Assertion: brainstem's part | /r/MadeOf | posterior surface of the pons
Facets:
Source sentences:
text: The floor of the fourth ventricle, often called the rhomboid fossa because of its shape, is divisible into an upper triangular part formed by the posterior surface of the pons; a lower triangular part formed by the upper part of the posterior surface of the medulla; and an intermediate part at the junction of the pons and medulla.