Fig. 13 Anatomic section demonstrating orbital septa 1.4 mm from behind the surface of the eye. Diameters vertically, 2.4 cm; transversally, 2.7 cm. Enlargement is approximately × 3.5. (ON, optic nerve; SOV, superior ophthalmic vein; SLP, superior levator palpebrae muscle; SRM, superior rectus muscle; LRM, lateral rectus muscle; IRM, inferior rectus muscle; MRM, medial rectus muscle; SOM, superior oblique muscle; *, connective tissue septa; ATC, adipose tissue compartment; IOA + IN, infraorbital artery and nerve; MM, Müller's muscle) (From Koornneef L: Spatial aspects of orbital musculofibrous tissue in man: A new anatomical and histological approach. Amsterdam: Swets en Zeitlinger, 1976)