Cracked Heels occurs most often in those who are overweight tend to wear open heel shoes and have dry thick skin around the periphery of the heel. The fat under the heel bone expands out sideways and if the skin is not supple, then it can crack. Severe cases will bleed and get infected.

Curated Resources:
http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=3587 (Podiatry Arena)
http://www.epodiatry.com/cracked_heels.htm (ePodiatry)
http://podiapaedia.org/wiki/dermatology/heel-fissures/ (PodiaPaedia)
http://www.podiatryexperts.net/question/127/Any-pearls-to-help-with-my-cracked-heels (Podiatry Experts)
http://www.foot-health-forum.com/forum/showthread.php?t=113 (Foot Health Forum)
http://www.foothealthguide.net/cracked-heels/ (Foot Health Guide)
http://www.podiatrystudent.net/cracked-heels-3/12067/ (Podiatry Students)
http://www.drthefootwithoutthedoc.com/cracked-heels/26/ (Dr the Foot)
http://www.therunninginjury.com/my-advice-for-cracked-heels/35/ (Running Injury Advice)

Splits in the dermis at the back of the heel are common, are uncomfortable, and never appear very good. They happen when the fat pad under the heel expands out sideways beneath the heel and the dried-out skin cracks or splits to develop a heel fissure. A great way to fully understand these is to use the analogy of a tomato being compressed. When you apply pressure to the tomato to squash it, the skin of the tomato cracks as the content pushes outwards. So it is with the heel. As bodyweight squashes the fat beneath the heel it stretches out laterally from beneath the heel, it attempts to split the skin around the edges of the heel. Whether or not it is successful or not will probably depend on how elastic and resilient that the epidermis is. If the skin is dry, thicker or callused, it is going to tear easily. If the skin is thicker with a layer of callus, that skin will crack easily and place stress on the healthy skin underneath that could become somewhat painful, perhaps bleeding. Each step which is taken with even further open the split and prevent it from healing. Cracked heels are more prevalent in those that wear open heel type shoes, as a closed in shoe will help keep the fat pad under the heel in position and help stop or lessen the effects of the crack.

The most efficient short term treatment of cracked heels is to have the callused skin removed by a podiatrist and then use strapping to hold the edges of the split together so that it can mend. The long term prevention of cracked skin around the heel should be apparent from the mechanism that was explained above. To start with, weight reduction will help decrease the issue, but this is a long term measure. To help prevent the fat pad beneath the heel from expanding out laterally and trying to crack the skin, a closed in shoe can be used and sometimes the use of deep heel cup insoles can help. A podiatric doctor should be consulted regularly to remove any thick callused skin. Emollients really should be applied regularly to keep the skin resilient so that it does not split. The use of filing tools to help keep the thick skin under control can also be used.