1700 AJR:184, May 2005

AJR 2005;184:1700–1705

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© American Roentgen Ray Society

Rhea and NovellineSimplifying the CT Diagnosis of Le Fort Fractures

Pictorial Essay

James T. Rhea1,2

Robert A. Novelline1Rhea JT, Novelline RA

Received June 2, 2004; accepted after revisionNovember 2, 2004.

1Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Fruit St., FH 210, Boston, MA 02114.2Present address: Department of Radiology, University of California San Francisco and San Francisco General Hospital, 1001 Potrero Ave., Rm. 1x55, San Francisco, CA 94110. Address correspondence to J. T. Rhea (jrhea@sfghrad.ucsf.edu).

How to Simplify the CT Diagnosis of Le Fort Fractures

OBJECTIVE. The numerous components seen in the Le Fort fractures make classificationdifficult. Our objective is to simplify the task of classifying Le Fort fractures.

CONCLUSION. Each of the Le Fort fractures has at least one unique component that iseasily recognizable: I, the anterolateral margin of the nasal fossa; II, the inferior orbital rim;and III, the zygomatic arch. Classification of the Le Fort fractures is simplified by using theseunique components to establish a tentative classification that is then confirmed.

ene Le Fort [1] described the planesof injury that result from significantforce to the midface. The classifica-tion of these fractures includes Le

Fort I, II, and III types of fractures [2]. Le Fortand maxillary fractures accounted for 25.5% of663 facial fractures recently reported from alevel 1 trauma center [3]. Although visualiza-tion of injury to the struts and buttresses of theface is required for repair of these fractures withrestoration of the 3D stability and symmetry ofthe face [4], the Le Fort classification appears tobe a succinct way of summarizing and commu-nicating the major planes of certain fractures.

Common to all Le Fort fractures is fractureof the pterygoid processes. It is rare for thepterygoid processes to be fractured in the ab-sence of a Le Fort fracture. In addition, eachof the Le Fort fractures has a unique compo-nent. The purpose of this pictorial essay is toillustrate the use of these unique componentsto easily and quickly identify which type ofLe Fort fracture is present.

Unique Component of Each Type of Le Fort Fracture

Figures 1, 2, and 3 illustrate the planes ofthe Le Fort I, II, and III fractures, respec-tively. The pterygoid processes are broken inall types of Le Fort fracture. Figure 4 high-lights a unique and easily recognizable com-ponent of each of the types of fracture.

The Le Fort I fracture is the only one thatinvolves the anterolateral margin of the nasalfossa just above the maxillary alveolar pro-cess. This fracture of the anterolateral marginof the nasal fossa is easily seen on coronal or3D CT images of the face (Fig. 5). If thepterygoid processes are broken and this por-tion of the maxilla is broken, a Le Fort I frac-ture most likely is present. If the anterolateralmargin of the nasal fossa is intact, a Le Fort Ifracture is excluded.

The Le Fort II fracture is the only one thatinvolves the inferior orbital rim. The inferiororbital rim is also easily seen on coronal or 3DCT images of the face (Fig. 6). If the ptery-goid processes are broken and the inferior or-bital rim is broken, probably a Le Fort IIfracture is present. If the inferior orbital rim isintact, a Le Fort II fracture is excluded.

The Le Fort III fracture is the only one thatinvolves the zygomatic arch. The zygomaticarch is easily seen on axial or 3D CT imagesof the face (Fig. 7). If the pterygoid processesare broken and the zygomatic arch is broken,probably a Le Fort III fracture is present. Ifthe zygomatic arch is intact, a Le Fort III frac-ture is excluded.

Three Steps in Diagnosing a Le Fort Fracture

First, always look at the pterygoid processes,especially on coronal images. A fracture of the

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Fig. 1.—Le Fort I fracture. (Reprinted with permissionfrom [2])A and B, Drawings in lateral (A) and frontal (B) projec-tions show Le Fort I fracture runs horizontally abovemaxillary alveolar process. Pterygoid plates are bro-ken, as is true in all types of Le Fort fracture. Walls ofmaxillary sinuses in this plane are broken, includingpoint at anterolateral margin of nasal fossa. Maxillaryteeth would be movable on physical examination rela-tive to remainder of face.

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Fig. 2.—Le Fort II fracture. (Reprinted with permissionfrom [2])A and B, Drawings show plane of Le Fort II fracture inlateral (A) and frontal (B) projections. Le Fort II fractureis pyramidal in shape with teeth at base of pyramid andnasofrontal suture at apex of pyramid. Pterygoid platesare broken, as is true in all types of Le Fort fracture.Posterior and lateral walls of maxillary sinus are bro-ken as fracture skirts inferior in relation to body ofzygoma. Fracture then crosses inferior orbital rim,orbital floor, and medial wall of orbit before crossingmidline near nasofrontal suture. Maxillary teeth andnose as a unit would be movable relative to zygomataand rest of skull.

