Inguinal region and descent of the gonad

Question 1

What are three ways that temperature of the testes is regulated

Answer 1

1. Cremaster muscles - innervated by the genitofemoral nerve-causes elevation of testis upon contraction. In cool environment, the testis will be brought closer to the abdomen and prevent heat loss.
2. Dartos muscle - smooth muscle that is sympathetically innervated. It will reduce the size of the scrotal sac and decreases surface area in cold environment
3. Pampiniform plexus - a venous plexus that is continuation of testicular vein. It surrounds the testicular artery in the spermatic cord. There is a large surface area for exchange of heat from arterial blood to venous blood (thermal counter current.) Less heat is going to the testes and being released into the environment.

Question 2

Describe indirect and direct inguinal hernias and how to tell internally the two apart and how to tell inguinal apart from femoral hernia.

Answer 2

Indirect inguinal hernia follows the inguinal canal (enters deep ring and exits superficial ring) and is therefore covered by all the same fascia layers as the spermatic cord (dartos fascia, external spermatic fascia, internal spermatic fascia, cremasteric fascia)

Direct inguinal hernia will tear through the abdominal wall. Because the external oblique aponeurosis is the strongest layer, they will go through the area where its weakest, the superficial ring. The only covering they have is the external spermatic fascia when passing through the external oblique aponeurosis.

Both come out of the superior inguinal ligament however, the inferior epigastric artery (branch of internal iliac) can be used as a land mark. It is between the superficial and deep inguinal rings. An indirect hernia enters the deep ring and so passes lateral to the artery. A direct hernia passes through the wall to the superficial ring through the region of the Hesselbach’s triangle and passes medial to the artery.

For distinguishing femoral from inguinal hernias, trace to the origin of the hernia. Femoral hernias pass deep to the inguinal ligament and inguinal hernias pass superficial.

Question 3

How do you palpate a direct from an indirect inguinal hernia?

Answer 3

Locate the superficial ring right lateral to the pubic tubercle and tell the patient to cough. The pressure will push the hernia outwards and you would feel it. That will tell you its an inguinal hernia.

Then you compress the area around the deep inguinal ring, around the midpoint of the anterior iliac spine and the pubic tubercle. Then you tell them to cough again. If you still feel it bulge out = direct, if you don’t = indirect.

Question 4

Describe the descent of the testes

Answer 4

The gonads originate in the extraperitoneal layer (right between the parietal peritoneum and the transversalis fascia). The first layer it goes through is the transversalis fascia as an evagination known as the deep inguinal ring. This fascia will become known as the internal spermatic fascia.

Then it travels under the falx inguinalis of the transversis abdominus and internal oblique layers. It will also become covered by some of the lower muscle fibers which become known as cremaster muscles. The fascia covering these muscle fibers (internal oblique fascia) become known as cremasteric fascia.

Then it passes through the superior inguinal ring and is covered by the external oblique fascia which becomes the external spermatic fascia.

The parietal peritoneum evaginates prior to the descent of the gonads. After the testis descent, then the parietal peritoneum fuses proximally and forms a double layer of peritoneum known as the tunica vaginalis.

The outpocketing of the scrotum lacks any camper’s fascia and is only continuous with the Scarpa’s fascia and Colle’s fascia becoming known as the dartos fascia

Question 5

How is the female inguinal region different?

Answer 5

The inguinal canals are the same, just what passes through them are different.

From the ovary to the uterus is the ovarian ligament

Entering the deep ring and running through the inguinal canal in females are the round ligaments rather than the spermatic cord in males. Round ligament is derived from the caudal genital ligament. In males the ligament descends and becomes known as the gubernaculum which connects the testis to the scrotum. The ovaries do not descend and the round ligament attaches the uterus to the labium majus.

As for the vasculature

Question 6

Compare the vasculature of the small intestine between the jejunum and the ilium

Answer 6

Jejunum - upper right

• more vasculature
• Longer vasa recta
• arcades, few large loops
• less fat in mesentary
• thick heavy wall with LARGE, tall and closely packed circular folds, few lymphoid nodules

Ileum - lower right

• less vasculature
• short vasa recta
• numerous short loops
• more fat
• thin and light wall, few folds, many lymphoid modules.

Question 7

Describe the structure of the large intenstine

Answer 7

So ileum meets large intestine at the cecum via the ileocecal valve. Branching off of the cecum is where all the tenia coli converge and subsequently emerge from, the appendix, providing the whole large intestine three longitudinal muscle strips

Cecum is the start of the large intestine and then ascending colon on the right side and ending with a slightly elevated hepatic flexure turn into the transverse colon.

Then another turn into the descending via the splenic flexure which is normally higher (if not, splenomegaly)
Then descending colon into the sigmoid colon and that is the last turn at the rectosigmoid junction and ending at the rectum.

Features

Omental appendices - small pouches of peritoneum filled with fat, dunno what they do but can be inflamed

The tenia coli tightly associated with the colon causes these ridges known as haustra.

Question 8

What innervates the cremaster muscles?

What innervates the dartos smooth muscle?

Answer 8

Cremaster: innervated by the genital branch of the genitofemoral nerve.

Dartos smooth muscle: innervated by sympathetics.

Question 9

What are the boundaries of hasslebach’s triangle and its clinical significance?

Answer 9

Medial- rectus abdominis

Lateral = inferior epigastric vessels

Base = inguinal ligament

Direct hernias go directly through this area and out the superfifical ring. If you push hernia back and feel the pulse lateral to your finger, that distinguishes direct hernia.