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There are two important foramina, or windows, two important fissures, or grooves, and one canal surrounding the globe in the orbit. There is a supraorbital foramen, an infraorbital foramen, a superior orbital fissure, an inferior orbital fissure and the optic canal, each of which contains structures that are crucial to normal eye functioning.
The Orbital Fascia forms the periosteum of the orbit. It is loosely connected to the bones and can be readily separated from them. Behind, it is united with the dura mater by processes which pass through the optic foramen and superior orbital fissure , and with the sheath of the optic nerve.
Tenon's capsule (/ t ə ˈ n oʊ n /), also known as the Tenon capsule, fascial sheath of the eyeball (Latin: vagina bulbi) or the fascia bulbi, is a thin membrane which envelops the eyeball from the optic nerve to the corneal limbus, separating it from the orbital fat and forming a socket in which it moves.
The inferior surface of each orbital plate is smooth and concave, and presents, laterally, under cover of the zygomatic process, a shallow depression, the lacrimal fossa, for the lacrimal gland; near the nasal part is a depression, the fovea trochlearis, or occasionally a small trochlear spine, for the attachment of the cartilaginous pulley of the obliquus oculi superior.
The attached or orbital margins are connected to the circumference of the orbit by the orbital septum. The lateral angles are attached to the zygomatic bone by the lateral palpebral raphe. The medial angles of the two plates end at the lacrimal lake, and are attached to the frontal process of the maxilla by the medial palpebral ligament).
The ethmoid bone (/ ˈ ɛ θ m ɔɪ d /; [1] [2] from Ancient Greek: ἡθμός, romanized: hēthmós, lit. 'sieve') is an unpaired bone in the skull that separates the nasal cavity from the brain. It is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction.
Orbital septum acts as a physical barrier that prevents the infection of the anterior part of the eye spreading posteriorly. For example, preseptal cellulitis mainly infects the eyelids, anterior to the orbital septum. Meanwhile, orbital cellulitis is located posterior the orbital septum, due to infections spreading from the ethmoidal sinuses.
The posterior lacrimal crest is a vertical bony ridge on the orbital (lateral) surface of the lacrimal bone. It divides the lacrimal bone into two parts. It is quite thin and fragile in most people. [1] The lacrimal groove is in front of this crest.