<prompt> Blow out fracture can be due to:Tennis ball injuryChisel and hammer injurySudden fallPunch at the chin from below  <response>: Blow out orbital fracture result from trauma to orbit by a relatively large often rounded object such as tennis ball, cricket ball, human fist, or a pa of automobile.The force of blow causes a backward displacement of the eyeball and increase in the intraorbital pressure. CLASSIFICATION 1 PURE BLOW OUT FRACTURE - NOT associated with involvement of the orbital rim 2 Impure blow out - associated with other fractures about the middle third of facial skeleton - Inferior wall MC involved - Entrapment of inferior rectus in inferior wall - not able to look up- Hanging drop or tear drop sign Features 1 Enophthalmos 2 Diplopia3 Infra orbital nerve anesthesia 