The bones of the cranial

The occipital bone (os occipitale), unpaired, located in the posterior part of the cranial and consists of four parts, arranged around a large hole (foramen magnum) in the anteroinferior part of the external surface.

The main, or basilar part (pars basilaris) lies anterior to the external opening. In children, it connects to the sphenoid bone and cartilage by means of wedge-formed occipital synchondrosis (synchondrosis sphenooccipitalis), and in young adulthood (after 18-20 years), the cartilage is replaced by bone tissue and bone are fused. The upper inner surface of the basilar part facing into the cavity of the skull, slightly concave and smooth. It is part of the brain. At the outside edge of the bottom is rocky sinus groove (sulcus sinus petrosi inferior), adjacent to the posterior surface of the petrous temporal bone. The lower outer surface is convex and rough. At its center is the pharyngeal tubercle (tuberculum pharyngeum).

Lateral, or lateral part (pars lateralis), steam room, has an elongated shape. At its lower external surface is elliptical articular process - the occipital condyle (condylus occipitalis). Each condyle has a joint surface, through which I articulated with the cervical vertebra. Behind the articular process is condylar fossa (fossa condylaris) from occurring in her unstable condylar canal (canalis condylaris). At the base of the condyle is threaded sublingual canal (canalis hypoglossi). The side edge is cutting the jugular (incisura jugularis), which is teaming up with the same name by cutting the temporal bone forms the jugular hole (foramen jugulare). Pass through the hole jugular Vienna, glossopharyngeal, and vagus nerve extension. On the back edge of the jugular notch is a small ledge, which is called the jugular appendage (processus intrajugularis). Behind him on the inner surface of the skull is broad sulcus sigmoid sinus (sulcus sinus sigmoidei), which has an arcuate shape which is a continuation of the same name and furrows of the temporal bone. Front of her, on the upper surface of the side, is smooth, flat jugular tubercle (tuberculum jugulare).

In Fig. 60.
The occipital bone on the outside view
1 - external occipital protuberance;
2 - occipital scales;
3 - top line nuchae;
4 - external occipital crest;
5 - bottom line nuchae;
6 - a big hole;
7 - condylar fossa;
8 - condylar canal;
9 - lateral;
10 - the jugular notch;
11 - occipital condyle;
12 - jugular process;
13 - pharyngeal tubercle;
14 - the main part

The most massive part of the occipital bone is the occipital scales (squama occipitalis), located behind the foramen magnum and taking part in the formation of the base and cranial vault. In the center of the outer surface of the occipital scales located outside the occipital protuberance (protuberantia occipittalis externa), which is easily palpated through the skin. From the external occipital protuberance to the foramen magnum is directed external occipital crest (crista occipitalis externa). On both sides of the external occipital crest depart paired upper and lower nuchal line (linea nuchae superiores et inferiores), representing the trace of attachment of muscles. The upper nuchal lines are at the outer ledge, and the bottom - at the middle of the outer ridge. The inner surface in the center of the cruciform eminence (eminentia cruciformis), internal occipital protuberance is (protuberantia occipittalis interna). Down from him, until the foramen magnum, down internal occipital crest (crista occipitalis interna). On both sides of the cruciform elevation sent a broad shallow groove of the transverse sinus (sulcus sinus transversi) is a vertically upper sagittal sinus groove (sulcus sinus sagittalis superioris).

In Fig. 61.
The occipital bone inside view
1 - occipital scales;
2 - sagittal sinus groove of the upper;
3 - internal occipital protuberance;
4 - furrow transverse sinus;
5 - internal occipital crest;
6 - a big hole;
7 - groove sigmoid sinus;
8 - condylar canal;
9 - jugular process;
10 - groove bottom of the rocky bosom;
11 - lateral;
12 - the main part

 

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

Sphenoid (os sphenoidale), unpaired, located in the center of the skull base. In the sphenoid bone, which has a complex shape, release the body, small wings, large wings and pterygoid processes.

