Frontal angle. 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 bone.

The weight of the prepared parietal bone is 42.5 grams.

The outer surface of the parietal bone is convex, with the parietal tubercle in the center. The superior temporal line is located along the lower edge of the parietal bone (linea temporalis superior), where the temporal fascia is attached, and the inferior temporal line ( linea temporalis inferior)- place of attachment of the temporal muscle. At the sagittal edge, closer to the occipital angle, the parietal foramen is located (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, internal view; 3 – occipital edge; 4 – scaly edge; 5 – sagittal edge; 6 – frontal edge; 7 – parietal foramen; 8 – superior temporal line; 9 – lower temporal line; 10 – groove of the superior sagittal sinus; 11 – groove of the sigmoid sinus; 12 – grooves 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. On the surface there are also grooves of the anterior and posterior branches of the middle meningeal artery ( sulcus arteriae meningeae mediae), groove of the superior sagittal sinus (sulcus sinus sagittalis superioris) on the sagittal edge, groove of the sigmoid sinus (sulcus sinus sigmoidei) near the mastoid angle. The sphenoparietal sinus groove runs along the frontal margin (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 edge in the segment between lambda And asterion. The occipital bone covers the parietal bone from lambda to the “core occipito-parietal point”, after which in the segment up to asterion The parietal bone covers the occipital bone.

From asterion before pterion the parietal bone is covered with the 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 core frontoparietal point, at the site of which the parietal and frontal bones change the direction of the suture cut. So, in the interval between bregma and the core fronto-parietal point, the frontal bone covers the parietal. On the segment between the core fronto-parietal point and pterion The parietal bone covers the frontal bone.

Connection of the parietal bone with sphenoid bone presented 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 inferior temporal line of the parietal bone. Temporal fascia (fascia temporalis) originates on the superior temporal line of the parietal bone and consists of two plates. Superficial plate (lamina superficialis) attaches to the outer edge of the zygomatic arch. Deep plate (lamina profunda) attaches to the inner edge of the zygomatic arch.

Attachment of the dura mater

The falciform ligament of the brain is attached 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 coverage area includes the most important motor (motor) and sensory (sensitive) areas of the cortex. Since the parietal bones cover most of the brain in children, correction of the parietal bones is more important 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 disorders.

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

The sensory or somatosensory area of the 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 extend almost to lambda. The primary zone makes distinctions between specific types of sensitivity, and the secondary zone interprets them more subtly and identifies various objects through touch. When fields 5 and 7 are affected, tactile agnosia occurs. The patient can feel an object placed in his 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

The anterior and posterior branches of the middle meningeal artery pass along the inner surface of the parietal bone, which exits through the foramen spinosum 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 edge. The middle meningeal veins are located on the inner surface of the parietal bone.

Scull protects the brain and sensory organs from external influences and provides support to the face and the initial parts of the digestive and respiratory systems. The structure of the skull is conventionally divided into the cerebral and facial sections. The cerebral part 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.

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 mandible;
mastoid;
external auditory canal;
lambdoid suture;
occipital bone scales;
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 nasal concha;
maxillary bone;
chin protuberance of the lower jaw;
nasal cavity;
vomer;
perpendicular plate of the ethmoid bone;
orbital surface of the maxillary bone;
inferior 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 human skull 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 the capsule (container) of the organs of smell, vision and hearing are cartilaginous. The lateral walls and vault of the cerebral part of the skull, bypassing the cartilaginous stage of development, begin to ossify already at the end of the 2nd month of intrauterine life. The individual parts of the bones are subsequently combined into a single bone; for example, it is formed from four parts. From the mesenchyme surrounding the head end of the primary gut, between the gill pouches, cartilaginous gill arches develop. The formation of the facial part of the skull is associated with them.

Structure of the skull: sections

The human skull consists of 23 bones: 8 paired and 7 unpaired. The cranial bones have a specific craniosacral rhythm. You can familiarize yourself with its amplitude in this. The bones of the skull roof 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 roof bones, these are finger impressions. The pits correspond to the cerebral convolutions, and the elevations between them correspond to the sulci. In addition, on the inner surface of the cranial bones, imprints of blood vessels are visible - arterial and venous grooves.

