PARIETAL AREA

From Big Medical Encyclopedia

PARIETAL AREA [regio parietalis (PNA, JNA, BNA)] — area of a calvaria within parietal bones.

On a skeleton side borders Thus are upper temporal lines (lineae temporales sup.) parietal bones; the front border passes across the line of a coronal seam (sutura coronalis) connecting frontal and parietal bones, back — in the area of a lambdoid seam (sutura lambdoidea) connecting parietal bones with occipital (see fig. 1 to St. Head ).

In Thus distinguish the following layers: skin, hypodermic cellulose, tendinous helmet, or nadcherepny aponeurosis (galea aponeurotica) of a nadcherepny muscle, subgaleal cellulose, periosteum, subperiostal cellulose, parietal bones, meninx.

Skin Thus is strongly tied by fibrous crossing points with a tendinous helmet owing to what it is a little mobile. Hypodermic cellulose is rich with sweat glands, in it there pass vessels and nerves of parietal area. A tendinous helmet is the monolithic tendinous stretching connecting frontal and occipital paunches an occipital forehead - ache muscles, under the Crimea the layer of friable cellulose separating a helmet from a periosteum lies. The possibility of scalping of integuments of the head together with a tendinous helmet at nek-ry types of an injury of a skull is defined by it. The periosteum is connected to bones of a skull by means of subperiostal cellulose; however along the line of seams of a skull the periosteum is strongly spliced with them. Parietal bones differ in ease and durability. At newborns on a joint between parietal, frontal and occipital bones sites of connecting fabric (so-called fontanels) remain, to-rye usually ossify within 1,5 years. Not fusion of fontanels in later terms is an essential sign of disturbance of the general development of the child. From an inner surface of a bone of a skull periosteums are deprived and directly adjoin to a firm cover of a brain (dura mater encephali). On an inner surface of bones there are deepenings from adjacent arteries, pakhionovy granulations and convolutions of the brain.

According to the centerline of a calvaria, dividing parencephalons, the so-called falx cerebri (falx cerebri) which is a shoot of a firm cover of a brain is located (see. Meninx ). Throughout a sickle, in its upper part the upper sagittal sine is located (sinus sagitta-lis sup.), belonging to venous system of a brain (see). Diameter of a sagittal sine together with lacunas on both sides of a sagittal seam (sutura sagittalis) borrows within Thus about 25 — 30 mm that is considered at trepanation in this area and assessment of wounds in a zone of a sagittal seam.

Vessels and nerves get in Thus from a forehead, a nape and from temporal areas from where they go radially to Thus. Here vessels are connected among themselves by the numerous anastomosis forming the collateral networks which are coming over to the opposite side. The arterial network Thus is presented by branches of a supraorbital artery (a. supraorbitalis) coming from system of an internal carotid artery (a. carotis int.), anastomoses edges with branches of superficial temporal (a. temporalis superficialis), back ear (a. auricularis post.) and occipital (a. occipitalis) the arteries coming from system of an outside carotid artery (a. carotis ext.). In venous system of a calvaria distinguish three types of vessels: extracranial veins of soft tissues, diploetichesky veins (vv. diploicae), put in a spongy layer of bones, and sine of a firm meninx. Veins of covers of a skull and a vein of a spongy layer of a bone are reported with sine of a firm meninx by means of emissarny veins (vv. emissaride). From them the most constant is the parietal emissarny vein (v. emissaria parietalis), edges opens in an upper sagittal sine.

Limf, vessels Thus fall into pre-ear (noduli lymphatici preauri-culares) and nizhneushny (noduli lymphatici infraauriculares) limf, nodes.

Sensory nerves pass in Thus from frontal, temporal and occipital areas, accompanying arteries and veins.

Feature of the getting damages Thus (in addition to danger of injury of a brain) is danger of disturbance of an integrity of an upper sagittal sine, a cut is followed by plentiful bleeding (see) and demands an urgent operative measure (see Cherepnomozgovaya an injury). The pressed (closed) fractures of parietal bones also demand an operative measure as in the presence, and at absence nevrol. symptoms of a prelum of a brain (see).

In Thus dermoid cysts can meet (see. Dermoid ), lipomas (see the Lipoma), atheromas (see. An epidermoid cyst), an anthrax (see the Anthrax), furuncles (see. Furuncle ), etc. As a rule, these processes have the limited development here that is explained by density of the fabrics covering a skull in this area.

Through Thus there pass quick accesses at nek-ry neurosurgical operations. Most often these accesses use for an exposure of an upper surface of a parietal lobe of a brain, penetration into a longitudinal crack of a great brain and for performance of operations at damage of an upper sagittal sine. Skin and aponeurotic and bone rags for access to a parietal lobe create the arc-shaped section, the top to-rogo passes in 20 — 30 mm from a sagittal seam, and the basis reaches a temporal muscle (see. Craniotrypesis ). Access in Thus make a puncture of a corpus collosum at an edema of a brain (see. Hydrocephaly ) for the purpose of creation of outflow of cerebrospinal liquid from cerebral cavities in a subarachnoid space (Anton's operation — Bramanna).

See also Head , Skull .



Bibliography: Zolotko Yu. L. Atlas of topographical anthropotomy, p.1, page 6, M., 1964; And r of e r I. M. Neyrokhirurgiya, M., 1982; L at about c to and y D. N. Fundamentals of topographical anatomy, page 230, M., 1953; Ostroverkhov G. E., L at-botsky D. N. and Yu. M Bomash. Operational surgery and topographical anatomy, M., 1972; Surgery of the central nervous system, under the editorship of V. M. Ugryu-mov, t. 1, L., 1969.


G.E. Ostroverkhov.

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