home » Plastic surgery » Temporal surface of the greater wing in Latin. Anatomy of the sphenoid bone

Temporal surface of the greater wing in Latin. Anatomy of the sphenoid bone

Sphenoid bone, os sphenoidale , unpaired, forms the central section of the base of the skull.

The middle part of the sphenoid bone - the body, corpus, is cubic in shape, has six surfaces. On the upper surface, facing the cranial cavity, there is a depression - the sella turcica, sella turcica, in the center of which is the pituitary fossa, fossa hypophysialis. It contains the pituitary gland, hypophysis. The size of the pit depends on the size of the pituitary gland. The front border of the sella turcica is the tubercle sellae, tuberculum sellae. Posterior to it, on the lateral surface of the sella, there is a non-constant middle inclined process, processus clinoideus medius.

Body of the sphenoid bone–corpusphenoidalis

Pituitary fossa–fossahypophysialis

Tubercle sella–tuberculumsellae

Posterior inclined processes– processus clinoidei posterioris

Anterior oblique process–processusclinoideusanterior

Carotid fissure–sulcuscaroticum

Wedge-shaped tongue– lingual sphenoidalis

Wedge-shaped beak–rostrum sphenoidale

Wedge-shaped shell– conchae sphenoidalis

Aperture of the sphenoid sinus– aperture sinus sphenoidalis

Sphenoid sinus– sinus sphenoidalis

Small wing– ala minor

Big wing–ala major

Visual channel–canalisopticus

Upper orbital fissure – fissura orbitalis superior

Round hole–foramen rotundum

Oval hole–foramenovale

Foramen spinosum–foramenspinosus

Brain surface–faciescerebralis

Finger-shaped impressions–impressionsdigitals

Arterial groove–sulcus arteriosi

Orbital surface–faciesorbitales

Maxillary surface–faciesmaxillaries

Temporal surface–facies temporalis

Infratemporal crest–cristainfratemporalis

Pterygoid process–processuspterygoideus

Pterygoid canal–canalispterygoideus

Spine of sphenoid bone–spinaossissphenoidalis

Medial plate–lamina medialis

Lateral plate–laminalateralis

Pterygoid fossa–fossapterygoidea

Pterygoid notch–incisurapterygoidea

Wing hook–hamulus pterygoideas

Body of the sphenoid bone

On the upper surface of the body there is a depression - the sella turcica, containing the pituitary gland. The anterior border of the sella is the tubercle of the sella, the posterior border is the dorsum of the sella. On the sides of the sella turcica there are carotid grooves with cavernous sinuses, in which the internal carotid arteries and accompanying nerve plexuses pass. Anterior to the tubercle sella is the fissure of the chiasm, on which the optic chiasm is located. The dorsum of the sella protrudes forward in the lateral sections, forming posterior inclined processes. The posterior surface of the dorsum of the sella turcica smoothly continues with the upper surface of the basilar part occipital bone, forming a slope.

Anteriorly, the body of the sphenoid bone is connected to the perpendicular plate of the ethmoid bone and the vomer through a vertically located wedge-shaped ridge. Posteriorly, the body of the sphenoid bone fuses with the basilar part of the occipital bone.

Most of the body of the sphenoid bone is made of an air-filled sphenoid sinus, divided into two halves by a septum. In front, the sinus is limited by wedge-shaped shells located on the sides of the sphenoid crest. The shells form openings - apertures, through which the wedge-shaped cavity communicates with the nasal cavity. The walls of the sphenoid sinus are lined with mucous membrane.

Small wings

The small wings are directed to the sides from the anterosuperior corners of the body in the form of two horizontal plates. At their base there are rounded holes, which are the beginning of the optic canals containing the optic nerves and ophthalmic arteries. The upper surfaces of the small wings face the cranial cavity, the lower ones face the cavity of the orbits, forming the upper walls of the superior orbital fissures. The anterior edges of the wings articulate with the orbital parts of the frontal bone. The posterior edges lie freely in the cranial cavity, being the border of the anterior and middle cranial fossae.

The lesser wings are connected to each other by a wedge-shaped eminence located in front of the decussation groove.

Big wings

Large wings extend outward from the lateral surfaces of the bone body. The large wing has four surfaces and three edges. At the base of the greater wing there are three openings: the foramen rotundum, through which the maxillary nerve passes; oval, through which the mandibular nerve passes; spinous (it passes the middle meningeal artery, vein and nerve).

Large wing surfaces

The upper surface of the brain faces the cranial cavity.

The orbital surface, anterosuperior, has a rhomboid shape. Facing the orbital cavity, forming part of its lateral wall. The lower edge of the orbital surface of the wing, along with the posterior edge of the orbital surface of the upper jaw, forms the lower orbital fissure.

The maxillary surface, anterior, is triangular in shape and small in size. It is limited from above by the orbital surface, from the side and below - by the root of the pterygoid process. The maxillary surface participates in the formation of the posterior wall of the pterygopalatine fossa. There is a round hole in it.

The temporal surface, superolateral, is divided by the infratemporal crest into the immediate temporal and pterygoid surfaces. The temporal surface is involved in the formation of the temporal fossa. The oval and spinous foramina open on the pterygoid surface. The pterygoid surface forms the anterior wall of the infratemporal fossa.

Edges of the large wing

The frontal edge, superior, is connected to the orbital part of the frontal bone through the sphenoid-frontal suture. The outer sections of the frontal edge end with a sharp parietal edge, forming a sphenoparietal suture with the parietal bone. The internal sections of the frontal margin pass into a thin free edge, limiting the superior orbital fissure below.

The zygomatic margin, anterior, connects with the frontal process of the zygomatic bone, forming the sphenoid-zygomatic suture.

Squamosal margin, posterior, connected to wedge-shaped margin temporal bone and forms a wedge-squamous suture. Posteriorly and externally, the scaly edge ends with the spine of the sphenoid bone. Inward from the spine, the scaly edge is located in front of the petrous part of the temporal bone, forming with it a sphenoid-petrous fissure, which passes medially into the foramen lacerum.

