The brain stem is the stalk-like portion of the brain that connects the cerebrum and cerebellum to the spinal cord. It consists of three parts: the midbrain, the pons, and the medulla oblongata, and it controls essential life functions including breathing, heart rate, blood pressure, and consciousness. On neonatal cranial ultrasound, the brain stem can be visualized through the anterior and mastoid fontanelles and appears as a hypoechoic structure anterior to the cerebellum and the fourth ventricle. Evaluation of the brain stem on ultrasound is important in neonates who have experienced hypoxic-ischemic events, as severe brain injury can affect this critical region.
Sonography Term