In orbital floor fracture, which extraocular muscle is most likely entrapped?

• A. Lateral Rectus
• B. Superior Oblique
• C. Medial Rectus
• D. Inferior Rectus

Answer: (D)

In a blowout fracture of the orbital floor, the muscle most likely to become entrapped is the inferior rectus. The floor forms the bottom of the orbit and lies directly over the inferior rectus; when the floor fractures, the inferior rectus is the muscle most commonly snagged or pulled into the break. This entrapment prevents the eye from moving upward, producing restricted elevation and diplopia that worsens with upgaze. The other extraocular muscles are less exposed to the fracture site, so they’re less likely to be entrapped. Clinically, you’d expect limited upward gaze with possible enophthalmos and infraorbital sensory changes, and imaging would often confirm the floor fracture with muscle entrapment.