Occipital bone 312030 210571025 2008-05-06T14:19:59Z Gracillis 4775916 [[th:กระดูกท้ายทอย]] {{Infobox Bone | Name = Occipital bone | Latin = | GraySubject = 31 | GrayPage = 129 | Image = Gray194.png | Caption = Sagittal section of skull. (Occipital bone is at right, in blue.) | Image2 = Gray193.png | Caption2 = Base of the skull. Upper surface. (Occipital bone is at bottom, in blue.) | Origins = | Insertions = | Articulations = the two [[parietal bone|parietals]], the two [[temporal bone|temporals]], the [[sphenoid bone|sphenoid]], and the [[atlas (anatomy)|atlas]] | MeshName = | MeshNumber = | }} The '''occipital bone''', a saucer-shaped membrane bone situated at the back and lower part of the [[skull|cranium]], is trapezoid in shape and curved on itself. It is pierced by a large oval [[aperture]], the [[foramen magnum]], through which the [[cranial cavity]] communicates with the [[vertebral canal]]. * The curved, expanded plate behind the foramen magnum is named the [[squama occipitalis]]. * The thick, somewhat quadrilateral piece in front of the foramen is called the [[basilar part of occipital bone]]. * On either side of the foramen are the [[lateral parts of occipital bone]]. == Foramen magnum == :''See also [[Foramen magnum]]'' The foramen magnum is a large oval aperture with its long diameter antero-posterior; it is wider behind than in front where it is encroached upon by the condyles. It transmits the [[medulla oblongata]] and its membranes, the [[accessory nerves]], the [[vertebral arteries]], the anterior and [[posterior spinal arteries]], and the [[membrana tectoria]] and [[alar ligaments]]. == Angles == The '''superior angle''' of the occipital bone articulates with the occipital angles of the [[parietal bones]] and, in the fetal skull, corresponds in position with the [[posterior fontanelle]]. The '''inferior angle''' is fused with the body of the sphenoid. The lateral angles are situated at the extremities of the grooves for the [[transverse sinuses]]: each is received into the interval between the mastoid angle of the parietal and the mastoid part of the [[temporal]]. == Borders == The '''superior borders''' extend from the superior to the lateral angles: they are deeply serrated for articulation with the occipital borders of the parietals, and form by this union the [[lambdoidal suture]]. The '''inferior borders''' extend from the lateral angles to the inferior angle; the upper half of each articulates with the mastoid portion of the corresponding [[temporal]], the lower half with the [[petrous]] part of the same bone. These two portions of the inferior border are separated from one another by the jugular process, the notch on the anterior surface of which forms the posterior part of the [[jugular foramen]]. == Structure == The occipital, like the other cranial the outer and inner tables, between which is the [[cancellous]] tissue or [[diploë]]; the bone is especially thick at the ridges, protuberances, [[condyles]], and anterior part of the [[basilar]] part; in the inferior fossæ it is thin, semitransparent, and destitute of diploë. ==Additional images== <gallery> Image:Illu cranial bones.jpg|Cranial bones Image:Gray187.png|Base of skull. Inferior surface. Image:Gray307.png|Membrana tectoria, transverse, and alar ligaments. Image:Gray308.png|Median sagittal section through the occipital bone and first three cervical vertebræ. Image:Gray409.png|Muscles connecting the upper extremity to the vertebral column. Image:Gray792.png|Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ. Image:Gray1031.png|Muscles of the pharynx, viewed from behind, together with the associated vessels and nerves. </gallery> {{Gray's}} == See also == * [[Bone#Terminology|Bone terminology]] * [[Comparative anatomy]] * [[Neanderthal]] * [[Occipital bun]] * [[Terms for anatomical location]] * [[Ossification of occipital bone]] {{Cranium}} [[Category:Skeletal system]] [[Category:Skull]] [[ar:عظم قذالي]] [[ca:Occipital]] [[da:Nakkeben]] [[de:Hinterhauptsbein]] [[es:Hueso occipital]] [[fr:Os occipital]] [[gl:Occipital]] [[ko:뒤통수뼈]] [[it:Osso occipitale]] [[he:עצם העורף]] [[la:Os occipitale]] [[lv:Pakauša kauls]] [[lt:Pakauškaulis]] [[ja:後頭骨]] [[pl:Kość potyliczna]] [[pt:Osso occipital]] [[sk:Záhlavná kosť]] [[sl:Zatilnica]] [[sr:Потиљачна кост]] [[fi:Takaraivoluu]] [[sv:Nackben]] [[th:กระดูกท้ายทอย]] [[uk:Потилична кістка]] [[zh:枕骨]]