Medical needle assemblies incorporating a needle cover are provided. According to one aspect, the needle cover is integrally formed from a material that: (1) is sufficiently rigid to prevent bending of an underlying cannula, (2) is suitable for allowing a frangible portion thereof to be broken under pre-selected conditions, and/or (3) has a moisture vapor transmission rate sufficient for steam sterilization of a needle tip enclosed by the needle cover. According to another aspect, at least part of a cap portion and a hub portion of the needle cover are translucent. According to yet another aspect, the needle cover is provided with a wing having an enlarged rib suitable for gripping during separation of a cap portion from the remainder of the needle cover.