Frontal corner. Human structure

The parietal bone forms the following sutures with neighboring bones: sagittal suture - with the paired parietal bone; coronal suture - with the frontal bone; lambdoid suture - with the occipital bone; scaly suture - with the temporal bone, where the parietal bone is covered by the temporal.

The weight of the prepared parietal bone is 42.5 grams.

The outer surface of the parietal bone is convex, with a parietal tubercle in the center. Along the lower edge of the parietal bone are the superior temporal line (linea temporalis superior), where the temporal fascia attaches, and the inferior temporal line ( linea temporalis inferior)- site of attachment of the temporalis muscle. At the sagittal edge, closer to the occipital angle, there is a parietal foramen (foramen parietale), in which the emissary vein passes.

Rice. Anatomy of the parietal bone (according to H. Feneis, 1994): 1 - left parietal bone, side view; 2 - right parietal bone, inside view; 3 - occipital margin; 4 - scaly edge; 5 - sagittal edge; 6 - frontal edge; 7 - parietal opening; 8 - upper temporal line; 9 - lower temporal line; 10 - furrow of the superior sagittal sinus; 11 - groove of the sigmoid sinus; 12 - furrows of the middle meningeal artery.

The inner surface is concave, with a hole in the center corresponding to the parietal tubercle on the outer surface. There are also grooves on the surface of the anterior and posterior branches of the middle meningeal artery ( sulcus arteriae meningeae mediae), sulcus of the superior sagittal sinus (sulcus sinus sagittalis superioris) on the sagittal margin, sulcus of the sigmoid sinus (sulcus sinus sigmoidei) near the mastoid angle. On the frontal edge there is a groove of the sphenoparietal sinus (sulcus sinus sphenoparietalis).

Functional relationships of the parietal bone

The parietal bone has 5 articular joints.

With a steam room parietal bone sagittal edge through a serrated sagittal suture.

WITH occipital bone occipital margin on the segment between lambda And asterion. The occipital bone covers the parietal bone from lambda to the “core occipital-parietal point”, after which, on the segment to asterion the parietal bone covers the occipital.

From asterion before pterion the parietal bone is covered with scales of the temporal bone, thus forming an articulation with temporal bone.

WITH frontal bone the parietal bone is connected by the frontal edge, forming a coronal suture from bregma before pterion. There is also a pivotal fronto-parietal point, where the parietal and frontal bones change the direction of the suture cut. So, between bregma and the pivotal fronto-parietal point, the frontal bone covers the parietal. On the segment between the pivotal fronto-parietal point and pterion the parietal bone covers the frontal.

Connection of the parietal bone with sphenoid bone represented at the level pterion. Here the large wing of the sphenoid bone covers the parietal bone.

Muscles and aponeuroses

temporalis muscle (m.temporalis) has an attachment on the lower temporal line of the parietal bone. temporal fascia (fascia temporalis) originates on the upper temporal line of the parietal bone and consists of two plates. surface plate (lamina superficialis) attached to the outer edge of the zygomatic arch. deep plate (lamina profunda) attached to the inner edge of the zygomatic arch.

Attachment of the layers of the dura mater

The falciform ligament of the brain attaches to the groove in which the superior sagittal sinus passes, along the entire sagittal suture.

Brain

The parietal bones cover the parietal lobes and the upper parts of the frontal lobes. In a child, the parietal bones cover most of the cerebral hemispheres. In an adult, the parietal bones cover the cerebral hemispheres to a lesser extent than in a child, and, nevertheless, the most important motor (motor) and sensory (sensitive) areas of the cortex are included in the coverage area. Since the parietal bones cover most of the brain in children, correction of the parietal bones is more relevant in children than in adults. Blockade of the sagittal suture leads to a decrease in the drainage function of the superior longitudinal sinus and disrupts the normal functioning of the central nervous system. Dysfunction of the sagittal suture often accompanies bronchial asthma, nocturnal enuresis, hyperexcitability, and sleep disturbances.

The motor area is divided into primary (motor) and secondary (premotor) cortex. The motor cortex, about 2.5 cm in size, initiates the muscular response with gross body movements, while the premotor cortex converts the impulses into more dexterous movements.

