Which abdominal muscle runs vertically from the rib cage to the pubic crest?

Which abdominal muscle runs vertically from the rib cage to the pubic crest?

• A. Rectus abdominis
• B. External oblique
• C. Internal oblique
• D. Transversus abdominis

Answer: (A)

The main concept tested is the orientation and attachment of abdominal muscles. The muscle that runs vertically along the front of the abdomen from the rib cage down to the pubic crest is the rectus abdominis. Its fibers travel straight up and down, attaching to the costal cartilages of the lower ribs (usually the 5th to 7th ribs) and the xiphoid process at the top, with its lower end attaching to the pubic crest and symphysis. This vertical alignment gives it the characteristic “six-pack” appearance when well developed. In contrast, the other muscles in the group have oblique or transverse fiber directions and attach in ways that don’t produce a vertical path. The external oblique runs downward and medially from the lower ribs to the linea alba and iliac crest; the internal oblique runs upward and medially; and the transversus abdominis runs horizontally deep to the others. Because their fiber directions and attachments are not vertical from rib cage to pubic crest, they don’t match the description in the question. The rectus abdominis is the one that does.

The main concept tested is the orientation and attachment of abdominal muscles. The muscle that runs vertically along the front of the abdomen from the rib cage down to the pubic crest is the rectus abdominis. Its fibers travel straight up and down, attaching to the costal cartilages of the lower ribs (usually the 5th to 7th ribs) and the xiphoid process at the top, with its lower end attaching to the pubic crest and symphysis. This vertical alignment gives it the characteristic “six-pack” appearance when well developed.

In contrast, the other muscles in the group have oblique or transverse fiber directions and attach in ways that don’t produce a vertical path. The external oblique runs downward and medially from the lower ribs to the linea alba and iliac crest; the internal oblique runs upward and medially; and the transversus abdominis runs horizontally deep to the others. Because their fiber directions and attachments are not vertical from rib cage to pubic crest, they don’t match the description in the question. The rectus abdominis is the one that does.