Bladder Exstrophy: A birth defect in which the URINARY BLADDER is malformed and exposed, inside out, and protruded through the ABDOMINAL WALL. It is caused by closure defects involving the top front surface of the bladder, as well as the lower abdominal wall; SKIN; MUSCLES; and the pubic bone.Epispadias: A birth defect due to malformation of the URETHRA in which the urethral opening is above its normal location. In the male, the malformed urethra generally opens on the top or the side of the PENIS, but the urethra can also be open the entire length of the penis. In the female, the malformed urethral opening is often between the CLITORIS and the labia, or in the ABDOMEN.Musculoskeletal System: The MUSCLES, bones (BONE AND BONES), and CARTILAGE of the body.Pelvis: The space or compartment surrounded by the pelvic girdle (bony pelvis). It is subdivided into the greater pelvis and LESSER PELVIS. The pelvic girdle is formed by the PELVIC BONES and SACRUM.Urologic Surgical Procedures: Surgery performed on the urinary tract or its parts in the male or female. For surgery of the male genitalia, UROLOGIC SURGICAL PROCEDURES, MALE is available.Osteotomy: The surgical cutting of a bone. (Dorland, 28th ed)Cloaca: A dilated cavity extended caudally from the hindgut. In adult birds, reptiles, amphibians, and many fishes but few mammals, cloaca is a common chamber into which the digestive, urinary and reproductive tracts discharge their contents. In most mammals, cloaca gives rise to LARGE INTESTINE; URINARY BLADDER; and GENITALIA.Urinary Bladder: A musculomembranous sac along the URINARY TRACT. URINE flows from the KIDNEYS into the bladder via the ureters (URETER), and is held there until URINATION.