ANATOMY OF THE ORBIT Dr Sheetal Savur
The orbit Protects, supports and maximizes the functions of the eyeball Shaped as a quadrilateral pyramid with its base in plane with the orbital rim
Alignment of the orbits medial walls are parallel lateral walls are perpendicular axes of the orbits bisect at a 45°angle The axes of the eyeballs make an angle of 22.5 with the orbital axes
Dimensions of the orbit Height of orbital margin - 40 mm Width of orbital margin - 35 mm Depth of orbit - 40-50 mm Volume of orbit - 30 cm3
Bones of the orbit Frontal bone Zygomatic bone Maxillary bone Sphenoid bone Ethmoid bone Lacrimal bone Palatine bone
The seven bones
The frontal bone
The zygomatic bone
The maxillary bone
The sphenoid bone
The ethmoid bone
The lacrimal bone
The palatine bone
The communications of the orbit
The superior orbital fissure
The optic foramen
The inferior orbital fissure
Contents of the orbit Eyeball Extra-ocular muscles Fascia Vessels Nerves Retro-orbital fat NO LYMPHATICS
Relations of the orbit
Orbital rim
Apex of the orbit Superior orbital fissure Optic foramen
II cranial nerve III cranial nerve (2 divisions) IV cranial nerve V cranial nerve (3 branches of the Ophthalmic division) VI cranial nerve Ophthalmic veins (superior and inferior) Ophthalmic artery
Inferior orbital fissure
Spaces of the orbit Sub-periosteal space Peribulbar space Retrobulbar space Sub Tenon’s space