Common surgical pitfalls in the skull.

BACKGROUND: A detailed knowledge of the morphologic variations in the ossicles, foramina, and ridges of the skull vault and skull base is vital to performing safe radical surgery.
METHODS: A surgical reminder of possible pitfalls was composed based on the incidences of most of the minor variations such as the supraorbital notch, frontal foramen, metopism, foramen caecum, parietal foramina, bony defects in the fossa occipitalis cerebellaris, Inca bone, foramen lacerum anterius, incomplete posterolateral wall of the foramen ovale, absence of the medial or posterior wall of the foramen spinosum, foramen innominatus, foramen meningoorbitale, bony dehiscence of the internal carotid canal, bony ridge or torus in the floor of the external auditory meatus, foramen of Huschke, precondylar tubercle, foramen hypoglossi, anterior condylar canal, hypoglossal bridging, divided articular surface of the occipital condyle, high jugular bulb, paramastoid process, atlanto-occipital assimilation, ossicle of Kerkring, delta or keyhole shaped bony defects in the anterior border of foramen magnum, foramen of Vesalius, posterior condylar canal, mastoid emissary foramen and occipital foramen in 200 skulls.
CONCLUSION: Recognition of these structures and their possible variations will help in distinguishing normal from potentially abnormal structures during computed tomography and magnetic resonance imaging examinations, and in avoiding misinterpretations that lead to confusion during surgical interventions. Instrumentation near potential bone gaps may traumatize important neural or vascular structures.