What Are Brain Ventricles?

Ventricular system inside the brain. There are left and right ventricles in the cerebral hemisphere; there is a third ventricle in the inter-brain; there is a fourth ventricle between the cerebellum and the medulla and the pontine; the third ventricle and the fourth ventricle are connected by the midbrain aqueduct. The intraventricular choroid plexus produces cerebrospinal fluid that overflows the ventricle and is injected into the subarachnoid space to nourish neural tissue, which acts as a buffer medium to protect brain tissue from shock. If an obstruction occurs in a part of the ventricular system, obstructive hydrocephalus occurs.

Ventricular system inside the brain. There are left and right ventricles in the cerebral hemisphere; there is a third ventricle in the inter-brain; there is a fourth ventricle between the cerebellum and the medulla and the pontine; the third ventricle and the fourth ventricle are connected by the midbrain aqueduct. The intraventricular choroid plexus produces cerebrospinal fluid that overflows the ventricle and is injected into the subarachnoid space to nourish neural tissue, which acts as a buffer medium to protect the brain tissue from shock. If an obstruction occurs in a part of the ventricular system, obstructive hydrocephalus occurs.

Chinese name

Ventricle

Foreign name

ventricle

Definition

Cavity in the brain

Pinyin

nao shi

Ventricle lateral ventricle

The lateral ventricle is composed of frontal angle, body, temporal angle, and occipital angle. The frontal angle and the inner wall of the body are transparent septa. The corpus callosum is closely related to the frontal angle. The lower part of the corpus callosum and the knee form the top and side walls of the anterior angle of the ventricle of the brain, and the interventricular foramen is the posterior boundary of the anterior angle. The lateral wall is the middle region of the caudate nucleus. Two to four small veins converge along the base of the anterior horn and lateral wall of the lateral ventricle, forming a caudate nucleus anterior vein, and a sulcus vein is added near the interventricular foramen. The lateral ventricle body connects the fornix and the corpus callosum from behind the interventricular foramen to the posterior edge of the transparent septum. The inferior wall is the thalamus, the top is the corpus callosum, the lateral wall is the caudate nucleus body, and the middle medial wall is the transparent septum. The inferior wall of the lateral ventricle has choroid fissures, where the choroid plexus is located, between the vault and thalamus, and outside and below the transparent septum. Here the dome is band-shaped, where the dome is band-shaped, histologically a two-layer structure, consisting of the ependymal membrane and the choroid, the diameter of the thalamic dome is less than 10mm, and the choroid plexus extends from the interforaminal to the temporal angle The length is 48 to 58mm, which surrounds the upper and lower back of the thalamus. The bilateral choroid fissure and the choroid plexus are the top of the three ventricles. The length of the choroid plexus below the transparent septum is 20 to 30 mm, and the body (between the dome and thalamus occipital) is 11 to 15 mm. Some important blood vessels can be seen in the body of the lateral ventricle, including the septal vein, the caudate nucleus vein, Branches of thalamic striatum vein, choroid, and posterior artery. The posterior septal vein is a collection of transparent septal veins (usually 2 to 4) in the corpus callosum, and a mural vein is added to the interventricular foramen. The posterior septal vein is 10-12 mm in length. The posterior caudate nucleus runs along the lateral ventricle wall near the interventricular foramen and merges into the sulcus vein. The thalamus vein can be used as an important symbol of the endoscopic surgical field. It travels along the caudate nucleus of the thalamus, mostly between 24 and 26 mm. It enters the third ventricle through the interventricular foramen, reaches the anterior medulla, and flows into the anterior cerebral vein. . The branches of the posterolateral and posteromedial arteries from the choroid plexus are more clearly distinguishable, and both blood vessels come from the cistern and interpodal cistern. Enter the lateral ventricle through the frontal horn, and often see the translucent structure on the medial side, that is, the transparent septum. The transparent septum is a double-layer translucent structure located between the ventricles on both sides, ranging from the corpus callosum to the dome, and the anterior and posterior diameter is 39 41mm, height 12 14mm, height 12 14mm at interventricular hole level, 8,5 10mm at anterior angle level, 7-9mm at lateral ventricle body, divide transparent compartment into two parts with interventricular hole as boundary The part is located in the anterior angle, with an area of 390-400 mm2, and the posterior part is located in the lateral ventricle body area of 510-530 mm2. There are no arterial blood vessels on the transparent septum, there are varying numbers of septal veins, and there are pit veins at the posterior edge of the interforaminal foramen, ranging from 1 to 3, with an average length of 16 to 35 mm.

