The abdomen is the area below the rib cage and above the iliac crest (groin).

part of the Human Anatomy project (tm).
/msg me for errors/omissions/comments/whatever.

Anterior abdominal wall muscles
the first four are roughly in order from superficial to deep.

• External abdominal oblique muscle
• Rectus abdominus muscle
• Internal abdominal oblique muscle
• Transversus abdominis muscle
• Cremaster muscle

Posterior abdominal wall muscles

• Lattisimus dorsi muscle