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What is Le Fort fracture of skull and explain in detail?
A Le Fort fracture of the skull is a classic transfacial fracture of the midface, involving the maxillary bone and surrounding structures in either a horizontal, pyramidal or transverse direction. The hallmark of Lefort fractures is traumatic pterygomaxillary separation, which signifies fractures between the pterygoid plates, horseshoe-shaped bony protuberances which extend from the inferior margin of the maxilla, and the maxillary sinuses. Continuity of this structure is a keystone for stability of the midface, involvement of which impacts surgical management of trauma victims, as it requires fixation to a horizontal bar of the frontal bone. The pterygoid plates lie posterior to the upper dental row, or alveolar ridge, when viewing the face from an anterior view. The fractures are named after French surgeon René Le Fort (1869–1951), who discovered the fracture patterns by examining crush injuries in cadavers.

Signs and symptoms
Le Fort I – Slight swelling of the upper lip, ecchymosis is present in the buccal sulcus beneath each zygomatic arch, malocclusion, mobility of teeth. Impacted type of fractures may be almost immobile and it is only by grasping the maxillary teeth and applying a little firm pressure that a characteristic grate can be felt which is diagnostic of the fracture. Percussion of upper teeth results in cracked pot sound. Guérins sign is present characterised by ecchymosis in the region of greater palatine vessels.Le Fort II and Le Fort III (common) – Gross edema of soft tissue over the middle third of the face, bilateral circumorbital ecchymosis, bilateral subconjunctival hemorrhage, epistaxis, CSF rhinorrhoea, dish face deformity, diplopia, enophthalmos, cracked pot sound.Le Fort II – Step deformity at infraorbital margin, mobile mid face, anesthesia or paresthesia of cheek.
Le Fort III – Tenderness and separation at frontozygomatic suture, lengthening of face, depression of ocular levels (enophthalmos), hooding of eyes, and tilting of occlusal plane, an imaginary curved plane between the edges of the incisors and the tips of the posterior teeth. As a result, there is gagging on the side of injury.

Diagnosis
Diagnosis is suspected by physical exam and history, in which, classically, the hard and soft palate of the midface are mobile with respect to the remainder of facial structures. This finding can be inconsistent due to the midfacial bleeding and swelling that typically accompany such injuries, and so confirmation is usually needed by radiograph or CT.

Classification
There are three types of Le Fort fractures. As the classification increases, the anatomic level of the maxillary fracture ascends from inferior to superior with respect to the maxilla:

Le Fort I fracture (horizontal), otherwise known as a floating palate, may result from a force of injury directed low on the maxillary alveolar rim, or upper dental row, in a downward direction. The essential component of these fractures, in addition to pterygoid plate involvement, is involvement of the lateral bony margin of the nasal opening. They also involve the medial and lateral buttresses, or walls, of the maxillary sinus, traveling through the face just above the alveolar ridge of the upper dental row. At the midline, the inferior nasal septum is involved. Historically, it has also been referred to as a Guérin fracture, although this name is less commonly used in practice.
Le Fort II fracture (pyramidal) may result from a blow to the lower or mid maxillary area. In addition to pterygoid plate disruption, their distinguishing component is involvement of inferior orbital rim. When viewed from the front, the fracture is classically shaped like a pyramid. It extends from the nasal bridge at or below the nasofrontal suture through the superior medial wall of the maxilla, inferolaterally through the lacrimal bones which contain the tear ducts, and inferior orbital floor through or near the infraorbital foramen.
Le Fort III fracture (transverse), otherwise known as craniofacial dissociation, may follow impact to the nasal bridge or upper maxilla. The salient feature of these fractures, beyond pterygoid plate involvement, is that they invariably involve the zygomatic arch, or cheek bone