Scull. Features of bone formations of the brain and facial parts of the skull

Inner base of the skullbasis cranii interna, has a concave uneven surface, reflecting the complex relief of the lower surface of the brain. It is divided into three cranial fossae: anterior, middle and posterior.

Anterior cranial fossa, fossa cranii anterior, formed by the orbital parts of the frontal bones, on which the cerebral eminences and finger-like impressions are well expressed. In the center, the fossa is deepened and is made by a cribriform plate of the ethmoid bone, through the openings of which the olfactory nerves (I pair) pass. A cockscomb rises in the middle of the lattice plate; in front of it are the blind opening and the frontal crest.

Middle cranial fossa, fossa cranii media, much deeper than the anterior one, its walls are 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. In the middle cranial fossa, the central part and lateral parts can be distinguished.

On the lateral surface of the body of the sphenoid bone there is a well-defined carotid groove, and near the top of the pyramid, an irregularly shaped ragged hole is visible. Here, between the small wing, the large wing and the body of the sphenoid bone, there is an upper orbital fissure, fissura orblalis superior, through which the oculomotor nerve (III pair), trochlear (IV pair), abducens (VI pair) and ophthalmic (first branch of the V pair) nerves pass into the orbit. Behind the superior orbital fissure is a round opening that serves to pass the maxillary nerve (the second branch of the V pair), then the oval opening for the mandibular nerve (the third branch of the V pair).

At the posterior edge of the large wing lies a spinous opening for passage into the skull of the middle meningeal artery. On the anterior surface of the pyramid of the temporal bone, on a relatively small area, there are a trigeminal depression, a cleft canal of the large stony nerve, a furrow of the large stony nerve, a cleft of the canal of the small stony

nerve, furrow of the small stony nerve, roof of the tympanic cavity and arcuate eminence.

Posterior cranial fossa, fossa cranii posterior, the deepest. The occipital bone, the posterior surfaces of the pyramids and the inner surface of the mastoid processes of the right and left temporal bones take part in its formation. The fossa is supplemented by a small part of the body of the sphenoid bone (in front) and the posterior lower corners of the parietal bones - from the sides. In the center of the fossa there is a large occipital foramen, in front of it is a slope, clivus, formed by the bodies of the sphenoid and occipital bones fused in an adult.

The (right and left) internal auditory opening opens into the posterior cranial fossa on each side, leading to the internal auditory meatus, in the depth of which the facial canal for the facial nerve (VII pair) originates. The vestibulocochlear nerve (VIII pair) emerges from the internal auditory opening.

It is impossible not to note two more paired large formations: the jugular opening through which the glossopharyngeal (IX pair), vagus (X pair) and accessory (XI pair) nerves pass, and the hypoglossal canal for the nerve of the same name (XII pair). In addition to the nerves, the internal jugular vein exits the cranial cavity through the jugular foramen, into which the sigmoid sinus continues, lying in the sulcus of the same name. The boundary between the vault and the inner base of the skull in the region of the posterior cranial fossa is the groove of the transverse sinus, which passes on each side into the groove of the sigmoid sinus.

Inner base of the skull

Internal base of the skull (basis cranii interna). Top view. 1-orbital part of the frontal bone; 2-rooster feben; 3-lattice plate.; 4 visual channel; 5-pituitary fossa; 6-back seat. 7-round hole; 8-oval hole; 9-torn hole; 10-spine hole; 11-internal auditory opening; 12 jugular hole; 13-hyoid and canal; 14-lambdoid seam; 15-slope; 16-groove of the transverse sinus; 17-internal occipital protrusion; 18-large (occipital) foramen; 19-occipital scales; 20-groove of the sigmoid sinus; 21-pyramid (stony part) of the temporal bone; 22-squamous part of the temporal bone; 23-large wing of the sphenoid bone; 24-small wing of the sphenoid bone;

In some places of the skull there are bony thickenings, or buttresses through which chewing pressure is transmitted to the calvaria. Between these buttresses are thinner bone formations called weak points. Fractures are more common in these areas. Thickenings are observed both on the upper and lower jaws. On upper jaw 4 buttresses are distinguished (Fig. 1).