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Fig. 3.—Le Fort III fracture. (Reprinted with permissionfrom [2])A and B, Drawings show plane of Le Fort III fracture inlateral (A) and frontal (B) projections. Le Fort III frac-ture separates bones of face from rest of skull. Ptery-goid plates are broken, as is true in all types of Le Fortfracture. Upper posterior margins of maxillary sinusesfracture, as does zygomatic arch, lateral orbital wall,and lateral orbital rim. There is fracture near junctionof frontal bone and greater wing of sphenoid in poste-rior aspect of orbit, fracture along medial orbital wall,and fracture across nasofrontal suture. Maxillaryteeth, nose, and zygomata as a unit would be movableon physical examination relative to rest of skull.

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Fig. 4.—Drawings show unique components of each type of Le Fort fracture. (Reprinted with permission from [2])A, In Le Fort I fracture, anterolateral margin of nasal fossa (arrow) is broken. This structure is intact in both Le Fort II and III fractures.B, In Le Fort II fracture, inferior orbital rim (arrow) is broken. This structure is intact in both Le Fort I and III fractures.C, In Le Fort III fracture, zygomatic arch (arrow) is broken. This structure is intact in both Le Fort I and II fractures.

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Fig. 5.—Le Fort I fracture. To classify this Le Fort fracture, lookat the following four facial segments: pterygoid processes(fractured in this case: Le Fort fracture is most likely present),anterolateral margins of nasal fossa above maxillary alveolarridge (fractured: Le Fort I is likely present), inferior orbital rims(intact: Le Fort II is excluded), and zygomatic arches (intact:Le Fort III is excluded). Le Fort I fracture is confirmed by notingother expected fractures in plane of Le Fort I fracture.A, Coronal CT image shows bilateral fractures of ptery-goid processes (arrows).B, Sagittal CT image shows fractures (arrows) in horizon-tal plane of walls of maxillary sinus.C, Three-dimensional image in lateral projection shows frac-ture of anterolateral margin of nasal fossa (white arrow),which indicates that Le Fort I fracture is present. Zygomaticarch (black arrows) is intact, thus excluding Le Fort III frac-ture.D, Coronal CT image shows fractures of lateral marginsof nasal fossa (solid arrows) and lateral wall of maxillarysinuses (open arrows).E, Three-dimensional image in frontal projection shows intactinferior orbital rims (black arrows), thus excluding Le Fort IIfracture. Horizontally oriented fractures across maxillarysinuses and nasal fossa (white arrows) are seen.

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pterygoid processes almost always indicatesthat fractures in at least one of the Le Fortplanes are present.

Second, to classify the type of Le Fortfracture, look at the three bony structuresthat are unique to a given type of Le Fortfracture: the anterolateral margin of the na-sal fossa, the inferior orbital rim, and the zy-gomatic arch. If one of these structures isintact, the corresponding type of Le Fort

fracture is excluded. If one of these struc-tures is broken, the corresponding type ofLe Fort fracture is most likely present (Ap-pendix 1).

Third, if one of the Le Fort fractures issuspected because of a break in its uniquecomponent, the fracture should be con-firmed by identifying the other fractures thatwould be expected in the plane of that typeof Le Fort fracture.

Avoiding PitfallsOne pitfall is to rely on the clinical history

that resulted in a diagnosis based on physicalexamination. The physical findings of a LeFort fracture may not always be present [5, 6].

Another pitfall is to terminate a search ofthe images after identifying one Le Fortfracture. Fractures may occur in more thanone Le Fort fracture plane on the same side[7]. For example, there may simultaneously

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Fig. 6.—Le Fort II fracture. To classify this Le Fort fracture, look at the following four facial segments: pterygoid processes (fractured in this case: Le Fort fracture is mostlikely present), anterolateral margins of nasal fossa above maxillary alveolar ridge (intact: Le Fort I is excluded), inferior orbital rims (fractured: Le Fort II is likely present),and zygomatic arches (intact: Le Fort III is excluded). Le Fort II fracture is confirmed by noting other expected fractures in plane of Le Fort II fracture.A, Coronal CT image shows bilateral fractures of pterygoid processes (arrows).B, Coronal CT image shows that anterolateral margins of nasal fossa (solid arrows) are intact, thus excluding Le Fort I fracture. Inferior orbital rims (open arrows) are broken,indicating that Le Fort II fracture is present. As expected in Le Fort II fracture, lateral walls of maxillary sinuses inferior in relation to the body of zygomata are broken.C, Axial CT image shows that zygomatic arches (arrows) are intact, thus excluding Le Fort III fracture. As is expected in Le Fort II fracture, anterior and posterolateral marginsof maxillary sinuses are broken.D, Axial CT image shows fractures of orbital floors (arrows), as is expected in Le Fort II fracture.E, Axial CT image shows fractures of anterior portion of medial orbital walls (arrows), as is expected in Le Fort II fracture.F, Sagittal CT image shows fracture across nasal bone (arrow) that might be seen in either Le Fort II or III fracture.

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be Le Fort II and III fractures on the sameside (Fig. 7). To avoid this pitfall, look at allthree unique components of the Le Fortfractures even after one component is seento be fractured.

