Parietal region

Anatomical borders

The frontoparietooccipital region occupies a dominant position on the cranial vault and is the most extensive part of the cerebral head. Its borders are clearly defined by the following bony landmarks:

• Anteriorly, the region is bounded by the supraorbital margin of the frontal bone and the glabella region (glabella).
• Posteriorly, the border runs along the superior nuchal line (linea nuchae superior), which separates the cranial vault from the posterior neck region.
• Laterally, the boundary is marked by the superior temporal line (linea temporalis superior). This line serves as the border separating the frontoparietooccipital zone from the paired temporal region.

Cellular spaces and surgical infection

A distinctive feature of the topographic anatomy of the cranial vault is the presence of three isolated cellular spaces. Each of them has a unique structure that dictates its specific scenario for the development of purulent inflammation.

1. Subcutaneous tissue. Located directly beneath the skin, superficial to the epicranial aponeurosis (galea aponeurotica). Due to numerous dense fibrous septa that firmly bind the skin to the aponeurosis, the tissue has a pronounced cellular structure. If an abscess develops here, it physically cannot spread across the plane. The fibrous partitions force the infection to penetrate primarily into the depth of the tissues.
2. Subaponeurotic space. Located deeper, between the epicranial aponeurosis and the periosteum. Unlike the subcutaneous layer, this tissue is very loose and completely devoid of fibrous partitions. Purulent processes in this zone are diffuse and capable of spreading rapidly and unhindered throughout the entire frontoparietooccipital region. This space poses the greatest clinical danger: via the emissary vein system, the infection can penetrate directly into the cranial cavity, posing a direct threat of severe complications such as meningitis or sinus thrombosis.
3. Subperiosteal space. This is the deepest layer of tissue, located between the periosteum and the outer table of the cranial bones. Its main topographic feature is strict confinement by the lines of the cranial sutures. In the area of the sutures, the periosteum fuses as tightly as possible with the bone, forming an insurmountable barrier. Therefore, subperiosteal abscesses are always strictly limited to the boundaries of one specific bone and never spread to adjacent areas of the cranial vault.

Applied significance in operative surgery

Knowledge of the topographic anatomy of the frontoparietooccipital region is an absolutely essential foundation for neurosurgical interventions, as well as for proper primary surgical management of head wounds.

• Temporary hemostasis. In head trauma, for emergency arrest of massive bleeding, it is necessary to clearly know the projection points of the main vessels. This allows the physician to effectively compress the damaged arteries directly against the underlying cranial bones.
• Creation of surgical flaps. When performing craniotomy and other open surgeries on the vault, surgical incisions are planned with mandatory consideration of the course of neurovascular bundles. There is a strict rule: the base of the formed musculocutaneous-aponeurotic flap must always face downward. It is from below that the blood supply sources approach the tissues of the cranial vault. This orientation of the flap pedicle guarantees the preservation of its adequate blood supply and reliably prevents ischemic tissue necrosis in the postoperative period.
• Rationale for scalp wounds. The features of the layered structure of the region — the firm connection of the skin with the epicranial aponeurosis combined with a very loose subaponeurotic layer underneath — determine the specifics of so-called scalp wounds of the head. In such injuries, a unified musculocutaneous-aponeurotic block is easily detached from the periosteum over a large extent.

Class and exam questions

What else to study on this topic

• Topography of blood vessels and nerves of the cranial vault
• Mechanism of scalp wound formation
• Emissary veins and their connection with the dural venous sinuses
• Points of digital arterial compression for hemostasis
• Technique of craniotomy

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.