Frontal-nasal buttress rests below on the alveolar elevations in the canine region, at the top it continues in the form of a reinforced plate of the frontal process of the upper jaw, reaching the nasal part of the frontal bone. The right and left buttresses in the area of the fore part of the frontal bone are strengthened by transverse bone ridges in the form of superciliary arches. This buttress balances the force of upward pressure developed by the fangs.

Alveolar-zygomatic buttress goes from the alveolar eminence of the 1st and 2nd molars, goes up the zygomatic-alveolar crest to the zygomatic bone, which redistributes pressure: posteriorly - to the zygomatic process of the temporal bone, from above - to the zygomatic process of the frontal bone, medially - to the zygomatic process and infraorbital margin upper jaw, towards the fronto-nasal buttress. The alveolar-zygomatic buttress is most pronounced and balances the force developed by the chewing teeth in the direction from bottom to top, from front to back and from the outside inwards.

Pterygopalatine buttress starts from the alveolar elevation of the molars and the tubercle of the upper jaw, goes up, where it is strengthened by the pterygoid process of the sphenoid bone and the perpendicular plate of the palatine bone. This buttress balances the force developed by the molars from bottom to top and from back to front.

palatine buttress formed by the palatine processes of the upper jaw and the horizontal plates of the palatine bone, connecting the right and left alveolar arches in the transverse direction. This buttress balances the force developed during chewing in the transverse direction.

In general, 2 buttresses are distinguished on the lower jaw:

1) alveolar (goes up to the alveolar cells);

2) ascending (goes up the branch of the lower jaw to the neck and head).

From here chewing pressure is transmitted to the mandibular fossa of the temporal bone.

On the inner base of the skull, as well as in the facial region, there are a number of buttresses that take up loads and form the walls of the cranial fossae (see Fig. 1, g).

Weak points of the skull bones (thin areas, holes, cracks) determine the direction of fractures.

On the inner base of the skull (Fig. 5) distinguish:

anterior, middle and posterior cranial fossae.

In the anterior cranial fossa:

Most anteriorly located: veins coming from the nasal cavity and flowing into the superior sagittal sinus. Through these veins, an infection from the facial region of the head can pass into the cranial cavity:

Behind the blind foramen are the perforated plate and the branches of the first, a pair of cranial nerves, passing through it.

Fig.5. Inner base of the skull:

1 - cockscomb; 2 - perforated plate of the ethmoid bone; 3 - panal of the optic nerve;
4 - oval hole; 5 - stony-scaly gap; 6 - jugular opening; 7 - large occipital foramen; 8 - internal occipital crest; 9 - internal occipital protrusion; 10 - groove of the transverse sinus; 11- mastoid opening; 12 - groove of the sigmoid sinus; 13 - furrow of the upper stony sinus; 14 - cleft of the large stony nerve; 15 - cleft of the small stony nerve; 16 - the back of the Turkish saddle; 17 - spinous opening; 18 - Turkish saddle;
19 - round hole; 20 - large wing of the sphenoid (main) bone; 21 - small wing of the sphenoid (main) bone.

In the middle cranial fossa:

The openings that communicate with neighboring areas are mainly in the sphenoid bone.

Most anteriorly lies the optic canal, which contains: 2 pair of cranial nerves, the ophthalmic artery, a branch of the carotid artery. Through the superior orbital fissure pass: 3rd, 4th, 6th pairs of cranial nerves and the first branch of the trigeminal nerve;

Behind the superior orbital fissure lies a round opening that passes the maxillary nerve, the 2nd branch of the trigeminal nerve;

Behind and outward from the foramen ovale is a small spinous foramen, which serves to pass the middle meningeal artery;

The next hole is torn, where the internal carotid artery passes;

On the side of it, the carotid canal, the internal carotid artery, opens.

Posterior cranial fossa:

In the posterior cranial fossa is the cerebellum, medulla oblongata, Varaliev bridge.

In the center is a large occipital foramen, where the medulla oblongata with membranes and arteries passes;

On the back surface of the pyramid is the internal auditory opening, where the facial and auditory nerves pass. The 9th, 10th, and 11th pairs of cranial nerves pass in the anterior part of it, and the internal jugular vein in the posterior part.

