上面の内側では蝶形骨体の蝶形骨隆起に移行している。
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小翼 |
小翼（部位解説） |
頭蓋底 |
蝶形骨（前面） |
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蝶形骨（上面） |
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以下は「Wikipedia」の解説文となる。
The lesser wings of the sphenoid or orbito-sphenoids are two thin triangular plates, which arise from the upper and anterior parts of the body, and, projecting lateralward, end in sharp points.
In some animals they remain as separate bones called orbitosphenoids.
【Structure】
The main features of the lesser wing are the optic canal, the anterior clinoid process, and the superior orbital fissure.
【 語 句 】
・optic canal：視神経管 ・anterior clinoid process：前床突起 ・superior orbital fissure：上眼窩裂
【Surfaces】
The superior surface of each is flat, and supports part of the frontal lobe of the brain. The inferior surface forms the back part of the roof of the orbit, and the upper boundary of the superior orbital fissure.
This fissure is of a triangular form, and leads from the cavity of the cranium into that of the orbit: it is bounded medially by the body; above, by the small wing; below, by the medial margin of the orbital surface of the great wing; and is completed laterally by the frontal bone.
It transmits the oculomotor nerve, the trochlear nerve, and the abducent nerve, the three branches of the ophthalmic division of the trigeminal nerve, some filaments from the cavernous plexus of the sympathetic nervous system, the orbital branch of the middle meningeal artery, a recurrent branch from the lacrimal artery to the dura mater, and the ophthalmic vein.
【 語 句 】
・frontal lobe：前頭葉 ・orbit：眼窩 ・superior orbital fissure：上眼窩裂 ・cranium：頭蓋 ・frontal bone：前頭骨 ・oculomotor nerve：動眼神経 ・trochlear nerve：滑車神経 ・abducent nerve：外転神経 ・trigeminal nerve：三叉神経 ・cavernous plexus：海綿静脈洞神経叢 ・sympathetic nervous system：交感神経系 ・middle meningeal artery：中硬膜動脈 ・lacrimal artery：涙腺動脈 ・dura mater：硬膜 ・ophthalmic vein：眼静脈
【Borders】
The anterior border is serrated for articulation with the frontal 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).
The lesser wing is connected to the body by two roots, the upper thin and flat, the lower thick and triangular; between the two roots is the optic foramen, for the transmission of the optic nerve and ophthalmic artery.
【 語 句 】
・serrated：鋸歯状の ・articulation：接合、関節 ・anterior clinoid process：前床突起 ・tentorium cerebelli：小脳テント ・spicule：骨片 ・internal carotid artery：内頚動脈 ・foramen：孔 ・optic foramen：視神経孔 ・optic nerve：視神経 ・ophthalmic artery：眼動脈
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