The sensory or somatosensory cortex occupies most of the parietal lobe, starting immediately posterior to the precentral gyrus. It is represented by 5 and 7 Brodmann fields. The somatosensory area interprets all incoming sensory stimuli such as temperature, touch, pressure, and pain. The primary and secondary somatosensory cortex are located posterior to the motor cortex and reach almost to lambda. The primary zone produces distinctions between specific types of sensitivity, while the secondary zone interprets them more subtly and identifies different objects through touch. With the defeat of 5 and 7 fields, tactile agnosia occurs. The patient can feel the object placed in the hand, but with his eyes closed he cannot identify it. This inability is caused by the loss of previously accumulated tactile experience (P. Duus, 1997).

Vessels

On the inner surface of the parietal bone are the anterior and posterior branches of the middle meningeal artery, which exits through the spinous foramen of the sphenoid bone.

The parietal bone is in close contact with the superior longitudinal sinus along the sagittal suture, and with the sphenoparietal sinus along the frontal margin. The middle meningeal veins are located on the inner surface of the parietal bone.

Scull protects the brain and sense organs from external influences and gives support to the face, the initial sections of the digestive and respiratory systems. The structure of the skull is conditionally divided into brain and facial sections. The medulla of the skull is the seat of the brain. The other (facial) section is the bone base of the face and the initial sections of the digestive and respiratory tract.

The structure of the skull

parietal bone;
coronal suture;
frontal tubercle;
temporal surface of the greater wing of the sphenoid bone;
lacrimal bone;
nasal bone;
temporal fossa;
anterior nasal spine;
body of the maxillary bone;
lower jaw;
cheekbone;
zygomatic arch;
styloid process;
condylar process of the lower jaw;
mastoid;
external auditory canal;
lambdoid seam;
scales of the occipital bone;
superior temporal line;
squamous part of the temporal bone.

coronal suture;
parietal bone;
orbital surface of the greater wing of the sphenoid bone;
cheekbone;
inferior turbinate;
maxillary bone;
chin protrusion of the lower jaw;
nasal cavity;
coulter;
perpendicular plate of the ethmoid bone;
orbital surface of the maxillary bone;
lower orbital fissure;
lacrimal bone;
orbital plate of the ethmoid bone;
superior orbital fissure;
zygomatic process of the frontal bone;
visual channel;
nasal bone;
frontal tubercle.

The structure of the skull of the human brain develops around the growing brain from mesenchyme, which gives rise to connective tissue (membranous stage); cartilage then develops at the base of the skull. At the beginning of the 3rd month of intrauterine life, the base of the skull and capsules (receptacles) of the organs of smell, vision and hearing are cartilaginous. The lateral walls and the cranial vault, bypassing the cartilaginous stage of development, begin to ossify already at the end of the 2nd month of intrauterine life. Separate parts of the bones are subsequently combined into a single bone; so, for example, is formed from four parts. From the mesenchyme surrounding the head end of the primary gut, between the gill pockets, cartilaginous gill arches develop. They are associated with the formation of the facial part of the skull.

The structure of the skull: departments

The human skull consists of 23 bones: 8 paired and 7 unpaired. The cranial bones have a certain craniosacral rhythm. You can familiarize yourself with its amplitude duty in this. The bones of the roof of the skull are flat, consisting of thicker outer and thinner inner plates of dense substance. Between them is a spongy substance (diploe), in the cells of which there are bone marrow and blood vessels. The structure of the skull is such that there are pits on the inner surface of the bones of the roof, these are finger impressions. The pits correspond to the cerebral convolutions, and the elevations between them correspond to the furrows. In addition, on the inner surface of the cranial bones, imprints of blood vessels are visible - arterial and venous grooves.

The cerebral part of the skull in an adult is formed by the following bones: unpaired - frontal, occipital, sphenoid, ethmoid and paired - parietal and temporal. The facial section of the skull is formed mostly by paired bones: maxillary, palatine, zygomatic, nasal, lacrimal, lower nasal conchas, as well as unpaired: vomer and lower jaw. The hyoid bone also belongs to the visceral (facial) skull.

Cerebral region of the skull

is part of the posterior wall and base of the brain region of the skull. It consists of four parts located around the large (occipital) foramen: the basilar part in front, two lateral parts and scales behind.

