What bone is involved in the formation of the brain skull. Scull

Departments of the skull. The skull (cranium) consists of cerebral And facial departments. All bones are interconnected relatively immobile, except for the lower jaw, which forms a combined joint, and the movable hyoid bone, which lies freely on the neck. The bones of the brain skull form a receptacle for the brain, cranial nerves and sensory organs.

TO brain department The skull (neurocranium) includes 8 bones:

unpaired- occipital, wedge-shaped, ethmoid, frontal;
paired- parietal and temporal.

TO facial department The skull (splanchnocranium) includes 15 bones:

unpaired- lower jaw, vomer, hyoid bone;
paired - upper jaw, palatine, zygomatic, nasal, lacrimal, inferior nasal concha.

Bones of the brain. The bones of the brain skull, in contrast to the bones of the facial skull, have a number of features: on their inner surface there are imprints of convolutions and furrows of the brain. Channels for veins lie in the spongy substance, and some bones (frontal, sphenoid, ethmoid and temporal) have air sinuses.

Occipital bone(os occipitale) consists of scales, two side parts And main part. These parts define a large opening through which the cranial cavity communicates with the spinal canal. Main part occipital bone fuses with the sphenoid bone, forming a slope with its upper surface. On outer surface scales have an external occipital protuberance. On the sides of the foramen magnum are the condyles (articular surfaces that are connected by synastosis with the articular surface of the first vertebra). At the base of each condyle passes the hypoglossal canal.

Occipital bone(outside). 1 - large occipital foramen; 2 - scales; 3 - side part; 4 - condyle; 5 - canal of the hypoglossal nerve; 6 - body (main part); 7 - external occipital crest; 8 - external occipital protuberance

wedge-shaped, or mainbone(os sphenoidale) consists of a body and three pairs of processes - large wings, small wings and pterygoid processes. On the upper surface of the body is the so-called Turkish saddle, in the fossa of which the pituitary gland is placed. At the base of the small wing there is an optic canal (optical opening).

Both wings (small and large) limit the superior orbital fissure. There are three holes on the large wing: round, oval and spinous. Inside the body of the sphenoid bone there is an air sinus, divided by a bony septum into two halves.

Wedge-shaped (main) And ethmoid bone. 1 - cockscomb of the ethmoid bone; 2 - perforated plate of the ethmoid bone; 3 - labyrinth of the ethmoid bone; 4 - hole leading to the sinus of the sphenoid bone; 5 - sinus of the sphenoid bone; 6 - small wing; 7 - large wing; 8 - round hole; 9 - oval hole; 10 - spinous opening; 11 - perpendicular plate of the ethmoid bone; 12 - Turkish saddle of the sphenoid bone; 13 - back of the Turkish saddle; 14 - tubercle of the Turkish saddle; 15 - upper orbital fissure; 16 - visual channel

Ethmoid bone(os ethmoidale) consists of a horizontal, or perforated, plate, a perpendicular plate, two orbital plates and two labyrinths. Each labyrinth consists of small air cavities - cells separated by thin bone plates. Two curved bone plates hang from the inner surface of each labyrinth - the upper and middle turbinates.

frontal bone(os frontale) consists of scales, two orbital parts and a nasal part. On the scales there are paired protrusions - frontal tubercles and superciliary arches. Each orbital part in front passes into the supraorbital region. Air sinus frontal bone(sinus frontalis) is divided into two halves by a bony septum.

Parietal bone(os parietale) has the shape of a quadrangular plate; on its outer surface there is a protrusion - the parietal tubercle.

Temporal bone (os temporale) consists of three parts: scales, stony part, or pyramid, and drum part.

The temporal bone contains the organ of hearing, as well as channels for auditory tube, internal carotid artery and facial nerve. Outside on the temporal bone there is an external ear canal. Anterior to it is the articular fossa for the articular process of the lower jaw. The zygomatic process departs from the scales, which connects with the process of the zygomatic bone and forms the zygomatic arch. The rocky part (pyramid) has three surfaces: front, back and bottom. On its back surface is the internal auditory canal, in which the facial and vestibulocochlear (stato-auditory) nerves pass. The facial nerve leaves the temporal bone through the awl-mastoid foramen. A long styloid process departs from the lower surface of the stony part. Inside the petrous part is the tympanic cavity (middle ear cavity) and inner ear. The stony part also has a mastoid process (processus mastoideus), inside which are small air cavities - cells. Inflammatory process in cells mastoid process is called mastoiditis.

The skull (cranium) consists of the brain and facial sections. All bones are interconnected relatively immobile, except for the lower jaw, which forms a combined joint, and the movable hyoid bone, which lies freely on the neck. The bones of the brain skull form a receptacle for the brain, cranial nerves and sensory organs.

The brain region of the skull (neurocranium) includes 8 bones: unpaired - occipital, sphenoid, frontal, ethmoid; paired - parietal and temporal.

The facial section of the skull (splanchnocranium) includes 15 bones: unpaired - the lower jaw, vomer, hyoid bone; paired - upper jaw, palatine, zygomatic, nasal, lacrimal, inferior nasal concha.

