Basilar part of occipital bone
Encyclopedia
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.
In the young skull this area is rough and uneven, and is joined to the body of the sphenoid
by a plate of cartilage.
By the twenty-fifth year this cartilaginous plate is ossified, and the occipital and sphenoid form a continuous bone.
which gives attachment to the fibrous raphé
of the pharynx
.
On either side of the middle line the Longus capitis and Rectus capitis anterior are inserted, and immediately in front of the foramen magnum the anterior atlantoöccipital membrane
is attached.
The upper surface presents a broad, shallow groove which inclines upward and forward from the foramen magnum; it supports the medulla oblongata
, and near the margin of the foramen magnum gives attachment to the membrana tectoria
.
On the lateral margins of this surface are faint grooves for the inferior petrosal sinus
es.
Occipital bone
The occipital bone, a saucer-shaped membrane bone situated at the back and lower part of the cranium, is trapezoidal in shape and curved on itself...
extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline.
In the young skull this area is rough and uneven, and is joined to the body of the sphenoid
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
by a plate of cartilage.
By the twenty-fifth year this cartilaginous plate is ossified, and the occipital and sphenoid form a continuous bone.
Surfaces
On its lower surface, about 1 cm. in front of the foramen magnum, is the pharyngeal tuberclePharyngeal tubercle
On the lower surface of the basilar part of occipital bone, about 1 cm. in front of the foramen magnum, is the pharyngeal tubercle which gives attachment to the fibrous raphé of the pharynx, also known as the pharyngeal raphe....
which gives attachment to the fibrous raphé
Raphé
Raphé can refer to:* Rafe, a diacritic ֿ a short horizontal overbar placed above certain letters to indicate that they are to be pronounced as fricatives* Raphe, scientific term...
of the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
.
On either side of the middle line the Longus capitis and Rectus capitis anterior are inserted, and immediately in front of the foramen magnum the anterior atlantoöccipital membrane
Anterior atlantoöccipital membrane
The anterior atlantoöccipital membrane is broad and composed of densely woven fibers, which pass between the anterior margin of the foramen magnum above, and the upper border of the anterior arch of the atlas below....
is attached.
The upper surface presents a broad, shallow groove which inclines upward and forward from the foramen magnum; it supports the medulla oblongata
Medulla oblongata
The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...
, and near the margin of the foramen magnum gives attachment to the membrana tectoria
Tectorial membrane (axis)
The Membrana Tectoria is situated within the vertebral canal.It is a broad, strong band which covers the dens and its ligaments, and appears to be a prolongation upward of the posterior longitudinal ligament of the vertebral column.It is fixed, below, to the posterior surface of the body of the...
.
On the lateral margins of this surface are faint grooves for the inferior petrosal sinus
Inferior petrosal sinus
The inferior petrosal sinuses, within the human head, are beneath the brain and allow blood to drain from the center of the head.They drain on either side inferiorly from the cavernous sinus and join with the sigmoid sinus to form the internal jugular vein, which continues inferiorly to drain...
es.