Pterygoid processes

The pterygoid processes (lat. processus pterygoidei) begin at the junction of the large wings with the body of the sphenoid bone and are located vertically downward. At the base of the processes there are pterygoid canals, in which the nerves and vessels of the same name pass. In front, each canal opens into the pterygopalatine fossa.

Each process consists of medial and lateral plates, which are fused in the anterior-superior sections, limiting the pterygoid fossa in front. The free, unfused ends of the plates limit the pterygoid notch, filled with the pyramidal process of the palatine bone. The lower end of the medial plate ends with a wing-shaped hook directed downward and outward.

Body of the sphenoid bone, corpus ossis sphenoidalis, the middle part of the bone, cubic in shape, has six surfaces. The upper surface of the body, facing the cranial cavity, has a depression in its middle sections - the sella turcica, sella turcica. in the center of which is the pituitary fossa. It contains the pituitary gland. The size of the fossa is determined by the size of the pituitary gland. The pituitary fossa is especially vulnerable in the case of premature birth. The fusion of the two ossification nuclei of the fossa occurs in the 8th month of intrauterine life. This raises the possibility of damage to the structure of the pituitary fossa with subsequent dysfunction of the pituitary gland. The sella turcica is limited in front by the tubercle of the sella, tuberculum sellae. Posterior to it, on the lateral surface of the saddle, there is a non-constant middle inclined process, processus clinoideus medius. Anterior to the tubercle sella there is a shallow transverse groove of the decussation, sulcus chiasmatis. It lies on the optic chiasm, chiasma opticum. On the sides the groove passes into the optic canal, canalis opticus. In front of the furrow there is a smooth surface - a wedge-shaped eminence, jugum sphenoidale, connecting the small wings of the sphenoid bone. The anterior edge of the upper surface of the body is serrated, protrudes slightly forward and connects with the posterior edge of the perforated plate, lamina cribrosa, ethmoid bone, forming a sphenoethmoidal suture, sutura sphenoethmoidalis. The perforated plate has a large number of holes (25-30), through which the branches of the anterior ethmoidal (olfactory) nerve and the vein accompanying the anterior ethmoidal artery go from the nasal cavity to the cranial cavity (there are olfactory grooves on the sides of the anterior edge of the sphenoid bone). If the sense of smell is impaired or absent, the kinetics of the anterior edge of the sphenoid bone should be checked. As a result of injury to the frontal bone, a violation of the relationship in the sphenoid-ethmoidal suture may occur with subsequent trauma to the olfactory bulbs.

The sella turcica is limited at the back by the back of the saddle, dorsum sellae, which ends on each side with a small posterior inclined process, processus clinoideus posterior. On the sides of the sella turcica, from back to front, runs the carotid groove, sulcus caroticus(imprint of the internal carotid artery located here and the accompanying nerve plexus).

Rice. Sphenoid bone (according to H. Feneis, 1994): 1 – body; 2 – wedge-shaped eminence; 3 – large wing, 4 – small wing; 5 – precross groove; 6 – sella turcica; 7 – pituitary fossa; 8 – anterior inclined process; 9 – posterior inclined process; 10 – back of the saddle; 11 – carotid groove; 12 – wedge-shaped ridge; 13 – wedge-shaped beak; 14 – aperture of the sphenoid sinus; 15 – visual channel; 16 – superior orbital fissure; 17 – brain surface; 18 – temporal surface; 19 – orbital surface; 20 – zygomatic edge; 21 – frontal edge; 22 – parietal edge; 23 – scaly edge; 24 – infratemporal crest; 25 – round hole; 26 – oval hole; 27 – foramen spinosum; 28 – spine of the sphenoid bone; 29 – pterygoid (vidian) canal; 30 – pterygoid process; 31 – lateral plate of the pterygoid process; 32 – medial plate of the pterygoid process; 33 – pterygoid hook; 34 – pterygoid notch; 35 – wedge-shaped surface spheno-basilar synchondrosis.

The posterior surface of the dorsum sella passes into the upper surface of the basilar part of the occipital bone, forming a slope, clivus. There is a bridge on the slope, medulla, basilar artery with its branches. The posterior surface of the body is rough. Through a cartilaginous layer, it is connected to the anterior surface of the basilar part of the occipital bone, forming the sphenoid-occipital synchondrosis (SSO), synchondrosis sphenooccipitalis. More often in the osteopathic literature and among osteopaths, another term is found - sphenobasilar symphysis. Despite the existence of the International Nomenclature, the latter anatomical term has taken root and is most common among osteopaths. It is believed that by the age of 25 the cartilage is replaced bone tissue and both bones grow together. However, there is still no consensus on this issue. It is likely that the bones are still not completely fused.

The front and part of the lower surface of the body are facing the nasal cavity. In the middle of the front surface of the body there is a vertically running wedge-shaped crest, crista sphenoidalis. Its anterior edge is adjacent to the posterior edge of the perpendicular plate, lamina perpendicularis, ethmoid bone. The lower segment of the crest is pointed, extended downwards, and forms a wedge-shaped beak, rostrum sphenoidale, which is wedged between the wings of the opener, alae vomeris. On the sides of the ridge lies a thin curved plate - a wedge-shaped shell, concha sphenoidalis. This shell, forming the anterior and partly lower walls of the sphenoid sinus, sinus sphenoidalis, has a small opening - the aperture of the sphenoid sinus, apertura sinus sphenoidalis. Outside the aperture there are small depressions that cover the cells of the posterior part of the labyrinth of the ethmoid bone. The outer edges of these recesses are partially connected to the orbital plate of the ethmoid bone, forming a sphenoethmoidal suture, sutura sphenoethmoidalis, and the lower ones - with the orbital process, processus orbitalis, palatine bone.

sphenoid sinus, sinus sphenoidalis, a paired cavity, fills most of the body of the sphenoid bone and belongs to the air-bearing paranasal sinuses. Both, right and left, sinuses are separated from one another by the septum of the sphenoid sinuses, which anteriorly continues into the sphenoid crest. As in the frontal sinuses, the septum sometimes lies asymmetrically, as a result of which the size of both sinuses may not be the same. Through the aperture, the cavity of each sphenoid sinus opens into the nasal cavity. The cavity of the sphenoid sinus is lined with mucous membrane.

