Frontal sinus drainage pathway (inverted funnel shape) is bordered... 

• Anteriorly by agger nasi and frontal recess Kuhn cells

• Posteriorly by bulla ethmoidalis, frontal bullar, suprabullar cell

• Posteriorlaterally by supraorbital ethmoidal cells. 

Management of frontal sinus fx depends on the displacement, comminution and sites involved including: thicker anterior table, thinner posterior table, frontal recess

• Posterior table involvement (almost always also w anterior table) confers risk of CSF leak and intracranial infection.

• Frontal recess disruption confers risk of frontal sinus mucocele/mucopyocele development.

Traumatic deformity of orbital floor (MC) OR medial wall resulting from impact of blunt object larger than orbital aperture; pure w/o orbital rim fx; impure w/ orbital rim fx

2 broad categories:

• Open door: large displaced frequently comminuted

• Trapdoor: linear, hinged, minimally displaced

Associated findings

• herniation of orbital contents

• Involvement of infraorbital canal

• Oribital ST injury

• Orbital emphysema can have mass effect -> compression/stretch of optic nerve insertion w/ tenting of globe.

• Can involve combo injury with nasal, LE fort, ZMC

Trapdoor fx: special type of floor blowout that usually occurs in children where the inferiorly displaced fx fragment recoils and entraps herniated orbital ST, which can cause restricted motility or necrosis of the inferior rectus mm. 

Large orbital blowouts (>2 cm defect area or >1.5 mL outward herniated volume) predicts development of noticeable enophthalmos after acute swelling subsides.

Report:

• Entrapment is a clinical diagnosis. Must note position, orientation and configuration of EOMs as functional entrapment can occur without significant displacement.

• Check for mass effect on optic nerve insertion from retrobulbar hematoma or emphysema

Medial canthal tendon inserts on the medial orbital rim

Involves the upper central midface classically along 5 key edges:

• Pyriform aperture across the lateral nasal wall

• Inferior orbital rim and floor

• Medial orbital wall

• Frontomaxillary suture

• Nasomaxillary suture

Classified based on morphology of central fragment:

• Type 1: noncomminuted large central fragment

• Type 2: comminuted central fragment not disrupting area of medial canthal tendon insertion

• Type 3: comminuted central fragment disrupting area of medial canthal tendon insertion.

Report

• Type of medial orbital rim fx and degree of surrounding comminution.

• Distance b/n 2 lacrimal fossae in coronal plane

• Involvement of frontal sinus drainage pathway and orbit

2nd MC facial fx and can lead to malocclusion.  Fx typically linear or branching.

Fx are described by the involved anatomic segments involved:

• Condylar process -> further subdivided head, neck, and/or base

• Coronoid process 

• Ramus and angle

• Body (3rd molar to canine)

• Parasymphysis/symphysis

Mandible simulates a bony ring, thus multiple breaks are common:

• Parasymphyseal fx on 1 side often associated w contralateral angle/body or subcondylar fx

• B/l subcondylar fx after direct impact to symphysis.

• Unilateral mandibular fx can occur w contralateral TMJ dislocation.

• Guardsman fx: parasymphyseal and b/l condylar fx

B/l parasymphyseal or body fx w posterior displacement of central fragment and tongue -> airway compromise! Emergency!

Fx that extend to periodontal ligament space of an erupted tooth should be especially noted as they are managed as open (contaminated) fractures.

Displaced or complex mandibular fx, especially those involving the condyles, are associated w increased risk of blunt vascular injury and warrant a neck CTA.