Thus, the bones of the base of the skull have unequal thickness and strength, many holes, channels, cracks. With skull injuries, these features contribute to fractures.

With fractures of the base of the skull, damage to the nerves and blood vessels of the corresponding area can easily occur.

With fractures of the base of the skull in the region anterior fossa there is bleeding from the nose, ears, with a rupture of the membranes - the outflow of cerebrospinal fluid. And also there are bleeding from the nasopharynx, hemorrhages in the cavity of the orbit, bulging eyes. If the cavernous sinus and the internal carotid artery are damaged, pulsating bulging eyes, paralysis of the abducens nerve, and a symptom of "glasses" in the orbit are observed.

For fractures in the area middle cranial fossa with damage to the pyramid of the temporal bone, bleeding and liquorrhea from the ear and symptoms of damage to the cranial nerves are observed.

External base of the skull(Fig. 6).

On the outer base of the skull, between the styloid and mastoid processes, the awl-mastoid foramen (foramen stylomastoideum) opens, through which the branches of the facial nerve exit. Inward from the temporomandibular joint is a stony-tympanic fissure (fissure petrotympanica), through which a thin branch of the facial nerve emerges - a drum string (chorda tympani). Anterior to the jugular foramen on the outer base of the skull is the opening of the carotid canal, to which the internal carotid artery is attached.

Inner surface of the base of the skull, basis cranii interna, is divided into three pits, of which a large brain is placed in the anterior and middle, and the cerebellum in the posterior. The border between the anterior and middle fossae is the posterior edges of the small wings of the sphenoid bone, between the middle and posterior - the upper face of the pyramids of the temporal bones.

Anterior cranial fossa, fossa cranii anterior, is formed by the orbital parts of the frontal bone, the ethmoid plate of the ethmoid bone, which lies in the recess, small wings and part of the body of the sphenoid bone. The frontal lobes of the cerebral hemispheres are located in the anterior cranial fossa. On the sides of the crista galli are laminae cribrosae, through which the olfactory nerves pass, nn. olfactorii (I pair) from the nasal cavity and a. ethmoidalis anterior (from a. ophthalmica) accompanied by the vein and nerve of the same name (from the I branch of the trigeminal nerve).

Middle cranial fossa, fossa cranii media, deeper than the front. It distinguishes the middle part, formed by the upper surface of the body of the sphenoid bone (the region of the Turkish saddle), and two lateral ones. They are formed by the large wings of the sphenoid bone, the anterior surfaces of the pyramids, and partly by the scales of the temporal bones. The central part of the middle fossa is occupied by the pituitary gland, and the lateral parts are occupied by the temporal lobes of the hemispheres. Cleredi from the Turkish saddle, in sulcus chiasmatis, is the intersection of the optic nerves, chiasma opticum. On the sides of the Turkish saddle lie the most important practical sinuses of the dura mater - cavernous, sinus cavernosus, into which the superior and inferior ophthalmic veins flow.

Middle cranial fossa communicates with the orbit through the optic canal, canalis opticus, and the superior orbital fissure, fissura orbitalis superior. The optic nerve passes through the canal, n. opticus (II pair), and ophthalmic artery, a. ophthalmica (from the internal carotid artery), and through the gap - the oculomotor nerve, n. oculomotorius (III pair), trochlear, n. trochlearis (IV pair), efferent, n. abducens (VI pair) and eye, n. ophthalmicus, nerves and ophthalmic veins.

Middle cranial fossa communicates through a round hole, foramen rotundum, where the maxillary nerve passes, n. maxillaris (II branch of the trigeminal nerve), with a pterygopalatine fossa. It is connected with the infratemporal fossa through the foramen ovale, foramen ovale, where the mandibular nerve passes, n. mandibularis (III branch of the trigeminal nerve), and spinous, foramen spinosum, where the middle meningeal artery passes, a. meningea media. At the top of the pyramid there is an irregularly shaped hole - foramen lacerum, in the area of \u200b\u200bwhich is the internal opening of the carotid canal, from where the internal carotid artery enters the cranial cavity, a. carotis interna.

Inner base of the skull (basis cranii interna)

Inner base of the skull(basis cranii interna).

