS THE CONTENT OF THE SUPERIFICIAL PERINEAL POUCH
what is the venous drainage perineum?
Corresponding veins to the arteries
what is the content of the superficial perineal pouch in females?
1- Root of clitoris :
Bulb of vestibule
Crus ( 2 crura )
2- 3 muscles :
Bulbospongiosus ( cover the bulb )
Ischiocavernosus ( cover the crus )
Superficial transverse perineal
3- Gland :
Greater vestibular
4- vessels and nerves :
2 labial nerves
2 labial vessels ( LABIAL INSTEAD OF SCROTUM)
compare the bulb in females and males?
the erectile tissue in females is :
Highly vascular susceptible to disruption of vessels as the result of trauma —> MORE PRONE TO VULVAR HEMATOMA IN LABIA MAJORA
what is the content of deep perineal pouch in males and females?
1- Urethra ( both females and males )
2- Bulbourethral / cowper glands in males ( the duct opens in the urethra )
3- Vagina in females
4- Muscles :
Deep transverse perineal ( forms urogenital diaphragm ) in both
sphincter urethrovaginalis and compressor urethra are extra in females —> found anteriorly to the urethra ( these muscles also partake in forming urogenital diaphragm in females )
5- Dorsal nerves of the penis / clitoris
6- Deep branches of the internal pudendal vessels + perineal nerve
where is sphincter urethrovaginalis located?
around the vagina and is attached to the urethra in females
where is compressor urethrae located?
around the urethra in females
what is perineal body?
fibromuscular tissue attached to the midline between the anal and urogenital triangles
Larger in females
Very important in the support of pelvic viscera particularly in the females
function of perineal body?
Attachment for :
External anal sphincter ( superficial party ) ( inferiorly )
Bulbospongiosus ( anteriorly )
Superficial transverse perineal ( the sides )
Deep transverse perineal ( from the deep perineal pouch )
Levator ani ( puborectalis/ pubovaginalis ) ( inferiorly )
what is the significance of perineal body?
childbirth can lead to damage/stretching/tearing of the perineal body
leading to prolapse of pelvic viscera
maybe avoided by episiotomy
Episiotomy : planned surgical incision during delivery
made starting at the frenulum and extending postero laterally to avoid anal sphincters
what are 4 bones that form the diamond shape?
Pubic symphysis
Ischial tuberosity ( on both sides )
coccyx
what is the name of the deep perineal /superficial investing fascia in penis ( GALLAUDETS )
deep fascia of the penis ( BUCKS )
what is the function of bulbospongiosus muscles?
Males :
maintain erection
Expel urine
Expel semen
FEMALES :
Help reduce the vaginal vestibule
what is the innervation of bulbospongiosus
?
pudendal nerve
describe transverse perinei?
transversely arranged fibers extending BETWEEN :
ischiopubic rami
what is the insertion of deep transverse muscles?
perineal body
in females :
Anterior fibers insert into the lateral wall of the vagina , supports pelvic viscera
what is the nerve supply of deep transverse perinei?
perineal branch of pudendal nerve
