|
Ophthalmic Artery
The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some structures in the nose, face, and meninges. Occlusion of the ophthalmic artery or its branches can produce sight-threatening conditions. Structure The ophthalmic artery emerges from the internal carotid artery. This is usually just after the internal carotid artery emerges from the cavernous sinus. In some cases, the ophthalmic artery branches just before the internal carotid exits the cavernous sinus. The ophthalmic artery emerges along the medial side of the anterior clinoid process. It runs anteriorly, passing through the optic canal inferolaterally to the optic nerve. It can also pass superiorly to the optic nerve in a minority of cases. In the posterior third of the cone of the orbit, the ophthalmic artery turns sharply and mediall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internal Carotid Artery
The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these bifurcate at cervical vertebrae C3 or C4. The internal carotid artery supplies the brain, including the eyes, while the external carotid nourishes other portions of the head, such as the face, scalp, skull, and meninges. Classification Terminologia Anatomica in 1998 subdivided the artery into four parts: "cervical", "petrous", "cavernous", and "cerebral". However, in clinical settings, the classification system of the internal carotid artery usually follows the 1996 recommendations by Bouthillier, describing seven anatomical segments of the internal carotid artery, each with a corresponding alphanumeric identifier—C1 cervical, C2 petrous, C3 lacerum, C4 cavernous, C5 clinoid, C6 ophthalmic, and C7 communicating. The Bouthillier nome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of which the eye occupies . The orbital contents comprise the eye, the orbital and retrobulbar fascia, extraocular muscles, cranial nerves II, III, IV, V, and VI, blood vessels, fat, the lacrimal gland with its sac and duct, the eyelids, medial and lateral palpebral ligaments, cheek ligaments, the suspensory ligament, septum, ciliary ganglion and short ciliary nerves. Structure The orbits are conical or four-sided pyramidal cavities, which open into the midline of the face and point back into the head. Each consists of a base, an apex and four walls."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009 Openings There are two important foramina, or windows, two important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Gland
The lacrimal glands are paired exocrine glands, one for each eye, found in most terrestrial vertebrates and some marine mammals, that secrete the aqueous layer of the tear film. In humans, they are situated in the upper lateral region of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. Inflammation of the lacrimal glands is called dacryoadenitis. The lacrimal gland produces tears which are secreted by the lacrimal ducts, and flow over the ocular surface, and then into canals that connect to the lacrimal sac. From that sac, the tears drain through the lacrimal duct into the nose. Anatomists divide the gland into two sections, a palpebral lobe, or portion, and an orbital lobe or portion. The smaller ''palpebral lobe'' lies close to the eye, along the inner surface of the eyelid; if the upper eyelid is everted, the palpebral portion can be seen. The orbital lobe of the gland, contains fine interlobular ducts that connect the orbital lobe and the palpebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Rectus Muscle
Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral consonant, an l-like consonant in which air flows along the sides of the tongue ** Lateral release (phonetics), the release of a plosive consonant into a lateral consonant Other uses *''Lateral'', journal of the Cultural Studies Association *Lateral canal, a canal built beside another stream * Lateral hiring, recruiting that targets employees of another organization *Lateral mark, a sea mark used in maritime pilotage to indicate the edge of a channel * Lateral stability of aircraft during flight *Lateral pass, a type of pass in American and Canadian football * Lateral support (other), various meanings * Lateral thinking, the solution of problems through an indirect and creative approach * Lateral number, a proposed alternate term f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Artery
The lacrimal artery is an artery of the orbit. It is a branch of the ophthalmic artery. It accompanies the lacrimal nerve along the upper border of the lateral rectus muscle, travelling forward to reach the lacrimal gland. It supplies the lacrimal gland, two rectus muscles of the eye, the eyelids, and the conjunctiva. Structure Origin The lacrimal artery is normally a branch of the ophthalmic artery and represents one of its largest branches. It's origin occurs near the optic canal. It usually branches off the ophthalmic artery just after the ophthalmic artery's entery into the orbit. It can rarely arise before the ophthalmic artery enters the optic canal. Course and relations The lacrimal artery accompanies the lacrimal nerve along the upper border of the lateral rectus muscle. It travels anterior-ward to supply the lacrimal gland. Branches and distribution The lacrimal artery supplies the lacrimal gland, the eyelids and conjunctiva, and the superior rectus mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Retinal Artery
The central retinal artery (retinal artery) branches off the ophthalmic artery, running inferior to the optic nerve within its dural sheath to the eyeball. Structure The central retinal artery pierces the eyeball close to the optic nerve, sending branches over the internal surface of the retina, and these terminal branches are the only blood supply to the larger part of it. The central part of the retina where the light rays are focused after passing through the pupil and the lens is a circular area called the macula. The center of this circular area is the fovea. The fovea and a small area surrounding it are not supplied by the central retinal artery or its branches, but instead by the choroid. The central retinal artery is approximately 160 micrometres in diameter. Variation In some cases - approximately 20% of the population - there is a branch of the ciliary circulation called the cilio-retinal artery which supplies the retina between the macula and the optic nerve, includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frontal Artery