The scales of the occipital bone form a bend in the place where the base of the skull at the back passes into its roof. Here is the external occipital protrusion, to which the nuchal ligament is attached. To the right and to the left of the elevation, a rough upper nuchal line runs along the surface of the bone, along which the trapezius muscles are attached to the right and left, which are involved in maintaining the skull in balance. From the middle of the external occipital protrusion down to the large (occipital) foramen there is a low external occipital crest, on the sides of which a rough lower nuchal line is visible. On the inner surface of the scales of the occipital bone, four large pits are visible, which are separated from one another by ridges that form a cruciform elevation. At the point of their intersection is the internal occipital protrusion. This protrusion passes into the internal occipital crest, which continues down to the large (occipital) foramen. Upward from the internal occipital protrusion, the groove of the superior sagittal sinus is directed. From the ledge to the right and to the left, the groove of the transverse sinus departs.

Occipital bone, posterior view

external occipital protrusion;
top line;
bottom line;
condylar fossa;
jugular process;
occipital condyle;
intrajugular process;
basilar part;
pharyngeal tubercle;
jugular notch;
condylar canal;
external occipital crest;
occipital scale.

Occipital bone, front view

lambdoid edge;
occipital scales;
internal occipital crest;
mastoid edge;
large occipital foramen;
groove of the sigmoid sinus;
condylar canal;
jugular notch;
slope;
basilar part;
lateral part;
jugular tubercle;
jugular process;
inferior occipital fossa;
groove of the transverse sinus;
cruciform elevation;
superior occipital fossa.

has a body from which large wings extend to the sides (laterally), small wings upward and laterally, pterygoid processes hang down. On the upper side of the body there is a depression called the Turkish saddle, in the center of it is the pituitary fossa, in which the pituitary gland, one of the endocrine glands, is placed. The pituitary fossa is bounded behind by the back of the saddle, and in front by the tubercle of the saddle. Inside the body of the sphenoid bone there is an air cavity - the sphenoid sinus, which communicates with the nasal cavity through the aperture of the sphenoid sinus, located on the front surface of the body and facing the nasal cavity.

From the anterior-upper surface of the body of the bone, two small wings extend to the sides. At the base of each of the small wings there is a large opening of the optic canal, through which the optic nerve passes into the orbit. Large wings extend laterally from the lower-lateral surfaces of the body, lying almost in the frontal plane and having four surfaces. The posterior, concave cerebral surface faces the cranial cavity. The flat orbital surface of a quadrangular shape faces the orbit. The convex temporal surface of the greater wing forms the medial wall of the temporal fossa. The infratemporal crest separates the temporal surface from the triangular maxillary surface located between the orbital surface and the base of the pterygoid process. Between the small and large wings is a wide upper orbital fissure leading from the cranial cavity to the orbit. There are openings at the base of the large wing: the anterior (medial) is a round opening (the maxillary nerve passes through it into the pterygo-palatine fossa); laterally and posteriorly - a larger oval foramen (the mandibular nerve passes through it into the infratemporal fossa); even more lateral - the spinous foramen (through it the middle meningeal artery enters the cranial cavity). From the base of the large wing, the pterygoid process extends downward on each side, at the base of which the pterygoid canal runs from front to back. Each pterygoid process is divided into two plates - medial, ending with a hook, and lateral. Between them on the back side is the pterygoid fossa.

Sphenoid bone, front view

aperture of the sphenoid sinus;
saddle back;
wedge-shaped shell;
small wing;
superior orbital fissure;
zygomatic edge;
infratemporal crest;
sphenoid bone;
pterygopalatine groove of the pterygoid process;
pterygoid hook;
vaginal process;
wedge-shaped beak (wedge-shaped crest);
pterygoid notch;
pterygoid canal;
round hole;
infratemporal crest;
orbital surface of the greater wing;
temporal surface of the greater wing.

Sphenoid bone, posterior view

visual channel;
saddle back;
posterior inclined process;
anterior inclined process;
small wing;
superior orbital fissure;
parietal edge;
big wing;
round hole;
pterygoid canal;
navicular fossa;
pterygoid fossa;
pterygoid notch;
groove of pterygoid hook;
vaginal process;
wedge-shaped beak;
body of the sphenoid bone;
medial plate of the pterygoid process;
pterygoid hook;
lateral plate of the pterygoid process;
sleep groove.

consists of three parts: squamous, tympanic and pyramid (stony), located around the external auditory meatus, which is limited mainly by the tympanic part of the temporal bone. The temporal bone is part of the lateral wall and base of the skull. In front, it adjoins the sphenoid, behind - to the occipital bone. The temporal bone serves as a receptacle for the organ of hearing and balance, which lies in the cavities of its pyramid.

