periorbita


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Related to periorbita: palpebral ligaments, Orbital septum, Wydase

periorbita

 [per″e-or´bĭ-tah]
the periosteum of the bones forming the orbit, or eye socket. adj., adj perior´bital.

per·i·or·bi·ta

(per'ē-ōr'bi-tă), [TA]
The periosteum of the orbit.
[peri- + L. orbita, orbit]

periorbita

/peri·or·bi·ta/ (-or´bĭ-tah) periosteum of the bones of the orbit, or eye socket.perior´bital

periorbita

[per′i·ôr′bitə]
Etymology: Gk, peri + L, orbita, wheel mark
the periosteum of the orbit of the eye. It is continuous with the dura mater and the sheath of the optic nerve and extends a process at the margin of the orbit to form the orbital septum. The periorbita is loosely connected to the bones of the orbit, from which it can be easily detached.
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Periorbita

per·i·or·bi·ta

(per'ē-ōr'bi-tă) [TA]
The periosteum of the orbit.
Synonym(s): periorbit.
[peri- + L. orbita, orbit]

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

periorbita

the fascial sheet that encloses the eyeball and its muscles that is continuous medially with the periosteum of the bones forming the orbit.
References in periodicals archive ?
Although the lamina papyracea was intact in patient 1, an iatrogenic bony defect with intact periorbita was identified in patient 2.
A similar heterogeneous enhancement was noted in the sinuses and in the left periorbita (figure 2, B).
To the best of our knowledge, masticatory diplopia as a result of adhesion of the temporalis muscle to the periorbita secondary to facial trauma has not been previously reported.