View from above.

1-orbital part of the frontal bone;
2-rooster feben;
3-lattice plate.;
4 visual channel;
5-pituitary fossa;
6-back seat.
7-round hole;
8-oval hole;
9-torn hole;
10-spine hole;
11-internal auditory opening;
12 jugular hole;
13-hyoid and canal;
14-lambdoid seam;
15-slope;
16-groove of the transverse sinus;
17-internal occipital protrusion;
18-large (occipital) foramen;
19-occipital scales;
20-groove of the sigmoid sinus;
21-pyramid (stony part) of the temporal bone;
22-squamous part of the temporal bone;
23-large wing of the sphenoid bone;
24-small wing of the sphenoid bone;

Middle cranial fossa, fossa cranii media, deeper than the front. It distinguishes the middle part, formed by the upper surface of the body of the sphenoid bone (the region of the Turkish saddle), and two lateral ones. They are formed by the large wings of the sphenoid bone, the anterior surfaces of the pyramids, and partly by the scales of the temporal bones. The central part of the middle fossa is occupied by the pituitary gland, and the lateral parts are occupied by the temporal lobes of the hemispheres. Cleredi from the Turkish saddle, in sulcus chiasmatis, is the intersection of the optic nerves, chiasma opticum. On the sides of the sella turcica lie the most important practical sinuses of the dura mater - cavernous, sinus cavernosus, into which the superior and inferior ophthalmic veins flow.

- junctions of individual bones of the brain and facial parts of the skull ...
Physical Anthropology. Illustrated explanatory dictionary
- brushwood, dry branches ...
Cossack dictionary-reference book
- fibrous connection of the adjacent edges of the skull bones ...
Big Medical Dictionary
- View from above. orbital part of the frontal bone; cock feben; lattice plate; visual channel; pituitary fossa; seat back. round hole; oval hole; torn hole; spiny hole...
Atlas of human anatomy
- The skeleton of the head is the skull, cranium, the individual bones of which are subdivided into the bones of the cerebral part of the skull, which form the cranial cavity, cavitas cranii, the receptacle for the brain and facial bones, ossa faciei ...
Atlas of human anatomy
- Bottom view. 1-palatine process of the upper jaw; 2 incisive hole; 3-median palatal suture; 4-transverse palatine suture; 5-choana; 6-lower orbital fissure; 7-zygomatic arch; 8-wing opener; 9-pterygoid fossa...
Atlas of human anatomy
- Bottom view. palatine process of the upper jaw; cutting hole; median palatine suture; transverse palatine suture; choana; lower orbital fissure; zygomatic arch; coulter wing; pterygoid fossa...
Atlas of human anatomy
- The inner base of the skull is a support for the base of the brain, therefore it has a characteristic relief ...
Atlas of human anatomy
- The base of the skull is called that part of the skull, which is located below the line running in front at the level of the infraorbital margin and further posteriorly along the zygomatic process of the frontal bone, sphenoid-zygomatic suture, infratemporal ...
Atlas of human anatomy
- see the list of anat. terms...
Big Medical Dictionary
- see Leontiasis ossea...
Big Medical Dictionary
- see the vault of the skull ...
Big Medical Dictionary
- the lower part of the brain skull, formed by the frontal, ethmoid, sphenoid, temporal and occipital bones ...
Big Medical Dictionary
- the surface of the base of the skull facing the brain ...
Big Medical Dictionary
- the lower surface of the base of the skull ...
Big Medical Dictionary
- SKULLS, -ov, SKULLS, -ov, pl. Parents. Houses? When they leave, come. Skulls on a wire - parents talking on the phone...
Dictionary of Russian Argo

"Inner base of the skull" in books

8. Oblong skulls and broad skulls

From the book Hitler and his God [Behind the Scenes of the Hitler Phenomenon] author Frekem George Wang

8. Elongated skulls and broad skulls We will never be rude or heartless unnecessarily. We Germans, the only people on earth who are kind to animals, will also be kind to animal people. Heinrich Himmler Pride of the White Man

