Table 1.

A Comparison of the Features of Trap Door Blowout Fractures in Children and Adults

	Children with Trap Door Fractures	Adults with Trap Door Fractures
Epidemiology	Trap door fractures are almost exclusively seen in children	Trap door fractures are very rare in adults
Pure vs impure subtype	Trap door fractures in children are only seen with pure fractures	Trap door fractures in adults are usually associated with pure fractures. Some cases are associated with impure fractures
Gerbino subtype	Most cases are Type 1 linear fractures	Most cases are Type II hinged fractures
The main presenting clinical picture	Limitation in supraduction of the globe with minimal periorbital soft-tissue injury	In patients with pure fractures: similar to children
		In patients with impure fractures: significant periorbital soft-tissue injury
Oculocardiac reflex and bradycardia	Very common	Bradycardia is very rarely seen. Some patients may have mild nausea
The tear drop sign on CT scan	Commonly seen and indicates the entrapment of a large piece of the inferior rectus muscle	Much less common and indicates the entrapment of the perimuscular tissue with or without a small piece of muscle