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Explain fracture line
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Le Fort I Fracture Line - Explained
The image is from Mastering the BDS IVth Year - II and describes the fracture line of Le Fort I fracture. Here is a clear, step-by-step breakdown:
What Is the Fracture Line?
The Le Fort I fracture line is a horizontal line running just above the apices (roots) of the upper teeth. It separates the tooth-bearing portion of the maxilla (the alveolar process + hard palate) from the rest of the facial skeleton - this detached segment is sometimes called the "floating palate."
Pathway of the Fracture Line (Step by Step)
Starting anteriorly and tracing laterally and posteriorly:
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Starts above the tooth apices - just above the root tips of the upper teeth, running horizontally.
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Passes the lateral margin of the anterior nasal aperture - the fracture line continues at or near the edge of the piriform (pear-shaped) nasal opening.
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Runs above the nasal floor - it stays superior to the floor of the nasal cavity.
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Passes above the canine fossa - the shallow depression on the front of the maxilla, lateral to the canine tooth.
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Traverses the lateral antral wall - crosses the outer wall of the maxillary sinus (antrum).
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Goes below the zygomatic buttress - dips downward, passing below the thick bony pillar where the zygoma meets the maxilla.
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Moves upward and posteriorly across the pterygomaxillary fissure - sweeps upward to reach the gap between the maxilla and the pterygoid plates.
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Fractures the pterygoid laminae - breaks the pterygoid plates of the sphenoid at the junction of their lower third and upper two-thirds. This is a constant and defining feature of all Le Fort fractures.
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Medial component (nasal wall) - from the same anterior starting point, the fracture also passes along the lateral wall of the nose, then curves behind the tuberosity of the maxilla to meet the lateral fracture line posteriorly.
Key Features
| Feature | Detail |
|---|---|
| Orientation | Horizontal |
| Segment separated | Tooth-bearing portion (alveolar process + palate) |
| Always involves | Pterygoid laminae fracture |
| Laterality | Typically bilateral; rarely unilateral |
| Nasal septum | Lower one-third is fractured |
| Displacement | Depends on force direction - can be posterior, lateral, or rotational |
Diagram (Fig. 37)
In the skull diagram, Le Fort I (labeled "I") is the lowest line, running just above the teeth. The handwritten note on the image - "Tooth bearing portion" - correctly identifies the segment that gets detached from the rest of the face. The lines labeled II and III represent higher-level Le Fort fractures involving the orbital rims and cheekbones.
In summary: The Le Fort I fracture line cuts horizontally across the lower maxilla, disconnecting the entire tooth-bearing upper jaw from the rest of the skull, with the pterygoid plate fracture being the single most constant feature.
Explain each line . Linewise
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Here is a detailed, line-by-line explanation of all three Le Fort fracture lines - with textbook diagrams from Bailey & Love's Surgery (28th Ed).
Le Fort Fractures - Line by Line
Le Fort I - "Horizontal" or "Guerin's Fracture" (Lowest Line)
What it separates: The tooth-bearing portion of the maxilla (alveolar process + hard palate) from the rest of the facial skeleton. This floating fragment is called the "floating palate."
Fracture line pathway - sentence by sentence:
| Step | Location | What happens |
|---|---|---|
| 1 | Above apex of teeth | A horizontal line begins just above the root tips of the upper teeth |
| 2 | Lateral margin of anterior nasal aperture (piriform rim) | Line passes at or near the edge of the pear-shaped nasal opening |
| 3 | Nasal floor | Passes above the floor of the nasal cavity |
| 4 | Canine fossa | Passes above the shallow depression on the front of the maxilla |
| 5 | Lateral antral wall | Traverses the outer wall of the maxillary sinus |
| 6 | Zygomatic buttress | Dips down below this bony pillar (the thick strut where zygoma meets maxilla) |
| 7 | Pterygomaxillary fissure | Moves upward and posteriorly to enter this gap between maxilla and pterygoid plates |
| 8 | Pterygoid laminae | Fractures them at the lower third/upper two-thirds junction - constant feature |
| 9 | Nasal wall (medial limb) | From the same starting point, fracture also runs along the lateral nasal wall, behind the tuberosity of maxilla, to meet the lateral line |
Key facts: Always bilateral. Lower 1/3 of nasal septum is fractured. Force applied above the teeth level.
