Abdominal Wall, Peritoneum, & Hernias

Question 1

What is a mesentery?

Answer 1

• two layers of peritoneum that envelop an organ, vessels, etc.

Question 2

What does intraperitoneal mean?

Answer 2

• something within the peritoneum; however, nothing is actually inside the peritoneal sac (it is a potential space) –> they are invaginated into it

Question 3

Is the peritoneal sac completely sealed?

Answer 3

• in men, yes

- in women, no; there are openings of the Fallopian tubes into the peritoneal sac

Question 4

What is parietal peritoneum? What is visceral peritoneum?

Answer 4

• parietal: the layer of peritoneum lining the body wall

- visceral: the layer of peritoneum covering any organ

Question 5

List the layers going from skin to peritoneum.

Answer 5

• skin –> superficial fascia (where the fat is) –> deep fascia (tightly bound to muscles) –> muscles –> transversalis fascia (just deep to the transversus abdominis muscles) –> extraperitoneal fat –> parietal peritoneum

Question 6

Name the 3 muscles that make up the lateral abdominal wall. What do they form?

Answer 6

• external oblique (outermost layer): fibers run down and in (“hands in pockets”)
• internal oblique (middle layer): fibers run down and out
• transversus abdominis (innermost layer): fibers run transversely
• they form the rectus sheath, which sheaths the rectus abdominis muscles (the two rectus abdomini are separated by the linea alba; the horizontal breaks within each rectus abdominis are called tendinous intersections)

Question 7

Do the aponeuroses of the external oblique, internal oblique, and transversus abdominis pass anteriorly or posteriorly to the rectus when forming the rectus sheath superior to the arcuate line? What about inferior to the arcuate line? (Arcuate line appears about 1/2 between the umbilicus and pubis.)

Answer 7

• superior to arcuate line (upper abdomen): external oblique passes anteriorlly, internal oblique splits in half (1/2 goes anteriorly, 1/2 goes posteriorly), transversus abdominis passes posteriorly; therefore, we have an anterior and posterior layer here
• inferior to arcuate line (lower abdomen): all three pass anteriorly; therefore, we only have an anterior layer here