Muscles of the Abdominal Wall Flashcards

Learn the abdominal wall muscles through their attachments, fiber directions, actions, innervation, fascial relationships, and clinical anatomy.

Card 1 of 30Question

What are the five principal paired muscles of the anterolateral abdominal wall?

External oblique, internal oblique, transversus abdominis, rectus abdominis, and pyramidalis.

In This Section

1. What are the five principal paired muscles of the anterolateral abdominal wall?

External oblique, internal oblique, transversus abdominis, rectus abdominis, and pyramidalis.

2. What are the three flat muscles of the anterolateral abdominal wall?

External oblique, internal oblique, and transversus abdominis.

3. Which abdominal wall muscle is the most superficial of the three flat muscles?

The external oblique muscle.

4. From which structures does the external oblique muscle originate?

The external surfaces of ribs 5 to 12.

5. Where does the external oblique muscle insert?

The linea alba, pubic tubercle, and anterior half of the iliac crest.

6. What is the predominant fiber direction of the external oblique muscle?

Inferomedial, resembling the direction of hands placed in front pockets.

7. What trunk movement results from unilateral contraction of the external oblique muscle?

Rotation of the trunk toward the opposite side.

8. Which abdominal wall muscle lies between the external oblique and transversus abdominis?

The internal oblique muscle.

9. What are the principal origins of the internal oblique muscle?

The thoracolumbar fascia, anterior two-thirds of the iliac crest, and lateral half of the inguinal ligament.

10. Where does the internal oblique muscle insert?

The inferior borders of ribs 10 to 12, linea alba, and pecten pubis through the conjoint tendon when present.

11. What is the predominant fiber direction of the internal oblique muscle?

Superomedial in its upper and middle portions, with more horizontal inferior fibers.

12. What trunk movement results from unilateral contraction of the internal oblique muscle?

Rotation of the trunk toward the same side.

13. Which is the deepest of the three flat anterolateral abdominal wall muscles?

The transversus abdominis muscle.

14. What are the principal origins of the transversus abdominis muscle?

The internal surfaces of costal cartilages 7 to 12, thoracolumbar fascia, iliac crest, and lateral third of the inguinal ligament.

15. Where does the transversus abdominis muscle insert?

The linea alba, pubic crest, and pecten pubis through the conjoint tendon when present.

16. What is the predominant fiber direction of the transversus abdominis muscle?

Approximately horizontal, extending transversely around the abdominal wall.

17. What is the principal action of the transversus abdominis muscle?

Compression of abdominal contents and stabilization of the abdominal wall and trunk.

18. Which long vertical muscle lies on either side of the linea alba?

The rectus abdominis muscle.

19. Where does the rectus abdominis muscle originate?

The pubic symphysis and pubic crest.

20. Where does the rectus abdominis muscle insert?

The xiphoid process and costal cartilages of ribs 5 to 7.

21. What is the primary action of the rectus abdominis muscle?

Flexion of the trunk and stabilization of the pelvis.

22. What are the tendinous intersections of the rectus abdominis?

Transverse fibrous bands that divide the muscle into multiple segments.

23. Where is the pyramidalis muscle located?

In the inferior anterior rectus sheath, anterior to the lower rectus abdominis.

24. What is the action of the pyramidalis muscle?

Tensing the linea alba.

25. Which nerves provide the principal motor innervation to the anterolateral abdominal wall muscles?

Thoracoabdominal nerves T7 to T11, the subcostal nerve T12, and contributions from L1.

26. Which nerves provide additional innervation to the internal oblique and transversus abdominis?

The iliohypogastric and ilioinguinal nerves, primarily from L1.

27. Between which abdominal wall muscles does the principal neurovascular plane lie?

Between the internal oblique and transversus abdominis muscles.

28. Which muscles contribute aponeuroses to the formation of the rectus sheath?

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

29. How do the abdominal wall muscles contribute to forced expiration?

They compress the abdominal viscera, raise intra-abdominal pressure, and push the diaphragm superiorly.

30. What is diastasis recti?

Widening of the linea alba with increased separation of the rectus abdominis muscles, without a true fascial defect.