The outer base of the skull is the anterior section. Inner base of the skull

The inner surface of the base of the skull, basis cranii interna, is divided into three pits, of which the 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.

The anterior cranial fossa, fossa cranii anterior, is formed by the orbital parts of the frontal bone, the ethmoid plate of the ethmoid bone lying in the recess, the lesser 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).

The middle cranial fossa, fossa cranii media, is deeper than the anterior one. In it, a middle part is distinguished, 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 upper and lower ophthalmic veins flow.

The 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.

The 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.

The posterior cranial fossa, fossa cranii posterior, is the deepest and is separated from the middle one by the upper edges of the pyramids and the back of the Turkish saddle. It is formed by almost the entire occipital bone, part of the body of the sphenoid bone, the posterior surfaces of the pyramids and the mastoid parts of the temporal bones, as well as the posterior lower corners of the parietal bones.

In the center of the posterior cranial fossa there is a large occipital foramen, in front of it is the slope of Blumenbach, clivus. On the back surface of each of the pyramids lies the internal auditory opening, poms acusticus internus; the facial, n. facialis (VII pair), intermediate, n. intermedins, and vestibulo-cochlear, n. vestibuloco-chlearis (VIII pair), nerves pass through it.

Between the pyramids of the temporal bones and the lateral parts of the occipital are the jugular foramina, foramina jugularia, through which the glossopharyngeal, n. glossopharyngeus (IX pair), wandering, n. vagus (X pair), and accessory, n. accessorius (XI pair), nerves, as well as the internal jugular vein, v. jugularis interna. The central part of the posterior cranial fossa is occupied by a large occipital foramen, foramen occipitale magnum, through which the medulla oblongata with its membranes and vertebral arteries pass, aa. vertebrales. In the lateral parts of the occipital bone there are canals of the hyoid nerves, canalis n. hypoglossi (XII pair). In the region of the middle and posterior cranial fossae, the sulci of the sinuses of the dura mater are especially well represented.

In the sigmoid groove or next to it is v. emissaria mastoidea, which connects the occipital vein and the veins of the external base of the skull with the sigmoid sinus.

External base of the skull (basis cranii externa) is not visible in the anterior part, since it is covered by the bones of the facial skull. The posterior part of the base of the skull is formed by the outer surfaces of the occipital, temporal and sphenoid bones. Numerous openings are visible here, through which arteries, veins and nerves pass in a living person. Almost in the center of this area is large (occipital) foramen (foramen magnum), and on the sides of it are oval ledges - occipital condyles (condyli occipitales). Behind each condyle is a weakly expressed condylar fossa (fossa condylaris) with a non-permanent opening leading to the condylar canal (canalis condylaris).

The base of each condyle is transversely pierced sublingual canal (canalis nervi hypoglossi). The posterior part of the base of the skull ends with the outer occipital protuberance (protuberantia occipitalis externa) with an upper protruding line extending from it to the right and to the left. Anterior to the large (occipital) foramen is the basilar part of the occipital bone (pars basilaris ossis occipitalis) with a well-defined pharyngeal tubercle (tuberculum pharyngeum). The basilar part passes into body of sphenoid bone (corpus ossis sphenoidalis).

On the sides of the occipital bone, on each side, the lower surface of the pyramid of the temporal bone is visible, on which the most important formations are located: the external openings of the carotid canal, the musculo-tubal canal, the jugular fossa and the jugular notch, which, with the jugular notch of the occipital bone, forms the jugular foramen, the styloid process, mastoid process, and between them - the stylomastoid opening, which ends Fallopian canal(syn.: facial channel, canalis nervi facialis) in the pyramid of the temporal bone, starting at the bottom of the internal auditory meatus; the facial and intermediate nerves pass in the facial canal and the knee knot is placed.

To the pyramid of the temporal bone from the lateral side adjoins the tympanic part of the temporal bone, surrounding external auditory canal(Fallopius Gabriele (Palloppio Gabriele, 1523-1562) - Italian anatomist).

In the greater wing of the sphenoid bone, the formation of orifices of Vesalius(syn.: venous orifice, foramen venosum) - a non-permanent hole located between the round and oval holes; an emissary vein passes through this opening (Vesalius Andreas (Vesalius Andreas, 1515-1564) - an outstanding scientist of the Renaissance, the founder of modern anatomy).

