Deviation from perfect symmetry in the bovine mandible.

Fluctuating asymmetry refers to small random deviations from perfect symmetry in bilaterally paired structures; it is thought to reflect an organism's ability to cope with genetic and environmental stress during development and its utility as an indicator of such stresses is based on the assumption that perfect symmetry is an a priori expectation for the ideal state of bilateral structures. Nineteen dry dentate and complete mandible samples belonging to different living bovine breeds were studied to assess the whole symmetry between their hemimandibles. Eleven linear distances between different landmarks allowed its evaluation. The fluctuating asymmetries were found to have a geometrical mean of zero, indicating a good individual quality in the specimens studied, although the detected DA in the mandibular ramus shows that the main masticatory muscle can have a left to right dominance, but with no clinical importance. The measurements presented here can also be used as a reference for researchers designing experimental studies, especially on mandibular catch-up growth, and as an aid for zooarchaeologists who must evaluate results from buried animal studies for comparison with living bovine populations