The identification of the skull as that of a participant, and the ditch as that of part of the defenses of the Battle of the Alamo each depends to some extent on the other. Without the ditch, the case for the skull is much weaker. Without the skull, the case for the ditch is noticeably weaker. The two taken together create a set of closely interlocked relationships. These in turn place very narrow limits on the range of events which would have produced these relationships.
The explanation given here is the simplest and requires the fewest assumptions. The final answer may never be known as fact, and the question of the actual relationship of the skull to the Battle of the Alamo can only be answered at present by probabilities. Other parts of the body of the individual to whom the skull belonged very likely remain in other parts of the straight trench as yet unexcavated. Perhaps the discovery of some of these parts will one day supply more evidence to aid in a definitive answer.