An important topographic and anatomical landmark in determining the projection of the base of the skull is raid line- a horizontal line drawn through the centers of the external auditory canals (Reid Robert William (1851 - 1939) - Scottish anatomist).

Behind the tympanic part of the temporal bone is separated from the mastoid process tympanomastoid fissure (fissura tympanomastoidea). On the posteromedial side of the mastoid process are the mastoid notch (incisura mastoidea) and the groove of the occipital artery (sulcus arteriae occipitalis).

Between the tympanic part of the temporal bone and the edge of the roof of the tympanic cavity protruding outwards, there is a narrow space - the exit point of the drum string - the Glaser's fissure (syn.: Hugier canal, Chivinini canal, stony-tympanic fissure, fissura petrotympanica) (Glaser Johann Heinrich, 1629 - 1675) - Swiss physician and anatomist; Civinini Philippo (Civinini Filippo, 1805-1854) - Italian anatomist).

In a horizontal area squamous part of the temporal bone (pars squamosa ossis temporalis) there is a mandibular fossa that serves to connect with the condylar process of the lower jaw. In front of this fossa is the articular tubercle (tuberculum articulare). The gap between the petrous and squamous parts of the temporal bone on the whole skull includes the posterior part greater wing of the sphenoid bone (ala major ossis sphenoidalis), in which one can clearly see spinous and oval foramen (foramina spinosum et ovalis).

Above the ear canal stony-squamous tubule - Vergi plumbing (tubule), which is constantly expressed in the fetus and is not always present in adults (Verga Andreas (Verga Andreas, 1811-1895) - Italian neuropathologist and anatomist). The tubule is located and opens to the surface with a stony-scaly fissure (Ott's hole). Otta hole (fissura petrosguamosa) is a narrow space between the squamous part of the temporal bone and the protruding edge of the pyramid, where the stony-squamous tubule opens (Otto Adolph W., 1786-1845 - German surgeon and anatomist).

On the outer surface of the temporal bone above the upper edge of the external auditory opening is a protrusion - Zuckerkand for awn(syn.: Henle awn(Henle Friedrich Gustav Jacob, 1809-1885) - German anatomist and pathologist), supraproliferative spine of the temporal bone, spina suprameatica (Emil Zuckerkandl (Zuckerkandl Emil), 1849-1910 - Austrian anatomist). On the lateral surface of the mastoid process there is a Thorn triangle - a triangle, the boundaries of which are: from above - the continuation of the lower temporal line of the parietal bone to the scales of the temporal bone, in front - a line running from the top of the mastoid process to the supra-anal spine, behind - the line of attachment on the mastoid process of the sternum clavicular-mastoid muscle.

The pyramid of the temporal bone is separated from the occipital bone petrooccipital fissure (fissura petrooccipitalis), and from the large wing of the sphenoid bone - wedge-stony fissure (fissura sphenopetrosa). On the lower surface of the outer base of the skull, a hole with uneven edges is also visible - a torn hole (foramen lacerum), limited laterally and posteriorly by the top of the pyramid (apex partis petrosae) of the temporal bone, which is wedged between the body of the occipital bone and the greater wing of the sphenoid bone.

On the anterior superior portion of the mastoid process, Shipo zone, which is limited by a horizontal line drawn through the middle of the posterior wall of the external auditory canal, and a vertical line corresponding to the bony crest on the surface of the mastoid process. This area is the site of the passage of vessels that connect the mucous membrane of the mastoid cave with the periosteum of the mastoid process, here is located around the vascular tissue, which can contribute to the spread of pus in mastoiditis.

When describing the forms of the skull in different races in anthropology, it is widely used serre angle term(syn. metafacial angle) - the angle formed by the pterygoid process of the main bone and the base of the skull (Serres Antoine Etienne Renaud Augustin, 1786-1868 - French biologist and anatomist).

Educational video of the anatomy of the external base of the skull (basis cranii externa)

The bones of the skull, connecting with each other, form a large number of cavities, depressions and pits.

On the brain skull, its upper part is distinguished - the roof of the skull and the lower part - the base of the skull.

