largest muscle of posterior abdominal wall
1 There are four important paired muscles in the anterior abdominal wall: three flat muscles (external oblique, internal oblique, and transversus abdominis) and one strap-like muscle (rectus abdominis).osterior Abdominal Wall. 1  The posterior abdominal wall is composed principally of muscles and fascia attached to the vertebrae, hip bones, and ribs. 2  It also contains fat, important nerves, vessels, and lymph nodes.