=Fractures of the internal table alone.= Ambrose Paré drew attention to this class of fracture in 1652, but it remained for Teevan to investigate more fully the condition in 1865. Previous to Teevan’s investigations, it had been considered that the internal table of the skull was the more brittle, and that fractures confined to the internal table were to be explained on that hypothesis. Teevan, however, demonstrated the incorrectness of such a theory, for, on firing bullets through the skull, from without inwards and from within outwards, it was found that on all occasions the more distal table suffered the more severely. This was explained in the following manner:--the fracture of the proximal table was produced by the bullet, whilst that of the distal table resulted, not from the passage of the bullet alone, but also from various fragments of bone driven along with the bullet. Teevan’s experiments also proved that a fracture of the internal table alone could be produced mechanically, this being in obedience to the law that ‘when a pressure is applied to a body the fracture commences on the line of extension, not that of compression’. Fractures of the internal table are undoubtedly more common in those situations where diploic tissue is prevalent, e.g. in the frontal, parietal, and upper occipital regions. In the squamo-temporal and cerebellar regions fractures of the internal table are almost unknown. Teevan also stated that ‘but little force is required to produce such a fracture, and that they are produced usually by some small body, such as a stone’. =Fractures involving the whole thickness of the skull.= Fractures which involve the whole thickness of the skull may be:-- (_a_) Simple or compound. (_b_) With or without depression. When depressed, the fragments of bone may be either loose or interlocked, forming in the latter case the so-called pond and gutter fractures. (_c_) Elevated, usually from sabre-cuts. (_d_) Fissured, stellate, comminuted, punctured, &c. (_e_) Explosive. =Symptoms associated with fracture of the vault.= A diagnosis of fracture of the vault is made:-- On the evidence obtained by local examination. On the evidence supplied by symptoms dependent on injury to the intracranial contents. The various intracranial lesions are discussed elsewhere (see Chapters III and IV). =Evidence supplied by local examination.= A compound fracture will be most readily determined by digital examination, previous to which the scalp-wound must be carefully cleansed. Digital examination is greatly preferable to investigation with the aid of the probe. In any case care must be taken to avoid mistaking one of the sutures of the skull for a fissured fracture.