The roof of the skull is composed of the parietal bones, partly the frontal, occipital and temporal bones. The base of the skull is formed by the orbital parts of the frontal bone, ethmoid, sphenoid, temporal, and occipital bones.

Having separated the roof of the skull, one can study the inner base of the skull, which is divided into three cranial fossae: anterior, middle and posterior. The anterior cranial fossa is formed by the orbital part of the frontal bone, the ethmoid plate of the ethmoid bone, and the lesser wings of the sphenoid bone; the middle cranial fossa is predominantly the cerebral surface of the large wings of the sphenoid bone, the upper surface of its body, as well as the anterior surface of the temporal bone pyramid; the posterior cranial fossa is the occipital bone and the posterior surface of the petrous part of the temporal bone.

In the anterior cranial fossa are the frontal lobes of the cerebral hemispheres, in the middle - the temporal lobes, in the back - the cerebellum, bridge and medulla oblongata. Each hole has a number of holes. The anterior cranial fossa has holes in the cribriform plate that communicate it with the nasal cavity. From the middle cranial fossa, the superior orbital fissure and optic canal lead into the cavity of the orbit; a round opening leads into the pterygopalatine fossa and through it into the orbit; the oval and spinous foramen communicate the middle cranial fossa with the outer base of the skull. In the posterior cranial fossa there are several openings: a large (occipital), which communicates the cranial cavity with the spinal canal; jugular, leading to the outer surface of the base of the skull, and internal auditory, leading to the inner ear.

Looking at the skull from below, one can see that the base of the skull in its anterior section is covered by the bones of the face, which form the bony palate, consisting of the palatine processes of the upper jaws and the palatine bones. In the middle and posterior sections, the base of the skull is formed by the lower surfaces of the sphenoid, occipital, and temporal bones. They have a large number of foramina, in particular the jugular foramen between the occipital and temporal bones and the lacerated foramen between the petrosal part of the temporal bone and the sphenoid bone.

The largest topographic and anatomical formations of the facial skull are the orbit, nasal and oral cavities.

The eye socket has the shape of a tetrahedral pyramid. Its medial wall is formed by the frontal process of the upper jaw, the lacrimal bone, the orbital plate of the ethmoid bone, and partly by the body of the sphenoid bone; the upper wall is the orbital part of the frontal bone, small wings of the sphenoid bone; lateral wall - large wings of the sphenoid bone and zygomatic bone; the lower wall is the upper surface of the body of the upper jaw. The orbit communicates with the cranial cavity through the superior orbital fissure and the optic canal; with the nasal - through the nasolacrimal canal formed by the lacrimal bone, the frontal process of the upper jaw and the lower nasal concha; with the infratemporal and pterygopalatine fossae - with the help of the lower orbital fissure, which is located between the large wings of the sphenoid bone and the body of the upper jaw.

The nasal cavity has upper, lower and side walls. It is separated by a bony septum located in the median plane. The septum is formed by the perpendicular plate of the ethmoid bone and the vomer. The upper wall of the nasal cavity is formed by the ethmoid plate of the ethmoid bone, as well as the nasal and frontal bones; the lower wall is the palatine process of the upper jaw and the horizontal plate of the palatine bone; lateral walls - the upper jaw, the lacrimal and ethmoid bones, the inferior nasal concha, the perpendicular plate of the palatine bone and the medial surface of the pterygoid process of the sphenoid bone. The anterior opening of the nasal cavity, called the pear-shaped opening, communicates it with the environment; the posterior openings, the choanae, face the outer base of the skull and communicate the nasal cavity with the pharyngeal cavity.

The nasal cavity on the right and left is subdivided by the turbinates located on its lateral wall into three passages: lower, middle and upper. All of them are connected to each other by a common nasal passage located on the sides of the nasal septum. The nasal cavity communicates with the cavity of the skull, orbit, nasal and oral cavities, with the airways. The upper nasal passage communicates with the cranial cavity through the holes of the ethmoid plate of the ethmoid bone, the middle one - with the sinus of the upper jaw, with cells of the ethmoid bone and with the frontal sinus. Behind, at the level of the superior nasal concha, the sinus of the sphenoid bone opens into the nasal cavity. The inferior nasal passage communicates with the orbital cavity through the nasolacrimal canal. The nasal cavity also communicates with the pterygopalatine fossa through the sphenopalatine foramen and with the oral cavity through the incisive foramen.