Bones of the brain skull

The bones of the brain skull, in contrast to the bones of the facial skull, have a number of features: on their inner surface there are imprints of convolutions and furrows of the brain. Channels for veins lie in the spongy substance, and some bones (frontal, sphenoid, ethmoid and temporal) have air sinuses.

Bones of the facial skull

The bones of the facial skull represent a special group of bones due to the fact that they have a different origin in phylo- and ontogenesis than the bones of the brain skull. They form receptacles for the sense organs and are closely related to the respiratory and digestive systems ami.

55. Small bones of the facial skull.
1 - os zygomaticum; 2 - os lacrimale; 3 - os nasale; 4 - concha nasalis inferior; 5 - vomer.

Scull

All bones of the skull are connected with sutures (suturae) into a single cranium. The exception is the connection of the lower jaw with the base of the skull by the temporomandibular joint and the isolated position of the hyoid bone.

TO brain department The skull (neurocranium) includes 8 bones:

unpaired- occipital, wedge-shaped, ethmoid, frontal;
paired- parietal and temporal.

TO facial department The skull (splanchnocranium) includes 15 bones:

unpaired- lower jaw, vomer, hyoid bone;
paired- maxilla, palatine, zygomatic, nasal, lacrimal, inferior nasal concha.

Occipital bone(os occipitale) consists of scales, two side parts And main part. These parts define a large opening through which the cranial cavity communicates with the spinal canal. The main part of the occipital bone fuses with the sphenoid bone, forming a clivus with its upper surface. On the outer surface of the scales there is an external occipital protuberance. On the sides of the foramen magnum are the condyles (articular surfaces that are connected by synastosis with the articular surface of the first vertebra). At the base of each condyle passes the hypoglossal canal.

frontal bone(os frontale) consists of scales, two orbital parts and a nasal part. On the scales there are paired protrusions - frontal tubercles and superciliary arches. Each orbital part in front passes into the supraorbital region. The airy sinus of the frontal bone (sinus frontalis) is divided into two halves by the bony septum.

Parietal bone(os parietale) has the shape of a quadrangular plate; on its outer surface there is a protrusion - the parietal tubercle.

Temporal bone(os temporale) consists of three parts: scales, stony part, or pyramid, and drum part.

The temporal bone contains the organ of hearing, as well as channels for the auditory tube, internal carotid artery and facial nerve. Outside on the temporal bone there is an external auditory meatus. Anterior to it is the articular fossa for the articular process of the lower jaw. The zygomatic process departs from the scales, which connects with the process of the zygomatic bone and forms the zygomatic arch. The rocky part (pyramid) has three surfaces: front, back and bottom. On its back surface is the internal auditory canal, in which the facial and vestibulocochlear (stato-auditory) nerves pass. The facial nerve leaves the temporal bone through the awl-mastoid foramen. A long styloid process departs from the lower surface of the stony part. Inside the petrous part is the tympanic cavity (middle ear cavity) and the inner ear. The stony part also has a mastoid process (processus mastoideus), inside which are small air cavities - cells. The inflammatory process in the cells of the mastoid process is called mastoiditis.

Temporal bone(right). A - outside view; B - inside view; 1 - scales; 2 - zygomatic process; 3 - front surface of the rocky part; 4 - articular fossa; 5 - sigmoid groove; 6 - the top of the pyramid; 7 - in the upper figure - the drum part; in the lower figure - the internal auditory opening; 8 - styloid process; 9 - external auditory opening; 10 - mastoid process; 11 - mastoid opening

The skeleton of the head is represented by bones, which, tightly connected with sutures, protect the brain and sensory organs from mechanical influences. It gives support to the face, the initial sections of the respiratory and digestive systems.

Scull(cranium) is divided into two departments - cerebral and facial. The bones of the cerebral skull form a cavity for the brain and partly a cavity for the sense organs. The bones of the facial skull make up the bone basis of the face and the skeleton of the initial sections of the respiratory and digestive systems. The bones of the brain skull include eight bones: two pairs - temporal and parietal and four unpaired- frontal, ethmoid, wedge-shaped and occipital.

Part of the bones of the facial skull makes up the skeleton chewing apparatus: paired maxilla and unpaired lower jaw. Other facial bones are smaller. This paired bones: palatine, nasal, lacrimal, zygomatic, inferior nasal concha, to unpaired are vomer and hyoid bone.

frontal bone participates in the formation of the anterior part of the cranial vault and the anterior cranial fossa: The frontal bone consists of the frontal scales, orbital and nasal parts. The frontal scales are involved in the formation of the cranial vault. On the convex outer surface of the frontal bone are paired protrusions - forehead bumps, and lower - superciliary arches. The flat surface between the brow ridges is called glabella (glabella).

