It depends ...
This question is about any clerkships that you have done (outside) your in campus core curriculum.
Any "clinical" units that you have mentioned in your medical school transcript is not considered as a clerkship and should not be included in item 21 of the online application.
There are medical schools which send their students outside their campus for clinical training (Caribbean Medical Schools for example). The ECFMG is looking particularly for these rotations. otherwise, anything that is in your educational curriculum and is include in your transcript you don't need to include it.
This issue has also been previously discussed here
http://www.usmle-forums.com/ecfmg-forum/1168-ecfmg-clerkship.html
This question is about any clerkships that you have done (outside) your in campus core curriculum.
Any "clinical" units that you have mentioned in your medical school transcript is not considered as a clerkship and should not be included in item 21 of the online application.
There are medical schools which send their students outside their campus for clinical training (Caribbean Medical Schools for example). The ECFMG is looking particularly for these rotations. otherwise, anything that is in your educational curriculum and is include in your transcript you don't need to include it.
This issue has also been previously discussed here
http://www.usmle-forums.com/ecfmg-forum/1168-ecfmg-clerkship.html