Everything about The Occipital Bone totally explained
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.
Foramen magnum
» See also Foramen magnum
The foramen magnum is a large oval aperture with its long diameter antero-posterior; it's wider behind than in front where it's 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're 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's thin, semitransparent, and destitute of diploë.
Additional images
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.
Further Information
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