Parietal bone - a paired plate that forms middle part vault of the skull. It has a convex (outer) and concave (inner) surface:

The upper (sagittal) edge is connected to the opposite parietal bone, anterior (frontal) and posterior (occipital) - respectively with the frontal and occipital bones. The scales of the temporal bone (squamous bone) are superimposed on the lower edge of the parietal bone. The relief of the inner surface of the parietal bone is due to the adjacent hard meninges and her vessels.

Occipital bone(os occipitale) consists of the basilar and two lateral parts, the occipital scales: They surround the large occipital foramen, through which the cranial cavity is connected to the spinal canal. Anterior to the large occipital foramen is the main (basilar) part of the occipital bone, which, fused with the body of the sphenoid bone, forms a somewhat inclined surface - slope

On the lower surface of the lateral (lateral) parts is occipital condyle, employee for connection with I cervical vertebra. The basilar and lateral parts and the lower sections of the occipital scales are involved in the formation of the base of the skull (posterior fossa), where the cerebellum and other brain structures are located.

The occipital scales are involved in the formation of the cranial vault. In the center of its inner surface is a cruciform elevation, which forms the internal occipital protrusion. The serrated edge of the scales is connected with the lambdoid suture. parietal and temporal bones.

Ethmoid bone together with other bones takes part in the formation anterior section the base of the brain skull, the walls of the orbits and the nasal cavity of the facial part of the skull.

The bone consists of a cribriform plate, from which a perpendicular plate extends downward, which participates in the formation of the septum of the nasal cavity. On both sides of the perpendicular plate are lattice labyrinths consisting of air cells. There are three pairs of ethmoid cells that connect to the nasal cavity: anterior, middle and posterior.

Sphenoid bone located between the frontal and occipital bones and is located in the center of the base of the skull: In shape, this bone resembles a butterfly. It consists of a body and three paired processes: large and small wings and pterygoid processes. On the upper surface of the body of the bone there is a recess (Turkish saddle), in which the main gland is located. internal secretion - pituitary. In the body of the sphenoid bone there is a sinus that connects to the nasal cavity. From the anterior superior surface of the sphenoid bone, two small wings depart to the sides, at the base of each there is a large opening of the optic canal, through which it passes into the orbit optic nerve. Between the small and large wings is the superior orbital fissure, through which the oculomotor, lateral, and abducens nerves pass from the cranial cavity to the orbit. ophthalmic nerve- I branch trigeminal nerve.

Temporal bone - a paired bone, which is part of the base of the skull and the lateral part of the cranial vault, connects in front with the sphenoid, behind - with the occipital and above - with the parietal bones. The temporal bone is container for the organs of hearing and balance, vessels and nerves pass through its channels. With the lower jaw, the temporal bone forms a joint, and with the zygomatic bone, the zygomatic arch.

On the inner surface of the squamous part there are finger-like depressions and cerebral eminences, a trace of the middle meningeal artery is visible.

On the outer convex surface of the scaly part, somewhat higher and anterior to the external auditory opening, a horizontally located zygomatic process begins. At the base of the latter is the mandibular fossa, with which the condylar process of the mandible forms a joint.

Pyramid (rocky part) the temporal bone has a trihedral shape. Behind the external opening of the carotid canal, the jugular fossa is visible, which in the region of the posterior edge of the pyramid passes into the jugular notch. The jugular notches of the temporal and occipital bones, when they are connected, on the whole skull form jugular foramen through which the internal jugular vein and three cranial nerve: glossopharyngeal, vagus and accessory.

In the pyramid of the temporal bone, the carotid and facial canals, as well as the tubule of the tympanic string, the tympanic tubule, the mastoid tubule, the carotid-tympanic tubules, in which the vessels, nerves and the muscle straining the eardrum are located, are located.

ANOTHER OPTION!!!

The skull is a collection of tightly connected bones and forms a cavity in which the vital organs are located.

The brain part of the skull is formed by the occipital, sphenoid, parietal, ethmoid, frontal and temporal bones.The sphenoid bone is located in the center of the base of the skull and has a body from which processes extend: large and small wings, pterygoid processes.The body of the sphenoid bone has six surfaces: anterior, inferior, superior, posterior, and two lateral.The large wing of the sphenoid bone has three openings at the base: round, oval and spinousThe lesser wing has an anterior inclined process on the medial side.The pterygoid process of the sphenoid bone has lateral and medial plates fused in front.

Occipital bone has a basilar part, lateral parts and scales. Connecting, these departments form a large occipital foramen.The lateral part of the occipital bone has an occipital condyle on its lower surface. Above the condyles passes the hypoglossal canal, behind the condyle is the fossa of the same name, at the bottom of which is the condylar canal.The occipital scales of the occipital bone have an external occipital protrusion in the center of the outer surface from which the crest of the same name descends.

frontal bone consists of the nasal and orbital parts and the frontal scales, which occupy most vault of the skull. The nasal part of the frontal bone on the sides and in front limits the ethmoid notch. The median line of the anterior part of this part ends with the nasal spine, to the right and left of which is the aperture of the frontal sinus, which leads to the right and left frontal sinuses. Right part the orbital part of the frontal bone is separated from the left ethmoid notch

Parietal bone has four edges: occipital, frontal, sagittal and scaly. The parietal bone forms the upper lateral vaults of the skull.

