Fetal station is measured relative to which pelvic landmark?

• A. Sacral promontory
• B. Pubic symphysis
• C. Iliac crest
• D. Ischial spines

Answer: (D)

Fetal station is measured relative to a fixed internal pelvic landmark—the ischial spines. The zero point is when the presenting part is at the level of the ischial spines; descent is noted as the part moves below the spines (positive stations) or remains above them (negative stations). This landmark is used because it provides a consistent reference point inside the pelvis to gauge labor progress during a vaginal exam. Other landmarks, like the sacral promontory, are used for estimating pelvic dimensions (inlet size) but not for staging station, and the pubic symphysis or iliac crest do not serve as the reference for fetal descent.