Which muscle lies between the external oblique and transversus abdominis and contributes to abdominal compression?

• A. Internal Oblique
• B. External Oblique
• C. Rectus Abdominis
• D. Transversus Abdominis

Answer: (A)

Think of the abdominal wall as layered from outside to inside: external oblique on the surface, then internal oblique, then transversus abdominis. The muscle that sits between the external oblique and the transversus abdominis is the internal oblique. Its fibers help tighten the abdominal wall and increase intra-abdominal pressure, which supports and compresses the abdominal contents—important for actions like coughing, lifting, and forced expiration. The other options don’t fit this placement: the external oblique is the outermost layer, the rectus abdominis runs along the midline, and the transversus abdominis lies deepest to the internal oblique.