Mesoamerican calendars was of ritual significance to a number of Mesoamerican cultures. A third major calendar form known as the Long Count is found in the inscriptions of several Mesoamerican cultures, most famously those of the Maya civilization who developed it to its fullest extent during the Classic period (ca. 200–900 CE). The Long Count provided the ability to uniquely identify days over a much longer period of time, by combining a sequence of day-counts or cycles of increasing length, calculated or set from a particular date in the mythical past. Most commonly, five such higher-order cycles in a modified vigesimal (base-20)
External fixation usually used when internal fixation is contraindicated- often to treat open fractures, or as a temporary solution. External fixation is also used in limb lengthening. People with short limbs can have, for example, legs lengthened. In most cases the thigh bone (femur) is cut diagonally in a surgical procedure under anesthesia. External fixator pins or wires (as above) are placed each side of the 'man made fracture' and the external metal apparatus is used to very gradually push the two sides of the bone apart millimetre by millimetre day by day and week by week. Bone will gradually grow into