Temporal bone is a receptacle for the organs of balance and hearing. The temporal bone, connecting with the zygomatic bone, forms the zygomatic arch. The temporal bone consists of three parts: squamous, tympanic and petrosal.

The ethmoid bone consists of the ethmoid labyrinth, the ethmoid and perpendicular plates.The ethmoid labyrinth of the ethmoid bone consists of communicating ethmoid cells.

The skeleton of the head, that is, the skull (cranium) (Fig. 59), consists of a cerebral and facial skull.

Rice. 59. Skull A - front view; B - side view:1 - parietal bone;2 - frontal bone;3 - sphenoid bone;4 - temporal bone;5 - lacrimal bone;6 - nasal bone;7 - zygomatic bone;8 - upper jaw;9 - lower jaw;10 - occipital bone

The brain skull is ovoid in shape and is formed by the occipital, frontal, sphenoid, ethmoid, a pair of temporal and a pair of parietal bones. facial skull formed by six paired bones (maxilla, inferior nasal concha, lacrimal, nasal, zygomatic and palatine bone) and three unpaired (lower jaw, hyoid bone, vomer) and represents the initial section of the digestive and respiratory apparatus. The bones of both skulls are connected to each other with sutures and are practically motionless. The lower jaw is connected to the skull by a joint, therefore it is the most mobile, which is necessary for its participation in the act of chewing.

The cranial cavity is a continuation spinal canal It contains the brain. The upper part of the brain skull, formed by the parietal bones and scales of the frontal, occipital and temporal bones, is called the vault or roof of the skull (calvaria cranii). The bones of the cranial vault are flat, their outer surface is smooth and even, and the inner surface is smooth, but uneven, since the furrows of the arteries, veins and adjacent convolutions of the brain are marked on it. Blood vessels are located in the spongy substance - diploe (diploe), located between the outer and inner plates of the compact substance. The inner plate is not as strong as the outer one, it is much thinner and more fragile. The lower part of the brain skull, formed by the frontal, occipital, sphenoid and temporal bones, is called the base of the skull (basis cranii).

Bones of the brain skull

The occipital bone (os occipitale) (Fig. 59) is unpaired, located in the posterior part of the brain skull and consists of four parts located around a large hole (foramen magnum) (Fig. 60, 61, 62) in the anteroinferior section of the outer surface.

The main, or basilar, part (pars basilaris) (Fig. 60, 61) lies anterior to the external opening. IN childhood it connects to the sphenoid bone with the help of cartilage and forms a wedge-occipital synchondrosis (synchondrosis sphenooccipitalis), and in adolescence (after 18–20 years) the cartilage is replaced bone tissue and the bones grow together. The upper inner surface of the basilar part, facing the cranial cavity, is slightly concave and smooth. It contains part of the brain stem. At the outer edge there is a groove of the lower petrosal sinus (sulcus sinus petrosi inferior) (Fig. 61), adjacent to the posterior surface of the petrous part of the temporal bone. The lower outer surface is convex and rough. In the center of it is the pharyngeal tubercle (tuberculum pharyngeum) (Fig. 60).

Lateral, or lateral, part (pars lateralis) (Fig. 60, 61) steam room, has an elongated shape. On its lower outer surface is an elliptical articular process - the occipital condyle (condylus occipitalis) (Fig. 60). Each condyle has an articular surface, through which it articulates with the I cervical vertebra. Behind the articular process is the condylar fossa (fossa condylaris) (Fig. 60) with the non-permanent condylar canal (canalis condylaris) lying in it (Fig. 60, 61). At the base, the condyle is pierced by the hypoglossal canal (canalis hypoglossi). On the lateral edge is the jugular notch (incisura jugularis) (Fig. 60), which, combined with the same notch of the temporal bone, forms the jugular foramen (foramen jugulare). Through this hole pass the jugular vein, glossopharyngeal, accessory and vagus nerves. On the posterior edge of the jugular notch is a small protrusion called the jugular process (processus intrajugularis) (Fig. 60). Behind him, along the inner surface of the skull, there is a wide groove of the sigmoid sinus (sulcus sinus sigmoidei) (Fig. 61, 65), which has an arcuate shape and is a continuation of the temporal bone groove of the same name. Anterior to it, on the upper surface of the lateral part, there is a smooth, gently sloping jugular tubercle (tuberculum jugulare) (Fig. 61).

