Orbital Floor Anatomy Ct

Imaging recommendations radiography ultrasound first line modality for intraocular lesions noninvasive readily available ct mr are complementary techniques.

Orbital floor anatomy ct. Between fat bone air soft tissues. It has a roof floor medial and lateral wall. Direct orbital floor fractures these fractures are rim fractures that have extended into the floor of the bony orbit. The crack on the floor can pinch the eye muscles and nearby anatomy preventing the eyeball from moving freely within the eye socket.

Inferior herniation of the intraorbital fat may result in a teardrop sign. The orbital floor forms the roof of the maxillary sinus and is relatively thin thus susceptible to blow out fracture or spread of severe sinus infection. The orbit is open anteriorly where it is bound by the orbital septum which forms part of the eyelids. The adult orbital floor is composed of the maxillary zygomatic and palatine bones see image below.

A full assessment does not require the administration of contrast. The orbital floor is formed by the orbital plate of the maxilla the orbital process of the palatine bone and the orbital surface of the zygomatic bone. The orbital floor is the shortest of all the walls. It opens into posterolateral aspect of orbital floor.

The inferior orbital fissure iof lies in the floor of the orbit inferior to the superior orbital fissure and it is bounded superiorly by the greater wing of sphenoid inferiorly by maxilla and orbital process of palatine bone and laterally by the zygomatic bone. These fractures are usually caused by an object larger than the eye opening such as a baseball. Both are indicated for evaluation of complex lesions ct excellent evaluation of orbit aided by natural contrast. Orbit imaging anatomy 2.

The arrow indicates the buttress of the transition zone between medial orbital wall and orbital floor coronal slice of a postoperative ct scan taken after transconjunctival repair of the complete left medial orbital wall and orbital floor. The orbital plate of the maxilla is thin and a common site of inferior blowout fracture. The orbital floor is composed primarily of the maxillary bone with the zygomatic bone forming the anterolateral portion and the palatine bone lying at the posterior extent of the floor. The medial orbital wall is composed of several bones maxilla frontal ethmoid lacrimal and sphenoid and separates the orbit from the ethmoid air cells.

It does not reach the orbital apex. Gross anatomy in the adult the orbit has a volume of approximately 30 ml of which the globe occupies 6 5 ml. Orbital emphysema may result in a black eyebrow sign. The floor is the shortest of the orbital walls extending back only about 35 40 mm from the inferior rim.