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

Brain section of the skull

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

The squama of the occipital bone forms a curve at the point where the base of the skull at the back meets its roof. Here is the external occipital protuberance, to which the nuchal ligament is attached. To the right and left of the eminence, a rough superior nuchal line runs along the surface of the bone, along which the trapezius muscles, which are involved in maintaining the skull in balance, are attached to the right and left. From the middle of the external occipital protuberance, a low external nuchal crest runs down to the foramen magnum, on the sides of which a rough inferior nuchal line is visible. On the inner surface of the squama of the occipital bone, four large pits are visible, which are separated from one another by ridges forming a cruciform eminence. At the point where they intersect there is the internal occipital protrusion. This protrusion passes into the internal occipital crest, which continues down to the foramen magnum (foramen magnum). The groove of the superior sagittal sinus runs upward from the internal occipital protuberance. The groove of the transverse sinus extends from the protrusion to the right and left.

Occipital bone, posterior view

external occipital protuberance;
superior nuchal line;
lower nuchal line;
condylar fossa;
jugular process;
occipital condyle;
intrajugular process;
basilar part;
pharyngeal tubercle;
jugular notch;
condylar canal;
external nuchal crest;
occipital scales.

Occipital bone, front view

lambdoid margin;
occipital scales;
internal nuchal crest;
mastoid edge;
foramen magnum;
sigmoid sinus groove;
condylar canal;
jugular notch;
stingray;
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 extend upward and laterally, and pterygoid processes hang downward. On the upper side of the body there is a depression called the sella turcica; in the center of it is the pituitary fossa, which houses the pituitary gland, one of the endocrine glands. The pituitary fossa is limited posteriorly by the dorsum of the sella, and in front by the tubercle of the sella. 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 anterior surface of the body and facing the nasal cavity.

Two small wings extend to the sides from the anterior-superior surface of the bone body. 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 surface of the brain 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-shaped maxillary surface, located between the orbital surface and the base of the pterygoid process. Between the lesser and greater wings there is a wide superior orbital fissure leading from the cranial cavity to the orbit. At the base of the greater wing there are openings: anterior (medial) – a round opening (through which the maxillary nerve passes into the pterygopalatine fossa); laterally and posteriorly there is a larger foramen ovale (through which the mandibular nerve passes into the infratemporal fossa); even more lateral is the foramen spinosum (through it the middle meningeal artery enters the cranial cavity). From the base of the large wing, a pterygoid process extends down on each side, at the base of which the pterygoid canal runs from front to back. Each pterygoid process is divided into two plates - the medial one, ending in a hook, and the lateral one. Between them on the back side there is a pterygoid fossa.

Sphenoid bone, front view

aperture of the sphenoid sinus;
saddle back;
wedge-shaped shell;
small wing;
superior orbital fissure;
zygomatic margin;
infratemporal crest;
sphenoid bone;
pterygopalatine groove of the pterygoid process;
wing-shaped hook;
processus vaginalis;
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;
large wing;
round hole;
pterygoid canal;
navicular fossa;
pterygoid fossa;
pterygoid notch;
groove of the pterygoid hook;
processus vaginalis;
wedge-shaped beak;
body of the sphenoid bone;
medial plate of the pterygoid process;
wing-shaped hook;
lateral plate of the pterygoid process;
carotid fissure.

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

The petrous part has the shape of a triangular pyramid, the apex of which is directed to the sella turcica of the body of the sphenoid bone, and the base is directed backward and laterally, passing into the mastoid process. The pyramid has three surfaces: the anterior and posterior, facing the cranial cavity, and the lower, involved in the formation of the outer base of the skull. On the front surface at the apex of the pyramid there is a trigeminal depression, in which lies the trigeminal nerve node, behind it there is an arcuate elevation formed by the superior semicircular canal of the bony labyrinth of the organ of hearing and balance located in the pyramid. Laterally from the eminence, a flat surface is visible - the roof of the tympanic cavity and two small openings located here - the clefts of the canals of the greater and lesser petrosal 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, lateral view

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

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

On the lower surface of the pyramid, at the jugular foramen, bounded 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 (medial side)

parietal edge;
arcuate elevation;
tympanosquamosal fissure;
parietal notch;
groove of the superior petrosal sinus;
mastoid foramen;
occipital edge;
sigmoid sinus groove;
back surface of the pyramid;
jugular notch;
external opening of the vestibule water supply;
subarc fossa;
external opening of the cochlear canaliculus;
groove of the inferior petrosal sinus;
trigeminal depression;
top of the pyramid;
zygomatic process;
wedge-shaped edge;
brain surface.

