*3.3.1 Urinary bladder*

Urinary bladder is scanned by placing the transducer in the suprapubic region in sagittal and transverse planes. A moderately filled bladder is ideal for visualization, which cannot be guaranteed in a trauma patient. If not visualized, then the probe is tilted inferiorly toward the pelvis to obtain a view. In some cases, normal saline may be introduced into the bladder via a per-urethral catheter to allow better imaging of the structures.

Bladder ultrasound can help guide suprapubic catheter placement in patients with urethral injury having urinary retention.