Rice. 60. Occipital bone (outside view):

1 - external occipital protrusion; 2 - occipital scale; 3 - upper vynynaya line; 4 - external occipital crest; 5 - lower vynynaya line; 6 - a large hole; 7 - condylar fossa; 8 - condylar canal; 9 - side part; 10 - jugular notch; 11 - occipital condyle; 12 - jugular process; 13 - pharyngeal tubercle; 14 - main part

The most massive part of the occipital bone is the occipital scales (squama occipitalis) (Fig. 60, 61, 62), located behind the large occipital foramen and taking part in the formation of the base and vault of the skull. In the center, on the outer surface of the occipital scales, there is an external occipital protrusion (protuberantia occipittalis externa) (Fig. 60), which is easily palpable through the skin. From the external occipital protrusion to the large occipital foramen, the external occipital crest (crista occipitalis externa) is directed (Fig. 60). Paired upper and lower nuchal lines (linea nuchae superiores et inferiores) (Fig. 60) depart from the external occipital crest on both sides, which are a trace of muscle attachment. The upper protruding lines are at the level of the outer protrusion, and the lower ones are at the level of the middle of the outer ridge. On the inner surface, in the center of the cruciform eminence (eminentia cruciformis), there is an internal occipital protrusion (protuberantia occipittalis interna) (Fig. 61). Down from it, up to the large occipital foramen, the internal occipital crest (crista occipitalis interna) descends (Fig. 61). A wide flat groove of the transverse sinus (sulcus sinus transversi) is directed to both sides of the cruciform eminence (Fig. 61); the furrow of the superior sagittal sinus (sulcus sinus sagittalis superioris) goes vertically upwards (Fig. 61).

Rice. 61. Occipital bone (inside view):

1 - occipital scales; 3 - internal occipital protrusion; 4 - groove of the transverse sinus; 5 - internal occipital crest; 6 - a large hole; 8 - condylar canal; 9 - jugular process; 10 - furrow of the lower stony sinus; 11 - side part; 12 - main part

The occipital bone is connected to the sphenoid, temporal and parietal bones.

The sphenoid bone (os sphenoidale) (Fig. 59) is unpaired, located in the center of the base of the skull. In the sphenoid bone, which has a complex shape, the body, small wings, large wings and pterygoid processes are distinguished.

The body of the sphenoid bone (corpus ossis sphenoidalis) has a cubic shape, six surfaces are distinguished in it. The upper surface of the body faces the cranial cavity and has a depression called the Turkish saddle (sella turcica), in the center of which is the pituitary fossa (fossa hypophysialis) with the lower appendage of the brain, the pituitary gland, lying in it. In front, the Turkish saddle is limited by the tubercle of the saddle (tuberculum sellae) (Fig. 62), and in the back by the back of the saddle (dorsum sellae). The posterior surface of the body of the sphenoid bone is connected to the basilar part of the occipital bone. On the front surface there are two openings leading to the airy sphenoid sinus (sinus sphenoidalis) and called the aperture of the sphenoid sinus (apertura sinus sphenoidalis) (Fig. 63). The sinus is finally formed after 7 years inside the body of the sphenoid bone and is a paired cavity separated by the septum of the sphenoid sinuses (septum sinuum sphenoidalium), which emerges on the front surface in the form of a sphenoid ridge (crista sphenoidalis) (Fig. 63). The lower section of the crest is pointed and is a wedge-shaped beak (rostrum sphenoidale) (Fig. 63), wedged between the wings of the vomer (alae vomeris), which is attached to the lower surface of the body of the sphenoid bone.

Small wings (alae minores) (Fig. 62, 63) of the sphenoid bone are directed in both directions from the anteroposterior corners of the body and represent two triangular plates. At the base, the small wings are pierced by the optic canal (canalis opticus) (Fig. 62), which contains the optic nerve and the ophthalmic artery. The upper surface of the small wings faces the cranial cavity, and the lower surface takes part in the formation of the upper wall of the orbit.

Large wings (alae majores) (Fig. 62, 63) of the sphenoid bone move away from the side surfaces of the body, heading outward. At the base of the large wings there is a round hole (foramen rotundum) (Fig. 62, 63), then an oval (foramen ovale) (Fig. 62), through which the branches of the trigeminal nerve pass, and outwards and backwards (in the region of the wing angle ) there is a spinous opening (foramen spinosum) (Fig. 62), passing the artery that feeds the hard shell of the brain. The inner, cerebral, surface (facies cerebralis) is concave, and the outer one is convex and consists of two parts: the orbital surface (facies orbitalis) (Fig. 62), which is involved in the formation of the walls of the orbit, and the temporal surface (facies temporalis) (Fig. 63) involved in the formation of the wall of the temporal fossa. Large and small wings limit the upper orbital fissure (fissura orbitalis superior) (Fig. 62, 63), through which blood vessels and nerves enter the orbit.

Rice. 62. Occipital and sphenoid bones (top view):

1 - a large wing of the sphenoid bone; 2 - small wing of the sphenoid bone; 3 - visual channel; 4 - tubercle of the Turkish saddle; 5 - occipital scales of the occipital bone; 6 - upper orbital fissure; 7 - round hole; 8 - oval hole; 9 - a large hole; 10 - spinous foramen

Pterygoid processes (processus pterygoidei) (Fig. 63) depart from the junction of large wings with the body and go down. Each process is formed by the outer and inner plates, fused in front, and diverging behind and limiting the pterygoid fossa (fossa pterygoidea).

