What Is the Frontalis?

The part of the cerebral hemisphere before the central sulcus and above the lateral sulcus of the brain can be divided into dorsal lateral, medial and bottom surfaces.

The part of the cerebral hemisphere before the central sulcus and above the lateral sulcus of the brain can be divided into dorsal lateral, medial and bottom surfaces.

Chinese name

Frontal lobe

Foreign name

frontal lobe

Include

Primary sports area, etc.

Location

Before the central ditch

Function

Subordinate activities to firm intentions and motivations

Frontal lobe 1. Overview:

On the dorsal outer side of the frontal lobe, there is a central anterior groove parallel to the central groove. This ditch is often divided into two sections, the upper section often bypasses the medial edge of the dorsal and reaches the central leaflet. Between the central ditch and the central anterior ditch is the central anterior gyrus. A groove leading to the frontal pole from the upper section of the central front groovethe upper front groove, and a groove from the lower section of the central front groove to the front pole is called the subfrontal groove. The forehead and inferior sulcus divides the frontal cortex before the central anterior sulcus into the forehead, middle and lower fold. The forehead gyrus is relatively wide, including the part above the cingulate groove on the inner side of the hemisphere, which extends forward to the forehead; the front part of the forehead gyrus sometimes has a forehead sulcus, which divides the forehead gyrus into two parts: the forehead gyrus is located in the forehead. Below the inferior sulcus, it forms the inferior wall of the lateral cleft of the brain. The posterior part of the frontal gyrus is divided into three parts by the anterior horizontal branch and the ascending branch of the lateral fissure: the part below the anterior horizontal branch is called the orbital part; the part between the anterior horizontal branch and the ascending branch is called the triangular part; The part after the ascending branch is the island cover, that is, the forehead (front cover) of the island cover.

On the underside of the frontal lobe, there is a straight groove parallel to the inner orbital rim, called the olfactory groove. There are olfactory bulbs and olfactory bundles in the groove. The medial part of the olfactory sulcus is called the straight gyrus; the lateral part of the olfactory sulcus is generally called the orbital gyrus.

The inner side of the frontal lobe, most of the anterior part belongs to the upper frontal gyrus, also known as the medial frontal gyrus. The rear of the medial frontal gyrus is bounded by the lateral central ditch and lateral central leaflets. The lateral central leaflet is the part between the marginal branch of the cingulate groove and the lateral central groove. The lateral central leaflets are divided into two parts, the front part and the back part, by the end of the central ditch.

Frontal lobe 2. Frontal lobe parenchymatous schwannomas:

(I) Introduction:

Schwannomas are common benign tumors of the peripheral nervous system. Intracranial schwannomas account for about 8% of intracranial lesions. They are most common in the trigeminal and vestibular nerves, and are rare in the brain parenchyma.

(2) Imaging inspection:

Lesions are usually located in the superficial part of the brain or in the brain parenchyma around the ventricle. CT and MRI show that the tumor is usually solid nodules or cysts. Edema of the brain parenchyma around the tumor is visible, and calcification is uncommon.

(3) Source of organization:

Nowadays there are several theories: Schwann cells are derived from mesenchymal cells with multidirectional differentiation potential in the brain parenchyma; Schwann cells are derived from the peripheral nerve plexus of blood vessels and aorta that originally exist in the subarachnoid space . derived from displaced neural crest cells; derived from pia mater cells. Some people think that there is a tissue similarity between ectoderm Schwann cells and mesoderm chondrocytes, and the transformation of chondrocytes to Schwann cells is the reason for the occurrence of intrathecal schwannomas. These theories and theories need to be further confirmed by accumulated cases.

(4) Differential diagnosis:

Membrane tumor

The clinical manifestations and imaging findings in the superficial part of the brain can be similar to the cerebral parenchymatous schwannomas. However, most meningiomas are closely related to the meninges, and a few have no adhesion to the meninges clinically and radiologically, and their histology has a typical meningiomas histology, such as a spiral arrangement. Immunohistochemical meningiomas are positive for EMA, negative for S100, SOX10, etc .;

2. Glioma:

In particular, hair cell astrocytoma is often distributed alternately in dense and loose regions of cells, thickening of some vessel walls, vitreous degeneration, etc. Immunohistochemistry can also be positive for S100, vimentin, etc. Human cytoma tumors are positive for GFAP and negative for SOX10 for differential diagnosis. And about 57% hair cell astrocytoma BRAFKIAA1549 gene fusion.

3. Tuberculosis:

When tuberculosis is tuberculous, the imaging is similar to that of parenchymal schwannomas, but tuberculosis has typical granulomas and caseous necrosis, and is negative for immunohistochemical S100 and SOX10.

4. Metastatic tumor:

Intracranial metastasis of malignant tumors is often difficult to distinguish from cerebral parenchymatous schwannomas. However, intracranial metastases often have a history of clinical malignancies, and histology is helpful in differential diagnosis.

5. Meningeal hemangioma disease:

Patients often have epilepsy. Imaging shows that the lesions are often located in the superficial part of the brain, and there may be peritumoral edema. Histologically, the tumor is formed by meningeal epithelial cells, fibroblasts, and perivascular fibroblasts. Invasive growth, immunohistochemical tumor cells vimentin, EMA positive, help differential diagnosis.

6. Other tumors of meningeal origin:

Such as solitary fibrous tumors, etc., its immunohistochemical STAT6 positive, SOX10 negative, which is helpful for differential diagnosis.