A cranial burr hole cover having a single, elongated internal bracing member, a locking external cover member joined by one or more connecting members, and a locking mechanism that precludes movement of the external cover member relative to the connecting members in the proximal direction once the cover is secured onto the skull. The internal bracing member is longer than it is wide. For a given burr hole, the cover will be chosen such that the longitudinal dimension is greater than the diameter of the burr hole and the width dimension is less than the diameter of the burr hole.