What is meant by "the limit of the head" mentioned in the description of ablution, and is it obligatory to wipe the white area between the head and the ears, and is it sufficient when wiping the ears to insert the index fingers into the ear canals and use the thumbs to wipe the back of the ears, or is it obligatory to wipe the inner folds of the ear?

The boundary of the head is from the usual hairline to the nape of the neck, and the white area between the head and the ear is part of it. The apparent opinion of the Hanbalis is that it is obligatory to wipe the entire head, whereas the Shafi'is and Hanafis consider wiping part of the head sufficient. Wiping the ears is recommended by the majority of scholars, and obligatory according to the relied-upon opinion of the Hanbalis. Omitting to wipe them is sufficient according to the view that it is not obligatory. It is not obligatory to wipe the parts of the ear covered by cartilage.