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orbit

 [or´bit]
1. the bony cavity containing the eyeball and its associated muscles, vessels, and nerves; the ethmoid, frontal, lacrimal, nasal, palatine, sphenoid, and zygomatic bones and the maxilla contribute to its formation.
2. the path of an electron around the nucleus of an atom. adj., adj or´bital.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

or·bit

(ōr'bit), [TA]
The bony cavity containing the eyeball and its adnexa; it is formed of parts of seven bones: the frontal, maxillary, sphenoid, lacrimal, zygomatic, ethmoid, and palatine.
Synonym(s): orbita [TA], eye socket
Farlex Partner Medical Dictionary © Farlex 2012

orbit

(ôr′bĭt)
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

ORBIT

Cardiology A clinical trial Oral Glycoprotein IIb/IIIa receptor Blockade to Inhibit Thrombosis
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

or·bit

(ōr'bit) [TA]
The bony cavity containing the eyeball and its adnexa; it is formed of parts of the frontal, maxillary, sphenoid, lacrimal, zygomatic, ethmoid, and palatine bones.
Synonym(s): orbita [TA] , orbital cavity.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

orbit

The bony cavern in the skull that contains the eyeball and OPTIC NERVE, the muscles that move the eye, the LACRIMAL GLAND, a quantity of fat and various arteries, veins and nerves.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005

orbit

the body cavity or socket in the vertebrate skull containing the eyeball.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

Orbit

The cavity in the skull containing the eye-ball; formed from seven bones: frontal, maxillary, sphenoid, lacrimal, zygomatic, ethmoid, and palatine.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

orbit 

A rigid bony cavity in the skull which contains an eyeball, orbital fat, the extraocular muscles, the optic nerve, nerves and blood vessels, lacrimal system and fibrous tissue of various kinds. This packing serves to keep the eyeball reasonably well fixed in place as it rotates. The orbital cavity has the approximate form of a pyramid. The walls of the orbital cavity are formed by seven bones. The medial wall of the orbit consists of: (1) the frontal process of the maxilla (maxillary); (2) the lacrimal bone; (3) the lamina papyracea of the ethmoid; and (4) a small part of the body of the sphenoid. The floor of the orbit consists of: (1) the orbital plate of the maxilla; (2) the orbital surface of the zygomatic (malar) bone and (3) the orbital process of the palatine bone. The lateral wall of the orbit consists of (1) the orbital surface of the greater wing of the sphenoid, and (2) the orbital surface of the zygomatic. The roof of the orbit is made up mainly by the frontal bone and behind this by the lesser wing of the sphenoid. The orbit is lined with a membrane of tissue called the periorbita (or orbital periosteum) which extends to the orbital margin (anterior rim of the orbit) where it becomes continuous with the periosteum covering the facial bones. The periorbita is loosely attached to the bones except at sutures, foramina and the orbital margin where it is firmly attached. The bones are much thicker at the margin (rim) than they are along the walls of the orbital cavity. There are many apertures and gaps in the orbit through which blood vessels and nerves pass (see Table O4). See orbital axis; optic canal; inferior orbital fissure; superior orbital fissure; orbital fracture; cavernous haemangioma; lamina papyracea.
Table O3 Bones forming the walls of the orbit
roofmedial wall
1. frontal1. maxilla
2. lesser wing of sphenoid2. lacrimal
3. ethmoid
4. sphenoid
floorlateral wall
1. maxilla1. greater wing of sphenoid
2. zygomatic
3. palatine2. zygomatic

Table O4 Orbital apertures
aperturelocationcontents
optic canalat the apex (in lesser sphenoid)optic nerve
ophthalmic artery
sympathetic nerve fibres
superior orbital fissureat the apex (gap between greater and lesser sphenoid)III, IV, V, VI nerves
sympathetic nerve fibres
ophthalmic vein
recurrent lacrimal artery
inferior orbital fissurebetween lateral wall and posterior part of the floorinfraorbital nerve
zygomatic nerve
branch of inferior ophthalmic vein
nerve fibres from the
pterygopalatine (sphenopalatine)
ganglion to orbital periosteum
ethmoidal foramina (anterior and post.)medial wall (frontal/ethmoidal suture)ethmoidal vessels
ethmoidal nerve/external nasal nerve
zygomatic foramenlateral wallzygomatic nerve and vessels
nasolacrimal canalmedial wall (maxilla/lacrimal)nasolacrimal duct
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann

or·bit

(ōr'bit) [TA]
Bony cavity containing eyeball and its adnexa.
Medical Dictionary for the Dental Professions © Farlex 2012
References in periodicals archive ?
1 Astrophysical Journal, Luhman and his colleagues used the Hubble Space Telescope to photograph an object, about 10 Jupiter masses, orbiting the star CHXR 73.
Just beyond this crowd resided a slowly orbiting band of ice, gas, and dust.
The star's small size suggests that it won't always be easy for planet hunters to discern whether an eclipsing body is a hot Jupiter--a large planet that lies within roasting distance of its parent star--or a diminutive stellar partner orbiting at the same distance.
A hot, closely orbiting planet is most likely to have this alignment.
Such tightly orbiting planets, nicknamed hot Jupiters, account for about 20 percent of the nearly 120 extrasolar planets identified so far (SN: 10/25/03, p.
Several teams have recently found that some of the irregulars orbiting each planet belong to the same family, an indication of a shared origin.
They might just be orbiting their parent stars at greater distances than astronomers had looked for in previous studies.
Genzel has tracked the motion of stars orbiting the galactic center since the late 1980s.
That could explain why among the roughly 100 extrasolar planets discovered to date, only 9 are so-called "hot Jupiters, orbiting their stars so closely that they complete one revolution in just a few days.
However, the wobble method measures changes in only one component of the star's velocity, so it can't reveal the true mass of an orbiting companion, only a lower limit.

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