The urinary bladder (or the bladder) is a hollow muscular organ with stretchable walls.

The bladder accumulates urine which it receives from the kidneys via the ureters. It can store about 400 to 600 ml of urine in healthy adults.

Another major function of the bladder is participation in the excretion of urine through the urethra by contractions of the muscles in its wall.

The bladder is located in the lesser pelvis directly behind the pubic symphysis. When it is full, it extends into the abdominal cavity.

In females, it lies anteriorly to the uterus, vesicouterine pouch, and upper part of the vagina. On the sides are located venous plexuses. Its floor lies against the pelvic floor and urogenital diaphragm.

Depending on the urine amount in the bladder, its appearance and position against the peritoneum can vary considerably.

An empty bladder is flattened, its muscles - shrunken, its walls - thick, its cavity is slit-like, and the mucous membrane forms large folds (rugae). As the bladder fills up, it rises upwards, acquires an oval shape, its muscles stretch, the folds of the mucous membrane smooth out, and the bladder wall becomes thinner.

When empty, only the upper part of the posterior wall is covered by the peritoneum, but a full bladder rises over the symphysis, and the peritoneum covers all of its posterior side and lateral parts.

The urinary bladder is compromised of several parts such as the:

Apex - located anterosuperiorly, pointing towards the pubic symphysis;
Body - the major part of the bladder, extending between the apex and the fundus;
Fundus - located posteroinferiorly, it has a triangular shape;
Neck - formed by the fusion of the fundus and the two inferolateral surfaces; it is continuous with the urethra.

The urinary bladder has four surfaces:

Superior
Posterior
Two inferolateral

Four borders separate the surfaces:

Anterior - between both inferolateral surfaces;
Posterior - between superior and posterior surfaces;
Two lateral - between superior and inferolateral surfaces on each side.

Unlock with Premium

Female bladder