The orbit and its contents

2021 ◽  
pp. 349-396
Author(s):  
Daniel R. van Gijn ◽  
Jonathan Dunne
Keyword(s):  
Dura Mater ◽  
Extraocular Muscles ◽  
Outer Margin ◽  
Medial Wall ◽  
Pyramidal Structure ◽  
Conical Shape

The function of the orbit is to protect and accommodate the globe in order to maximise its function. The bony orbits are paired four-sided conical cavities within the skull each comprising seven bones – ranging from the paper thin ethmoid and lacrimal plate medially to the buttress thick zygoma laterally. The conical shape consists of an apex posteriorly and a base anteriorly forming the outer margin. The medial wall and floor begin to blend towards the apex forming a posteromedial bulge as the orbit takes on a three-walled pyramidal structure. The walls are lined by periosteum (periorbita), which is continuous with the periosteal layer of the dura mater at the apex, the orbital septa and the fascial sheaths of the extraocular muscles. There are five principal openings of the orbit – three principal foramina located at the apex that transmit the neurovascular supply of the orbit and two lesser foramina located on the medial wall.

scholarly journals DOES DECUBITUS AFFECT NEURAL ELEMENTS POSITIONING? A MRI STUDY COMPARING DORSAL AND LATERAL POSITION

2020 ◽  
Vol 19 (4) ◽  
pp. 255-257
Author(s):  
LUCAS NUNES SALES DE MELO ◽  
RAFAEL BARRETO SILVA ◽  
JOSÉ CARLOS BARBE GONÇALVES ◽  
GABRIELA AIELLO FERNANDES PANTAROTO
Keyword(s):  
Dura Mater ◽  
Lateral Position ◽  
Medial Wall ◽  
Level Of Evidence ◽  
Shortest Distance ◽  
Lateral Decubitus ◽  
The Mean ◽  
Magnetic Resonance Imaging Mri ◽  
The Right ◽  
Mri Study

ABSTRACT Objective To evaluate the displacement of nerve structures according to the decubitus position of the patient in a magnetic resonance imaging (MRI) study. Methods MRI was performed at a radiology clinic in 20 patients in dorsal and right lateral decubitus. The measurement considered was the shortest distance between the dura mater and the medial wall of the pedicle. Results The largest measurement was 11.6 mm in left lateral decubitus, 12.2 mm in right lateral decubitus, 10.5 mm in right dorsal decubitus, and 9.2 mm in left dorsal decubitus. In some patients the space between the medial wall of the pedicle and the dura mater was larger when in lateral decubitus, while in others when in dorsal decubitus. The mean displacement of the measurements on the left was 1.14 mm and on the right 1.355 mm. Conclusions The structures moved on average little more than 1 mm in the positions studied. The positioning of the patient for surgery does not change the space to be approached, being the surgeon’s choice according to his learning curve. Level of evidence II; Prospective study of lower quality.

Medial Wall Orbital Decompression in Graves’ Orbitopathy

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P40-P40
Author(s):  
Stefano Sellari-Franceschini
Keyword(s):  
Retrospective Analysis ◽  
Extraocular Muscles ◽  
Medial Wall ◽  
Orbital Decompression ◽  
Graves Orbitopathy ◽  
New Onset

Objective 1) To delineate useful criteria when choosing between different techniques for orbital decompression. 2) To discuss indications and limits of the medial wall only approach. Methods A retrospective analysis was made of the medical charts of 256 patients operated on by a single surgeon from 1998 to 2006. 228 patients were operated on using a balanced technique, 17 by an inferomedial decompression, 11 by a medial decompression. Patients operated on by the medial wall removal had a mild to moderate proptosis, and a slight involvement of the extraocular muscles in the disease. Results Mean proptosis reduction was 4 mm with the inferomedial approach, 5.5 mm with the balanced procedure, and 2.6 mm with the medial wall removal. Postoperative deterioration or new onset of diplopia was 29% after inferomedial orbital decompression, 17.1% after balanced decompression, and 9% after medial wall removal. Conclusions When a proptosis reduction of less than 3 mm is needed, the medial wall approach is suggested. When a greater proptosis reduction is needed, a balanced decompression is advisable, since the inferomedial approach carries with it a higher risk of postoperative diplopia.

Structural Organization and Distribution of Fiber Types in Extraocular Muscles of Cats

1972 ◽  
Vol 30 ◽  
pp. 34-35
Author(s):  
Asish C. Nag ◽  
Lee D. Peachey
Keyword(s):  
Fiber Type ◽  
Light And Electron Microscopy ◽  
Small Diameter ◽  
Extraocular Muscles ◽  
Fiber Types ◽  
Distinctive Features ◽  
Superior Rectus ◽  
Adult Cats ◽  
Different Diameters ◽  
Orbital Region

Cat extraocular muscles consist of two regions: orbital, and global. The orbital region contains predominantly small diameter fibers, while the global region contains a variety of fibers of different diameters. The differences in ultrastructural features among these muscle fibers indicate that the extraocular muscles of cats contain at least five structurally distinguishable types of fibers.Superior rectus muscles were studied by light and electron microscopy, mapping the distribution of each fiber type with its distinctive features. A mixture of 4% paraformaldehyde and 4% glutaraldehyde was perfused through the carotid arteries of anesthetized adult cats and applied locally to exposed superior rectus muscles during the perfusion.

