TBL15 - Fascial Layers and Internal Surface of Abdominal Wall

Question 1

What reinforces the superficial fascia below the umbilicus? What are therefore the two subcutaneous layers of the superficial fascia?

Answer 1

1) Below the umbilicus, the superficial fascia is reinforced by elastic and collagen fibers
2) Thus, in addition to the superficial fatty layer (Camper’s fascia), the superficial fascia contains a deep fibrous layer (Scarpa’s fascia)

Question 2

What nerves innervate the anterolateral abdominal wall and what are their origins? What fibers provide somatic sensory innervation to the epigastric, umbilical, and hypogastric (pubic) regions?

Answer 2

1) Intercostal nerves (T5-T11), the subcostal nerve (T12), and the iliohypogastric and ilioinguinal nerves (L1) innervate the anterolateral abdominal wall
2) Peripheral fibers from the DRG (cutaneous branches) at T5-T9, the DRG at T10-T11, and the DRG at T12-L1 provide somatic sensory fibers to the epigastric, umbilical, and hypogastric (pubic) regions, respectively

Question 3

What resides in the Camper’s fascia? Compare lymph nodes that receive lymph formed above and below the transumbilical plane.

Answer 3

1) Superficial lymphatic vessels reside in Camper’s fascia
2) Superficial lymphatic vessels accompany the subcutaneous veins; those superior to the transumbilical plane drain mainly to the axillary lymph nodes; however, a few drain to the parasternal lymph nodes. Superficial lymphatic vessels inferior to the transumbilical plane drain to the superficial inguinal lymph nodes

Question 4

What is the transversalis fascia? What does it line?

Answer 4

Endoabdominal fascia lines the internal surface of the musculotendinous sheet and is called transversalis fascia where it lines the internal surface of the transverse abdominis muscle (ignore other regional names)

Question 5

What is analogous to the paretial pleura of the pleural cavities? Name the tissue layer that separates the parietal peritoneum from the transversalis fascia.

Answer 5

1) Parietal peritoneum is analogous to parietal pleura of the pleural cavities
2) Extraperitoneal fat separates the parietal peritoneum from the transversalis fascia

Question 6

Why is the endoabdominal fascia of special importance to abdominal surgery?

Answer 6

The endoabdominal fascia is of special importance in surgery. It provides a plane that can be opened, enabling the surgeon to approach structures on or in the anterior aspect of the posterior abdominal wall, such as the kidneys or bodies of lumbar vertebrae, without entering the membranous peritoneal sac containing the abdominal viscera. Thus, the risk of contamination is minimized

Question 7

What creates the median, medial, and lateral umbilical folds? What do these folds cover? Cite the structures covered by each of the folds.

Answer 7

1) Inferior to the umbilicus on the internal surface of the anterior abdominal wall, longitudinal folds of parietal peritoneum create the median, medial, and lateral umbilical folds
2) The folds cover embryonic remnants and blood vessels
3) The median umbilical fold extends from the apex of the urinary bladder to the umbilicus and covers the median umbilical ligament, a fibrous remnant of the urachus that joined the apex of the fetal bladder to the umbilicus
4) Two medial umbilical folds, lateral to the median
umbilical fold, cover the medial umbilical ligaments,
formed by occluded parts of the umbilical arteries
5) Two lateral umbilical folds, lateral to the medial umbilical folds, cover the inferior epigastric vessels and therefore bleed if cut

Question 8

What is the falciform ligament? Cite the patent and obliterated veins in its inferior free edge.

Answer 8

1) The falciform ligament is a reflection of parietal peritoneum off the superoanterior abdominal wall that extends to the liver
2) The supra-umbilical falciform ligament encloses the remnant of the embryonic umbilical vein and the accompanying para-umbilical veins (tributaries of the hepatic portal vein) in its free edge