Small wings, alae minores, the sphenoid bone has two roots extending in both directions from the anterior-superior corners of the body in the form of two horizontally located plates, at the base of which there is a rounded hole. It represents the beginning of a bone canal up to 5-6 mm long - the optic canal, canalis opticus. It contains the optic nerve, n. opticus, And ophthalmic artery, a. ophthalmica. The small wings have an upper surface facing the cranial cavity and a lower surface directed into the orbital cavity and closing the superior orbital fissure from above, fissura orbitalis superior. The anterior edge of the lesser wing, thickened and jagged, connects to the orbital part of the frontal bone. The posterior concave and smooth edge protrudes freely into the cranial cavity and is the boundary between the anterior and middle cranial fossae, fossae cranii anterior et media. The medial posterior edge ends in a prominent, well-defined, anterior inclined process, processus clinoideus anterior(a part of the dura mater is attached to it, forming the diaphragm of the sella turcica, diaphragma sellae).

Large wings of the sphenoid bone, alae majores, extend from the lateral surfaces of the body of the sphenoid bone and are oriented outward. The large wing has five surfaces and three edges. Upper, medullary surface facies cerebralis, concave and facing the cranial cavity. It forms the anterior section of the middle cranial fossa and bears sulcal depressions, cerebral eminences and arterial grooves, sulci arteriosi(relief imprints of the adjacent surface of the brain and middle meningeal arteries). At the base of the large wing there are three openings: a round opening is located inwardly and anteriorly, foramen rotundum(the maxillary nerve exits through it, n. maxillaris). Outside and posterior to the round there is an oval foramen, foramen ovale (it passes the mandibular nerve, n. mandibularis, and the vascular network of the foramen ovale). Also lateral and posterior to the foramen ovale is the foramen spinosum, foramen spinosum(the middle meningeal artery, vein and nerve pass through it). Anterosuperior, orbital surface, facies orbitalis, smooth, diamond-shaped, facing the cavity of the orbit, where it forms most of its outer wall. The lower edge of this surface is distant from the posterior edge of the orbital surface of the body of the upper jaw; the inferior orbital fissure is formed here, fissura orbitalis inferior. Anterior, maxillary surface, facies maxillaris, a small triangular-shaped area, limited above by the orbital surface, and on the side and below by the root of the pterygoid process of the sphenoid bone. It is part of the posterior wall of the pterygopalatine fossa, fossa pterygopalatina. There is a round hole on the surface. Superolateral, temporal surface, facies temporalis, somewhat concave, takes part in the formation of the wall of the temporal fossa, fossa temporalis(the temporalis muscle is attached to it, m. temporalis). Below this surface is limited by the infratemporal crest, crista infratemporalis, below which is the surface where the foramen ovale opens, foramen ovale, and the foramen spinosum. It forms the superior wall of the infratemporal fossa, fossa infratemporalis. This is where part of the lateral pterygoid muscle begins, m. pterygoideus lateralis. The upper, frontal, edge is widely serrated, connected to the orbital part of the frontal bone in the sphenoid-frontal suture ( sutura sphenofrontalis). The outer sections of the frontal edge end with a sharp parietal edge, margo parietalis, which with the wedge-shaped angle of the parietal bone forms the sphenoid-parietal suture ( sutura sphenoparietalis). The internal sections of the frontal edge pass into a thin free edge, which is spaced from the lower surface of the lesser wing, limiting the superior orbital fissure from below fissura orbitalis superior. Anterior, zygomatic margin, margo zygomaticus, serrated, connected to the frontal process, processus frontalis, zygomatic bone, forming the sphenoid-zygomatic suture ( sutura sphenozygomatica). Posterior, scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, temporal bone in the sphenosquamosal suture ( sutura sphenosquamosa). Posteriorly and outwardly, the scaly edge ends with the spine of the sphenoid bone, spina ossis sphenoidalis. Here is the place of attachment of the sphenomandibular ligament, lig. sphenomandibulare, and bundles of the muscle that strains the velum palatine, m. tensor veli palatini. Inward to the spine of the sphenoid bone, the posterior edge of the greater wing lies in front of the petrous part, pars petrosa, temporal bone and limits the sphenoid-petrosal fissure, fissura sphenopetrosa, passing medially into the foramen lacerum, foramen lacerum. This gap is filled with cartilaginous tissue, forming a wedge-shaped petrosal synchondrosis, synchondrosis sphenopetrosa.