SKULL ASHTRAY

From the book Remember, you can not forget author Kolosova Marianna

SKULL ASHTRAY There were many, not just one. From swampy swamps and bogs At the crimson reflections of dawn In Rus', rebels were born. With a whistle, the Nightingale the Robber on the oak tree intimidated the fate. And the merchants of the travelers and the boyars Robbed along the roads Kudeyar. Pugachev's hat and caftan

adicinallura skulls

From the book The Secret of the Blue Mountain Tribe author Shaposhnikova Ludmila Vasilievna

Adicinallura skulls Archaeological material supports the assumption that the Toda were closely associated with the ancient megalithic culture of South India. What does anthropology say about this? Its reliable data more than once helped to restore the lost link in

SCREAMING SKULLS

From the book The Book of Secrets. The Incredible Obvious on Earth and Beyond author Vyatkin Arkady Dmitrievich

SCREAMING SKULLS Screaming or screeching skulls are found in a number of places in the UK. When they are tried to be removed from the house, they protest by making specific sounds. The former owners of many of the skulls of this kind were victims of violent

crystal skulls

From the book Gates to other worlds by Philip Gardiner

Crystal Skulls In Secrets of the Crystal Skulls, Chris Morton and Keri Louise Thomas told the story of the crystal skull, a phenomenon that the mainstream scientific community seems to be oblivious to. This book is great for a first introduction to the subject. She's worth it

giant skulls

From the book All the secrets of the subconscious. Encyclopedia of practical esotericism author Naumenko Georgy

Giant skulls Ica Stones find waqueros (as they call "black archeologists" in Peru) in the burial complexes of all pre-Columbian cultures without exception. And the finds come not only from the vicinity of Ica, but from a much wider area - from Paracas in the north

egg-headed skulls

From the book The Old Gods - who are they author Sklyarov Andrey Yurievich

Egg-headed skulls A quite logical question arises: if there are traces of representatives of some civilization on Earth, who, of course, should have been mortal after all (even if they lived much longer than ordinary people), and if there are so many of these traces, then are there

Skulls and bones

From the book From the life of English ghosts author Volkov Alexander Vladimirovich

Skulls and Bones The king said that once there is a head, it means that it can be chopped off - and there is nothing to talk nonsense! Carroll L. Alice in Wonderland The "skeletal" theme culminates in the lore of restless skulls and bones. They must be distinguished from the skeletons already described.

Skulls and bones

From the book Aryan Rus' [Heritage of ancestors. Forgotten gods of the Slavs] author Belov Alexander Ivanovich

Skulls and bones From the skulls of the leaders of hostile clans, the Scythians made ritual bowls, from which they drank ritual wine on special occasions when it was necessary to attract the soul of a defeated enemy to their allies. Subsequently, the Huns adopted this custom from the Saks and began to

skull find

From the book Prehistoric Europe author Nepomniachtchi Nikolai Nikolaevich

The discovery of the skull Around 1908, Englishman Charles Dawson, a lawyer by training and an anthropologist by vocation, noticed that after repair work, the country road near Piltdown, Sussex, was in some places covered with flint gravel. Dawson, who

skull shape

From the book Myths about Belarus author Deruzhinsky Vadim Vladimirovich

The shape of the skull I. N. Danilevsky in the course of lectures “Ancient Rus' through the eyes of contemporaries and descendants (IX-XII centuries)” (Moscow, 1998) wrote that the skulls of Belarusians have not changed for 3500 years: “On the territory of Belarus, a third anthropological type of eastern Slavdom - dolichocranic

STRANGE SKULLS

From the book Mysteries of Antiquity. White spots in the history of civilization author Burgansky Gary Eremeevich

STRANGE SKULLS The symbol of modern medicine is a snake that releases a drop of poison into a bowl. He came to us from very ancient times. For many peoples, the snake personified wisdom, and its poison is a medicine, a large dose of which can kill a person, and a small one can cure it. Successes

Statues and skulls

From the book Address - Lemuria? author Kondratov Alexander Mikhailovich

Statues and skulls Race and language are different concepts. Indo-European languages, for example, are spoken by blond Scandinavian Caucasians and dark-skinned Negroids, residents of many islands of the West Indies and blacks in the USA. Indo-European speech is native to Russians and Gypsies, Persians and Portuguese,

Foundation, expansion and internal development of the Church in the struggle with the Jewish and Greco-Roman world.

