Mesoamerican Long Count calendar Mesoamerican Long Count calendar The Mesoamerican Long Count calendar is a non-repeating, vigesimal (base-20) and base-18 calendar used by several pre-Columbian Mesoamerican cultures, most notably the Maya. For this reason, it is often known as the Maya (or Mayan) Long Count calendar. Using a modified vigesimal tally, the Long Count calendar identifies a day by counting the number of days passed since a mythical creation date that corresponds to August 11, 3114 BCE in the Proleptic Gregorian calendar. The Long Count calendar was widely used on monuments. The two most widely used calendars in pre-Columbian Mesoamerica, were the 260-day Tzolk'in
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