Pterygoid processes, processus pterygoidei, extend from the junction of the large wings with the body of the sphenoid bone and are directed downwards. The pterygoid processes are formed by two plates - lateral and medial. Lateral plate, lamina lateralis processus pterygoidei, wider, but thinner and shorter than the inner one (the lateral pterygoid muscle begins from its outer surface, m. pterygoideus lateralis). medial plate, lamina medialis processus pterygoidei, narrower, thicker and slightly longer than the outer one. Both plates grow together with their anterior edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea(here begins the medial pterygoid muscle, m. pterygoideus medialis). In the lower sections, both plates do not fuse and limit the pterygoid notch, incisura pterygoidea, filled with a pyramidal process, processus pyramidalis, palatine bone. The free end of the inner plate ends with a wing-shaped hook directed downwards and outwards, hamulus pterygoideus, on the outer surface of which there is a groove of the pterygoid hook, sulcus hamuli pterygoidei(the tendon of the muscle that strains the velum palatine is thrown through it, m. tensor veli palatini). The posterior-superior edge of the inner plate at the base expands and forms an oblong scaphoid fossa, fossa scaphoidea(bundles of muscles that strain the velum palatine begin in it, m. tensor veli palatini). A shallow groove runs outward from the scaphoid fossa auditory tube, sulcus tubae audilivae, which laterally passes onto the greater wing and reaches the spine of the sphenoid bone (the cartilaginous part of the auditory tube is adjacent to this groove). Above the scaphoid fossa and medial from it there is an opening leading to the pterygoid canal, canalis pterygoideus(vessels and nerves pass through it). The canal runs in the sagittal direction in the thickness of the base of the pterygoid process and opens on the maxillary surface of the large wing of the sphenoid bone on the posterior wall of the pterygopalatine fossa. Under the exit opening, along the anterior edge of the pterygoid process, is the pterygopalatine groove. The internal plate at its base gives off an inwardly directed flat horizontally running vaginal process, processus vaginalis, which is located under the body of the sphenoid bone, covering the side of the vomer wing. As a result of this, the groove of the vaginal process facing the wing is the vomerovaginal groove, sulcus vomerovaginalis, turns into the vomerovaginal canal, canalis vomerovaginalis. Outside of the process there is sometimes a small sagittal sulcus running sagittally, sulcus palatovaginalis. In the latter case, the sphenoid process of the palatine bone, adjacent below, closes the groove into the canal of the same name (in both canals there are nerve branches of the pterygopalatine ganglion, and in the palatovaginal canal there are also branches of the sphenopalatine artery). Sometimes the pterygospinous process is directed from the posterior edge of the outer plate towards the spine of the sphenoid bone. processus pterygospinosus, which can reach the specified spine and form a hole.

The sphenoid bone (os sphenoidale) is unpaired, located in the center of the base of the skull, and has four parts (Fig. 46).

The body (corpus) occupies a central position. On the upper surface of the body, from front to back, the following formations are located: the groove of the optic chiasm (sulcus chiasmatis), the tubercle of the sella (tuberculum sellae), the sella turcica (sellaV turcica). In its center there is a fossa for the location of the pituitary gland (fossa hypophysialis). Behind the pituitary fossa is the back of the sella turcica (dorsum sellae), which has the shape of a plate, on the upper edge of which there are two inclined posterior processes directed forward (processus clinoidei posteriores). On the sides of the body of the bone and the sella turcica there is an imprint from the pressure of the internal carotid artery (sulcus caroticus).

The anterior surface of the body of the sphenoid bone faces the nasal cavity. A wedge-shaped ridge (crista sphenoidal) runs along its midline, connecting to the vomer. To the right and left of the ridge there are openings of the sphenoid sinus (aperturae sinus sphenoidalis), opening into paired air sinuses (sinus sphenoidales).

The large wing (ala major) is paired and extends laterally from the body of the bone. It has a cerebral surface facing upward, an orbital surface facing forward, an inferotemporal surface visible from the outside, and a maxillary surface facing downwards. At the base of the large wing there is a round hole (for. rotundum); posterior to it there is an oval foramen (for. ovale) and then a spinous foramen of smaller diameter (for. spinosum).

The minor wing (ala minor) is paired. Each in the form of a triangular plate starts from the lateral surfaces of the body. Closer to the midline, an anterior inclined process (processus clinoideus anterior), facing posteriorly, extends from the posterior edge of the lesser wing. At the base of the lesser wing there is the optic canal (canalis opticus), in which the optic nerve and ophthalmic artery pass. Between the wings is the superior orbital fissure (fissura orbitalis superior).

The pterygoid process (processus pterygoideus) is paired, starting from the lower surface of the base of the large wing. At the beginning of the process, a pterygoid canal runs from front to back, connecting the foramen lacerum (for. lacerum) with the pterygopalatine fossa. Each process has a lateral and medial plate (lamina lateralis et medialis). The latter bends at the bottom in the form of a wing-shaped hook (hamulus pterygoideus); the tendon of the muscle that strains the soft palate is thrown through it.

Ossification. At 8 weeks embryonic development In the cartilaginous rudiments of the large wings, bone points appear, which grow into the outer plates of the pterygoid processes. At the same time, ossification points are formed in the connective tissue medial plates. At 9-10 weeks, bone buds also appear in the small wings. Three pairs of bone points are formed in the body, of which at the 12th week of intrauterine development the two posterior ones are connected into one. The bone points are located in front and behind the sella turcica and fuse at the 10-13th year.

The sinus of the sphenoid bone in a newborn is represented by a protrusion of the mucous membrane of the nasal cavity with a depth of 2-3 mm, directed downward and backward. At the age of 4 years, the protrusion of the mucous membrane penetrates into the resorbed cavity of the cartilaginous body of the sphenoid bone, at 8-10 years - into the body of the sphenoid bone to its middle, and by 12-15 years it grows to the place of fusion of the body of the sphenoid and occipital bones (Fig. 47) .

Anomalies. Between the front and rear parts the body of the bone may have a hole (the remnant of the canal connecting the cranial cavity with the pharynx). This anomaly occurs as a result of non-fusion of the anterior and posterior parts of the bone body. In animals, a cartilaginous layer remains for a long time between the anterior and posterior parts of the bone body.

Sphenoid bone, os sphenoidale, unpaired, resembles a flying insect, which explains the name of its parts (wings, pterygoid processes).

The sphenoid bone is the product of the fusion of several bones that independently exist in animals, therefore it develops as a mixed bone from several paired and unpaired ossification points, forming 3 parts at the time of birth, which in turn fuse into a single bone by the end of the first year of life.

It has the following parts:

1) body, corpus;

2) big arms, alae majores;

3) small wings,alae minores;

4)pterygoid processes, processus pterygoidei(its medial plate is the former double pterygoid, develops on the basis of connective tissue, while all other parts of the bone arise on the basis of cartilage).

