Constipation can last from days to months, with interludes of diarrhea or normal bowel function. Stools are often hard and may be described as pellet shaped in at least 25% of bowel movements, or Bristol Stool Form Scale 1-2 (separate hard lumps like nuts that are difficult to pass, or sausage shaped but lumpy).
The external abdominal oblique muscle is the largest and most superficial of the 3 paired, flat abdominal muscles. It arises from the lower 8 ribs and interdigitations of the serratus anterior muscle.
Transversus abdominis is the deepest of the abdominal muscles and wraps around the abdomen between the lower ribs and top of the pelvis, functioning like a corset. This picture shows the anatomy of this muscle with the outer two abdominal layers (internal and external oblique) removed.