It is a quadrangular plate, its outer surface is convex, and the parietal tubercle is visible in the center. The inner surface of the bone is concave and has arterial grooves. The four edges of the parietal bone are connected to other bones, forming corresponding sutures. The frontal and occipital sutures are formed with the frontal and occipital bones, the sagittal suture is formed with the opposite parietal bone, and the squamosal suture is formed with the scales of the temporal bone. The first three edges of the bone are jagged and participate in the formation of jagged sutures, the last is pointed and 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;
inferior temporal line;
wedge angle;
scaly edge;
mastoid angle;
occipital edge;
occipital angle;
parietal foramen.

consists of vertical frontal scales and horizontal orbital parts, which, turning into each other, form the supraorbital edges; the nasal part is located between the orbital parts.

The frontal scales are convex, with frontal tubercles visible on it. Above the supraorbital margins are the brow ridges, 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 connects to the zygomatic bone. The inner surface of the frontal bone is concave and passes into the orbital parts. It shows the sagittally oriented groove of the superior sagittal sinus.

The orbital part - right and left - are horizontally located bone plates, with the lower surface facing the cavity of the orbit, and the upper surface facing the cavity of the skull. 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 into 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 represents the bony basis of the face and the initial sections of the digestive and respiratory tract; the masticatory muscles are attached to the bones of the facial section of the skull.

Frontal bone, front view

frontal scales;
frontal tubercle;
parietal edge;
frontal suture;
glabella;
zygomatic process;
supraorbital margin;
bow;
nasal bone;
frontal notch;
supraorbital foramen;
temporal surface;
brow ridge;
temporal line.

parietal edge;
groove of the superior sagittal sinus;
brain surface;
frontal ridge;
zygomatic process;
finger impressions;
blind hole;
nasal bone;
lattice tenderloin;
orbital part.

formed by the lower surface of the cerebral part of the skull and part of the facial part. 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 openings 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, and its posterior border is the anterior edge of the foramen magnum. Anterior to the foramen magnum (occipital) is the pharyngeal tubercle.

Structure of the skull. External base of the skull

palatine process of the maxillary bone;
incisive foramen;
median palatal suture;
transverse palatal suture;
choana;
inferior orbital fissure;
zygomatic arch;
opener wing;
pterygoid fossa;
lateral plate of the pterygoid process;
pterygoid process;
oval foramen;
mandibular fossa;
styloid process;
external auditory canal;
mastoid;
mastoid notch;
occipital condyle;
condylar fossa;
lower nuchal line;
external occipital protuberance;
pharyngeal tubercle;
condylar canal;
jugular foramen;
occipital-mastoid suture;
external carotid foramen;
stylomastoid foramen;
torn hole;
petrotympanic fissure;
foramen spinosum;
articular tubercle;
wedge-squamous suture;
wing-shaped hook;
greater palatine foramen;
zygomaticomaxillary 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 section is as follows: on the internal base of the skull there are three cranial fossae: 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 cribriform plate of the ethmoid bone, part of the body and the small wings of the sphenoid bone. The posterior edge of the lesser 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 squamosal part of the temporal bones. Anterior to the pituitary fossa is the precross groove, and the dorsum sellae rises behind it. 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 apex of the pyramid there is a ragged opening. Between the lesser and greater wings and the body of the sphenoid bone on each side there is a superior orbital fissure, narrowing in the lateral direction, through which the oculomotor, trochlear and trigeminal cranial nerves and the ophthalmic nerve (a branch of the trigeminal nerve) pass. Posterior and inferior to the fissure are the round, oval and spinous foramina described above. On the anterior surface of the pyramid of the temporal bone, near its apex, a trigeminal depression is visible.

