Final answer:
The postural landmarks used to assess the pelvis posteriorly are the ischial tuberosity and sacrum.
Step-by-step explanation:
The postural landmarks used to assess the pelvis posteriorly are the ischial tuberosity and the sacrum. The ischial tuberosity is a large, roughened protuberance that forms the posteroinferior portion of the hip bone and serves as the weight-bearing region of the pelvis when sitting. The sacrum is a triangular bone located at the base of the spine, and its position can be used to assess the alignment of the pelvis.