10- Muscles of the Anterior and Lateral Abdominal Wall

Question 1

Rectus Abdominis

Answer 1

Extend from pubis to rib cage; ensheathed by aponeuroses of lateral muscles; segmented by 3 tendinous intersections.

Flex and rotate lumbar region of vertebral column; fix and depress ribs, stabilize pelvis during walking, increase intra- abdominal pressure; used in sit ups, curls.

Question 2

External Oblique

Answer 2

Largest and most superficial of the three lateral muscles; fibers run downward and medially. Aponeurosis turns under inferiorly, forming inguinal ligament.

When pair contract simultaneously, aid rectus abdominis muscles in flexing vertebral column and in compressing abdominal wall and increasing intra-abdominal pressure; individually muscles of back in trunk rotation and lateral flexion; used in oblique curls.

Question 3

Internal Oblique

Answer 3

Fibers run upward and medially; muscle fans so its inferior fibers run downward and medially.

As for external oblique.

Question 4

Transversus Abdominis

Answer 4

Deepest muscle of abdominal wall; fibers run horizontally.

Compresses abdominal contents.