Structure of the skull. Inner base of the skull

orbital part of the frontal bone;
cockscomb;
cribriform plate;
visual channel;
pituitary fossa;
saddle back;
round hole;
oval foramen;
torn hole;
bony opening;
internal auditory opening;
jugular foramen;
sublingual canal;
lambdoid suture;
stingray;
groove of the transverse sinus;
internal occipital protuberance;
foramen magnum (occipital);
occipital scales;
sigmoid sinus groove;
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.

Based on materials from the site telegra.ph

Osparietale - steam room, quadrangular in shape, has the appearance of a bowl, forms the upper and lateral parts of the cranial vault. Develops on soil. It distinguishes two surfaces - external, fades externa, and internal, fades interna, and four edges: upper (sagittal, margo sagittalis), lower (squamosal, margo squamosus), anterior (frontal, margo frontalis) and posterior (occipital, margo occipitalis).
According to the four edges, the parietal bone has four angles: 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 horizontally located upper and lower temporal lines, linea temporales superior et inferior. The superior temporal line is the attachment site of the temporalis fascia, and the inferior temporal line is the attachment site of the temporalis muscle.
The inner surface is concave. It shows imprints of the brain's relief - finger-like squeezing, impressiones digitatae, as well as arterial grooves, sulci arterioles, middle meningeal artery, sul. a. meningae mediae.
Along the upper edge of the cerebral surface there is an incomplete groove of the superior sagittal sinus, sul. sinus sagittalis superior. In the posterior part of the same superior edge of the bone there is a small parietal foramen, foramen parietale, which is a venous outlet, emissario, in which passes the parietal emissary vein, connecting the superficial temporal vein with the superior sagittal sinus. In the depths of the sagittal groove and next to it, a large number of dimples of granulation of the arachnoid membrane, foveolae granulares, are observed. On the cerebral surface, at the mastoid angle, there is a small deep groove of the sigmoid sinus, sul. sinus sigmoidei, one end of which passes into the groove of the same name of the temporal bone, and the second into the groove of the occipital sinus of the occipital bone.
The upper (sagittal) edge is longer than all the others and participates in the formation of the sagittal suture, sutura sagittalis.
The lower (scaly) edge is arched and participates in the formation of the scaly, parietal-mastoid and sphenoid-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 connects with the lambdoid edge of the occipital bone, forming a lambdoid suture, sutura lambdoidea.
Ossification. Ossification points appear at 2 months of intrauterine development in the region of the parietal tubercle. Ossification of the parietal bone is completed at the 2nd year of life.

The human brain is a complex evolutionary achievement that requires special protection provided by the bones of the cranial vault. One of them, the parietal bone, is a convex quadrangular segment. Injuring it can lead to serious consequences, which are reversible in some cases if the victim receives professional assistance in a timely manner.

Structure of the parietal bone

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

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

The protruding outer surface of the bone is relatively smooth, its relief is determined by the need for attachment of soft tissues. The apex of the convexity of the segment is called the parietal tubercle; it is from here that the process of ossification of the pliable membrane tissue of the human embryo begins. Under these formations are the temporal lines. The upper one serves to attach the temporalis fascia, the lower one – the temporalis muscle. The inner, curved surface has grooves that copy the relief of the venous sinuses and the membrane of the brain. The connections between bone and adjacent fragments are called sutures.

The sagittal suture is the articulation of the serrated edges of the two parietal bones with each other. Towards the back of the sagittal suture there is an opening for a vein on the parietal bone;
The frontal and occipital edges, which have the same jagged structure, are connected to the frontal and occipital bones, forming the coronoid and lambdoid sutures;
The lower edge has a scaly shape, is beveled and covered by the edges of the sphenoid bone, forming a scaly suture. Two connections - the sphenoid-parietal and parietal-mastoid sutures, are formed by the overlap of the parietal edge of the temporal bone and its mastoid process.

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

The frontal angles (upper anterior) of the vertex bones are straight, forming the anterior fontanelle at the intersection of the sagittal and coronal sutures;
The rounded obtuse occipital angles (posterior superior) in the area of convergence of the lambdoid sutures with the sagittal suture form the posterior fontanelle;

The connection of the mastoid, obtuse angles (posterior lower) 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 other bones of the cranial vault, protects the brain from any damage and harmful environmental influences.