Rice. 63. Sphenoid bone (front view):

1 - large wing; 2 - small wing; 3 - upper orbital fissure; 4 - temporal surface; 5 - aperture of the sphenoid sinus; 6 - orbital surface; 7 - round hole; 8 - wedge-shaped ridge; 9 - wedge-shaped channel; 10 - wedge-shaped beak; 11 - pterygoid process; 12 - lateral plate of the pterygoid process; 13 - medial plate of the pterygoid process; 14 - pterygoid hook

The inner medial plate of the pterygoid process (lamina medialis processus pterygoideus) (Fig. 63) takes part in the formation of the nasal cavity and ends with a pterygoid hook (hamulus pterygoideus) (Fig. 63). The outer lateral plate of the pterygoid process (lamina lateralis processus pterygoideus) (Fig. 63) is wider, but less long. Its outer surface faces the infratemporal fossa (fossa infratemporalis). At the base, each pterygoid process is pierced by the pterygoid canal (canalis pterygoideus) (Fig. 63), through which the vessels and nerves pass.

The sphenoid bone is connected to all the bones of the brain skull.

Rice. 64. Temporal bone (outside view): 1 - scaly part;2 - zygomatic process;3 - mandibular fossa;4 - articular tubercle;5 - external auditory opening;6 - stony-scaly gap;7 - drum part;8 - mastoid process;9 - styloid process

The temporal bone (os temporale) (Fig. 59) is paired, takes part in the formation of the base of the skull, lateral wall and arch. It contains the organ of hearing and balance (see the "Sense Organs" section), the internal carotid artery, part of the sigmoid venous sinus, the vestibulocochlear and facial nerves, the trigeminal ganglion, the branches of the vagus and glossopharyngeal nerves. In addition, connecting with the lower jaw, the temporal bone serves as a support for the masticatory apparatus. It is divided into three parts: stony, scaly and drum.

Rice. 65. Temporal bone (inside view): 1 - scaly part;2 - zygomatic process;3 - arched elevation;4 - drum roof;5 - subarc fossa;6 - internal auditory opening;7 - groove of the sigmoid sinus;8 - mastoid opening;9 - rocky part;10 - outer opening of the water supply vestibule;11 - styloid process

The stony part (pars petrosa) (Fig. 65) has the shape of a tripartite pyramid, the top of which is facing anteriorly and medially, and the base, which passes into the mastoid process (processus mastoideus), is posteriorly and laterally. On the smooth front surface of the stony part (facies anterior partis petrosae), near the top of the pyramid, there is a wide depression, which is the place of the adjoining trigeminal nerve, the trigeminal depression (impressio trigemini), and almost at the base of the pyramid there is an arcuate elevation (eminentia arcuata) (Fig. 65), formed by the upper semicircular canal of the inner ear lying under it. The front surface is separated from the inner stony-scaly fissure (fissura petrosquamosa) (Fig. 64, 66). Between the gap and the arcuate elevation is a vast platform - the tympanic roof (tegmen tympani) (Fig. 65), under which lies the tympanic cavity of the middle ear. Almost in the center of the posterior surface of the stony part (facies posterior partis petrosae), the internal auditory opening (porus acusticus internus) (Fig. 65) is noticeable, heading into the internal auditory meatus. Vessels, facial and vestibulocochlear nerves pass through it. Above and lateral to the internal auditory opening is the subarc fossa (fossa subarcuata) (Fig. 65), into which the process of the dura mater penetrates. Even more lateral to the opening is the external opening of the vestibule aqueduct (apertura externa aquaeductus vestibuli) (Fig. 65), through which the endolymphatic duct exits the cavity of the inner ear. In the center of the rough lower surface (facies inferior partis petrosae) there is an opening leading to the carotid canal (canalis caroticus), and behind it is the jugular fossa (fossa jugularis) (Fig. 66). Lateral to the jugular fossa, a long styloid process (processus styloideus) (Fig. 64, 65, 66), which is the point of origin of muscles and ligaments, protrudes downward and anteriorly. At the base of this process is the stylomastoid foramen (foramen stylomastoideum) (Fig. 66, 67), through which the facial nerve. The mastoid process (processus mastoideus) (Fig. 64, 66), which is a continuation of the base of the stony part, serves as an attachment point for the sternocleidomastoid muscle.

On the medial side, the mastoid process is limited by the mastoid notch (incisura mastoidea) (Fig. 66), and along its inner, cerebral side, there is an S-shaped groove of the sigmoid sinus (sulcus sinus sigmoidei) (Fig. 65), from which to the outer surface of the skull leads mastoid opening (foramen mastoideum) (Fig. 65), relating to non-permanent venous graduates. Inside the mastoid process there are air cavities - mastoid cells (cellulae mastoideae) (Fig. 67), communicating with the middle ear cavity through the mastoid cave (antrium mastoideum) (Fig. 67).