The body of the sphenoid bone (corpus ossis sphenoidalis) has a cubic shape, there are six surfaces. The upper surface of the body is turned into the cranial cavity and a cavity, called the Turkish saddle (sella turcica), which lies at the center of the hypophyseal fossa (fossa hypophysialis) from occurring in the lower appendage of her brain - the pituitary gland. Ephippium front seats is limited tubercle (tuberculum sellae), and back - a back seat (dorsum sellae). The rear surface of the body of sphenoid bone is connected to the basilar part of occipital bone. On the front surface there are two openings leading into the respiratory sphenoid sinus (sinus sphenoidalis) and are called sphenoid sinus aperture (apertura sinus sphenoidalis). Sinus is finally formed after 7 years within the body of sphenoid bone and a steam chamber, divided sphenoid sinus septum (septum sinuum sphenoidalium), leaving the front surface in the form of a wedge-shaped ridge (crista sphenoidalis). The lower part of the crest of pointed and wedge-shaped beak is (rostrum sphenoidale), wedged between the wings of the vomer (alae vomeris), attach to the bottom surface of the body of sphenoid bone.

Small wings (alae minores) are sent to the sphenoid bone on both sides of the body and peredneverhnih angles are two triangular plates. At the base of the small wings penetrated the optic canal (canalis opticus), which contains the optic nerve and ophthalmic artery. The upper surface of the small wings turned into the cranial cavity, and the lower is involved in the formation of the upper wall of the orbit.

The large wings (alae majores), the sphenoid bone recede into the side of the lateral surfaces of the body, heading outside. At the base of large wings located laterally and anteriorly a round hole (foramen rotundum), followed by oval (foramen ovale), through which pass branches of the trigeminal nerve, and laterally and posteriorly (in the angle of the wing ) is the neural hole (foramen spinosum), transmits an artery supplying the solid shell of the brain. The internal, cerebral, surface (facies cerebralis) is concave and the outer convex and consists of two parts: the orbital surface (facies orbitalis) involved in the formation of the walls of the orbit, and temporal surface (facies temporalis) involved in the formation of temporal fossa wall. Large and small wings limit the top orbital slot (fissura orbitalis superior), through which the orbit penetrate blood vessels and nerves.

In Fig. 62.
The occipital and sphenoid bones form the top
1 - the big wing of sphenoid bone;
2 - a small wing of the sphenoid bone;
3 - the visual channel;
4 - Mount of the sella turcica;
5 - Occipital scales occipital bone;
6 - upper orbital slot;
7 - a round hole;
8 - foramen ovale;
9 - a big hole;
10 - opening the neural

Pterygoid processes (processus pterygoidei) away from the junction of large wings to the body and head down. Each arm is formed by the outer and inner plates, connate in front and the rear wing divergent and restrictive fossa (fossa pterygoidea).

In Fig. 63.
Sphenoid bone, front view
1 - the big wing;
2 - little wing;
3 - upper orbital slot;
4 - Temporal surface;
5 - aperture sphenoid sinus;
6 - orbital surface;
7 - a round hole;
8 - wedge-shaped ridge;
9 - wedge-shaped channel;
10 - wedge-shaped beak;
11 - pterygoid bone;
12 - lateral plate pterygoid process;
13 - Medial pterygoid plate process;
14 - pterygoid hook

The inner plate of the medial pterygoid process (lamina medialis processus pterygoideus) is involved in the formation of the nasal cavity, and ends with wing-hook (hamulus pterygoideus). The outer lateral plate pterygoid process (lamina lateralis processus pterygoideus) wider, but less long. Its outer surface facing in the infratemporal fossa (fossa infratemporalis). At the base of each pterygoid bone is permeated with wing-channel (canalis pterygoideus), through which vessels and nerves.

Sphenoid bone connects to all the cranial bones.