Sphenoid bone. Back view. 1. Visual channel; 2. Saddle back; 3. Posterior inclined process; 4. Anterior inclined process; 5. Small wing; 6. Superior orbital fissure; 7. Parietal angle; 8. Large wing (cerebral surface); 9. Round hole; 10. Pterygoid canal; 11. Scaphoid fossa; 12. Lateral plate (pterygoid process); 13. Pterygoid notch; 14. Groove of the pterygoid hook; 15. Vaginal process; 16. Wedge-shaped ridge; 17. Body of the sphenoid bone; 18. Medial plate (pterygoid process); 19. Wing-shaped hook; 20. Pterygoid fossa; 21. Groove of the internal carotid artery.

Body, corpus, on its upper surface has a depression along the midline - saddle turcica, sella turcica, at the bottom of which lies hole For pituitary gland, fossa hypophysialis.In front of it there is an elevation, tuberculum sellae, along which passes transversely sulcus chiasmatis for cross ( chiasma) optic nerves; at the ends sulcus chiasmatis visible visual channels, canales optici, through which the optic nerves pass from the cavity of the orbits to the cavity of the skull. Posteriorly, the sella turcica is limited by a bony plate, back of the saddle, dorsum sellae. On the lateral surface of the body there is a curved carotid sulcus, sulcus caroticus, trace of the internal carotid artery.

On the anterior surface of the body, which is part of the posterior wall of the nasal cavity, is visible crest, crista sphenoidalis, below entering between the wings of the opener. Christa sphenoidalis connects anteriorly with the perpendicular plate of the ethmoid bone. Irregularly shaped holes are visible on the sides of the ridge, aperturae sinus sphenoidalis, leading to air sinus, sinus sphenoidalis, which is placed in the body of the sphenoid bone and is divided partition, septum sinum sphenoidalium, in two halves. Through these openings the sinus communicates with the nasal cavity. In a newborn, the sinus is of very small size and only around the 7th year of life begins to grow rapidly.

Small wings, alae minores, are two flat triangular plates, which with two roots extend anteriorly laterally from the anterosuperior edge of the body of the sphenoid bone; between the roots of the small wings are the mentioned visual channels, canales optici. Between the lesser and greater wings there is the superior orbital fissure, fissura orbitalis superior, leading from the cranial cavity to the orbital cavity.

Big wings, alae majores, extend from the lateral surfaces of the body laterally and upward. Near the body, behind fissura orbitalis superior available round hole, foramen rotundum, leading anteriorly into the pterygopalatine fossa, caused by the passage of the second branch trigeminal nerve, n. trigemini. At the back, a large wing in the form of an acute angle protrudes between the scales and the pyramid of the temporal bone. There is a foramen spinosum, foramen spinosum, through which it passes a. meningea media. Much more is visible in front of him foramen ovale, foramen ovale, through which the third branch passes n.trigemini.

Large wings have four surfaces: brain,facies cerebralis, orbital,facies orbitalis, temporal, facies temporalis, And maxillary, facies maxillaris. The names of the surfaces indicate the areas of the skull where they face. The temporal surface is divided into the temporal and pterygoid parts by infratemporal crest, crista infritemporalis.

Pterygoid processes, processus pterygoidei extend vertically downward from the junction of the greater wings and the body of the sphenoid bone. Their base is pierced by a sagittal canal, canalis pterygoideus, - the place of passage of the named nerve and vessels. The anterior opening of the canal opens into the pterygopalatine fossa.

Each process consists of two plates - lamina medialis And lamina lateralis, between which a fossa, fossa pterygoidea, is formed at the back.

The medial plate is bent at the bottom crochet, hamulus pterygoideus, through which the tendon that begins on this plate is thrown m. tensor veli palatini(one of the muscles of the soft palate).

Sphenoid bone. Front view. 1. Aperture of the sphenoid sinus; 2. Saddle back; 3. Wedge-shaped shell; 4. Small wing; 5. Superior orbital fissure; 6. Zygomatic edge; 7. Infratemporal surface, 8. Spine of the sphenoid bone; 9. Pterygopalatine groove; 10. Lateral plate; 11. Wing-shaped hook; 12. Medial plate of the pterygoid process; 13. Vaginal process; 14. Wedge-shaped ridge; 15. Pterygoid notch; 16. Pterygoid canal; 17. Round hole; 18. Infratemporal crest; 19. Orbital surface of the greater wing; 20. Temporal surface of the greater wing.

Variants and anomalies

Failure of fusion of the anterior and posterior halves of the body of the sphenoid bone leads to the formation of a narrow, so-called craniopharyngeal canal, in the center of the sella turcica. The foramen ovale and foramen spinosum sometimes merge into one common foramen; the foramen spinosum may be absent.

Occipital bone, os occipitale, forms the posterior and lower walls of the cranium, participating simultaneously in both the cranial vault and its base. Accordingly, it (being a mixed bone) ossifies both as a covering bone on the basis of connective tissue (squama of the occipital bone), as well as on the basis of cartilage (the rest of the bone). In humans, it is the result of the fusion of several bones that exist independently in some animals. Therefore, it consists of 4 separately laid parts that grow together into a single bone only at the age of 3-6 years. These closing parts big hole occipital bone, foramen magnum(place of transition spinal cord into the oblong from the spinal canal into the cranial cavity), the following: in front - the main part, pars basilaris(in animals - os basilare), on the sides - lateral parts, partes latrales(in animals - ossa lateralia), and behind - occipital scales, squama occipitalis(in animals - os superius). Top part The scales wedged between the parietal bones ossify separately and often remain separated for life by a transverse suture, which is also a reflection of the existence in some animals of an independent interparietal bone, os interparietal, as it is called in humans.

