Electronic clock movement housed in synthetic casing of which rim has bosses

The clock movement includes a casing comprising synthetic material (1) which contains the components of the movement. The outside edge or rim has bosses (5) and the peripheral wall has hollow parts (6) which are located opposite the bosses, so as to allow the elastic deformation of the casing at the level of the bosses. The side of the casing which is designed to be supported against the back of the watch casing and has two bosses (8) located equally opposite hollows (9).