In Fig. 64.
Temporal view from outside
1 - Scale of;
2 - the zygomatic process;
3 - mandibular fossa;
4 - articular tubercle;
5 - external auditory aperture;
6 - stony-scaled slit;
7 - drum part;
8 - mastoid;
9 - subulate appendage

 Temporal bone (os temporale), doubles, takes part in the formation of the skull base, the side wall and arch. In it are the organ of hearing and balance (see "Special Senses"), internal carotid artery, part of sigmoid venous sinus, preddverno-cochlear and facial nerves, the trigeminal nerve node, the branches of the vagus and glossopharyngeal nerve. In addition, connecting to the mandible, temporal bone serves as a support masticatory apparatus. It is divided into three parts: the stony, scaly, and drums.

In Fig. 65.
Temporal view from inside
1 - Scale of;
2 - the zygomatic process;
3 - arcuate eminence;
4 - Drum roof;
5 - poddugovaya fossa;
6 - the internal auditory opening;
7 - groove sigmoid sinus;
8 - mastoid hole;
9 - rocky part;
10 - external opening of the vestibular aqueduct;
11 - subulate appendage

The rocky part (pars petrosa)has the shape of triangular pyramid whose vertex faces anteriorly and medially, and the base, passing into mastoid bone (processus mastoideus), - posteriorly and laterally. On a smooth front surface of the petrous part (facies anterior partis petrosae), near the top of the pyramid is broad groove, which is a place adjoining the trigeminal nerve - the trigeminal indentation (impressio trigemini), and almost at the base of the pyramid are arcuate eminence (eminentia arcuata) formed by lying beneath the upper semicircular canals of the inner ear. The anterior surface is separated from the inner stone-flaked gap (fissura petrosquamosa). Between the slit and the arcuate eminence is a vast playground - tympanic roof (tegmen tympani), under which lies the tympanic cavity of the middle ear. Almost in the center of the rear surface of the rocky (facies posterior partis petrosae) noticeably internal auditory opening (porus acusticus internus), is directed to the internal auditory canal. Pass through the blood vessels, facial and cochlear nerves, preddverno. Above and lateral to the inner ear openings are poddugovaya fossa (fossa subarcuata), which penetrates the dura mater process. Another lateral hole is the external opening of the vestibule aqueduct (apertura externa aquaeductus vestibuli), through which the cavity of the inner ear endolymphatic duct exits. In the center of a rough bottom surface (facies inferior partis petrosae) there is an opening leading into a sleepy canal (canalis caroticus), and behind them is the jugular fossa (fossa jugularis). Lateral to the jugular fossa appears heading downwards and in front of a long subulate process (processus styloideus), a start point of the muscles and ligaments. At the base of this process is stylomastoid hole (foramen stylomastoideum), through which the cranial cavity leaves the facial nerve. Mastoid bone (processus mastoideus), which is a continuation of the rocky foundation, serves as a mounting sternocleidomastoid muscle.

On the medial side mastoid mastoid notch limits (incisura mastoidea), and on its internal, cerebral, side passes the S-shaped sigmoid sinus groove (sulcus sinus sigmoidei), from which the outer surface of the skull is the mastoid hole (foramen mastoideum), referring to the non-permanent venous graduates. Within the mastoid cavity are pneumatic - mastoid cells (cellulae mastoideae), communicating with the cavity of the middle ear through the mastoid caves (antrium mastoideum).

 In Fig. 66.
Temporal view from below
1 - the zygomatic process;
2 - musculo-Tube channel;
3 - articular tubercle;
4 - mandibular fossa;
5 - stony-scaled slit;
6 - subulate appendage;
7 - the jugular fossa;
8 - stylomastoid opening;
9 - mastoid;
10 - mastoid notch

Squamous portion (pars squamosa) has the shape of an oval plate, which is almost vertical. The outer surface of the temporal lobe (facies temporalis) slightly rough and slightly arched, and participates in the formation of temporal fossa (fossa temporalis), which is the point of beginning of the temporalis muscle. The inner surface of the brain (facies cerebralis) is concave, with traces of adjacent convolutions and arteries of finger indentations, cerebral arterial elevations and furrows. Front of the ear canal sideways and forwards up the zygomatic process (processus zygomaticus), which combines with temporal appendage, forming zygomatic arch (arcus zygomaticus). At the base of the appendix on the outer surface of the squamosal fossa is located mandibular (fossa mandibularis), which provides a connection to the lower jaw, which is limited to articular tubercle in front (tuberculum articularae).