From the book History of the Christian Church author Posnov Mikhail Emmanuilovich

Foundation, expansion and internal development of the Church in the struggle with the Jewish and Greco-Roman world. The first period from the beginning of the Church to the Edict of Milan by Constantine the Great, from the year 29-30 of the Christian era to 313, is the time of the founding of the Church and the gradual

Skull cleaning

From the book Hunting Animals and Trophies author Fandeev Alexey Alexandrovich

Cleaning the skull First, you should clean the skull from the meat, which is most conveniently done at the place of cutting the carcass. To do this, cut off the largest muscles with a sharp knife, remove the eyes and tongue. After abundant salting, the skull can be safely transported for several days.

46788 0

Inner base of the skull (basis cranii interna) represents an uneven concave surface, in which three cranial fossae are distinguished: anterior, middle, and posterior (Fig. 1).

Anterior cranial fossa formed by the nasal and orbital parts of the frontal bone, small wings of the sphenoid bone, ethmoid plate of the ethmoid bone. The olfactory filaments of the first pair of cranial nerves pass through the holes in the plate. In the middle of it rises cockscomb, in front of which is located blind hole. On the orbital processes of the frontal bone are visible cerebral elevations and depressions of the convolutions, from the fit of the furrows and convolutions of the brain.

Middle cranial fossa formed by the sphenoid and temporal bones. It is delimited from the anterior cranial fossa by the posterior edge of the small wings, from the posterior by the upper edge of the pyramid of the temporal bone and the back of the Turkish saddle. The middle cranial fossa consists of three parts: two lateral and central. The central part is formed by the Turkish saddle, at the bottom of which there is a pituitary fossa, a place for the pituitary gland. Anterior to it are the tubercle of the saddle and precross sulcus, continuing into the optic canal, through which the second pair of cranial nerves exits the orbit. The carotid groove runs along the lateral surface of the body of the sphenoid bone. Behind and downward from it there is torn hole, next to which at the top of the pyramid of the temporal bone opens internal aperture of the carotid canal.

On the anterior surface of the pyramid of the temporal bone is trigeminal depression: here lies the trigeminal ganglion under the dura mater. Behind the depression, furrows pass along the anterior surface of the pyramid, leading to small canal clefts And greater stony nerve, even further away arcuate eminence And roof of the tympanic cavity.

Rice. 1. Internal base of the skull: a - anatomical formations of the internal base of the skull: 1 - blind hole; 2 - cockscomb; 3 - orbital part of the frontal bone; 4 - anterior cranial fossa; 5 - precross furrow; 6 - tubercle of the saddle; 7 - visual channel; 8 - pituitary fossa; 9 - a large wing of the sphenoid bone; 10 - round hole; 11 - oval hole; 12 - torn hole; 13 - spinous opening; 14 - stony-occipital fissure; 15 - internal auditory opening; 16 - furrow of the lower stony sinus; 17 - jugular hole; 18 - canal of the hypoglossal nerve; 19 - a large hole; 20 - occipital scales; 21 - internal occipital crest; 22 - posterior cranial fossa; 23 - condylar canal; 24 - groove of the sigmoid sinus; 25 - furrow of the upper stony sinus; 26 - stony-scaly gap; 27 - slope; 28 - middle cranial fossa; 29 - wedge-shaped stony gap; 30 - trigeminal depression; 31 - wedge-occipital synchondrosis; 32 - back of the saddle; 33 - carotid furrow; 34 - small wing of the sphenoid bone; 35 - wedge-shaped elevation; 36 - lattice plate

b - details of the structure of the middle cranial fossa: 1 - wedge-shaped eminence; 2 - precross furrow; 3 - visual channel; 4 - anterior inclined process; 5 - upper orbital fissure; 6 - round hole; 7 - tubercle of the saddle; 8 - carotid furrow; 9 - spinous opening; 10 — a fissure and a furrow of a small stony nerve; 11 - roof of the tympanic cavity; 12 - arcuate elevation; 13 - furrow of the upper stony sinus; 14 - oval hole; 15 - torn hole; 16 - posterior inclined process; 17 - back of the saddle; 18 - pituitary fossa; 19 — a fissure and a furrow of a big stony nerve; 20 - trigeminal depression; 21 - the top of the pyramid of the temporal bone; 22 - a large wing of the sphenoid bone; 23 - small wing of the sphenoid bone

