Ultrasonography is becoming increasingly accessible and widely used by practitioners to complement the physical exam and gain a better understanding of patient's physiology in critical care. The portable nature allows expeditious real-time information at point of care to improve clinical diagnostic accuracy, especially patients who are unstable and thus not safe to be transported for other advanced imaging modalities such as computed tomography (CT). It is noninvasive and without risk of radiation. While ultrasound of thorax, abdomen, and pelvis has become prevalent in critical care, brain ultrasound, also referred to as transcranial sonography or brain echography, is being increasingly used to explore intracranial pathology to aid in the diagnostics and management of critically ill patients.