Rice. 66. Temporal bone (bottom view):

1 - zygomatic process; 2 - muscular-tubal channel; 3 - articular tubercle; 4 - mandibular fossa; 5 - stony-scaly gap; 6 - styloid process; 7 - jugular fossa; 8 - stylomastoid opening; 9 - mastoid process; 10 - mastoid notch

The scaly part (pars squamosa) (Fig. 64, 65) has the shape of an oval plate, which is located almost vertically. The outer temporal surface (facies temporalis) is slightly rough and slightly convex, participates in the formation of the temporal fossa (fossa temporalis), which is the starting point of the temporal muscle. The inner cerebral surface (facies cerebralis) is concave, with traces of adjacent convolutions and arteries: digital depressions, cerebral eminences and arterial grooves. Anterior to the external auditory canal, the zygomatic process (processus zygomaticus) rises sideways and forward (Fig. 64, 65, 66), which, connecting with the temporal process, forms the zygomatic arch (arcus zygomaticus). At the base of the process, on the outer surface of the scaly part, there is a mandibular fossa (fossa mandibularis) (Fig. 64, 66), which provides a connection with the lower jaw, which is limited in front by the articular tubercle (tuberculum articularae) (Fig. 64, 66).

Rice. 67. Temporal bone (vertical section):

1 - the probe is inserted into the facial canal; 2 - mastoid cave; 3 - mastoid cells; 4 - semi-channel of the muscle straining the eardrum; 5 - semi-canal of the auditory tube; 6 - the probe is inserted into the carotid canal; 7 - the probe is inserted into the stylomastoid foramen

The tympanic part (pars tympanica) (Fig. 64) is fused with the mastoid process and the squamous part, it is a thin plate that limits the external auditory opening and the external auditory meatus in front, behind and below.

Rice. 68. Parietal bone (outside view):

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

The temporal bone contains several canals:

Carotid canal (canalis caroticus) (Fig. 67), in which lies the internal carotid artery. It starts from the outer opening on the lower surface of the rocky part, goes vertically upwards, then, gently curving, passes horizontally and exits at the top of the pyramid;

The facial canal (canalis facialis) (Fig. 67), in which the facial nerve is located. It begins in the internal auditory meatus, goes horizontally forward to the middle of the anterior surface of the petrous part, where, turning at a right angle to the side and passing into the posterior part of the medial wall of the tympanic cavity, it goes vertically down and opens with a stylomastoid opening;

The muscular-tubal canal (canalis musculotubarius) (Fig. 66) is divided by a septum into two parts: the semi-canal of the muscle that strains the eardrum (semicanalis m. tensoris tympani) (Fig. 67), and the semi-canal of the auditory tube (semicanalis tubae auditivae) (Fig. 67), connecting the tympanic cavity with the pharyngeal cavity. The canal opens with an external opening lying between the anterior end of the petrous part and the scales of the occipital bone, and ends in the tympanic cavity.

The temporal bone is connected to the occipital, parietal and sphenoid bones.

The parietal bone (os parietale) (Fig. 59) is paired, flat, has a quadrangular shape and takes part in the formation of the upper and lateral parts of the cranial vault.

The outer surface (facies externa) of the parietal bone is smooth and convex. The place of its greatest convexity is called the parietal tubercle (tuber parietale) (Fig. 68). Below the hillock are the upper temporal line (linea temporalis superior) (Fig. 68), which is the site of attachment of the temporal fascia, and the lower temporal line (linea temporalis inferior) (Fig. 68), which serves as the site of attachment of the temporal muscle.

The inner, cerebral, surface (facies interna) is concave, with a characteristic relief of the adjacent brain, the so-called digital impressions (impressiones digitatae) (Fig. 71) and tree-like branching arterial grooves (sulci arteriosi) (Fig. 69, 71).

Four edges are distinguished in the bone. The anterior frontal edge (margo frontalis) (Fig. 68, 69) is connected to the frontal bone. Rear occipital margin (margo occipitalis) (Fig. 68, 69) - with the occipital bone. The upper swept, or sagittal, edge (margo sagittalis) (Fig. 68, 69) is connected to the same edge of the other parietal bone. The lower squamous edge (margo squamosus) (Fig. 68, 69) is covered in front by the large wing of the sphenoid bone, a little further by the scales of the temporal bone, and behind it is connected to the teeth and mastoid process of the temporal bone.

Rice. 69. Parietal bone (inside view): 1 - sagittal edge;2 - furrow of the superior sagittal sinus;3 - occipital angle;4 - frontal angle;5 - occipital margin;6 - frontal edge;7 - arterial grooves;8 - groove of the sigmoid sinus;9 - mastoid angle;10 - wedge-shaped angle;11 - scaly edge

Also, according to the edges, four corners are distinguished: frontal (angulus frontalis) (Fig. 68, 69), occipital (angulus occipitalis) (Fig. 68, 69), wedge-shaped (angulus sphenoidalis) (Fig. 68, 69) and mastoid (angulus mastoideus ) (Fig. 68, 69).