Formation of the parietal bone

The membranous tissue covering the rudiments of the embryonic brain 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 approximately the 7th week of embryo development, in the place where the parietal tubercle is “planned” (the largest convexity 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 human life: the areas farthest from the middle (angles) 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 have a very important function: they provide the necessary deformation of the child’s skull during birth and during the rapid development of the brain.

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

Pathologies of the parietal bone

The causes of deviations may 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 patient’s appearance; moreover, it is often discovered by chance based on the results of radiography or computed tomography (CT).

Craniosynostosis

This is premature fusion of the cranial bones. The occurrence of pathology can be explained by heredity or abnormalities of intrauterine development. The degree of deformation of the skull depends on the period of fusion of the cranial sutures. The most pronounced distortions of the shape occur if the overgrowth took place in the womb. Depending on the location of the pathology, the following forms of craniosynostosis are distinguished.

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

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

vomit;
high-pitched scream;
convulsions;
muscle hypertonicity;
sluggish sucking;
bulging of the fontanelles, lack of pulse in them;
eye rolling;
dilation of veins on the scalp.

Craniosynostosis can lead to serious pathologies and developmental abnormalities - from difficulty breathing to visual impairment or joint disease. Pathology is diagnosed by visual examination and treated surgically.

Cephalohematoma

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

Most often, hemorrhage occurs in a newborn if he is injured due to compression of 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:

A small hematoma that will resolve without outside intervention;
In case of extensive hematoma, puncture (here: removal of contents) and application of a pressure bandage with further observation by a pediatrician and pediatric surgeon are necessary;
If the 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 can ossify over time, distorting the shape of the skull. In this case, the ossified tissue is excised and the edges of the wound are sutured. The child should be systematically examined by a surgeon and neurologist for at least another year from the date of surgery.

Cephalohematoma is diagnosed by visual examination or ultrasound. Externally, the formation looks like a lump: large hemorrhages can follow the contour of the bone, making a frightening impression on an unprepared viewer. When palpated, the soft, elastic bulge will hurt, which the child will signal by crying or trying to defend himself with his hands.

Osteoma of the skull

The pathology is an exophytic (i.e., in an outward direction) slow, benign growth of bone tissue. Causes include heredity, syphilis, gout, and rheumatism. There is no threat to the brain, due to the specific location of the tumor, and it does not develop into a malignant one. Hypertension, absent-minded attention, and memory impairment are sometimes noted.

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

Parietal bone injuries

A common occurrence in human life is a broken bone. Its cause 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.

A fracture has the following symptoms:

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

The classification of skull fractures is described below.

Depressed fractures. The bone fragment exerts a compressive effect on the brain. Possible consequences of injury include hematomas, crushing of the brain, damage to its blood supply system;
Linear fractures. They are characterized by the corresponding form of damage – cracks. No bone displacements occur, however, the danger lies in the likelihood of hemorrhages in the spaces between the skull bone and the dura mater;
Comminuted fractures. They are recognized as the most dangerous, since bone fragments can damage brain tissue, which threatens the loss of some of its functions, depending on the location and extent of the damage.

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

14346 -1

(osparietale), steam room. This quadrangular plate forms the majority of the cranial vault (Fig. 1). It has a convex outer surface and a concave inner surface, 4 edges that pass into each other through four corners. Front, frontal edge (margo frontalis), connects to the frontal scales, superior, sagittal edge (margo sagittalis), - with the corresponding edge of the opposite side, rear, 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) spicy and mastoid angle (angulus mastoideus) blunt. In the center outer surface located parietal tubercle (tuber parietale). Below the hillock they 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 grooves (sulci arteriosi)- trace of adjacent arteries of the dura mater of the brain. Visible along the sagittal edge groove 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 appear as canals. In the area of the mastoid angle there is sigmoid sinus groove.

Ossification: at the end of the 2nd month of the intrauterine period, 2 points of ossification 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 - inferior temporal line; 6 - superior temporal line; 7 - scaly edge; 8 - mastoid angle; 9 - parietal tubercle; 10 - occipital edge; 11 - occipital angle, 12 - parietal foramen;

c—inner surface: 1—sulcus of the superior sagittal sinus; 2 — sagittal edge; 3 - occipital angle; 4 - occipital edge; 5 - groove of the sigmoid sinus; 6 - mastoid angle; 7 - scaly edge; 8 - arterial grooves; 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