The stony part has the shape of a trihedral pyramid, the top of which is directed to the Turkish saddle of the body of the sphenoid bone, and the base is turned back and laterally, passing into the mastoid process. The pyramid has three surfaces: the anterior and posterior, facing the cranial cavity, and the lower, participating in the formation of the outer base of the skull. On the front surface at the top of the pyramid there is a trigeminal depression, in which the trigeminal nerve node lies, behind it there is an arcuate elevation formed by the upper semicircular canal of the bony labyrinth of the organ of hearing and balance located in the pyramid. Laterally from the elevation, a flat surface is visible - the roof of the tympanic cavity and two small openings located here - clefts of the canals of the large and small stony nerves. Along the upper edge of the pyramid, separating the anterior and posterior surfaces, there is a groove of the superior petrosal sinus.

Temporal bone, external view, side

scaly part;
temporal surface;
wedge-shaped edge;
zygomatic process;
articular tubercle;
stony-scaly gap;
stony-tympanic fissure;
drum part;
styloid process;
external auditory opening;
mastoid;
mastoid notch;
tympanomastoid fissure;
mastoid opening;
supra-anal spine;
parietal notch;
groove of the middle temporal artery;
parietal edge.

On the back surface of the pyramid there is an internal auditory opening, passing into the internal auditory meatus, which ends with a plate with holes. The largest opening leads to the facial canal. Small openings serve to pass the vestibulocochlear nerve. On the back surface of the pyramid is the outer opening of the vestibule aqueduct, and the cochlear canaliculus opens on the lower edge. Both canals lead to the bony labyrinth of the vestibulocochlear organ. At the base of the posterior surface of the pyramid is the groove of the sigmoid sinus.

On the lower surface of the pyramid, at the jugular foramen, limited by the notches of the temporal and occipital bones, there is a jugular fossa. Lateral to it, a long styloid process is visible.

Temporal bone, internal view (from the medial side)

parietal edge;
arched elevation;
tympanic-squamous fissure;
parietal notch;
furrow of the superior stony sinus;
mastoid opening;
occipital edge;
groove of the sigmoid sinus;
back surface of the pyramid;
jugular notch;
external opening of the water supply vestibule;
subarc fossa;
external opening of the cochlear tubule;
furrow of the inferior stony sinus;
trigeminal depression;
top of the pyramid
zygomatic process;
wedge-shaped edge;
cerebral surface.

It is a quadrangular plate, its outer surface is convex, in the center the parietal tubercle is visible. The inner surface of the bone is concave, it has arterial grooves. The four edges of the parietal bone are connected to other bones, forming the corresponding sutures. With the frontal and occipital, the frontal and occipital sutures are formed, with the opposite parietal bone - the sagittal suture, with the scales of the temporal bone - scaly. The first three edges of the bone are serrated, participate in the formation of serrated sutures, the last is pointed - forms a scaly suture. The bone has four angles: occipital, sphenoid, mastoid and frontal.

Parietal bone, outer surface

parietal tubercle;
sagittal edge;
frontal angle;
superior temporal line;
frontal edge;
lower temporal line;
wedge-shaped angle;
scaly edge;
mastoid angle;
occipital edge;
occipital angle;
parietal opening.

consists of a vertical frontal scale and horizontal orbital parts, which, passing into each other, form the supraorbital margins; the nasal part is located between the orbital parts.

The frontal scales are convex, frontal tubercles are visible on it. Above the supraorbital edges are the superciliary arches, which, converging in the medial direction, form a platform above the root of the nose - the glabella. Laterally, the orbital margin continues into the zygomatic process, which joins with the zygomatic bone. The inner surface of the frontal bone is concave and passes into the orbital parts. It shows the sagittally oriented sulcus of the superior sagittal sinus.

The orbital part - right and left - is horizontally located bone plates, facing the orbital cavity with the lower surface, and with the upper surface into the cranial cavity. The plates are separated from each other by a lattice notch. On the nasal part there is a nasal spine, which participates in the formation of the nasal septum, on the sides of it there are openings (apertures) leading to the frontal sinus - an air cavity located in the thickness of the frontal bone at the level of the glabella and superciliary arches.

