A fetal position notation LSA indicates which part presenting?

A fetal position notation LSA indicates which part presenting?

• A. Buttocks
• B. Occiput
• C. Chin
• D. Sacrum

Answer: (A)

In fetal position notation, the middle letter shows the presenting part. O stands for occiput (head), S for sacrum (buttocks), and M for mentum (chin). So a notation with S as the presenting part means the sacrum is presenting, i.e., the buttocks are leading. The first letter tells you the side (left) and the third letter tells you the orientation (anterior toward the front). Therefore, Left Sacrum Anterior means the fetus is in a breech presentation with the buttocks presenting on the left side toward the front of the pelvis.

In fetal position notation, the middle letter shows the presenting part. O stands for occiput (head), S for sacrum (buttocks), and M for mentum (chin). So a notation with S as the presenting part means the sacrum is presenting, i.e., the buttocks are leading. The first letter tells you the side (left) and the third letter tells you the orientation (anterior toward the front). Therefore, Left Sacrum Anterior means the fetus is in a breech presentation with the buttocks presenting on the left side toward the front of the pelvis.