Occipital bone scales, squama occipitalis, as the integumentary bone has the appearance of a plate, convex on the outside and concave on the inside. Its external relief is due to the attachment of muscles and ligaments. So, in the center of the outer surface there is external occipital protuberance, protuberdntia occipitalis externa(place of appearance of the ossification nucleus). From the tubercle it goes laterally on each side along a curved line - upper you are a different line, tinea nuchae superior. A little higher there is a less noticeable one - linea nuchae suprema (highest). From the occipital protuberance down to the posterior edge of the foramen magnum it runs along the midline external nuchal crest, crista occipitalis externa. From the middle of the ridge they go to the sides you are different lines, lineae nuchae inferiores. The relief of the internal surface is determined by the shape of the brain and the attachment of its membranes, as a result of which this surface is divided by two ridges intersecting at right angles into four pits; both of these ridges together form cruciform eminence, emineniia cruciformis, and at the place of their intersection - internal occipital protuberance, protuberdntia occipitalis interna. The lower half of the longitudinal ridge is sharper and is called crista occipitalis interna, while the upper and both halves (usually the right) of the transverse ridge are equipped with well-defined grooves: sagittal, sulcus sinus sagittdlis superioris, and transverse, sulcus sinus transversi (traces of the junction of the venous sinuses of the same name).

Each of side parts, partes laterales, participates in the connection of the skull with the spine, therefore it carries on its lower surface occipital condyle, condylus occipitalis- place of articulation with the atlas. Approximately about the middle of the condylus occipitalis passes through the bone canal of the hypoglossal nerve, candlis (nervi) hypoglossi.

On the upper surface of the pars lateralis there is the sulcus sinus sigmoidei (trace of the venous sinus).

Main part, pars basilaris, by the age of 18 fuses with sphenoid bone, forming a single bone at the center of the base of the skull os basilare. On the upper surface of this bone there is a slope, clivus, fused from two parts, on which the medulla oblongata lies. On the lower surface, which is part of the upper wall of the pharynx, protrudes pharyngeal tubercle, tuberculum pharyngeum, to which the fibrous membrane of the pharynx is attached.

Sphenoid bone

Sphenoid bone, os sphenoidale, unpaired, resembles a flying insect, which explains the name of its parts (wings, pterygoid processes). Therefore, the term “wedge-shaped” is unfortunate and arose, apparently, by mistake *. It is also called the main one, as it is located in the center of the base of the skull.

* (In Galen's manuscript this bone was called sphecoidal (wasp-shaped), but the copyist is believed to have made a mistake and wrote sphenoidal (wedge-shaped).)

The sphenoid bone is the product of the fusion of several bones that independently exist in animals, therefore it develops as a mixed bone from several paired and unpaired foci of ossification, merging at the time of birth into 3 parts, which in turn fuse into a single bone by the end of the first year of life. It distinguishes the following parts: 1) body, corpus(in animals - unpaired basisphenoid and presphenoid); 2) big wings, alae majores(in animals - paired alisphenoid); 3) small wings, alae minores(in animals - paired orbitosphenoid), and 4) pterygoid processes, processus pterygofdei(its medial plate is a former paired pterygoid, develops on the basis of connective tissue, while all other parts of the bone arise on the basis of cartilage).

Body, corpus, on its upper surface has a depression along the midline - Turkish saddle, sella turcica, at the bottom of which lies a fossa for the appendage of the brain, fossa hypophysidlis. In front of it there is an elevation, tuberculum sellae, along which the sulcus chiasmatis for the chiasma * of the optic nerves runs transversely; the ends of the sulcus chiasmatis are visible visual channels, candles optici, through which the optic nerves pass from the cavity of the orbits to the cavity of the skull. At the back, the sella turcica is limited by the bony plate, the dorsum sella turcica, dorsum sellae. On the lateral surface of the body there is a curved carotid fissure, sulcus caroticus, trace of the internal carotid artery.

* (The correct pronunciation is chiasma, chiasmatis.)

On the anterior surface of the body, which is part of the posterior wall of the nasal cavity, a crest is visible, crista sphenoidlis, which enters below between the wings of the vomer. The crista sphenoidalis connects anteriorly to the perpendicular plate of the ethmoid bone. On the sides of the scallop, irregularly shaped openings are visible, aperturae sinus sphenoiddlis, leading into the air sinus, sinus sphenoiddlis, which is located in the body of the sphenoid bone and is divided by a septum, septum sinuum sphenoiddlium, into two halves. Through these openings the sinus communicates with the nasal cavity.

In a newborn, the sinus is of very small size and only around the 7th year of life begins to grow rapidly.

Small wings, alae minores, are two flat triangular plates, which with two roots extend forward and laterally from the anterosuperior edge of the body of the sphenoid bone; between the roots of the small wings there are the mentioned visual canals, canales optici. Between the small and large wings is superior orbital fissure, fissura orbitlis superior, leading from the cranial cavity to the orbital cavity.

Big wings, alae majores, extend from the lateral surfaces of the body laterally and upward. Near the body, posterior to fissura orbitalis superior there is round hole, foramen rotundum, leading anteriorly into the pterygopalatine fossa, caused by the passage of the second branch trigeminal nerve, n. trigemini. Posteriorly, a large wing in the form of an acute angle protrudes between the scales and the pyramid of the temporal bone. There is a spinous foramen, foramen spinosum, through which a passes. meningea media. Much more is visible in front of him oval foramen, foramen ovale, through which the third branch n passes. trigemini.

Large wings have four surfaces: brain, fades cerebrodlis, orbital, fdcies orbitdlis, temporal, fades temporalis, And maxillary, fdcies maxilldris. The names of the surfaces indicate the areas of the skull where they face. The last two surfaces are separated by a ridge, crista infratempordlis.

Pterygoid processes, processus pterygoidei, extend vertically downward from the junction of the large wings with the body of the sphenoid bone. Their base is pierced by a sagittal canal, candlis pterygoideus, the place of passage of the nerve and vessels of the same name. The anterior opening of the canal opens into the pterygopalatine fossa.

Each process consists of two plates - lamina medidlis and lamina lateralis, between which a pit, fossa pterygoidea, is formed at the back.

The medial plate below is bent by a hook, hamulus pterygoideus, through which the tendon of the m that begins on this plate is thrown. tensor veli palatini (one of the muscles of the soft palate).

Temporal bone

Temporal bone, os tempordle, a paired bone, has a complex structure, as it performs all 3 functions of the skeleton and not only forms part of the side wall and base of the skull, but also contains the organs of hearing and balance. It is the product of the fusion of several bones (mixed bone), which independently exist in some animals, and therefore consists of three parts: 1) the scaly part, pars squamosa(in animals - os squamosum); 2) drum part, pars tympanica(in animals - tympanicum), and 3) stony part, pars petrosa(in animals - petrosum).

