What is the normal appearance of the bladder on fluoroscopic studies?
The underdistended bladder may show slightly irregular contours and is wider in the left-right direction than in the craniocaudal direction. The fully distended bladder is usually smooth in outline, unless there is bladder wall thickening due to muscle hypertrophy to overcome bladder outlet obstruction; this is usually seen in older men with an enlarged prostate gland, and it is referred to as bladder trabeculation.
The bladder neck is the widest part of the outlet of the bladder. It is closed at rest and opens only during voiding.