Rectus Sheath Flashcards

Explore rectus sheath anatomy, including its aponeurotic layers, arcuate line, muscular contents, blood supply, and surgical relationships.

Card 1 of 26Question

What is the rectus sheath?

A fibrous aponeurotic envelope enclosing the rectus abdominis and, when present, pyramidalis muscles.

In This Section

1. What is the rectus sheath?

A fibrous aponeurotic envelope enclosing the rectus abdominis and, when present, pyramidalis muscles.

2. Which three abdominal muscles contribute aponeuroses to the rectus sheath?

The external oblique, internal oblique, and transversus abdominis muscles.

3. Which muscle is the principal muscular content of the rectus sheath?

The rectus abdominis muscle.

4. Which small, variable muscle lies within the inferior part of the rectus sheath?

The pyramidalis muscle.

5. Which fibrous structure forms the medial boundary of the rectus sheath?

The linea alba.

6. Which anatomical landmark marks the lateral border of the rectus sheath?

The linea semilunaris.

7. Which aponeuroses form the anterior rectus sheath above the arcuate line?

The external oblique aponeurosis and anterior lamina of the internal oblique aponeurosis.

8. Which aponeuroses form the posterior rectus sheath above the arcuate line?

The posterior lamina of the internal oblique aponeurosis and the transversus abdominis aponeurosis.

9. How does the internal oblique aponeurosis divide above the arcuate line?

It splits into anterior and posterior laminae that pass around the rectus abdominis.

10. What is the arcuate line of the rectus sheath?

The inferior boundary of the posterior aponeurotic layer of the rectus sheath.

11. Where is the arcuate line typically located?

Approximately one-third of the distance from the umbilicus to the pubic symphysis, although its position varies.

12. How is the anterior rectus sheath formed below the arcuate line?

All three flat abdominal muscle aponeuroses pass anterior to the rectus abdominis.

13. What happens to the posterior aponeurotic rectus sheath below the arcuate line?

It is absent, leaving the rectus abdominis directly anterior to the transversalis fascia.

14. Which layers lie deep to the rectus abdominis below the arcuate line?

The transversalis fascia, extraperitoneal connective tissue, and parietal peritoneum.

15. How does the posterior rectus sheath differ superior to the costal margin?

The posterior aponeurotic sheath is absent, and the rectus abdominis lies against the costal cartilages.

16. Which two major arteries travel within the rectus sheath?

The superior and inferior epigastric arteries.

17. From which artery does the superior epigastric artery originate?

The internal thoracic artery.

18. From which artery does the inferior epigastric artery originate?

The external iliac artery.

19. Where do the superior and inferior epigastric arteries anastomose?

Within the rectus sheath, mainly posterior to the rectus abdominis.

20. Which nerves enter the rectus sheath to supply the rectus abdominis?

The terminal portions of thoracoabdominal nerves T7 to T11 and the subcostal nerve T12.

21. What are the tendinous intersections of the rectus abdominis attached to?

The anterior layer of the rectus sheath.

22. What is a rectus sheath hematoma?

A collection of blood within the rectus sheath caused by epigastric vessel injury or rectus muscle tearing.

23. Why can a rectus sheath hematoma spread extensively below the arcuate line?

The absence of a posterior aponeurotic sheath permits blood to spread through less confined tissue planes.

24. What is the anatomical basis of a rectus sheath nerve block?

Local anesthetic is deposited between the rectus abdominis and posterior rectus sheath to block terminal abdominal wall nerves.

25. Why is the rectus sheath important during midline abdominal surgery?

Its aponeuroses form the linea alba, providing a relatively avascular plane for surgical entry.

26. What is a Spigelian hernia?

A hernia through the Spigelian fascia near the lateral border of the rectus sheath, often close to the arcuate line.