The oral cavity is limited by bony walls only from above, in front and from the sides. Its upper wall is formed by the bony palate, composed of the palatine processes of the right and left upper jaws and the horizontal plates of the palatine bones; the lateral and anterior walls are formed by the lower jaw and the alveolar processes of the upper jaws. The oral cavity communicates through the incisal opening with the nasal cavity, and through the large palatine canal - with the pterygo-palatine fossa.

On the lateral surface of the skull are the pterygopalatine, infratemporal, and temporal fossae.

The pterygopalatine fossa is located between the bones of the facial and cerebral skulls and is bounded in front by the body of the upper jaw, on the medial side by the palatine bone, behind by the pterygoid process of the sphenoid bone, and from above by the body of this bone. It communicates with the nasal cavity, with the middle cranial fossa, with a ragged foramen, eye socket, and oral cavity. The pterygopalatine fossa does not have a lateral wall and passes outwards into the infratemporal fossa.

The infratemporal fossa is located behind the body of the upper jaw, inward from the zygomatic bone and zygomatic arch, and externally from the pterygoid process of the sphenoid bone. It forms part of the outer base of the brain skull. It is separated from the temporal fossa by the infratemporal crest.

The temporal fossa is a flat depression in which the temporalis muscle lies. The temporal surface of the large wings of the sphenoid bone, the scales of the temporal bone, and partly the parietal and frontal bones participate in the formation of the temporal fossa.

44859 0

External base of the skull (basis cranii externa) in the anterior section, 1/3 is covered by the facial skull, and only the posterior and middle sections are formed by the bones of the brain skull (Fig. 1). The base of the skull is uneven, has many holes through which the vessels and nerves pass (Table 1). In the posterior region is the occipital bone, along the midline of which are visible external occipital protuberance and descending external occipital crest. Anterior to the scales of the occipital bone lies big hole, bounded laterally occipital condyles, and in front - the basilar part of the occipital bone. Behind the occipital condyles there is a condylar fossa, turning into a non-permanent condylar canal (canalis condylaris) passing through the emissary vein. Passes at the base of the occipital condyles hypoglossal canal, in which the nerve of the same name lies. At the base of the mastoid process there is a mastoid notch and a groove of the occipital artery, behind which is located mastoid foramen through which the emissary foam passes. Medially and anterior to the mastoid process is awl mastoid foramen, and in front of him - styloid process. On the lower surface of the pyramid there is a well-defined jugular fossalimiting in front jugular foramen, where the internal jugular vein is formed and the IX-XI pair of cranial nerves exit the skull. At the top of the pyramid is a torn hole (foramen lacerum), anterior to which at the base of the pterygoid processes passes pterygoid canal opening into the pterygopalatine fossa. At the base of the large wings of the sphenoid bone there is an oval hole, and somewhat posteriorly - a spinous hole.

Rice. 1. External base of the skull (the infratemporal fossa is highlighted in color):

1 - bone palate; 2 - choana; 3 - medial plate of the pterygoid process; 4 - lateral plate of the pterygoid process; 5 - infratemporal fossa; 6 - oval hole; 7 - spinous opening; 8 - pharyngeal tubercle; 9 - mastoid process; 10 - external occipital crest; 11 - lower nuchal line; 12 - upper vynynaya line; 13 - external occipital protrusion; 14 - a large hole; 15 - occipital condyle; 16 - jugular fossa; 17 - stylomastoid opening; 18 - styloid process; 19 - mandibular fossa; 20 - external aperture of the carotid canal; 21 - zygomatic arch; 22 - infratemporal crest; 23 - torn hole

Table 1. Holes in the outer base of the skull and their purpose

Outside of the pyramid of the temporal bone is visible mandibular fossa, and in front of it - articular tubercle.

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

In the outer base, three sections are distinguished: anterior, middle and posterior, the relief of which is formed by the bones of the facial and cerebral skulls.

Anterior section or base of the facial skull.

