A 28-year-old man was struck in the left orbit by a cricket ball 2 days ago. He has vertical diplopia worse on attempted upgaze, hypoesthesia over the left cheek, and slight enophthalmos. Forced duction testing shows restriction of passive elevation. The MOST likely diagnosis is:
- A Inferior rectus entrapment in an orbital floor blowout fracture ✓
- B Superior oblique palsy
- C Retrobulbar haemorrhage
- D Traumatic third nerve palsy
Correct answer: A. Inferior rectus entrapment in an orbital floor blowout fracture
Explanation
Blunt orbital trauma classically fractures the thin orbital floor into the maxillary sinus, herniating or entrapping the inferior rectus and inferior oblique. This produces limited elevation with positive forced ductions, infraorbital nerve hypoesthesia along the cheek, and delayed enophthalmos. Retrobulbar haemorrhage causes proptosis with tense orbit and vision threat rather than enophthalmos, and a third nerve palsy would not give a positive forced duction test.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.