The vertex constitutes the upper part of the skull, which can also be called the sinciput. The vertex is therefore the top of the head, the upper part of the cranial box, in humans but also in all vertebrates or even in arthropods. The vertex, also referred to as the skullcap, is made up of four bones in humans.

The vertex constitutes, in vertexes, including man, as well as in insects, the top of the skull. Sometimes called the cranial cap, the vertex is therefore, in anatomy, the upper part of the cranial box: it is the upper surface of the head. It is also called sinciput.

In anatomy, in humans, the cranial vertex consists of four bones of the skull:

• the frontal bone;
• the two parietal bones;
• l’os occipital. 

These bones are connected together by sutures. The coronal suture connects the frontal and parietal bones, the sagittal suture is located between the two parietal bones, and the lambdoid suture joins the parietal and occipital bones.

Like all bone tissue, the vertex contains four types of cells:

• osteoblasts;
• osteocytes;
• bordering cells;
• osteoclasts. 

In addition, its extracellular matrix is ​​calcified, giving this tissue its solid nature. In addition, this makes it opaque to x-rays, thus allowing the study of bones by x-ray.

The vertex participates in the protection of the brain, in its upper part. In fact, the vertex being a bone tissue, therefore a skeletal tissue, it has a mechanical function.

Indeed, bone tissue is one of the most resistant in the body, so it is able to withstand mechanical stresses. This is how the vertex plays its protective role towards the brain at the level of the top of the head.

Extra-dural hematoma

A pathology affecting the vertex is constituted by the extradural hematoma, which most often follows a major shock resulting in the rupture of an artery located on the surface of the meninges. This hematoma is in fact formed by a collection of blood located between the bone of the skull and the dura, or the outermost layer of the meninges, an envelope that protects the brain. It is therefore an effusion of blood between one of the bones of the skull that constitutes the vertex and the dura of the brain.

Extra-dural hematoma localized to the vertex is rare, it is only a small percentage of all extra-dural hematomas. Indeed, this type of hematoma only affects the vertex in 1 to 8% of all cases of extra-dural hematoma. It can be caused by a tear in the sagittal sinus, although extradural hematomas of the vertex appearing spontaneously have also been described in the literature.

Extra-dural hematoma (EDH) of the vertex has nonspecific clinical features, therefore the clinical localization of the lesions is complex. This pathology can be acute or chronic.

The origin of the bleeding can be linked, as already mentioned, to a tear in the sagittal sinus, but the cause of the bleeding can also be arterial. The most common symptoms are a severe headache, associated with vomiting.

In addition, cases of EDH of the vertex have been associated with hemiplegia, paraplegia, or hemiparesis. This extra-dural hematoma of the vertex remains rare.

Other pathologies

The other pathologies that can affect the vertex are bone pathologies, such as benign or malignant tumors, Paget’s disease or even fractures, in the event of trauma. Tumors or pseudotumors of the cranial vault, in particular, are lesions frequently encountered in current practice and the discovery of which is often fortuitous. They are mostly benign.

An extra-dural hematoma located at the level of the vertex may, depending on the size of the hematoma, the clinical status of the patient and other associated radiological findings, be treated surgically. Great care should be taken during surgery, as a tear in the sagittal sinus could lead to significant blood loss and even embolism.

The other pathologies of the vertex will be treated either by means of drugs to treat the pain, or by means of surgery, or, in the case of a tumor, by surgery, or even chemotherapy and radiotherapy in the case of a tumor. malignant of this bone.

The diagnosis of an extra-dural hematoma located at the level of the vertex can cause diagnostic confusion. A CT scan (computed tomography) of the head can aid in the diagnosis. However, care must be taken not to make a mistake with an artefact or a subdural hematoma.

In fact, MRI (magnetic resonance imaging) is a better diagnostic tool that can confirm this. Early diagnosis as well as rapid treatment of extradural hematoma may help reduce mortality as well as morbidity linked to this rare pathology.

For the diagnosis of other bone pathologies, the clinical picture is frequently associated with imaging tools in order to identify either a fracture or a crack, or a benign or malignant tumor, or Paget’s disease.

The first case of extra-dural vertex hematoma was reported in 1862, by Guthrie. As for the first case described in the scientific literature for which MRI was used in the diagnosis of an extra-dural hematoma of the vertex, it dates from 1995.

Finally, it turned out that the pathophysiology of a hematoma affecting the vertex is very different from that of extra-dural hematomas located on other sites of the skull: indeed, even a small amount of blood may require surgery. , when the hematoma is located in the vertex, while at the same time a small, asymptomatic hematoma located in other places of the skull may not require surgery.