Sem 2 - C - Urogenital triangle - boundaries, fascia, urogenital diaphragm, Deep/Superficial pouch, Pudendal vessles/nerve Flashcards
What are the boundaries of the anal and urogenital triangle?
Anal triangle - line between coccyx and ischial tuberosities with a horizontal line drawn between the ischial tuberosities
Uorgenital triangle - line between pubic spympysis and ischial tuberoisities with a horizontal line between ischial tuberosities
The anterior portion of the perineum is the urogenital triangle The posterior portion of the perineum is the anal triangle What makes up the centre point of the perineum?
The centre point of the perineum is where the perineal body lies - it serves as a site for muscle attachment of the perineal structures
What is the urogenital diaphragm and what forms it?
Urogenital diaphragm is a triangular muscoulofascial diaphragm situated in the anterior portion of the perineum (in the urogenital triangle)
It is formed by a layer of muscles in the deep perineal pouch, which lies between the superior (deep)&inferior (superficial) fascial layers of the urogenital diaphragm
What is special about the superficial fascia of the anterior abomindal wall below the level of the umbilicus?
Superficial fascia of the abdominal wall separates into 2 layers below the umbilicus Superficial fatty layer - Camper’s fascia Deep membranous layer - Scarpa’s fascia
Camper’s fascia is continuous over the inguinal ligament into the thigh and perineum What are the continuations of Camper’s fascia in the perineum for both males and females?
Camper’s fascia In males - Camper’s fascia continues into the fascia of the penis. It loses its fatty layer and fuses with the deeper superficial fascia to become the dartos fascia of the scrotum In females - It retains its fatty layer and contributes to the fascia of the labia majora
Scarpa’s fascia is the thin membranous superifical fascia layer with little fat attaching to the linea alba and pubic symphysis in the midline Below the inguinal ligament, Scarpa’s fascia fuses with the fascia of the thigh to form the fascia lata What are the continuations of Scarpa’s fascia in the perineum for both males and females?
Scarpa’s fascia attaches to the posterior part of the perineal membrane (the superficial fascial layer of the urogenital diaphragm)
- In males - it is continous with the fascia of the penis, dartos fascia of scrotum and the fundiform ligament of the penis
- In females - it contirbutes to the labia majora
What is Camper’s fascia continous with in the anogenital triangle? What is Scarpa’s fascia known as in the perineum?
Camper’s fascia is continuous into the ischioanal fossa (ischiorectal fossa)
Scarpa’s fascia is known as Colle’s fascia in the perineum - attaches to the posterior perineal membrane
As said, between the urogenital diaphragm superior (deep) and inferior (superficial) fascial layers we have the deep perineal pouch containing muscles
What does the superior layer of fascia blend with? What muscles are found in the deep perineal pouch? What is the inferior layer of fascia also known as?
- The superior layer of fascia of the urogenital diaphragm blends with the perineal body and membrane posteriorly
- The sphincter urethra and deep transverse perineal muscles are found in the deep perineal pouch
- The inferior layer of fascia is also known as the perineal membrane
The layers of the urogenital diaphragm fuse anteriorly and posteriorly Why is there a small gap between urogenital diaphragm and pubic symphysis? What do the posterior aspect of the layers also fuse with?
The layers fuse anteriorly leaving a small gap near the pubic symphysis for the passage of the blood vessels to the clitoris and penis (dorsal vein of penis and clitoris) The posterior aspect of the layers also fuse with the membranous superficial fascia (Colle’s fascia) and the perineal body
What is the space between the fascial layers of the urogenital diaphragm known as?
Space between the fascial layers of the urogenital diaphragm is known as th deep perineal pouch and the muscles found here are the deep transverse perineal muscles and the sphincter urethra
Deep perineal pouch between the fascial layers of the urogenital diaphragm What is located in this pouch? (muscle, neurovasculature and other structures)
* Sphincter urethrae * Deep transverse perineal muscles * Urethra in males and females * Internal pudendal vessels and branches * Pudendal (perineal) nerve and its branches
Females - vagina, dorsal nerves of clitoris
Males - membranous urethra, dorsal nerves of penis, bulbourethral glands, penile arteries
Where are the bulbourethral glands located and what is their function? What are they homologous to in the females?
Bulbourethral glands (Cowper’s glands) are located posterolateral to the membranous urethra in the deep perineal pouch
Bulbourethral glands secrete mucous to lubricate the urethra
They are homologous to the Bartholin’s glands (greater vestibular glands) in females
Where is the superficial perineal pouch located?