The facial structure of the skull is the bone base of the face and the initial sections of the digestive and respiratory tracts, chewing muscles are attached to the bones of the facial part of the skull.

Frontal bone, front view

frontal scales;
frontal tubercle;
parietal edge;
frontal seam;
glabella;
zygomatic process;
supraorbital margin;
nose;
nasal bone;
frontal notch;
supraorbital foramen;
temporal surface;
superciliary arch;
temporal line.

parietal edge;
sulcus of the superior sagittal sinus;
cerebral surface;
frontal crest;
zygomatic process;
finger impressions;
blind hole;
nasal bone;
lattice notch;
eye part.

formed by the lower surface of the brain region of the skull and part of the facial region. The structure of the anterior skull is formed by the bony palate and the alveolar arch formed by the maxillary bones. In the median suture of the hard palate and in its posterolateral sections, small holes are visible through which thin arteries and nerves pass. The middle section is formed by the temporal and sphenoid bones, its anterior border is the choanae, the posterior one is the anterior edge of the large (occipital) foramen. In front of the large (occipital) opening is the pharyngeal tubercle.

The structure of the skull. External base of the skull

palatine process of the maxillary bone;
cutting hole;
median palatine suture;
transverse palatine suture;
choana;
lower orbital fissure;
zygomatic arch;
coulter wing;
pterygoid fossa;
lateral plate of the pterygoid process;
pterygoid process;
oval hole;
mandibular fossa;
styloid process;
external auditory canal;
mastoid;
mastoid notch;
occipital condyle;
condylar fossa;
bottom line;
external occipital protrusion;
pharyngeal tubercle;
condylar canal;
jugular foramen;
occipital-mastoid suture;
external carotid opening;
stylomastoid foramen;
torn hole;
stony-tympanic fissure;
spinous foramen;
articular tubercle;
wedge-scaly suture;
pterygoid hook;
large palatine opening;
zygomatic-maxillary suture.

Relief internal base of the skull due to the structure of the lower surface of the brain. The structure of the skull of this department is as follows: on the inner base of the skull, three cranial fossae are distinguished: anterior, middle and posterior. The anterior cranial fossa, in which the frontal lobes of the cerebral hemispheres are located, is formed by the orbital parts of the frontal bone, the ethmoid plate of the ethmoid bone, part of the body and small wings of the sphenoid bone. The posterior edge of the small wings separates the anterior cranial fossa from the middle cranial fossa, in which the temporal lobes of the cerebral hemispheres are located. The pituitary gland is located in the pituitary fossa of the sella turcica. Here the structure of the skull has its own characteristics. The middle cranial fossa is formed by the body and large wings of the sphenoid bone, the anterior surface of the pyramids and the squamous part of the temporal bones. Anterior to the pituitary fossa is the precross groove, and the back of the saddle rises behind. On the lateral surface of the body of the sphenoid bone, a carotid groove is visible, which leads to the internal opening of the carotid canal, at the top of the pyramid there is a torn opening. Between the small, large wings and the body of the sphenoid bone, on each side, there is an upper orbital fissure tapering in the lateral direction, through which the oculomotor, trochlear and trigeminal cranial nerves and the ophthalmic nerve (a branch of the trigeminal nerve) pass. Behind and downward from the gap are the round, oval and spinous openings described above. On the anterior surface of the pyramid of the temporal bone, near its apex, a trigeminal depression is visible.

The structure of the skull. Inner base of the skull

orbital part of the frontal bone;
cockscomb;
lattice plate;
visual channel;
pituitary fossa;
saddle back;
round hole;
oval hole;
torn hole;
bony opening;
internal auditory opening;
jugular foramen;
sublingual canal;
lambdoid seam;
slope;
groove of the transverse sinus;
internal occipital protrusion;
large (occipital) foramen;
occipital scales;
groove of the sigmoid sinus;
pyramid (stony part) of the temporal bone;
squamous part of the temporal bone;
greater wing of the sphenoid bone;
lesser wing of the sphenoid bone.