The supratrochlear artery (or frontal artery) is one of the terminal branches of the ophthalmic artery. It arises within the orbit. It exits the orbit alongside the supratrochlear nerve. It contributes arterial supply to the skin, muscles and pericranium of the forehead. Anatomy It branches from the ophthalmic artery near the trochlea of the superior oblique muscle in the orbit. Origin The supratrochlear artery branches from the ophthalmic artery in the orbit near the trochlea of the superior oblique muscle. Course After branching from the ophthalmic artery, it passes anteriorly through the superomedial orbit. It travels medial to the trochlear nerve. With the supratrochlear nerve, the supratrochlear artery exits the orbit through the supratrochlear notch (variably present), medial to the supraorbital foramen. It then ascends on the forehead. Anastomoses The supratrochlear artery anastomoses with the contralateral supratrochlear artery, and the ipsilateral supraorbital ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medial Palpebral Artery
The medial palpebral arteries (internal palpebral arteries) are arteries of the head that contribute arterial blood supply to the eyelids. They are derived from the ophthalmic artery; a single medial palpebral artery issues from the ophthalmic artery before splitting into a superior and an inferior medial palpebral artery, each supplying one eyelid. Anatomy Origin A single medial palpebral artery issues from the ophthalmic artery before bifurcating into a superior and an inferior medial palpebral artery. The origin occurs near the trochlea of the superior oblique muscle. Course The medial palpebral arteries leave the orbit to encircle the eyelids near their free margins, forming a superior and an inferior arch, which lie between the orbicularis oculi and the tarsi. Anastomoses The superior medial palpebral artery anastomoses (at lateral angle of the orbit) with the upper lateral palpebral artery, and the zygomaticoorbital branch of the temporal artery. The inferior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elsevier
Elsevier () is a Dutch academic publishing company specializing in scientific, technical, and medical content. Its products include journals such as '' The Lancet'', ''Cell'', the ScienceDirect collection of electronic journals, '' Trends'', the '' Current Opinion'' series, the online citation database Scopus, the SciVal tool for measuring research performance, the ClinicalKey search engine for clinicians, and the ClinicalPath evidence-based cancer care service. Elsevier's products and services also include digital tools for data management, instruction, research analytics and assessment. Elsevier is part of the RELX Group (known until 2015 as Reed Elsevier), a publicly traded company. According to RELX reports, in 2021 Elsevier published more than 600,000 articles annually in over 2,700 journals; as of 2018 its archives contained over 17 million documents and 40,000 e-books, with over one billion annual downloads. Researchers have criticized Elsevier for its high profit m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual information from the retina to the brain. In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells; it extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, pretectal nuclei, and superior colliculus. Structure The optic nerve has been classified as the second of twelve paired cranial nerves, but it is technically part of the central nervous system, rather than the peripheral nervous system because it is derived from an out-pouching of the diencephalon ( optic stalks) during embryonic development. As a consequence, the fibers of the optic nerve are covered with myelin produced by oligodendrocytes, rather than Schwann cells of the peripheral nervous system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Canal
The ''optic foramen'' is the opening to the optic canal. The canal is located in the sphenoid bone; it is bounded medially by the body of the sphenoid and laterally by the lesser wing of the sphenoid. The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery (with accompanying sympathetic nerve fibres) into the orbital cavity. Compared to the optic nerve, the ophthalmic artery is located inferolaterally within the canal. The left and right optic canals are 25mm apart posteriorly and 30mm apart anteriorly. The canals themselves are funnel-shaped (narrowest anteriorly). Additional images File:Orbital_bones.png, The seven bones which articulate to form the orbit. File:Gray145.png, Sphenoid bone The sphenoid bon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anterior Clinoid Process
In the sphenoid bone, the posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes joined to the middle clinoid process by a spicule of bone, and when this occurs the termination of the groove for the internal carotid artery is converted into a foramen (carotico-clinoid). Etymology The anterior and posterior clinoid processes surround the sella turcica like the four corners of a four poster bed. Cline is Greek for bed. –oid, as usual, indicates a similarity to. The term may also come from the Greek root ''klinein'' or the Latin ''clinare'', both meaning "sloped" as in "inclined". Additional images Image:Anterior clinoid process.jpg, Anterior clinoid process Petroclinoid ligament The petroclinoid ligament is a fold of dura mater. It extends between the posterior clinoid process and anterior clinoid process and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
