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Encyclopedia > Occipital bone
Bone: Occipital bone
Sagittal section of skull. (Occipital bone is at right, in blue.)
Base of the skull. Upper surface. (Occipital bone is at bottom, in blue.)
Gray's subject #31 129
Articulations the two parietals, the two temporals, the sphenoid, and the atlas

The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the 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. Image File history File links Gray194. ... Image File history File links Download high resolution version (719x1057, 150 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The parietal bones (os parietale) are bones in the human skull and form, by their union, the sides and roof of the cranium. ... The temporal bones (os temporales) are situated at the sides and base of the skull. ... The sphenoid bone (from Greek sphenoeides, wedgelike) is a bone situated at the base of the skull in front of the temporals and basilar part of the occipital. ... In anatomy, the atlas (C1) is the topmost (first) cervical vertebra of the spine. ... It has been suggested that temporal fenestra be merged into this article or section. ... a big (1) and a small (2) aperture For other uses, see Aperture (disambiguation). ... In anatomy, the foramen magum is the large hole through the occipital bone in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) exits the skull vault. ...   The cranial cavity isj the relatively large space formed inside the skull. ... The spinal canal (or vertebral canal) is the space in vertebrae through which the spinal cord passes. ...

Contents

The squama of the occipital bone, situated above and behind the foramen magnum, is curved from above downward and from side to side. ... The basilar part of the occipital bone extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. ... The lateral parts of the occipital bone are situated at the sides of the foramen magnum; on their under surfaces are the condyles for articulation with the superior facets of the atlas. ...

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. In anatomy, the foramen magum is the large hole through the occipital bone in the base of the skull, through which the medulla oblongata (an extension of the spinal cord) exits the skull vault. ...


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. The medulla oblongata is the lower portion of the brainstem. ... The accessory nerve (or Spinal accessory nerve) is the eleventh of twelve cranial nerves. ... The vertebral arteries are branches of the subclavian arteries. ... The posterior spinal artery (dorsal spinal artery) arises from the vertebral artery, beside the medulla oblongata. ... Tectorial membrane can refer to: Tectorial membrane (cochlea) Tectorial membrane (axis) Category: ... The alar ligaments connect the sides of the dens (on the axis, or the second cervical vertebra) to tubercles on the medial side of the occipital condyle. ...


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 parietal bones (os parietale) are bones in the human skull and form, by their union, the sides and roof of the cranium. ... The posterior fontanelle (or occipital fontanelle) is triangular in form and is situated at the junction of the sagittal suture and lambdoidal suture. ...


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. For the transverse pericardial sinus, see pericardial sinus. ... For alternate uses of time, see Time (disambiguation) or see TIME (magazine). ...


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 lambdoid suture (or Lambdoidal suture) is a dense, fibrous connective tissue joint that separates the parietal and temporal bones of the skull from the occipital bone. ...


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. For alternate uses of time, see Time (disambiguation) or see TIME (magazine). ... Petrous portion can refer to: Petrous portion of the temporal bone Petrous portion of the internal carotid artery Andreas Petrou, descendent of the same generation, was the greatest, smartest, most athletic man to ever live. ...


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. Behind the carotid canal is the jugular foramen, a large aperture, formed in front by the petrous portion of the temporal, and behind by the occipital; it is generally larger on the right than on the left side, and may be subdivided into three compartments. ...


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. Cancellous is a type of cancer in the bone. ... The diploic veins are found in the skull, and drain the diploic space. ... Condyle L. fr. ... In human anatomy, the basilar artery is one of the arteries that supplies the brain with oxygen-rich blood. ...


Additional images

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy after Henry Gray, is an anatomy textbook widely regarded as a classic work on human anatomy. ...


See also


  Results from FactBites:
 
Occipital bone - Wikipedia, the free encyclopedia (492 words)
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoid in shape and curved on itself.
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 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.
Head Lecture notes (1219 words)
The last piece of cartilage to ossify is between the body of the sphenoid bone and the occipital bone, anterior to the foramen magnum: this is the spheno-occipital synchondrosis (the epiphyseal plate for growth in length of the base of the skull and it ossifies at age 25).
The parietal bones are separated by the sagittal suture and from the frontal bone by the coronal suture.
The hypoglossal canal (anterior condylar) canal and the posterior condylar canal.
  More results at FactBites »

 
 

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