During the 1st year of life, they merge into a single bone, closing the external auditory canal, meatus acusticus externus, in such a way that the scaly part lies above it, the stony part medially from it, and the tympanic part behind, below and in front. Traces of the fusion of individual parts of the temporal bone remain for life in the form of intermediate sutures and fissures, namely: at the border of pars squamosa and pars petrosa, on the anterosuperior surface of the latter - fissura petrosquamosa; in the depths of the jaw fossa - fissura tympanosquamosa, which is divided by a process of the stony part into fissura petrosquamosa and fissura petrotympdnica (the chorda tympani nerve exits through it).

Scaly part, pars squamosa, participates in the formation of the lateral walls of the skull. It belongs to the integumentary bones, i.e. it ossifies on the basis of connective tissue and has a relatively simple structure in the form of a vertical plate with a rounded edge overlapping the corresponding edge of the parietal bone, margo squamosa, in the form of fish scales, which is where its name comes from.

On brain surface her, fdcies cerebrdlis, traces of the brain are visible, finger impressions, impressiones digitdtae, and a groove ascending upward from a. meningea media. The outer surface of the scales is smooth, participates in the formation of the temporal fossa and is therefore called fdcies temporalis. Moves away from her zygomatic process, processus zygomdticus, which goes forward to connect with the zygomatic bone. At its origin, the zygomatic process has two roots: anterior and posterior, between which there is a fossa for articulation with the lower jaw, fossa, mandibularis. On the lower surface of the anterior root is placed articular tubercle, tuberculum articuldre preventing dislocation of the head lower jaw forward with a significant opening of the mouth.

Drum part, pars tympanica, the temporal bone forms the anterior, lower and part of the posterior edge of the external auditory canal, ossifies endesmally and, like all integumentary bones, has the appearance of a plate, only sharply curved.

External auditory canal, meatus acusticus externus, is a short canal directed inward and somewhat forward and leading into the tympanic cavity. The upper edge of its external opening, porus acusticus externus, and part of the posterior edge are formed by the scales of the temporal bone, and along the remaining length by the tympanic part.

In a newborn the external auditory canal has not yet been formed, since the tympanic part is an incomplete ring (anulus tympanicus), covered by the eardrum. Due to such a close position of the eardrum outward in newborns and children early age Diseases of the tympanic cavity are more common.

An important part of the temporal bone is rocky part, pars petrosa, so named for the strength of its bone substance, due to the fact that this part of the bone is both involved in the base of the skull and is the bone receptacle for the organs of hearing and balance, which have a very delicate structure and require strong protection from damage. It develops on the basis of cartilage. The second name of this part is the pyramid, given by its shape as a triangular pyramid, the base of which faces outward, and the apex faces forward and inward towards the sphenoid bone.

The pyramid has three surfaces; front, back and bottom. The anterior surface is part of the bottom of the middle cranial fossa; the posterior surface faces posteriorly and medially and forms part of the anterior wall of the posterior cranial fossa; the lower surface faces down and is visible only on the outer surface of the base of the skull. The external relief of the pyramid is complex and is determined by its structure as a container for the middle (tympanic cavity) and inner ear(bone labyrinth, consisting of the cochlea and semicircular canals), as well as the passage of nerves and blood vessels. On anterior surface pyramid, near its apex, there is a noticeable small depression, impressio trigemini, from the trigeminal ganglion (n. trigeminus). Two thin grooves run outward from it, the medial one is sulcus n. petrosi majoris, and lateral - sulcus n. petrosi minoris. They lead to two foramina of the same name: the medial one, hiatus candlis n. petrosi majoris, and lateral, hiatus candlis n. petrosi minoris. Outward from these holes it is noticeable arcuate eminence, eminentia arcudta, formed due to the protrusion of a rapidly developing labyrinth, in particular the superior semicircular canal. The surface of the bone between eminentia arcuata and squama temporalis forms the roof of the tympanic cavity, tegmen tympani.

About halfway back surface the pyramid is located internal auditory opening, porus acusticus internus, which leads to internal auditory canal, meatus acusticus internus, where the facial and auditory nerves, as well as the internal auditory artery and veins, pass.

From bottom surface pyramid facing the base of the skull, a thin pointed styloid process, processus styloideus, serving as a place of attachment for the muscles of the “anatomical bouquet” (mm. styloglossus, stylohyoideus, stylopharyngeus), as well as ligaments - ligg. stylohyoideum and stylomandibular. The styloid process represents a part of the temporal bone of branchial origin. Together with lig. stylohyoideum it is a remnant of the second visceral arch, the sublingual (hyoid).

Between the styloid and mastoid processes is stylomastoid foramen, foramen stylomastoideum, through which n comes out. facialis and one of the arteries enters. Medial to the styloid process there is a deep jugular fossa, fossa juguldris. Anterior to the fossa jugularis, separated from it by a sharp ridge, is the external opening of the carotid canal, foramen caroticum externum.

The pyramid has three edges: anterior, posterior and upper. The short anterior margin forms an acute angle with the scales. There is a noticeable hole in this corner myotubal canal, canalis musculotubdrius leading into the tympanic cavity. This channel is divided by a partition into two sections: upper and lower. Upper, smaller, semicanal, semicanalis m. tensoris tympani, houses this muscle, and the lower, larger one, semicanalis tubae auditivae, is the bony part of the auditory tube, which serves to conduct air from the pharynx into the tympanic cavity.

Along the upper edge of the pyramid, dividing the anterior and posterior surfaces, there runs a clearly visible groove, sulcus sinus petrosi superidris, a trace of the venous sinus of the same name.

The posterior edge of the pyramid anterior to the fossa jugularis connects to the main part of the occipital bone and, together with this bone, forms the sulcus sinus petrosi inferioris - a trace of the inferior petrosal venous sinus.

