Final answer:
Fetal movements felt by the examiner occur typically after 20-24 weeks when the fetus is large enough for its movements to be discernible externally. This period corresponds with various developmental milestones, including the fetus's sensory development and the production of protective coverings.
Step-by-step explanation:
Fetal movements felt by the examiner typically occur after 20-24 weeks. During the second trimester, specifically between weeks 16-20, as the fetus grows and limb movements become more powerful, the pregnant person may begin to feel quickening, which are the initial fetal movements. It's during this time that space restrictions limit these movements and typically force the growing fetus into the "fetal position," with the arms crossed and the legs bent at the knees.
By about week 20, the fetus is getting large enough that the movements are more discernible, which marks the answer to when fetal movements are likely to be felt by an external examiner. Additionally, other developmental changes such as bone marrow beginning to produce blood cells, and the development of protective coverings like the waxy vernix caseosa and fine hair called lanugo are also occurring.