In the middle there is a bony palate from the palatine processes of the upper jaws and horizontal plates of the palatine bones, bounded along the edge by the alveolar processes. The bone palate separates the cavities of the nose and mouth, and the muscles of the soft palate are attached to it from behind. The gingiva is located along the alveolar processes.

Between the palatine processes of the upper jaws and the horizontal plates of the palatine bones are the palatine median and transverse flat sutures.

An incisive foramen lies anteriorly in the bony palate, passing into the incisive canal for the nasopalatine vessels and nerve. On the surface there are transverse palatine furrows and palatine ridges between them, which smooth out the sky with age.

Large palatine openings lie behind, passing into the same canals - for the vessels and nerves of the same name.

The pyramidal process of the palatine bone contains openings of the small palatine tubules for the vessels and nerves of the same name.

The lateral sections of the base of the facial skull (right and left) consist of the pterygopalatine fossa, inferior orbital fissure and infratemporal crest, infratemporal fossa.

In the middle section (from the posterior edge of the bony palate and pterygoid processes to the anterior edge of the foramen magnum, styloid processes and external auditory foramen of the temporal bones) are:

the posterior edges of the nasal septum, vomer and nasal crest with the posterior spine, the sphenoid process of the palatine bone to delimit the choanae;

Pterygoid processes of the sphenoid bone with medial and lateral plates, pterygoid fossa between them, pterygoid notch and pterygoid hook for attaching pterygoid masticatory muscles and pharynx;

choanas - for air transfer to the nasopharynx;

The body of the sphenoid bone - the external carotid and torn foramina - for the internal carotid artery and nerve, large wings with holes: oval - for the second branch of the Y pair, spinous - for the middle meningeal artery;

pterygoid canal at the base of the pterygoid processes - for the same name autonomic nerves and vessels;

awn of the sphenoid bone - attachment of the ligament of the temporomandibular joint;

in the lateral sections - infratemporal fossa and mandibular fossa of the temporal bone, retromandibular fossa,

On the temporal bone - the mandibular fossa, the base of the zygomatic process - the articular tubercle for the temporomandibular joint, the sphenoid-stony and stony-tympanic fissures;

At the top of the temporal pyramid - the muscular-tubal canal for the auditory tube and the muscles of the eardrum;

Basilar part of the occipital bone - pharyngeal tubercle - the beginning of the pharynx.

In the posterior section (from the anterior edge of the large opening to the external occipital protrusion and the superior nuchal line) are:

The lower surface of the pyramid tympanic part of the temporal bone - the lower edge of the external auditory opening;

styloid, mastoid processes of the temporal bone;

jugular fossa, jugular notch, jugular foramen - for the internal jugular vein and IX, X, XI pairs of cranial nerves;

stylomastoid foramen - exit of the canal of the facial nerve - II pair;

Occipital condyles, condylar fossae behind them, canals of the hypoglossal nerves at the base of the occipital condyles;

occipital foramen magnum for the spinal cord and vertebral vessels;

Stony-occipital fissure filled with cartilage - synchondrosis;

external occipital crest and protrusion, inferior nuchal line for attachment of ligaments and muscles.

The temporal fossa is located in the anterolateral part of the fornix, bounded from above by the inferior temporal line, from below by the infratemporal crest of the sphenoid bone. On the lateral side, the temporal fossa has a zygomatic arch, and in front - the temporal surface of the zygomatic bone. It is filled with the temporal muscle and fiber of the interaponeurotic, subaponeurotic and deep temporal spaces. Above the muscle are superficial temporal vessels. Down, i.e. at the lateral edge of the outer base of the skull, it passes into the infratemporal fossa. The border between them is the infratemporal crest of the sphenoid bone.

The infratemporal fossa has:

upper border along the infratemporal crest;

lower - along the base and lateral plate of the pterygoid process;

anterior border - along the orbital edge of the sphenoid bone;

back - along the edge of the base of the zygomatic process of the temporal bone.

Laterally, the fossa is bounded by the inner surface of the lower jaw branch.

In the infratemporal fossa there is tissue of the temporal-pterygoid, inter-pterygoid and pterygo-mandibular spaces, the pterygoid muscles and the maxillary artery pass nearby, part of the pterygoid venous plexus and the retromaxillary vein lie. Through the pterygomaxillary fissure, the fossa communicates with the pterygopalatine fossa.