Third ventricle

The third ventricle is mostly located between the lateral optic mounds, showing a narrow gap. The upper ventricle communicates with the lateral ventricle via the interventricular foramen, and the lower posterior part connects with the midbrain aqueduct. The sagittal plane is approximately a quadrangle, with a height of 2, 5 to 3 cm, and a slightly longer anterior-posterior diameter. A little above the center of the third ventricle, there is a gray matter block connecting the left and right optic cumulus, called the middle joint or middle block. There are two crypts before and below the third ventricle. The upper crypt extends slightly above the optic cross and is called the visual crypt; the lower crypt extends into the pituitary pedicle and is shaped like a funnel called a funnel crypt. The lower part of the front wall is the end plate, and the upper part is the front joint and the fornix. The interventricular foramen is located between the fornix and the optic mound. The top is a middle sail composed of a layer of epithelium with choroid plexus protruding. Followed by pineal gland, posterior commissure and midbrain aqueduct. From the front to the back of the third ventricle, they are the optic cross, the funnel, the gray nodules, the papillary body, the posterior perineum, the cerebral feet and the middle cover. The side wall is the inner surface of the visual mound and the inferior mound.

Fourth ventricle

The fourth ventricle is a gap between the medulla oblongata, the pons and the cerebellum. It is connected to the middle cerebral aqueduct to the third ventricle and to the central tube of the spinal cord. The bottom is a diamond-shaped nest with the top of the chamber facing the cerebellum, which looks like a tent. The ventricle expands to both sides to form a fourth ventricular lateral recess, and the distal opening forms a lateral hole (Luscgha hole) leading to the subarachnoid space.

The fourth ventricle communicates with the subarachnoid space through the three holes on its top. The lateral foramen are located at the cerebellar angle of the pontine, the inner side is the rope body, and the outer side is the cerebellum. The hole near the lower corner of the diamond-shaped fossa is the median hole (Magendie hole), and the lower boundary is the latch. The cerebrospinal fluid in the ventricle of the brain can directly enter the subarachnoid space through these three holes.

The bottom of the fourth ventricle is diamond-shaped and can be divided into upper, middle and lower parts. The upper part is triangular, pointed upward, leading to the midbrain aqueduct; the middle part is wide, reaching outward to the lateral recess; the lower part is also triangular, pointed downward, and leads to the closed central tube. The transverse fiber bundles on the middle surface are called pith, which define the boundary between the pontine and the medulla.

The superficial depression above the medullary pattern is called the upper depression, and the inner circular bulge is called the facial mound. The deep part of the facial nerve bypasses the abductor nucleus. The medial bulge is connected below the face mound, and the outer edge of the medial bulge is the boundary groove, which is the boundary between the motor nucleus of the trigeminal nerve and the lateral sensory nucleus.

The triangular plate formed at the lower end of the diamond-shaped fossa (inferior corner of the fourth ventricle) is called a latch, and the dynamic changes of the cerebrospinal fluid of the latch are closely related to the formation of cervical cavity.

Ventricular choroid plexus

It protrudes into the chamber cavity in a wrinkle shape, and is composed of a vascular-rich soft membrane and an ependymal membrane. The ependymal membrane forms a layer of choroid plexus epithelium with secretory function and consists of a single layer of cubic or columnar cells. These epithelial cells have many microvilli on the free side, the cytoplasm is rich in mitochondria, and the nucleus is large and round. The choroid plexus is found in the parietal ventricles of the third and fourth ventricles and the lateral ventricles.