Anatomy of orbit

Contents • 1 Arterial Supply to the Orbit • 1.1 Orbital Group • 1.2 Ocular Group • 1.3 Orbital Veins • 2 References Arterial Supply to the Orbit Blood supply to the orbital arises primarily from the ophthalmic artery - the first branch off of the internal carotid as it emerges from the cavernous sinus on the medial side of the clinoid process. The ophthalmic artery has many branches which may be separated into 2 groups: *Orbital Group *Ocular Group Orbital Group • Lacrimal artery: Runs along the lateral wall of the orbit and supplies the lacrimal gland. Terminal branches of the lacrimal artery include the superior and inferior lateral palpebral arteries which supply the lateral upper and lower eyelids and conjunctiva. • Supraorbital artery: In the orbit supplies the supeior rectus and levator palpebral muscles. It then passes through the supraorbital foramen and its terminal branches supply the eyebrow and forhead. • Anterior ethmoidal artery: In the orbit supplies the superior oblique muscle. Also supplies the anterior and middle ethmoidal cells, frontal sinus, lateral wall nose, and nasal septum. • Posterior ethmoidal artery: Passes through the posterior ethmoidal canal, supplying the posterior ethmoidal cells. • Internal palpebral artery: Terminal branches include superior and inferior medial palpebral arteries. These vessels supply the lacrimal sac and eyelids creating an anastomosis with the two lateral palpebral branches from the lacrimal artery. • Frontal artery: Le...

The bony orbit refers to the bones that constitute the margins of the orbital margin or rim refers to the anterior circular margin of the orbit. The There are seven bones that contribute to the bony orbit: • pars orbitalis of the • • • orbital process of the • orbital surface of the • orbital process of the • The four bones of the medial wall are remembered with this • 1. Moore KL, Agur AMR, Dalley AF. Clinically oriented anatomy. LWW. ISBN:1451119453. • 2. Butler P, Mitchell A, Healy JC. Applied Radiological Anatomy. Cambridge University Press. (2012) ISBN:0521766664. • 3. Robert H. Whitaker, Neil R. Borley. Instant Anatomy. • 4. Last's anatomy, regional and applied. Churchill Livingstone. ISBN:044304662X.

• Home Currently selected • Current Issue • Previous Issues • Archive 2002 Onwards • Archive 1953-2001 • Published Ahead-of-Print • For Authors • Submit a Manuscript • Information for Authors • Conflicts of Interest Disclosure • Contributors' Copyright Release Form • Language Editing Services • Journal Info • About the Journal • Editorial Board • Affiliated Society • Advertising • Subscriptions • Reprints • Rights and Permissions Consultant, Neurovascular and Interventional Radiology, Apollo Speciality Hospital, Bengaluru, Karnataka, India 1Consultant, Orbit and Oculoplasty, Narayana Nethralaya, Bengaluru, Karnataka, India 2Clinical Fellow, Division of Neuroradiology, Department of Medical Imaging, The Ottawa Hospital - Civic Campus, Ottawa, Canada 3Consultant, Orbit& Oculoplasty, Centre for Sight, Banjara Hills, Hyderabad, Telangana, India Correspondence to: Dr. Chinmay P Nagesh, Neurovascular and Interventional Radiology, Apollo Speciality Hospital, #2, 14 th Cross, 3 rd Block Jayanagar, Bangalore, Karnataka, India. E-mail: [emailprotected] This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 4.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Magnetic resonance imaging ( MRI) is an eloquent, noninvasive, cross-sectional imaging modality that offers superior tissue characterization of orbital pathologies. The ophthalmol...