According to telegra.ph

Osparietale - a steam room, quadrangular in shape, has the form of a bowl, forms the upper and side parts of the cranial vault. Develops on the ground. It distinguishes two surfaces - external, fades externa, and internal, fades interna, and four edges: upper (sagittal, margo sagittalis), lower (scaly, margo squamosus), anterior (frontal, margo frontalis) and rear (occipital, margo occipitalis).
According to the four edges, the parietal bone has four corners: frontal, angulus frontalis; occipital, angulus occipitalis; wedge-shaped, angulus sphenoidalis; mastoid, angulus mastoideus.
The outer surface of the parietal bone is smooth and convex. The place of greatest convexity is called the parietal tubercles, tuber perietale. Below the hill are horizontal upper and lower temporal lines, linea temporales superior et inferior. The upper temporal line is the site of attachment of the temporal fascia, and the lower line is the site of attachment of the temporalis muscle.
The inner surface is concave. It shows the imprints of the relief of the brain - finger-shaped squeezes, impressiones digitatae, as well as arterial grooves, sulci arterioles, middle meningeal artery, sul. a. meningea mediae.
An incomplete furrow of the superior sagittal sinus, sul, runs along the upper edge of the cerebral surface. sinus sagittalis superior. In the back of the same upper edge of the bone there is a small parietal opening, foramen parietale, which is a venous graduate, emissario, in which the parietal emissary vein passes, connecting the superficial temporal vein with the superior sagittal sinus. In the depth of the sagittal groove and next to it, a large number of dimples of granulations of the arachnoid membrane, foveolae granulares, are observed. On the cerebral surface, at the mastoid angle, lies a small deep groove of the sigmoid sinus, sul. sinus sigmoidei, one end of which passes into the temporal bone groove of the same name, and the second into the groove of the occipital sinus of the occipital bone.
The upper (sagittal) edge is longer than all the others, participates in the formation of the sagittal suture, sutura sagittalis.
The lower (scaly) edge is arcuate, participates in the formation of scaly, parieto-mastoid and wedge-parietal sutures.
The anterior (frontal) edge connects with the parietal edge of the scales of the frontal bone, forming the coronal suture, sutura coronalis.
The posterior (occipital) edge is connected to the lambda-shaped edge of the occipital bone, forming a lambda-shaped suture, sutura lambdoidea.
ossification. Ossification points occur at 2 months of intrauterine development in the region of the parietal tubercle. The ossification of the parietal bone is completed at the 2nd year of life.

The human brain is a complex evolutionary achievement that needs the special protection provided by the bones of the cranial vault. One of them, the parietal bone, is a convex quadrangular segment. Her injury can lead to serious consequences, reversible in some cases, if the victim is provided with professional assistance in time.

The structure of the parietal bone

Like some other fragments of the skull, the parietal bone is paired and has a flat shape. The left and right segments are located symmetrically, interconnected, and fit quite tightly to the brain tissues, which explains their convex-concave shape.

Important! There are no tubular and spongy bones in the skull, only flat and mixed.

The protruding outer surface of the bone is relatively smooth, its relief is due to the need for attachment of soft tissues. The top of the convexity of the segment is called the parietal tubercle, it is from it that the process of ossification of the pliable membrane tissue of the human embryo begins. Under these formations are the temporal lines. The upper serves to attach the temporal fascia, the lower - the temporal muscle. The inner, curved surface has furrows that copy the relief of the venous sinuses and the membranes of the brain. Connections of bone with neighboring fragments are called sutures.

The sagittal suture is the articulation of the serrated edges of the same name of the two parietal bones with each other. Closer to the back of the sagittal suture on the parietal bone there is an opening for a vein;
Having the same jagged structure, the frontal and occipital edges are connected to the frontal and occipital bones, forming the coronal and lambdoid sutures;
The lower edge is scaly in shape, beveled and covered by the edges of the sphenoid bone, forming a scaly suture. Two joints - the wedge-parietal and parieto-mastoid sutures, are formed by the imposition of the parietal edge of the temporal bone and its mastoid process.

In anatomy, the vertices of an impromptu quadrilateral, the shape of which the parietal bone has, are called angles. The joints of the corners of three or more flat bones form fontanelles - membranous (in the first months of life) parts of the skull, which subsequently ossify (ossify).

