The ventral portion of the neck is formed by the strong crista inferior, on the median side of which is the deep fosses subtrochanterica by which air sacs enter the humerus.
The documents discovered by Dom Germain Morin, the Belgian Benedictine, about 1888, point to the conclusion that Guido was a Frenchman and lived from his youth upwards in the Benedictine monastery of St Maur des Fosses where he invented his novel system of notation and taught the brothers to sing by it.
Surrounded with walls and fosses in 1435, it was able in 1481 to defend itself against the Hungarians under Matthias Corvinus, and in 1529 and 1532 the Turks attacked it with as little success.
Among the Hova and Betsileo the old villages were always built for security on the summits of lofty hills, around which were dug several deep fosses, one within the other.
The fosses have been filled up and the ramparts in part levelled to make way, as the suburbs extended, for avenues stretching out on all sides.