I'm going to shift gears a little bit and start reviews on some of the other sections. I originally had planned to go in order of the BCSC sections and follow the OKAP content outline, but I realized that of all the sections to cover, General Medicine is one of the smallest sections in terms of content to know. So while I will likely get back to it sometime in the future, I wanted to make sure the key subjects were discussed prior to the test. There are many facts in the Fundamentals and Principles of Ophthalmology section of the BCSC that will likely be tested as quick recall. I promise, I will eventually provide numerous resources and tools to help remember these facts; for this article, I will try to cover the most important concepts. I am intentionally leaving out details that may be more challenging to test (meaning I have a hard time coming up with a practice question about it). Orbital Anatomy Bones of the Orbit There are 7 bones that make up the orbit (in no particular order): • Ethmoid • Lacrimal • Frontal • Sphenoid • Maxillary • Palatine • Zygomatic Check out our Orbital Roof • The orbital roof consists of two bones: the frontal and sphenoid bone (lesser wing). • The frontal bone contains the lacrimal gland fossa temporally and the trochlear fossa nasally. Lateral Orbital Wall • The lateral orbital wall consists of two bones: the zygomatic and the sphenoid bone (greater wing). • The lateral orbital wall is the strongest wall of the orbit. Orbital Floor • The orb...

Article: • • • • • • • • Images: • Terminology Ocular or optic refers specifically to the Gross anatomy Orbits are roughly pyramidal in shape, broad based anteriorly and tapering to an apex, posteriorly. The normal volume in an adult is approximately 30 mL, of which the The orbit has a roof, floor, medial and lateral wall. The orbit is open anteriorly where it is bound by the Contents • • • • • branches of the • superior division • inferior division • • branches of the ophthalmic division of the • • • • • • • • • • • • branches of the maxillary division of the trigeminal nerve (CN Vb) • • • • • • • • sympathetic root to the ciliary ganglion ( • arteries • • • veins • • • • fat • • Bony margins The bony margins of the orbits, known as the • pars orbitalis of the • • • orbital process of the • orbital surface of the • orbital process of the • The four bones of the medial wall are remembered with this Spaces Other than the globe of the eye, and the optic nerve the orbit can be thought of containing two compartments with reference to the • • Communications Three major communications of the orbit are: 1. The • superior and inferior ophthalmic veins • cranial nerves lll, lV, V1 and VI 2. The 3. The Communications of the pterygopalatine fossa (PPF): • medially: PPF opens into the nasal cavity via the • laterally: PPF communicates with the inferior temporal fossa via the • posterosuperiorly: PPF opens into the middle cranial fossa via • posteroinferiorly: PPF opens into the The Me...

Bones of the orbit and some of the major landmarks. Image credit: There are 7 bones that form the orbit: • Sphenoid • Ethmoid • Lacrimal • Frontal • Palatine • Maxillary • Zygomatic Orbital Roof Bones • Orbital plate of the frontal bone • Lesser wing of the sphenoid bone Landmarks • Lacrimal gland fossa: anterolateral orbit, behind zygomatic process of frontal bone • Trochlear fossa: superomedial orbit, along frontal bone approximately 4 mm from orbital margin • Site of trochlea Medial Orbital Wall Bones • Frontal process of the maxillary bone • Lacrimal bone • Orbital plate of the ethmoid bone • Lesser wing of the sphenoid bone Landmarks • Ethmoid bone: largest portion of the medial wall • Lacrimal fossa: formed by frontal process of maxilla and lacrimal bone • Continuous with nasolacrimal canal (connects to inferior meatus of nose) • Lamina papyracea: name given to medial wall of ethmoid bone due to paper-thin structure Orbital Floor Bones • Maxillary bone • Palatine bone • Orbital plate of the zygomatic bone Landmarks • Infraorbital groove and foramen • Origin of the inferior oblique muscle: just lateral to opening of the nasolacrimal canal • More prone to “trapdoor” fractures in childhood Lateral Orbital Wall Bones • Zygomatic bone • Greater wing of the sphenoid bone Landmarks • Whitnall (lateral orbital) tubercle: orbital margin of the zygomatic bone, 11 mm below frontozygomatic suture ( the 4 “Ls”) • Ligament of the lateral rectus muscle • Suspensory ligament of the ...