The frontal angles (upper anterior) of the bones of the crown are straight, at the intersection of the sagittal and coronal sutures form the anterior fontanel;
Rounded obtuse occipital angles (posterior upper) in the zone of convergence of the lambdoid sutures with the sagittal one form the posterior fontanelle;

The connection of the mastoid, obtuse angles (posterior inferior) with the occipital and temporal bones is called the mastoid fontanel;
The wedge-shaped (anterior lower) acute angle, connecting with the temporal bone, sphenoid and frontal, creates an H-shaped connection - a wedge-shaped fontanelle, vulnerable to force even after reaching adulthood.

Functions

The parietal bone, like the rest of the bones of the cranial vault, protects the brain from any damage and harmful effects of the environment.

The formation of the parietal bone

The membranous tissue covering the rudiments of the brain of the embryo is gradually replaced by bone. Unlike, for example, the ethmoid bone, which is formed from cartilage, the parietal fragment of the skull bypasses the cartilaginous stage. At about the 7th week of embryo development, in the place where the parietal tubercle is “planned” (the largest bulge of this zone), the rudiments of the future bone arise from the connective tissue.

Merging with each other, they grow, and ossification occurs radially - from the center towards the edges. Ossification of the segment is completed in the first months of a person’s life: the areas (corners) most distant from the middle harden, which, connecting with other bones of the skull, form fontanelles in the newborn. The elastic tissues of the fontanelles leave vulnerable spots on the head, but they have the most important function: they provide the necessary deformation of the child's skull during birth and during the advanced development of the brain.

It happens that the parietal bone is divided into two or more fragments.

Parietal bone pathologies

The causes of deviations can be hereditary, associated with intrauterine development or complications during childbirth.

hyperosto

Thickening of the parietal bone due to layers of bone tissue. The pathology is harmless and does not affect the appearance of the patient, moreover, it is often detected incidentally on the results of x-rays or computed tomography (CT).

Craniosynostosis

This is premature fusion of the cranial bones. The occurrence of pathology can be explained by heredity or deviations in fetal development. The degree of deformation of the skull depends on the period of fusion of the cranial sutures. The most pronounced distortions of the form occur if overgrowing took place even in the womb. Depending on the localization of the pathology, the following forms of craniosynostosis are distinguished.

Scaphocephaly. The head is laterally compressed, while elongated in the direction from the forehead to the back of the head. Occurs in the case of fusion of the sagittal suture;
Turriccephaly is a swelling of the temporal bones, along with narrowing of the rest of the skull. Caused by closure of the sagittal and coronal sutures;
Brachycephaly - premature fusion of the lambdoid suture with the coronal suture. Leads to an increase in the width of the skull;
Trigonocephaly. Manifested due to early closure of the metopic suture connecting the halves of the frontal lobes. The skull takes on a teardrop shape, with a bulge in the forehead.

Limiting the volume of the cranium can lead to hypertension (increased intracranial pressure), which is detected in a newborn by the combination of the following signs:

vomit;
piercing cry;
convulsions;
muscle hypertonicity;
sluggish sucking;
bulging fontanelles, lack of a pulse in them;
eye rolling;
varicose veins in the scalp.

Craniosynostosis can lead to severe pathologies and developmental disabilities, from difficulty breathing to visual disability or joint disease. Pathology is diagnosed by visual examination, treated with surgical methods.

cephalohematoma

Cephalhematoma refers to birth injuries, but in itself is not a pathology of the bone, it is an accumulation of blood that is located between the periosteum (a thin layer of connective tissue that covers the outside of the skull) and the skull itself. In advanced cases, ossification may occur.

Most often, hemorrhage occurs in a newborn if he was injured due to squeezing the head during a difficult birth. Passing through the birth canal of a woman with a narrow pelvis, or using obstetric instruments during childbirth, can lead to the formation of a hematoma. Poor blood clotting in newborns complicates the situation. The baby's blood gradually (up to 3 days) accumulates in the damaged area. The following scenarios are possible here:

A small hematoma that will resolve without outside intervention;
In the case of extensive hematoma, a puncture is necessary (here: removal of the contents) and the application of a pressure bandage with further observation by a pediatrician and a pediatric surgeon;
If cephalohematoma is accompanied by damage to the skin of the skull, a course of antibiotics is prescribed, otherwise suppuration may occur, which will also require surgical intervention;
An extensive hematoma may eventually ossify, distorting the shape of the skull. In this case, the ossified tissues are excised, the edges of the wound are sutured. The child must be systematically examined by a surgeon and a neurologist for at least another year from the date of surgery.

