This posterior dorsal view of a preserved crayfish shows the arrangement of the abdominal muscles. Note the abdominal flexor muscles (1) that fill most of the abdomen. These powerful muscles serve to flex (bend) the abdomen, providing the force for the quick backward thrust of the tail when the crayfish is alarmed. Also observe the two longitudinal bands of the abdominal extensor muscles (2), which have been deflected backward to make them more visible.  These muscles, which  run along the dorsal side of the thorax and abdomen, are used in the weak recovery stroke after the tail has been flexed by the abdominal flexor muscles. It is these two sets of muscles that provide most of the "meat" that is eaten in crayfish (or lobster) tails!  Also visible on the dissection are the intestine (3), one of the fifth walking legs (4), carapace (7), uropods (5) and telson (7).