Structures between the superficial fascia of the urogenital diaphragm (the perineal membrane) and the skin are located within the superficial perineal pouch
What is found within the superficial perineal pouch?
Superficial perineal pouch:
- Urethra & vagina clitoris, penis
- Nerves & vessels
- Muscles - ischiocavernosus, bulbospongiosus, superficial transverse perineal muscles
- Erectile tissue - crura, bulb of penis, bulb of vestibule
As said within the superficial perineal pouch in both males and females are the muscles ischiocavernosos, bulbospongiosus and the superficial transverse perineal muscles * What is the difference between these muscles in males and females?
In males, the muscles are larger as they are covering larger because the erectile tissue they are covering is larger
How do the ischiocavernosus and bulbospongosus get their name? What do the muscles cover?
The ischiocavernosos covers the crura (which is continuous with the corpus cavernosum in males)
- This muscles runs along the ischiopubic ramus from ischial tuberosity to pubic symphysis
The bulbospongiosus covers the bulb of the penis in males (which is continuous with the corpus spongiosum in males) and the bulb of the vestibule in females
What is the crura continuous as in males? What is the bulb continous as in males? Do the crura fuse in males or females? What lies at the base of the bulbs of the vestibule?
Crura - continuous as corpus cavernosum
Bulb - continuous as corpus spongiosum
- The crura does not fuse in males. In females, crura fuse to form the clitoris
At the base of the bulbs of the vestibule are Bartholin’s glands - these secrete mucous in to the vaginal canal to lubricate the vagina
Where are the mucous secreting glands found in males and females? (ie what part of the urogenital diaphragm) What are the different parts of the clitoris known as?
- Males - Bulbourethral glands are located posterolateral to the membranous urethra in the deep perineal pouch
- Females - Greater vestibular glands are located in the superficial perineal pouch at the base of the bulb of the vestibule
Parts of clitoris = Glans & body of clitoris
What is the perineal body and where is it located?
The perineal body is a small fibrous structure located at the posterior margin of the urogenital diaphragm
What muscles attach to the perineal body?
* The external anal sphincter * The deep/superficial transverse perineal muscles * The bulbospongiosus * Levator postatae/ pubovaginalis
What column of erectile tissue does the urethra of the penis travel within?
The urethra of the penis travels through the bulb of the penis and into the coprus spongisum - covered by the bublbospongiosus muscle
Describe the different regions of the male urethra? Where is the widest and narrowest parts of the urethra?
- Pre-prostatic - at neck of bladder just before prostate
- Prostatic - widest part of urethra and drains ejaculatory duct
- Membranous - passes through urogenital diaphragm, narrowest part
- Penile (spongy) -through the bulb of penis and corpus spongiosum to the external urethral orifice
The male urethra is both a urinary and reproductive structure, is this the same for the female urethra?
The female urethra is just a urinary structure travelling from the bladder to external urethra orifice just inferior to the clitoris
Describe the course of the pudendal nerve from exiting the pelvis to the pudendal canal (will ask about the branches shortly)
The pudendal nerve exits the pevlis via the greater sciatic foramen before crossing over the sacrospinous ligament at the ischial spine to re-enter the pelvis through the lesser sciatic foramen
After re-entry, it joins with internal pudendal artery & vein to travel through the pudendal canal where it divides into branches
What is the pudendal canal also known as and what forms it?
The pudendal canal is also own as Alcock’s canal formed by the fascia of the obturtor internus in the lateral pelvic wall The canal ends near the ischial tuberosities
At the ischial tuberosities, there are neurovascular structures passing close to this – the internal pudendal vessels and the pudendal nerve What branches does the pudendal nerve give whilst in the pudendal canal?
The inferior rectal nerve
The perineal nerve which branches into superficial and deep branches :
- Superficial branches go to perineum (posterior sctoral nerves,posterior labial nerves)
- Deep branches include the dorsal nerve of the penis and clitoris
What branches does the internal pudendal artery give to the perineum?
Internal pudendal artery gives the inferior rectal artery as well as perineal branches to supply other structures within the perineum ie deep and dorsal artery of the penis, dorsal artery of the clitoris, artery of the bulb etc
WHat nerve branch supplies the external urethral sphincter?
The perineal nerve branch fom the pudendal nerve
- Levator ani, deep and superficial perineal pouch muscles innervated by perineal branch of pudendal nerve
- External anal sphincter innervated by inferior rectal branch of pudendal nerve