There are three openings at the base of the large wings (from front to back): round, oval, and spinous. The maxillary nerve passes through the round opening into the pterygopalatine fossa, the mandibular nerve passes through the oval opening into the infratemporal fossa, and the middle meningeal artery passes through the spinous opening into the middle cranial fossa. In the anterolateral parts of the middle cranial fossa, between the small and large wings is located superior orbital fissure (fissura orbitalis superior) through which the III, IV, VI cranial nerves and the optic nerve pass.

Posterior cranial fossa formed by the occipital bone, the posterior surface of the pyramid, the body of the sphenoid bone and partially the parietal bone. This fossa is deeper than the anterior and middle. At its center lies big hole. Anterior to it is a slope (clivus), formed by the body of the sphenoid and basilar part of the occipital bone. Behind and above the large hole is located internal occipital protuberance, to the side of which goes groove of the transverse sinus. It continues in sulcus of the sigmoid sinus leading to jugular foramen. On the posterior surface of the pyramid, one can see internal auditory opening where the facial nerve enters and where the vestibulocochlear nerve exits. Between the lateral part of the body of the occipital bone and the medial edge of the pyramid is furrow of the lower stony sinus (sulcus sinus petrosi inferioris). In the posterior cranial fossa, to the side of the foramen magnum, lie the hemispheres of the cerebellum, and on the slope - the medulla oblongata and the bridge.

On the border of the brain and facial skull there are very important fossae in practical terms: temporal, infratemporal, and pterygopalatine (Fig. 2).

Temporal fossa (fossa temporalis) bounded above and behind by the temporal line, outside by the zygomatic arch, below by the infratemporal crest of the greater wing of the sphenoid bone, and in front by the zygomatic bone. The temporalis muscle lies in the temporal fossa.

Infratemporal fossa (fossa infratemporalis) bounded above by the infratemporal surface of the greater wing of the sphenoid bone and the temporal scales, medially by the lateral plate of the pterygoid process, anteriorly by the infratemporal surface of the maxilla and partly by the temporal surface of the zygomatic bone, laterally by the zygomatic arch and the branch of the mandible. The infratemporal fossa communicates with the orbit through the inferior orbital fissure pterygomaxillary fissure (fissura pterygomaxillaris)- with the pterygopalatine fossa and through the spinous and oval foramen - with the middle cranial fossa.

Pterygopalatine fossa (fossa pterygopalatina) limited in front tubercle of the upper jaw, medially - by a perpendicular plate of the palatine bone, behind - by the anterior edge of the pterygoid process, from above - by the maxillary surface of the large wing of the sphenoid bone (see Fig. 2). Through the pterygomaxillary fissure, this fossa opens from the outside into the infratemporal fossa. Through the pterygoid canal, it communicates with the region of the ragged foramen, through the round hole - with the middle cranial fossa, through sphenopalatine foramen (foramen sphenopalatinum)- with the nasal cavity, through the infraorbital fissure - with the orbit and through the large palatine canal - with the oral cavity.

Rice. 2. Temporal, infratemporal and pterygopalatine fossa:

a - the position of the temporal fossa;

b - temporal, infratemporal and pterygopalatine fossa (zygomatic arch removed): 1 - temporal surface of the greater wing of the sphenoid bone; 2 - infratemporal crest; 3 - lateral plate of the pterygoid process; 4 - hook of the medial plate of the pterygoid process; 5 - external auditory opening; 6 - mandibular fossa; 7 - articular tubercle; 8 - styloid process; 9 - spine of the sphenoid bone; 10 - perpendicular plate of the palatine bone; 11 - wedge-palatine opening; 12 - rear upper alveolar openings; 13 - tubercle of the upper jaw; 14 - lower orbital fissure; 15 - entrance to the pterygopalatine fossa; 16 - borders of the infratemporal fossa

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