Fig. 67.
Temporal elevation
1 - probe introduced into the front channel;
2 - mastoid cave;
3 - mastoid cells;
4 - polukanal muscles that bend the ear drum;
5 - polukanal auditory tube;
6 - probe was put into a sleepy canal;
7 - a probe introduced into the hole stylomastoid
The drum part (pars tympanica) fused with the squamosal and mastoid part, is a thin plate, bounding in front, behind and below the external auditory opening and ear canal.
In Fig. 68.
Parietal bone on the outside view
1 - sagittal region;
2 - occipital angle;
3 - frontal angle;
4 - the parietal lobe;
5 - the superior temporal line;
6 - occipital region;
7 - frontal margin;
8 - lower temporal line;
9 - mastoid angle;
10 - wedge angle;
11 - scaly edge

The temporal bone contains several channels:

- Sleepy canal (canalis caroticus), which overlies the internal carotid artery. It starts from the outer holes on the bottom of the rocky part, is directed vertically upward, then curving smoothly, runs horizontally and comes on top of the pyramid;

- Facial canal (canalis facialis), which houses the facial nerve. It begins in the inner ear canal, directed horizontally forward to mid-anterior surface of petrous part, where, turning at right angles to the side and passing to the rear section the medial wall of the tympanum, is vertically downward and opens stylomastoid opening;

- Musculo-Tube channel (canalis musculotubarius) partition into two parts: polukanal muscles that bend the ear drum (semicanalis m. tensoris tympani), and polukanal auditory tube (semicanalis tubae auditivae) connecting the tympanum with the pharynx. Channel is opened outside the hole, lying between the front end of the rocky part of the occipital bone and scales, and ends at the tympanum.

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

Parietal bone (os parietale), steam room, flat, is rectangular in shape and is involved in the formation of the upper and lateral part of the cranial vault.

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

The internal, cerebral, surface (facies interna) is concave, with a characteristic topography of adjacent brain, the so-called finger indentations (impressiones digitatae) and tree-like branching arterial grooves (sulci arteriosi).

In the bone is divided into four edges. The anterior frontal margin (margo frontalis) connects to the frontal bone. The rear edge of the occipital (margo occipitalis) - with the occipital bone. The upper sagittal or sagittal, the edge (margo sagittalis) is connected with the same edge of the other parietal bone. The lower edge of the flake (margo squamosus) on the front is covered large wing of sphenoid bone, a bit further - the scales of the temporal bone, and connects to the back teeth and mastoid temporal bone.

In Fig. 69.
Parietal bone inside view
1 - sagittal region;
2 - sagittal sinus groove of the upper;
3 - occipital angle;
4 - frontal angle;
5 - occipital region;
6 - frontal margin;
7 - arterial furrows;
8 - sigmoid sinus sulcus;
9 - mastoid angle;
10 - wedge angle;
11 - scaly edge
Also, there are four edges, respectively, the angle: frontal (angulus frontalis), occipital (angulus occipitalis), wedge (angulus sphenoidalis) and mastoid (angulus mastoideus ).
In Fig. 70.
The frontal bone outside view
1 - Frontal scales;
2 - frontal lobe;
3 - temporal line;
4 - Temporal surface;
5 - glabella;
6 - brow;
7 - supraorbital notch;
8 - supraorbital region;
9 - the zygomatic process;
10 - nose;
11 - nasal spine
In Fig. 71.
The frontal bone inside view
1 - sagittal sinus groove of the upper;
2 - arterial furrows;
3 - frontal crest;
4 - finger pressing;
5 - the zygomatic process;
6 - orbital part;
7 - nasal spine

The frontal bone (os frontale) unpaired, participates in the formation of the front of the vault and skull base, orbit, temporal fossa and nasal cavity. There are three parts: the frontal scales, orbital part and nose. 

