A 16-year-old male with left orbital trauma has diplopia on extraocular movement testing, enophthalmos, and decreased sensation over the left cheek. Imaging shows an orbital fracture. What is the most likely fracture type?

A 16-year-old male with left orbital trauma has diplopia on extraocular movement testing, enophthalmos, and decreased sensation over the left cheek. Imaging shows an orbital fracture. What is the most likely fracture type?

• A. Zygomatic arch fracture
• B. Orbital blowout fracture
• C. Le Fort I fracture
• D. Le Fort II fracture

Answer: (B)

The key idea is that blunt trauma can cause a blowout fracture of the orbital floor, and the signs here point to that pattern. When the orbital floor (thin bony wall between the eye socket and the maxillary sinus) fractures, the contents of the orbit can herniate into the sinus and the inferior rectus muscle can become entrapped. This explains the diplopia on extraocular movements, especially with upgaze, because the inferior rectus is restricted. The same fracture also often leads to enophthalmos, since the orbital volume increases and the globe sits slightly back in the socket after the fracture and herniation. Additionally, the infraorbital nerve runs in the floor and can be injured, causing decreased sensation over the cheek. Other midface fractures, like a zygomatic arch fracture, would more typically present with malar flattening or step-offs and facial numbness without the characteristic diplopia and enophthalmos from orbital floor involvement. Le Fort I and II fractures involve broader maxillary disruption with dental occlusion changes and midface instability rather than isolated orbital signs.

The key idea is that blunt trauma can cause a blowout fracture of the orbital floor, and the signs here point to that pattern. When the orbital floor (thin bony wall between the eye socket and the maxillary sinus) fractures, the contents of the orbit can herniate into the sinus and the inferior rectus muscle can become entrapped. This explains the diplopia on extraocular movements, especially with upgaze, because the inferior rectus is restricted. The same fracture also often leads to enophthalmos, since the orbital volume increases and the globe sits slightly back in the socket after the fracture and herniation. Additionally, the infraorbital nerve runs in the floor and can be injured, causing decreased sensation over the cheek.

Other midface fractures, like a zygomatic arch fracture, would more typically present with malar flattening or step-offs and facial numbness without the characteristic diplopia and enophthalmos from orbital floor involvement. Le Fort I and II fractures involve broader maxillary disruption with dental occlusion changes and midface instability rather than isolated orbital signs.