Orbit (anatomy)
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Orbit (anatomy) | |
|---|---|
 | |
| The seven bones which articulate to form the orbit. yellow = Frontal bone green = Lacrimal bone brown = Ethmoid bone blue = Zygomatic bone purple = Maxillary bone aqua = Palatine bone red = Sphenoid bone | |
| Latin | orbitae |
| Gray's | subject #46 188 |
| MeSH | Orbit |
| Dorlands/Elsevier | o_05/12594914 |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753
Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [2] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
In anatomy, the orbital bone is the cavity or socket of the skull in which the eye and its appendages are situated.
It can also mean the skin which surrounds the eye of a bird.
In the adult human, the volume of the orbit is 30 ml, of which the eye occupies 6.5 ml. [1]
Definition
The orbits are conical cavities, which open into the midline of the face. Each consists of a base, an apex and four walls.
The base, which opens in the face, has four borders. The following bones take part in their formation:
- 1. Superior margin: frontal bone
- 2. Inferior margin: maxilla and zygomatic
- 3. Medial margin: frontal, lacrimal and maxilla
- 4. Lateral margin: zygomatic and frontal
The apex lies near the medial end of superior orbital fissure and contain the optic canal which communicates with middle cranial fossa.
The roof (superior wall) is formed by the orbital plate frontal bone and the lesser wing of sphenoid. The orbital surface presents medially by trochlear fovea and laterally by lacrimal fossa
The floor (inferior wall) is formed by the orbital surface of maxilla, the orbital surface of zygomatic bone and the orbital process of palatine bone. Medially near the orbital margin is located the groove for nasolacrimal duct. Near the middle of the floor, located infraorbital groove, which leads to the infraorbital foramen. The floor is separated from the lateral wall by inferior orbital fissure, which connects the orbit to pterygopalatine and infratemporal fossa.
The medial wall is formed by the frontal process of maxilla, lacrimal bone, orbital plate of ethmoid and a small part of the body of the sphenoid.
The Lateral wall is formed by the orbital process of zygomatic and the orbital plate of greater wing of sphenoid. The bones meet at the zygomaticosphenoid suture. The lateral wall is the thickest wall of the orbit.
Fat cushion
In the orbit, surrounding the eyeball and its muscles, is a layer of fat that helps the eye rotate around a fixed center of rotation. If excess liquid is collected in the fat cushion tissue, the eye may protrude. [2]
Contents
- Eyeball
- Fascias: Orbital, Bulbar
- Extraocular muscles (Levator Palpebrae Superioris, Superior, Inferior, Lateral and Medial Rectus muscles, Superior and Inferior Oblique Muscles)
- Nerves: cranial nerves II, III, IV, V, and VI
- Blood vessels
- Extraocular Fat
- Lacrimal gland, Lacrimal sac, Nasolacrimal duct
- Eyelids
- Medial and Lateral Palpebral ligaments
- Medial and Lateral Check ligaments
- Suspensory ligament of the eyeball
- Conjunctiva
- Trochlea
- Orbital septum
- Ciliary ganglion and short ciliary nerves
Bones
In humans, seven bones make up the bony orbit:
- Frontal bone (Pars orbitalis)
- Lacrimal bone
- Ethmoid bone (Lamina papyracea)
- Zygomatic bone (Orbital process of the the zygomatic bone)
- Maxillary bone (Orbital surface of the body of the maxilla)
- Palatine bone (Orbital process of palatine bone)
- Sphenoid bone (Greater and lesser wings)
Foramina and openings
- Optic foramen
- Superior orbital fissure
- Inferior orbital fissure
- Anterior ethmoid foramen
- Posterior ethmoidal foramen
- Infraorbital foramen
- Supraorbital foramen
- Naso-lacrimal canal opening
- Zygomatic orbital foramen
Additional images
 The skull from the front. |
 Medial wall of left orbit. |
 Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure. |
 Coronal section of nasal cavities. |
 |
 Lateral orbit anatomy |
 Lateral orbit nerves |
References
- ↑ Duane's Ophthalmology, Chapter 32 Embryology and Anatomy of the Orbit and Lacrimal System . (eds Tasman W, Jaeger EA) Lippincott/Williams & Wilkins, 2007
- ↑ "eye, human."Encyclopædia Britannica. 2008. Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 5 Apr. 2008
External links
- oph/2 at eMedicine - "Arterial Supply, Orbit"
- SUNY Labs 29:os-0501
- Atlas of anatomy at UMich eye_5
- Atlas of anatomy at UMich rsa2p4
- Interactive tutorial at anatome.ncl.ac.uk
de:Orbitait:Orbita oculare
la:Orbita (anatomia)
nl:Orbitafi:Silmäkuoppa
sv:Ögonhåla
| ||||
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
