Blowout injury refers to what?

Ref: Basok Essentials of Ophthalmology 5th edition, pg no 421: Kanski: Clinical Ophthalmology; 7th edition, pg no 873- 874Explanation:Blow out fracture of orbit:Caused by a sudden increase in the orbital pressure by an impacting object of size > 5cm like tennis ball or fist.The fracture usually involves the floor of the orbit, along the thin bone covering the infra orbital canal.Two types:Pure Blow Out fracture does not involve the orbital rim or the other bones.Impure Form involves other bones.Symptoms:Diplopia - due to the entrapment of muscle into the fracture, intraorbital hemorrhage or injury to the muscle itself.Double Diplopia - Diplopia in both upgaze & downgaze due to entrapment of both Inferior rectus (Depression) & inferior oblique (Elevation).Periocular ecchymosis & edema.Enophthalmos.Infraorbital nerve ana esthesia.Investigations: X-ray (WATER'S view) - 'Tear Drop Sign' because of the protruding orbital tissue from the floor if the orbit into the maxillary antrum.Management:Conservative management with antibiotics & anti inflammatory drugs.Orbital floor repair with bone graft, silicone plate within 2 weeks.Indications:Fracture involving > one third of the floorPersisting diplopiaEnophthalmos > 2mmBlow-In Fracture:Sudden rise of pressure in the maxillary antrum due to trauma to the face with subsequent elevation of bone fragments into the orbit.