A third pitfall is to expect that Le Fort frac-tures are bilaterally symmetric. Fractures canoccur in different Le Fort planes on each side.

For example, a Le Fort I fracture may occur onone side and another type of Le Fort fracture onthe contralateral side (Fig. 7). To avoid this pit-fall, look at the pterygoid processes and each ofthe three unique components first on one sideand then on the other side.

A fourth pitfall is the occurrence of a LeFort fracture simultaneously with other fa-

cial fractures. Having postulated that a LeFort fracture is present because of a fractureof the pterygoid processes and a unique LeFort component, it is necessary to confirmthe type of Le Fort fracture that you think ispresent and look for fractures that do not fitthe plane of the Le Fort fracture you have di-agnosed. Confirming the type of Le Fort

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Fig. 7.—Combined Le Fort I fracture on right and Le Fort II and III fractures on left. Look at four facial segments one side at a time. First, look at the right side: pterygoid process(fractured in this case: Le Fort fracture is most likely present), right anterolateral margin of nasal fossa above maxillary alveolar ridge (fractured: Le Fort I is likely present),inferior orbital rim on right (intact: Le Fort II is excluded), and zygomatic arch on right (intact: Le Fort III is excluded). Right-sided Le Fort I fracture is confirmed by noting otherexpected fractures in plane of Le Fort I fracture. Next, look at the left side: pterygoid process (fractured in this case: Le Fort fracture is most likely present), left anterolateralmargin of nasal fossa above maxillary alveolar ridge (intact: Le Fort I is excluded), left inferior orbital rim (fractured: Le Fort II is likely present), and left zygomatic arch (frac-tured: Le Fort III is likely present). Left-sided Le Fort II and III fractures are confirmed by noting other expected fractures in planes of Le Fort II and III fractures.A, Coronal CT image shows bilateral fractures of pterygoid processes (arrows).B, Coronal CT image shows fracture of anterolateral margin of nasal fossa on right side only (lower arrow); Le Fort I fracture is present on right. Note also that there is sep-aration at nasofrontal suture on left (upper arrow). This could be seen in either Le Fort II or III fracture.C, Coronal CT image shows inferior orbital rim on right (white arrows) is intact, so Le Fort II on right is excluded. Fracture of inferior orbital rim on left (black arrow) is seen;thus, Le Fort II is present on left.D, Coronal CT image shows fracture of lateral orbital rim (frontal process of zygoma) on left (solid arrow); Le Fort III fracture is present on left, because lateral rim is also aunique feature of Le Fort III fractures. Left orbital floor on left (open arrow) is fractured, as is expected in Le Fort II fractures. Right orbital floor is intact.E, Axial CT image shows only left zygomatic arch because of patient tilt in scanner. This arch (arrows) is intact, thus excluding Le Fort III on left.F, Axial CT image shows fracture of zygomatic arch on left (arrow) at zygomaticotemporal suture; Le Fort III is present on left.

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fracture involves ensuring that fractures areseen throughout the plane of the expected LeFort fracture type.

SummaryThe use of the Le Fort classification, al-

though an oversimplification and inadequatefor surgical planning in an individual case, isa succinct way of communicating and sum-marizing the major fracture planes that exist.It is possible to quickly and accurately diag-nosis the presence and type of Le Fort fractureby evaluating the pterygoid processes and the

unique components of each type of Le Fortfracture. It is then necessary to confirm thatfractures are present throughout the expectedLe Fort plane.

References1. Le Fort R. Etude experimentale sur les fractures de

la machoire superieure. Rev Chir 1901;23:208–227,360–379, 479–507

2. Rhea JT, Mullins ME, Novelline RA. The face.In: Rogers LF. Radiology of skeletal trauma, 3rded., vol. 1. Philadelphia, PA: Churchill Living-stone, 2002:315–375

3. Turner BG, Rhea JT, Thrall JH, Small AB, NovellineRA. Trends in the use of CT and radiography in theevaluation of facial trauma, 1992–2002: implicationsfor current costs. AJR 2004;183:751–754

4. Donat TL, Endress C, Mathog RH. Facial fractureclassification according to skeletal support mech-anisms. Arch Otolaryngol Head Neck Surg1998;124:1306–1314

5. Manson PN, Markowitz B, Mirvis S, Dunham M,Yaremchuk M. Toward CT-based facial fracturetreatment. Plast Reconstr Surg 1990;85:202–212

6. Romano JJ, Manson PN, Mirvis SE, Dunham M,Crawley W. Le Fort fractures without mobility.Plast Reconstr Surg 1990;85:355–362

7. Levine RS, Grossman RI. Head and facial trauma.Emerg Med Clin North Am 1985;3:447–473

APPENDIX 1. Diagnosing Le Fort Fractures

First, evaluate the following four structures for fracture:

1. Pterygoid process Le Fort fracture almost always present2. Lateral margin of nasal fossa Unique to Le Fort I3. Inferior orbital rim Unique to Le Fort II4. Zygomatic arch Unique to Le Fort III

Second, confirm presence of other fractures in the suspected Le Fort plane.