The frontal scales (squama frontalis) is directed vertically and posteriorly. The outer surface (facies externa) is convex and smooth. Below the frontal scales pointed ends supraorbital margin (margo supraorbitalis), in which there is medial supraorbital notch (incisura supraorbitalis), which contains blood vessels and nerves of the same name. Front lateral supraorbital region ends triangular malar appendage (processus zygomaticus), which connects to the frontal process of malar bone. Backwards and upwards from the zygomatic process of the temporal lobe is arcuate line (linea temporalis), which separates the outer surface of the frontal temporal scales on its surface. The temporal surface (facies temporalis) is involved in the formation of the temporal fossa. Above the supraorbital edges on each side is brow (arcus superciliaris), which is the arcuate eminence. Between and just above the brow is smooth flat ground - glabella (glabella). Above each arch is rounded elevation - the frontal lobe (tuber frontale). The internal surface (facies interna) of the frontal scales concave, with the characteristic imprint of the convolutions of the brain and arteries. In the center of the inner surface of the upper sagittal sulcus is sinus (sulcus sinus sagittalis superioris), whose edges are united in the lower part of the frontal crest (crista frontalis).

 In Fig. 72.
The frontal bone is a bottom view
1 - nasal spine;
2 - supraorbital region;
3 - Block fossa;
4 - Block spine;
5 - lacrimal fossa;
6 - orbital surface;
7 - trellis cut
 In Fig. 73.
Ethmoid top view
1 - perpendicular to the plate;
2 - lattice cell;
3 - cockscomb;
4 - latticed labyrinth;
5 - grid plate;
6 - orbital plate
The orbital portion (pars orbitalis) pair, is involved in the formation of the upper wall of the orbit and has the form of a horizontal triangular plate. Lower orbital surface (facies orbitalis) is smooth and convex faces into the cavity of the orbit. At the base of the zygomatic bone in its lateral division is the lacrimal gland fossa (fossa glandulae lacrimalis). Medial orbital surface contains a bloc pit (fovea trochlearis), which lies in Block spine (spina trochlearis). The upper surface of the brain convex, with a distinctive topography.
NosoIn Fig. 74.
Ethmoid bottom view
1 - perpendicular to the plate;
2 - mesh plate;
3 - lattice cell;
4 - average turbinate;
5 - supraturbinal

The nose part (pars nasalis) of the frontal bone in an arc around grilled tenderloin (incisura ethmoidalis) and contains the fovea, articulates with the ethmoid labyrinth cells. In the anterior region is going down the nasal spine (spina nasalis). In the interior of the nose lies the frontal sinus (sinus frontalis), which is a septate cavity pair related to the respiratory paranasal sinuses.

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

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

In Fig. 75.
Ethmoid side view
1 - cock's comb;
2 - lattice cell;
3 - orbital plate;
4 - average turbinate;
5 - perpendicular to the plate
Ethmoid plate (lamina cribosa) is located in a lattice cutting out the frontal bone. On either side of it there is a lattice maze (labyrinthus ethmoidalis), consisting of a pneumatic lattice cells (cellulae ethmoidales). On the inner surface of the ethmoidal labyrinth has two curved appendage: the upper (concha nasalis superior) and average (concha nasalis media) turbinates.

Perpendicular plate (lamina perpendicularis) participates in the formation of the nasal cavity wall. Its upper part ends with a cock's crest (crista galli), which is attached a large sickle-shaped process of the solid shell of the brain.




List of Abbreviations

a., aa. — arteria, arteriae (artery, the artery)

lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)

m., mm. — musculus, musculi (muscle, the muscle)

n., nn. — nervus, nervi (nerve, the nerve)

r., rr. — ramus, rami (branch)

s. — seu (or)

v., vv. — vena, venae (vienna)