Session 24: GU 1 Flashcards
What is the inguinal canal
The location where the blood vessels/nerves/lymphatics/vas deferens required for the normal functioning of the testis have to pass through
What is the inguinal canal a common site for?
Hernias
What is the superficial inguinal ring?
A triangle shaped area within the aponeurosis of the external oblique muscle. Have fibres running below the spermatic cord (attaching to pubic tubercle) and in front of the spermatic cord (attaching to pubic bone). Creates this triangle shaped area
How do the fibres of external oblique and internal oblique differ in the flank?
External: run downwards and outwards
Internal: run upwards and inwards (at superior iliac spine fibres run horizontally)
What does the inguinal ligament attach to?
Attaches to the pubic tubercle
What is the purpose of the internal oblique muscle?
It contracts -> shortens-> closes inguinal canal -> prevent bowel coming down from abdomen and causing a hernial
Origin of the transversus layer of muscle (below the internal oblique)
Takes its origin from the lateral one third of the inguinal ligament. Its lowermost fibres pass over and behind contents of the inguinal canal
What is the deep inguinal ring
Just below the internal oblique there are a number of tubular structures
Where is the deep inguinal ring?
Lies lateral to location of the femoral pulse in the upper part of the thigh. Just lateral to the blood vessels here too (next Q)
What blood vessels supply this area/are located here?
The inferior epigastric artery comes off the external iliac artery as it passes underneath the inguinal ligament. Runs up the abdominal wall.
What surround the contents of the spermatic cord
A layer of fascia
Thus what are the contents of the inguinal canal covered in
Transverses fascia
What else is the inguinal canal covered in
A layer of the cremesteric muscle (derived from internal oblique)
What is the third layer that covers the I.C when it emerges from the superficial inguinal ring
The external spermatic fascia
What are the three layers of spermatic cord and testis
- ) Transverses fascia
- ) Cremesteric muscle
- ) External spermatic fascia
What are the structures within the spermatic cord
- ) Testicular veins
- ) Pampiniform plexus of veins
- ) Testicular artery
- ) Vas deferens
Why are there multiple veins
Spermagtogenesis needs a body temp lower than normal. High surface area of scrotum cools down testis (which has veins) for correct spermatogenesis
Why does the testicle not have a large artery?
As it isn’t very metabolically active
Function of the vas deferens
Carries sperm from testis to the penis for ejaculation
What makes up the testis
The testicle itself and the epidydimus
What is the epidydimus
It is a convoluted tube. Runs from top of testis to bottom of testis
What is the sac that covers the testis
The tunica vaginalis
What is present on the superior pole of the testis
The ducti efferentes
What is covers the testis
A white tunic: the tunic albuginia
What is the tube that runs from the peritoneum to the tunica vaginalis
The processus vaginalis
Below the skin, what covers the penis
Buck’s fascia
Purpose of Buck’s fascia
Limit amount of blood that flows into the penis during erection
What is the main shaft of the penis formed from?
Three cylinders of erectile tissue: two corpora cavernosus/one copus spongiosus
What is the glans penis entirely formed from?
The corpora spongiosus
What is the urogenital triangle*
The perineum
What is the ano-rectal triangle
Between the ischial tuberosities and the coccyx
What is the name of the membrane that sits on the peroneal triangle
The peroneal membrane. External genitalia are attached to its superficial surface
Whats deep to the peroneal membrane
Layer of muscle: deep peroneal pouch. Forms part of sphincters for the vagina + urethra
What is the crura cavernosus
Where the column of erectile tissue lies by the inferior rami. Aka the foot of the penis or clitoris
What is the name of the muscle that lies over the erectile tissue
Skeletal muscle: ischio-cavernosus
In males: what is the bulb shape erectile tissue
The crura spongiosus (forms foot of corpora spongiosis)
In males: What is the muscle that overlies the crura spongiosus
The bulbospongiosus muscle
How does this differ in females?
- The spongiosis is in 2 bodies of erectile tissue
- 2 bodies are separated by the interoitus
What are the labia minora
Skin that has no hair follicles
What is the hair bearing bulge that sits over the labia minora
The labia majora
What is between the two labia minora
- ) An orifice for the urethra
2. ) An orifice for the vagina
What do the four parts of the erectile tissue do in females
They form a small protrusion: the clitoris
In males: how is the scrotum formed
The labia majora fuse together
What is the nervous supply here?
- ) L1: ilio-inguinal nerve
2. ) S2: sacral nerve (supplies ring round anal ring)
The peudenal nerve root
Passes out of the greater sciatic formaina with the sciatic nerve
What is the nerve that supplies the peroneum
The peudendal nerve. It is a branch of sacral roots 2/3/4
What muscle fibres lie on the surface of the sacrotuberous ligament
Glutus maximus muscle fibres
What is the levatorani muscle
Thin sheet of muscle that closes off the pelvic outlet
What does the peudendal nerve pass deep to to enter the ischio-rectal fossa
The sacrotuberous ligament
Function of the peudendal nerve
Sensory nerve supply to the posterior 2/3 of the external genitalia and the lower 2/3 of the anal canal
