What is the anatomical landmark for S2?

The anatomical landmark for the S2 vertebra is the posterior superior iliac spine (PSIS). The PSIS is easily palpated on the dorsal aspect of the pelvis and serves as a reliable reference point for identifying the sacral region. S2 is located at the level of the PSIS, making it a critical landmark for healthcare providers, particularly in fields like orthotics and prosthetics, where accurate anatomical localization is essential for assessment and intervention.

The other options, such as the inferior angle of the scapula, umbilicus, and sternal angle, correspond to different anatomical structures and levels in the body that do not directly relate to the location of the S2 vertebra. These landmarks are used in various contexts but are not pertinent when identifying the sacral segment S2 specifically.