Cephalhematoma is diagnosed by visual inspection or ultrasound. Outwardly, the formation looks like a bump: large hemorrhages can correspond to the contour of the bone, making a frightening impression on an unprepared viewer. When probing, the soft elastic bulge will hurt, about which the child will give signals - by crying or trying to defend himself with his hands.

Skull osteoma

Pathology is an exophytic (i.e., outward) slow benign growth of bone tissue. Among the causes are heredity, syphilis, gout, rheumatism. There is no threat to the brain, due to the peculiarities of the localization of the tumor, it does not develop into a malignant one. Hypertension, scattered attention, memory impairment are sometimes noted.

The aesthetic defect is eliminated along with a certain amount of bone tissue after X-ray diagnostics or CT. The resulting cavity is filled with artificial materials.

Parietal injury

A common occurrence in human life is bone fracture. The reason for it is a mechanical impact in any of its manifestations: a blow with a hard, non-sharp object, compression, a fall on the head from a height, a wound - this is an incomplete list of options for the origin of the injury.

The fracture has the following symptoms:

severe pain at the site of injury;
hematoma;
scalp wound (detachment of the scalp or tendons);
the formation of edema;
loss of consciousness (not always).

The classification of skull fractures is described below.

Depressed fractures. The bone fragment exerts a compression effect on the brain. Among the possible consequences of an injury are hematomas, crushing of the brain, damage to its blood supply system;
Linear breaks. They are characterized by the corresponding form of damage - cracks. Bone displacement does not occur, however, the danger lies in the likelihood of hemorrhages in the spaces between the skull bone and the dura mater;
Comminuted fractures. Recognized as the most dangerous, since bone fragments can damage brain tissue, which threatens to lose some of its functions, depending on the location and extent of the damage.

If a skull fracture is detected, an ambulance should be called immediately: only a study will allow to assess the nature of the damage, provide a prognosis and prescribe the necessary treatment.

14346 -1

(osparietale), steam room. This quadrangular plate forms most of the cranial vault (Fig. 1). It distinguishes between a convex outer surface and a concave inner, 4 edges, passing one into the other through four corners. Front, frontal edge (margo frontalis), connects with the frontal scales, upper, sagittal margin (margo sagittalis), - with the corresponding edge of the opposite side, back, occipital margin (margo occipitalis), adjacent to the occipital scales and lower, scaly edge (margo xquamosus), - to the squamous part of the temporal bone. Frontal (angulus frontalis) And occipital angles (angulus occipitalis) almost straight, wedge-shaped angle (angulus sphenoidalis) sharp and mastoid angle (angulus mastoideus) blunt. In the center outer surface located parietal tubercle (tuber parietale). Below the mound pass superior and inferior temporal lines (lineae temporalia superior et inferior). Near the sagittal edge there is parietal foramen (foramenparietale) through which the emissary vein passes.

Inner surface the parietal bone bears arterial sulci- a trace of the adjacent arteries of the dura mater of the brain. Noticeable along the sagittal margin sulcus of the superior sagittal sinus, near which there are dimples of granulations (foveolae granulares). Here are the granulations of the arachnoid membrane. Sometimes, especially in older people, these dimples are presented in the form of channels. In the region of the mastoid angle passes groove of the sigmoid sinus.

Ossification: at the end of the 2nd month of the intrauterine period, 2 ossification points appear in the region of the parietal tubercle. The process of ossification of the parietal bone ends in the 2nd year of life.

Rice. 1. Parietal bone, right:

a - topography of the parietal bone;

b - outer surface: 1 - sagittal edge; 2 - frontal angle; 3 - frontal edge; 4 - wedge-shaped angle; 5 - lower temporal line; 6 - upper temporal line; 7 - scaly edge; 8 - mastoid angle; 9 - parietal tubercle; 10 - occipital margin; 11 - occipital angle, 12 - parietal opening;

c - inner surface: 1 - groove of the superior sagittal sinus; 2 - sagittal edge; 3 - occipital angle; 4 - occipital margin; 5 - groove of the sigmoid sinus; 6 - mastoid angle; 7 - scaly edge; 8 - arterial furrows; 9 - wedge-shaped angle; 10 - frontal edge; 11 - frontal angle; 12 - dimples of granulations

Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin