Final answer:
The cervix is no longer palpable once it has fully dilated to about 10 cm during the second stage of labor, which is necessary for the delivery of the baby.
Step-by-step explanation:
The cervix can no longer be palpated once it has fully dilated during the second stage of labor. This stage involves increasingly more forceful contractions which continue until the baby has been delivered. After the cervix has thinned and reached the necessary dilation of approximately 10 cm, it has completed its purpose to allow passage for the baby. Subsequently, the third stage of labor occurs wherein the placenta is passed after the baby has been born. If cervical palpation is in the context of cervical cancer, then once symptoms start to become apparent, the cancer may have reached an advanced stage, potentially making treatment success more challenging.