Rice. 70. Frontal bone (outside view):

1 - frontal scales; 2 - frontal tubercle; 3 - temporal line; 4 - temporal surface; 5 - glabella; 6 - superciliary arch; 7 - supraorbital notch; 8 - supraorbital margin; 9 - zygomatic process; 10 - bow; 11 - nasal spine

Rice. 71. Frontal bone (inside view):

1 - furrow of the superior sagittal sinus; 2 - arterial grooves; 3 - frontal scallop; 4 - finger indentations; 5 - zygomatic process; 6 - orbital part; 7 - nasal spine

The frontal bone (os frontale) (Fig. 59) is unpaired, participates in the formation of the anterior part of the vault and base of the skull, eye sockets, temporal fossa and nasal cavity. Three parts are distinguished in it: the frontal scales, the orbital part and the nasal part.

Frontal scales (squama frontalis) (Fig. 70) is directed vertically and backwards. The outer surface (facies externa) is convex and smooth. From below, the frontal scales end in a pointed supraorbital margin (margo supraorbitalis) (Fig. 70, 72), in the medial part of which there is an supraorbital notch (incisura supraorbitalis) (Fig. 70), containing the vessels and nerves of the same name. The lateral section of the supraorbital margin ends with a triangular zygomatic process (processus zygomaticus) (Fig. 70, 71), which connects to the frontal process of the zygomatic bone. Behind and upward from the zygomatic process, an arcuate temporal line (linea temporalis) (Fig. 70) passes, separating the outer surface of the frontal scale from its temporal surface. The temporal surface (facies temporalis) (Fig. 70) is involved in the formation of the temporal fossa. Above the supraorbital margin on each side is the superciliary arch (arcus superciliaris) (Fig. 70), which is an arcuate elevation. Between and slightly above the superciliary arches there is a flat, smooth area - the glabella (glabella) (Fig. 70). Above each arc there is a rounded elevation - the frontal tubercle (tuber frontale) (Fig. 70). The inner surface (facies interna) of the frontal scales is concave, with characteristic indentations from the convolutions of the brain and arteries. The groove of the superior sagittal sinus (sulcus sinus sagittalis superioris) (Fig. 71) runs along the center of the inner surface, the edges of which in the lower section are combined into the frontal scallop (crista frontalis) (Fig. 71).

Rice. 72. Frontal bone (view from below):

1 - nasal spine; 2 - supraorbital margin; 3 - block hole; 4 - block awn; 5 - fossa of the lacrimal gland; 6 - orbital surface; 7 - lattice cut

Rice. 73. Ethmoid bone (top view):

2 - lattice cells; 3 - cockscomb; 4 - lattice labyrinth; 5 - lattice plate; 6 - orbital plate

The orbital part (pars orbitalis) (Fig. 71) is steam room, takes part in the formation of the upper wall of the orbit and has the form of a horizontally located triangular plate. The lower orbital surface (facies orbitalis) (Fig. 72) is smooth and convex, facing the cavity of the orbit. At the base of the zygomatic process in its lateral section is the fossa of the lacrimal gland (fossa glandulae lacrimalis) (Fig. 72). The medial part of the orbital surface contains a trochlear fossa (fovea trochlearis) (Fig. 72), in which lies the trochlear spine (spina trochlearis) (Fig. 72). The upper cerebral surface is convex, with a characteristic relief.

Rice. 74. Ethmoid bone (bottom view):

1 - perpendicular plate; 2 - lattice plate; 3 - lattice cells; 5 - superior turbinate

The nasal part (pars nasalis) (Fig. 70) of the frontal bone in an arc surrounds the ethmoid notch (incisura ethmoidalis) (Fig. 72) and contains pits that articulate with the cells of the labyrinths of the ethmoid bone. In the anterior section there is a descending nasal spine (spina nasalis) (Fig. 70, 71, 72). In the thickness of the bow lies frontal sinus(sinus frontalis), which is a paired cavity separated by a septum, related to the air-bearing paranasal sinuses.

The frontal bone is connected to the sphenoid, ethmoid and parietal bones.

The ethmoid bone (os ethmoidale) is unpaired, participates in the formation of the base of the skull, the orbit and the nasal cavity. It consists of two parts: a lattice, or horizontal, plate and a perpendicular, or vertical, plate.

Rice. 75. Ethmoid bone (side view): 1 - cockscomb;2 - lattice cells;3 - orbital plate;4 - middle nasal concha;5 - perpendicular plate

Ethmoid plate (lamina cribosa) (Fig. 73, 74, 75) is located in the ethmoid notch of the frontal bone. On both sides of it is a lattice labyrinth (labyrinthus ethmoidalis) (Fig. 73), consisting of air-bearing lattice cells (cellulae ethmoidales) (Fig. 73, 74, 75). On the inner surface of the ethmoid labyrinth there are two curved processes: the upper (concha nasalis superior) (Fig. 74) and the middle (concha nasalis media) (Fig. 74, 75) nasal conchas.

Perpendicular plate (lamina perpendicularis) (Fig. 73, 74, 75) is involved in the formation of the septum of the nasal cavity. Her top part ends with a cockscomb (crista galli) (Fig. 73, 75), to which is attached a large falciform process of the dura mater.