Intramuscular Nerve and Neuromuscular Junction Alteration In Extraocular Muscles of Diabetic Mice

1985 ◽  
Vol 43 ◽  
pp. 682-683
Author(s):  
Bruce R. Pachter
Keyword(s):  
Diabetes Mellitus ◽  
Peripheral Nerves ◽  
Sudden Onset ◽  
Extraocular Muscles ◽  
Diabetic Patients ◽  
Oculomotor Palsy ◽  
Third Nerve Palsy ◽  
Patients With Diabetes ◽  
Intramuscular Nerve ◽  
Oculomotor Nerves

Diabetes mellitus is one of the commonest causes of neuropathy. Diabetic neuropathy is a heterogeneous group of neuropathic disorders to which patients with diabetes mellitus are susceptible; more than one kind of neuropathy can frequently occur in the same individual. Abnormalities are also known to occur in nearly every anatomic subdivision of the eye in diabetic patients. Oculomotor palsy appears to be common in diabetes mellitus for their occurrence in isolation to suggest diabetes. Nerves to the external ocular muscles are most commonly affected, particularly the oculomotor or third cranial nerve. The third nerve palsy of diabetes is characteristic, being of sudden onset, accompanied by orbital and retro-orbital pain, often associated with complete involvement of the external ocular muscles innervated by the nerve. While the human and experimental animal literature is replete with studies on the peripheral nerves in diabetes mellitus, there is but a paucity of reported studies dealing with the oculomotor nerves and their associated extraocular muscles (EOMs).

Ultrastructural evidence for mast cell-macrophage interrelationships in the dura mater of the rat: Infrequent mast cell-nerve associations

1990 ◽  
Vol 48 (3) ◽  
pp. 352-353
Author(s):  
Ruth V.W. Dimlich
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Dura Mater ◽  
Spatial Relationship ◽  
Potassium Phosphate ◽  
Plasma Extravasation ◽  
Close Spatial Relationship ◽  
Male Wistar Rats ◽  
Headache Pain ◽  
Relationship Of

Mast cells in the dura mater of the rat may play a role in cerebral pathologies including neurogenic inflammation (vasodilation; plasma extravasation) and headache pain . As has been suggested for other tissues, dural mast cells may exhibit a close spatial relationship to nerves. There has been no detailed ultrastructural description of mast cells in this tissue; therefore, the goals of this study were to provide this analysis and to determine the spatial relationship of mast cells to nerves and other components of the dura mater in the rat.Four adult anesthetized male Wistar rats (290-400 g) were fixed by perfusion through the heart with 2% glutaraldehyde and 2.8% paraformaldehyde in a potassium phosphate buffer (pH 7.4) for 30 min. The head of each rat was removed and stored in fixative for a minimum of 24 h at which time the dural coverings were removed and dissected into samples that included the middle meningeal vasculature. Samples were routinely processed and flat embedded in LX 112. Thick (1 um) sections from a minimum of 3 blocks per rat were stained with toluidine blue (0.5% aqueous).

Metastasierendes malignes Melanom mit Festliegen ante partum infolge Rückenmarkskompression bei einer Stute

2013 ◽  
Vol 41 (03) ◽  
pp. 190-194
Author(s):  
K. Jäger ◽  
A. Snyder ◽  
A. Sobiraj ◽  
L. Hildebrandt
Keyword(s):  
Dura Mater ◽  
Malignes Melanom

ZusammenfassungDer Fallbericht beschreibt die Einengung des Rückenmarkskanals durch ein malignes Melanom mit resultierendem akutem Festliegen bei einer hochtragenden, 17 Jahre alten Welsh-B-Ponystute. Als ursächlich für das akute Festliegen war der Einbruch von Metastasen des malignen Melanoms in den Wirbelkanal im Bereich der letzten Lendenwirbel und des Kreuzbeins anzusehen, wo der Tumor die Dura mater infiltriert und das Lenden- sowie Sakralmark auf einer Länge von 10 cm mittelgradig komprimiert hatte. Dargestellt werden neben dem klinischen Bild labordiagnostische, pathologisch-anatomische und histopathologische Befunde.

Imaging and Demographic Characteristics Associated with Invasion of the Medial Wall of the Cavernous Sinus in Patients with Invasive Pituitary Adenomas

2019 ◽  
Author(s):  
Ezequiel Goldschmidt ◽  
Salomon Cohen-Cohen ◽  
Federico Angriman ◽  
Carl Snyderman ◽  
Eric Wang ◽  
...  
Keyword(s):  
Cavernous Sinus ◽  
Pituitary Adenomas ◽  
Demographic Characteristics ◽  
Medial Wall
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