19: Eye and Orbit

CHAPTER 19

EYE AND ORBIT

Overview and Topographic Anatomy of the Orbit

Osteology of the Orbit

Contents of the Orbit

Clinical Correlates

Questions

Overview and Topographic Anatomy of the Orbit

GENERAL INFORMATION

Orbit: a pyramid-shaped bony recess in the anterior part of the skull, lined by periosteum called the periorbital fascia

Contents include:

Eye—organ associated with vision

Extrinsic muscles

Optic nerve

Oculomotor nerve

Ciliary ganglion

Trochlear nerve

Ophthalmic division of the trigeminal nerve

Abducens nerve

Ophthalmic artery and branches

Superior and inferior ophthalmic veins

Lacrimal apparatus

Much fatty tissue

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Osteology of the Orbit

OPENINGS IN THE ORBIT

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BONES CREATING THE ORBITAL MARGIN

WALLS OF THE ORBIT

Superior

Frontal (orbital plate)

Lesser wing of the sphenoid

Inferior

Maxilla

Zygomatic

Palatine (orbital process)

Medial

Ethmoid (lamina papyracea)

Lacrimal

Sphenoid

Maxilla

Lateral

Zygomatic

Greater wing of the sphenoid

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Contents of the Orbit

EYE

Eye: a spherical globe with a diameter of approximately 2.5 cm that lies in the orbit’s anterior portion

Surrounded by a thin capsule called the fascia bulbi (Tenon’s capsule):

Provides support

Allows for movement

Composed of 3 coats:

Sclera

Uveal tract

Retina

Divided into an anterior and a posterior segment:

Anterior Segment:

Filled with aqueous humor

Separated into anterior and posterior chambers by the iris

Contains aqueous humor secreted by the ciliary body and drained through a trabeculated network eventually into the superior ophthalmic vein

Intraocular pressure is measured in the anterior segment, normally 10 to 20 mm Hg

Posterior Segment:

Filled with vitreous fluid

Called the vitreous cavity

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Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 19: Eye and Orbit
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