Le Fort II - "Pyramidal Fracture" (Middle Line)
What it separates: The entire central midface block (maxilla + nasal bones + ethmoids) as a pyramid shape from the rest of the skull. The zygoma stays attached to the skull.
Fracture line pathway - sentence by sentence:
| Step | Location | What happens |
|---|---|---|
| 1 | Zygomaticomaxillary buttress | Starts at the junction of the zygomatic and maxillary bones, laterally |
| 2 | Maxillary sinus / anterior wall | Crosses upward across the front wall of the maxillary sinus |
| 3 | Infraorbital rim | Crosses the inferior orbital margin (lower rim of the eye socket) |
| 4 | Infraorbital foramen | Passes near or through this foramen - infraorbital nerve often damaged, causing cheek numbness |
| 5 | Medial orbital wall / lacrimal bone | Runs inward across the lacrimal bone (medial wall of orbit) |
| 6 | Nasofrontal suture / nasal bridge | Crosses the nasal bridge at the top, completing the pyramid apex |
| 7 | Pterygoid laminae (posteriorly) | Fractures the pterygoid plates - constant in ALL Le Fort fractures |
| 8 | Nasal septum | Middle third of nasal septum is involved |
Key facts: Pyramid-shaped block. The zygomatic arch is NOT fractured. Bilateral.
Le Fort III - "Craniofacial Dysjunction" (Highest Line)
What it separates: The entire midface from the skull base. The whole face "floats" away from the cranium - sometimes called "dish face" deformity.
Fracture line pathway - sentence by sentence:
| Step | Location | What happens |
|---|---|---|
| 1 | Zygomaticofrontal (ZF) suture | Starts at the junction between zygomatic bone and frontal bone (outer corner of orbit) |
| 2 | Lateral orbital wall | Runs inward along the lateral wall of the orbit (greater wing of sphenoid) |
| 3 | Superior orbital fissure | Passes near the superior orbital fissure |
| 4 | Medial orbital wall | Continues across the medial wall of the orbit |
| 5 | Nasofrontal suture / nasal bridge | Crosses the bridge of the nose at the nasofrontal junction |
| 6 | Opposite side (mirror image) | Identical path on the other side - always bilateral |
| 7 | Zygomatic arch | The zygomatic arch is also broken - distinguishes Le Fort III from Le Fort II |
| 8 | Pterygoid laminae (posteriorly) | Fractures all the way back through the pterygomaxillary fissure and pterygoid plates |
Key facts: Most severe of the three. Dish-face deformity, mobile midface, possible CSF rhinorrhoea (cribriform plate involvement), and bilateral zygomatic arch fractures.
Quick Comparison Summary
| Feature | Le Fort I | Le Fort II | Le Fort III |
|---|---|---|---|
| Level | Lowest - just above teeth | Middle - pyramidal | Highest - orbital level |
| Shape | Horizontal | Pyramidal | Horizontal but high |
| Segment detached | Tooth-bearing maxilla (palate) | Central midface pyramid | Entire midface |
| Zygomatic arch | Intact | Intact | Fractured |
| Infraorbital rim | Not involved | Involved | Involved |
| Pterygoid plates | Always fractured | Always fractured | Always fractured |
| Nasal septum | Lower 1/3 | Middle 1/3 | Upper portion |
| Clinical sign | "Floating palate" | "Floating pyramid" | "Dish face" / craniofacial dysjunction |
Common to all three: Pterygoid plate fracture is the single constant landmark in every Le Fort fracture.
- Bailey and Love's Short Practice of Surgery, 28th Ed., p. 433
- Scott-Brown's Otorhinolaryngology Head & Neck Surgery, p. 1243
Traverse meaning
Traverse means to cross or pass through/across something.
In the context of fracture lines:
"Traverses the lateral antral wall"
= The fracture line crosses over / passes through the lateral wall of the maxillary sinus.
Simple examples:
- A road traverses a mountain = the road crosses over the mountain
- The fracture traverses the orbital rim = the fracture line runs across/through the orbital rim
In one word: traverse = cross
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