Blow out fracture of the orbit, most commonly leads to fracture of:
"The most common site for a blowout fracture to occur is the posteromedial aspect of the orbital floor, medial to the infraorbital neurovascular bundle where the maxillary bone is very thin." - The Internet Journal of Otorhinolaryngology Blow out fracture: The usual mechanism is a blow to the eye, with the forces being transmitted by the soft tissues of the orbit downward to the thin floor of the orbit. The floor is usually the path of least resistance, and fractures downward into the maxillary sinus. Clinical features: Enophthalmos Recession of the eyeball within the orbit Diplopia: Double vision Especially on upward gaze Due to inferior rectus entrapment Forced Duction test is positive confirming the presence of muscle restriction Hypesthesia: Reduced sense of touch or sensation Due to injury of infraorbital nerve Usually have numbness of the gingiva and of the skin of the midface Investigation: Radiograph (Waters view) may see a soft tissue mass on the superior margin of the maxillary sinus, representing the herniated periorbital tissues into the sinus. Hanging drop or tear drop sign: hanging opacity of superior maxillary antrum. Computed tomography is the gold standard. Coronals provide best view. Extraocular muscle rounding and herniation of fat into maxillary sinus can be clearly viewed. Management: Medical management for asymptomatic patients-IV antibiotics and sho course of oral steriods. Surgical management for symptomatic patients. Ref: Parson's Disease of the eye, 20th Edition, Page 468; Comprehensive opthalmology, By A.K Khurana, 4th Edition, Page 397
Posteromedial floor of orbit
Medial wall of orbit
Lateral wall of orbit
Roof of orbit