Embryology Week 10

What is the name of the tissues destined to become the testes?

primordial testicular germ cells

Where do the primordial testicular germ cells raise from?

Secondary yolk sac

When do the primordial testicular germ cells migrate out of the yolk sac?

Week 4

Where do the primordial testicular germ cells pile up?

Caudal-dorsal part of the gut tube

What is the term for the pile of primordial testicular germ cells?

Genital ridge

Where do the testes originate from?

Genital ridge

What other accessory testicular structures morph from the genital ridge?

Tunica albuginea

Testicular arteries

Vas deferens (ductus deferens)

Genitofemoral nerve

Pampiniform plexus

What are the layers of the testes superficial to deep?

Parietal layer of the tunica vaginalis

Tunica vaginalis cavity

Visceral layer of tunica vaginalis

Tunica albuginea

Seminiferous tubules

Rete testis

T or F: Testes form intraperitoneal

False (extraperitoneal)

What is the name of the cord of mesenchyme that grows from the inferior pole of the testes towards the anteroinferior abdominal wall?

Gubernaculum

What is the AKA of the gubernaculum?

genitoinguinal ligament

T or F: While the testes are extraperitoneal, the gubernaculum is actually intraperitoneal

False (they are both extraperitoneal)

What does the gubernaculum attach to on the anterior inferior pelvic wall?

Future scrotum and inguinal canal

What is the name of the future scrotum and inguinal canal on the anterior inferior pelvic wall?

Labioscrotal swelling/fold

What happens to the gubernaculum as the trunk elongates during gestation?

It shortens

What happens when the gubernaculum shortens?

It pulls the testes through the anteroinferior wall and into the growing scortum

What is created by the gubernaculum passes through the abdominal?

Inguinal canal

What assists in testicular descent?

increasing intra abdominal pressure

What is the name of the invagination of visceral peritoneum that pushes down to form the inguinal canal?

Processus vaginalis

What is the function of the processes vaginalis during development?

pull the testes down into the scrotum

Which layer of the abdomen is not pulled down with the processes vaginalis?

Transversus abdominis muscle

What are the layers of the abdominal wall?

External oblique

Internal oblique

Transversus abdominis

What are the layers abdominal fascia?

Transversalis fascia

Extraperitoneal fascia (preperitoneal fat)

Parietal peritoneum

When do the testicles complete their descent?

Week 32 gestation

T or F: The testes are pulled through the processes vaginalis

False (pulled with it, not through it)

What type of fluid is in the processus vaginalis?

Peritoneal fluid

What structures are created by the passing of the processus vaginalis?

Deep inguinal ring

superficial inguinal ring

What does the processus vaginalis disintegrate into?

A thin fibrous cord

In what % of men does the processus vaginalis never completely close?

26%

What condition can be caused by a patent processus vaginalis?

Indirect inguinal hernia

What part of the testes does the distal portion of processus vaginalis cover?

Front and sides

What surrounds most of the testes?

Double membrane of peritoneum

What is the name of the sac formed by mushrooming of the processus vaginalis to cover the testes?

Tunica vaginalis

What are the layers of the tunica vaginalis?

Visceral layer of the tunica vaginalis

Tunica vaginalis cavity

Parietal layer of the tunica vaginalis

What does the visceral layer of the tunica vaginalis stick to?

outer layer of the testes (tunica albuginea)

What does the parietal layer of the tunica vaginalis stick to?

innermost layer of the scrotum

What are the layers of the scrotum superficial to deep?

Epidermis

Dermis

Superficial fascia (dartos fascia)

External spermatic fascia

Internal spermatic fascia

Parietal layer of the tunica vaginalis

Cavity of the tunica vaginalis

Visceral layer of the tunica vaginalis

Tunica albuginea

What is the term for when the tunica vaginalis fills with fluid?

Hydrocele

How many divisions does the tunica vaginalis have?

3

What is the term for the herniation of the abdominal wall created by passage of the gubernaculum and processus vaginalis?

Spermatic cord

Which layer of the abdominal wall is not part of the spermatic cord?

Transversus abdominis muscle

At what end of the testes does the spermatic cord occur?

Superior

What are the 3 layers of the spermatic cord?

External spermatic fascia

Cremasteric fascia/muscle

Internal spermatic fascia

Preperitoneal fascia

What is the external spermatic fascia derived from?

External oblique aponeurosis

What is the cremastic fascia/muscle derived from?

internal oblique muscle/fascia

What is the internal spermatic fascia derived from?

Transversalis fascia

What is not contained in the spermatic cord layers?

parietal peritoneum or transversus abdominis muscle/fascia

What structures are contained within the spermatic cord?

Ductus deferens

Artery to the ductus deferens

Testicular artery

Pampiniform plexus

Cremasteric artery and veins

General branch of the genitofemoral nerve

Innervates cremaster muscle/fascia

Sympathetic and visceral parasympathetic afferent nerve fibers

Lymphatics

Remnant of the processus vaginalis (in 26% of men)

What is the deep inguinal ring an outpouching of?

transversalis fascia

What is the term for a processus vaginalis that has not degenerated away?

persistent processus vaginalis

What two structures does a persistent processus vaginalis create a communication between?

the cavity of the processus vaginalis and peritoneal cavity

What is the region that surrounds the inguinal ligament?

Groin

What landmarks does the groin lie between?

ASIS and pubic tubercle

What category of hernia are groin hernias a part of?

Abdominal wall hernia

What are the two major types of groin hernia?

Inguinal hernia

Femoral hernia

What is the most common type of hernia?

Inguinal Hernias (specifically indirect)

What is the least common type of all hernias?

Femoral hernia

What are the two types of inguinal hernia?

Direct

Indirect

What is the AKA of direct inguinal hernia?

Acquired

What is the AKA of indirect inguinal hernia?

Congenital

What is the cause of inguinal hernia?

Greater momentum and/or bowel

Where does a direct inguinal hernia occur?

Hesselbach's triangle

Where does an indirect inguinal hernia occur?

Deep inguinal ring or persistent processus vaginalis

What % of abdominal hernias occur in the groin?

75%

What % of men get an abdominal wall hernia at some point in their lives?

27%

What % of women get an abdominal wall hernia at some point in their lives?

3%

What is the prevalence of inguinal hernia in 75 yo men?

45%

T or F: Inguinal hernias are always symptomatic

False

What type of persistent processus vaginalis can allow istenstines to herniate into the tunica vaginalis cavity?

Complete

What can be sucked through a persistent processus vaginalis in females?

ovaries

fallopian tube

uterus

What will fill the scrotum in a congenital hydrocele?

Peritoneal fluid

Where can fluid accumulate in females with a small patent processus vaginalis?

Canal of neck

What is the canal of neck?

Lumen of the processus vaginalis under the labia majora in females

What is the term for when a hernia sac goes all the way into the scrotum?

complete congenital indirect inguinal hernia

What is the term for when an indirect inguinal hernia stays in the spermatic cord?

incomplete congenital indirect inguinal hernia

What can occur when intestines herniate into a PPV?

Mechanical small bowel obstruction

Strangulation

What is the most common complication of indirect inguinal hernia?

Strangulated indirect inguinal hernia

Which blood vessels can be constricted by an indirect inguinal hernia?

Testicular artery

Testicular vein (pampiniform venous plexus)

What complications can arise from testicular ischemia due to an indirect inguinal hernia?

Testicular death

Peritonitis