Fig. 4.3  Combined cranio-maxillo-orbital fractures. (a) Complex cranio-facial fracture limited to the external midfacial frame (type 1). (b) Complex cranio-facial fracture (“high velocity fracture pattern”) with polyfragmentation of the anterior and posterior­ midfacial pillars, and comminuted basal fracture with dural and

intracranial injuries (type 2). The small arrows indicate the fractures of the cribriform plate and the ethmoid causing injury to the dura (mod. a. Lädrach et al. 1999) (The thick arrows indicates the excessive force on frontal impact)

4.3.4  Impact Surface

A localized impact on a small, well-defined area of the facial skeleton will result in a different damage pattern than a traumatic force affecting a wide surface area of the face and skull. Small objects with minor velocity and energy will cause only limited injuries or fractures. The impact of a traumatic force with major velocity and energy acting on a large surface area, on the other hand, will result in extensive damage to the anatomical structures of the skull and face. Adjacent anatomical regions, such as the skull base or neurocranium, may be damaged as well.

4.3.4.1  Small Impact Surface

Objects with a diameter smaller than the diameter of the face will result in localized fractures of the nasomaxillary or dento-alveolar-premaxillary complex in the lower midfacial region; impacts in the central middle to upper part of the midface with moderate energy can lead to impression fractures of the naso-ethmoido- maxillary complex.

Fracture lines display a characteristic pattern and the central midface complex slides like a telescope into the interorbital cavity.

The impaction leads to a comminuted destruction of the thin osseous lamellae of the lacrimal bone and the ethmoid. The medial palpebral ligaments and periorbital soft tissues are regularly involved in such cases. The nasolacrimal ducts and the anterior skull base are frequently involved in the region of the cribriform plate or the orbital roofs.

An impact on the lateral region of the upper midface with limited energy and size will lead to fractures of the zygomatico-orbital complex.

4.3.4.2  Large Impact Surface

Large objects hitting the face and skull with a diameter larger than the diameter of the face or skull will result in an extended injury. The Le Fort fractures are typical results of these impacts.

Le Fort I fractures are caused by frontal and lateral impacts on the lower third of the midface. As a rule, the dislocation occurs in the direction of the acting force, mostly in a dorso-lateral direction; sometimes a