Parietal bone

Parietal bone . It is a bone of the Skull , flat, even, quadrilateral in shape, with two faces, internal (endocraneal) and external (exocranial), and four edges with their respective angles. It is found covering the superior and lateral portion of the skull, behind the Frontal , in front of the Occipital and mounted on the Temporal and the Sphenoid . Both parietal bones are articulated, through a midline: the sagittal suture. The parietal term means of the wall.

Summary

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  • 1 Anatomical description
    • 1 Exocranial face
    • 2 Endocranial face
    • 3 Edges
    • 4 Angles
    • 5 Bone architecture
    • 6 Joints
    • 7 Surfaces
      • 7.1 Edges
      • 7.2 Angles
    • 8 Joints
    • 9 Physiological movement
  • 2 External links
  • 3 Sources

Anatomical description

For the study of the parietal bone, two faces, four edges and their respective angles are recognized. The most important bone accidents are detailed for each part.

Exocranial face

  • superior temporal curve line: for insertion of the temporal fascia.
  • Lower temporal curve line: where the temporal muscle is inserted.
  • parietal hump (parietal eminence), a curved bulge of bone.
  • parietal foramen: makes its way into the cranial cavity for an emissary vein.

Endocranial face

  • parietal fossa, crossed by branched vascular grooves, product of the impression on the bone of the branches of the middle meningeal artery and its satellite veins.
  • frontal longitudinal sinus hemichannel
  • Paccioni pits like those of the frontal bone.
  • Sylvian crest, bone outgrowth shaped by the corresponding lateral fissure of the cerebral hemisphere.

Edges

4 edges are described:

  • the joint of the upper edge of both parietals gives rise to the sagittal suture (interparietal or parietoparietal joint).
  • the obelion is a craniometricpoint located on the sagittal suture line slightly in front of the parietal holes.
  • the lower edge articulates with the scale of the storm.
  • the anterior border articulates with the frontal forming the frontoparietal or coronal suture.
  • the posterior border joins the occipital scale to form the parietooccipital or lambdoid suture (because it is shaped like the Greek letter lambda)

Angles

4 angles are described:

  • the anterosuperior or frontal angle indicates the union of the sagittal and coronal sutures. Bregma is the name of the craniometric point located on this angle.
  • the posterosuperior or occipital angle indicates the union of the sagittal and lambdoid sutures. Above this angle is the lambda craniometric point.
  • the anteroinferior or sphenoid angle. Pterion craniometric point.
  • the posteroinferior or mastoid angle. Asterion craniometric point.

Bone architecture

It is a flat bone and shares the structure of the bones of the cranial vault. Two tables of compact bone tissue covering a mid region of cancellous tissue.

Joints

The parietal bone is articulated by symphibrosis with other cranial bones:

  • the contralateral parietal bone: sagittal suture;
  • the frontal bone: coronal suture;
  • the temporal bone
  • the sphenoid;
  • the occipital: Lamdoid suture.

There are two parietal bones located between the frontal and the occipital, which form the sides of the cranial vault. The internal surface of these two large cranial bones is made up of slight depressions where the blood vessels that supply the meninx or the outermost fascia of the brain called the dura are accommodated. The parietal bone is like a square plate that attaches to the sides of the large and heavy skull, almost as much as the front. The parietal is divided into two surfaces, four edges and four angles.

Surfaces

External. It’s formed by:

  • Parietal hole.
  • Parietal eminence.
  • Time lines, top and bottom. Internal.

It’s formed by:

  • Concavity for meningeal granulations, such as the bodies or eminences of Pacchioni.
  • Cavity for the brain, for the meningeal veins and for the superior sagittal sinus.
  • Joints for the sickle of the brain.

Edges

Here we have four edges or sides for each well formed and defined parietal.

  • Sagittal or medial side, here we have the sagittal suture. With deep indentations. Wide on the back side and narrow on the front side.
  • Front or anterior side, here is the coronal suture, with deep, chamfered indentations. In the outer zone the indentations are medially and in the internal zone they are laterally.
  • Occipital or posterior side, here we have the lambdoid suture. With deep and chamfered indentations. On the outer side medially and on the inner side laterally.

Angles

Here we have four angles of great importance to the craniosacral system due to the congruence of cranial sutures.

  • Front angle. Located in its superior antero art. Anterior fontanel.
  • Sphenoid angle, located in its lower anterior part. Here are the internal grooves for the meningeal veins. It is called a sphenoidal fontanelle.
  • Occipital angle, located in the upper Posteroarea . It is called the posterior fontanel.
  • Mastoid angle, on the lower postero side. Here we have the transverse groove for the transverse sinus of the dura. Mastoid fontanelle.

In the parietal bone we have to distinguish the temporal fossa, the superior temporal line and the inferior temporal line. At the top and slightly posterior we have a hole in each storm for the emissary vein. It is called a parietal hole. In the inner part of the parietals we have several pits or small depressions for the Arachnoid granulations , as well as grooves for the middle meningeal vessels. The bregma point and the lambda point are two areas of special interest for the congruence of sutures, forming three Sutural angles . Here the mental tension produces tension in the sickle of the brain and this causes one or more of the three sutures to block, the coronal, the sagittal, or the lambdoid.

The bregma point and lambda will be seriously affected. We have to help them breathe these three points as well as possible. By sending attention and energy to this area we can free them from possible tensions. Almost always it is possible to release and improve the primary respiratory movement of any joint. If we want, we can put pressure with our fingers on the sutures and visualize that they open and that the cerebrospinal fluid enters and circulates through the sutures.

Joints

We define five joints in each parietal. It is important to look at the overlapping of the bezels.

  • It articulates with the occipital in its lambdoid suture. In the lateral zone the parietal covers the occipital and in its medial zone it is the other way around.
  • It articulates with the frontal due to its coronal suture. The parietal laterally covers the front and medially it is the other way around.
  • It articulates with the sphenoid at its lower Posteroangle . The tip of the main wing is chamfered.
  • It articulates with the storm. On the lower edge of the scale, beveled.
  • It articulates with the opposite parietal bone, through the sagittal suture, with different folds.

Physiological movement

Each parietal can express its movement independently of the other. Their correct primary respiratory movement is the one that both rise and just before reaching their end of the rise they make an external separation. That is, they rise and open, and they descend and close. This is the correct movement and together with a good rhythm and symmetry we will find a perfect physiological movement of the parietals. We will define axes of movement for each of the parietal bones. The movement of the temporal bones adapts to the other movements of the sphenoid bones, especially to the temporal bones, the occipital bone and the frontal bone. If some of these bones have a distorted or non-existent movement, it can influence the correct movement of the parietals.

In many of us we can find pathological movements in the parietals, due to head injuries as well as those caused in complicated births and with forceps, or in blows due to an accident or simply because of huge repetitive mental blocks. A deviation in some of these large bones will cause great strain on the cranial meningeal membrane. The dura, arachnoid, and pia madre are forced into a kind of facial drag. This is simply due to mental strains or poorly assimilated mental problems that have suppressed the cranial fasciae. There is no longer a complete mental fluidity, since the thoughts are seized, stuck, sclerotic. It both happens in one direction, as in another. Physical trauma causes stiffness and mental problems. Conversely, poorly digested mental problems cause head trauma.

 

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