A 28-year-old man was struck in the left orbit by a cricket ball one week ago. He now notices vertical diplopia and a sunken appearance of the left eye. Examination shows enophthalmos, restriction of elevation, hypoesthesia over the left cheek, and a step deformity of the inferior orbital rim on CT. The structure MOST commonly involved producing these findings is:
- A Lateral orbital wall
- B Floor of the orbit involving the maxillary sinus ✓
- C Roof of the orbit
- D Medial orbital wall with ethmoid sinus
Correct answer: B. Floor of the orbit involving the maxillary sinus
Explanation
Blowout fractures most frequently involve the orbital floor along the thin bone over the infraorbital canal, herniating contents into the maxillary sinus. Entrapment of the inferior rectus and inferior oblique restricts elevation, while injury to the infraorbital nerve in the floor causes cheek hypoesthesia. Medial wall fractures into the ethmoid air cells occur but do not explain infraorbital sensory loss or the classic vertical diplopia pattern.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.