Sonography has been well known to be one of the most commonly used equipments in emergency medicine due to its non-invasiveness and cost-effectiveness. In usual practice, emergent ultrasound could be applied mainly in two organs, kidney and testis in some specific diseases such as hydronephrosis, retention of urine, diagnosis of acute renal failure, kidney infection, testicular diseases and some trauma.

　　Acute scrotum accounts for approximately 0.5 % of all complaints presenting to the emergency department. Differential diagnosis of acute scrotal pain includes epididymitis, torsion, trauma, and incarcerated hernia. Though history and physical examination findings play major roles in differential diagnosis of these problems. Misdiagnosing testicular torsion can lead to organ loss and infertility, bedside ultrasonography of the acute scrotum is a relatively easy way to emergency medicine ultrasound and has high utility for emergency physicians managing patients with acute scrotum.

　　Acute flank pain and abdominal pain with hematuria are relatively common presenting complaints in the emergency department. Although urinary obstruction is a likely diagnosis in such patients, the differential diagnosis includes life-threatening disease processes, most importantly an expanding or ruptured abdominal aortic aneurysm. Emergency bedside sonography is a tool that can rapidly confirm the diagnosis of acute urinary obstruction and help exclude life-threatening processes. Bedside renal sonography in the emergency department is useful in differentiation of the aforementioned problems. In addition, it allows the examiner to narrow the differential diagnosis by evaluating the retroperitoneal anatomical structures for abnormalities.