The outer surface of the base of the pyramid serves as a place for muscle attachment, which determines its external relief (process, notches, roughness). Downwards it extends into mastoid process, processus mastoideus. The sternocleidomastoid muscle is attached to it, which maintains the head in the balance necessary for an upright position of the body. Therefore, the mastoid process is absent in quadrupeds and even apes and develops only in humans in connection with their upright posture. On the medial side of the mastoid process there is a deep mastoid notch, incisdra mastoidea, - place of attachment of m. digastricus; even more inward - a small groove, sulcus a. occipitalis, - trace of the artery of the same name.

On the outer surface of the base of the mastoid process, a smooth triangle is distinguished, which is a place for rapid access to the cells of the mastoid process when they are filled with pus.

Inside the mastoid process contains these cells or cells, cellulae mastoideae, which are air cavities separated by bone bars, receiving air from the tympanic cavity, with which they communicate through the antrum mastoideum. On the cerebral surface of the base of the pyramid there is a deep groove, sulcus sinus sigmoidei, where the venous sinus of the same name lies.

Temporal bone canals. The largest channel is canalis caroticus, through which the internal carotid artery passes. Beginning with its external opening, foramen caroticum externum, on the lower surface of the pyramid, it rises upward, then bends at a right angle and opens with its internal opening, foramen caroticum internum, at the apex of the pyramid medial to the canalis musculotubarius. Facial nerve canal(Fig. 27), canalis facialis, begins in the depths of the porus acusticus internus, from where the canal first goes forward and laterally to the cracks (hiatus) on the anterior surface of the pyramid; at these openings the canal, remaining horizontal, turns at a right angle laterally and backwards, forming a bend - the genu, geniculum canalis facialis, and then goes down and ends through the foramen stylomastoideum, located on the lower surface of the pyramid of the temporal bone.

Parietal bone

Parietal bone, os parietale, steam room, forms the middle part of the cranial vault. In humans, it reaches the greatest development in comparison with all animals due to the highest development of his brain. It represents a typical integumentary bone, performing primarily a protective function. Therefore, it has a relatively simple structure in the form of a quadrangular plate, convex on the outside and concave on the inside. Its four edges serve to connect with neighboring bones, namely: the anterior - with the frontal, margo frontalis, posterior - from the occipital, margo occipitalis, upper - with the same bone of the other side, margo sagittalis, and the lower one - with the scales of the temporal bone, margo squamosus. The first three edges are serrated, and the last is adapted to form a scaly suture. Of the four corners, the anterosuperior one connects to the frontal bone, angulus frontalis, anteroinferior with sphenoid bone, angulus sphenoidalis, posterior-superior with occipital bone, angulus occipitalis, and posteroinferior with the base of the mastoid process of the temporal bone, angulus mastofdeus. The relief of the outer convex surface is caused by the attachment of muscles and fascia. In its center stands parietal tubercle, tuber parietale(place of beginning of ossification). Below it there are curved temporal lines - lineae tempordles (superior et inferior) - for the temporal fascia and muscle. Near the upper edge there is an opening, foramen parietale (for the artery and venous outlet). The relief of the internal concave surface, fdcies interna, is due to the fit of the brain and especially the dura mater; the places of attachment of the latter to the bone look like a sagittal groove running along the upper edge, sulcus sinus sagittalis superioris (trace of the venous sinus, sinus sagittalis superior), as well as in the area of the angulus mastoideus transverse groove, sulcus sinus sigmoidei (trace of the venous sinus of the same name). The vessels of this shell seem to be imprinted in the form of branching grooves on almost the entire inner surface. On the sides of the sulcus sinus sagittalis superioris traces of the so-called pachyon granulations, foveolae granuldres (see meninges) are visible.

Frontal bone

Frontal bone, os frontale, unpaired, participates in the formation of the cranial vault and belongs to its integumentary bones, developing on the basis of connective tissue. In addition, it is associated with the senses (smell and vision). According to this dual function, it consists of two sections: vertical - scales, squama frontalis, and horizontal. The latter, in relation to the organs of vision and smell, is divided into a paired orbital part, pars orbitalis, and unpaired nasal, pars nasalis. As a result, the frontal bone is divided into 4 parts:

1. Scales, squama frontalis, like any integumentary bone, has the appearance of a plate, convex on the outside and concave on the inside. It ossifies from two points of ossification, noticeable even in an adult outer surface, fades externa, in the form of two frontal tuberosities, tubera frontdlia. These bumps are expressed only in humans due to brain development. They are absent not only in apes, but even in extinct forms of humans. The lower edge of the scales is called the supraorbital, mdrgo supraorbitalis. Approximately on the border between the inner and middle third of this edge there is supraorbital notch, incisura supraorbitalis(sometimes turns into foramen supraorbital), the place of passage of the arteries and nerve of the same name. Immediately above the supraorbital margin, elevations that vary greatly in size and extent are noticeable - brow ridges, arcus superciliares, which pass medially along the midline into a more or less protruding platform, glabella (glabella). It is a reference point when comparing skulls modern man with a fossil. The outer end of the supraorbital margin extends into zygomatic process, processus zygomatics, connecting to the zygomatic bone. From this process goes upward a clearly noticeable temporal line, llnea temporalis, which limits temporal surface scales, facies temporalis. On inner surface, facies interna, along the midline there is a groove running from the posterior edge, sulcus sinus sagittdlis superioris, which below turns into frontal crest, crista frontalis. These formations are the attachment of the dura mater. Near the midline, pits of pachyonic granulations (outgrowths of the arachnoid membrane of the brain) are noticeable.

2 and 3. Orbital parts, partes orbitaies, represent two horizontally located plates, which with their lower concave surface face the orbit, the upper one faces the cranial cavity, and their posterior edge connects to the sphenoid bone. On the upper cerebral surface there are traces of the brain - impressiones digitatae. Lower surface, facies orbitlis, forms the upper wall of the orbit and bears traces of the attachment of the auxiliary devices of the eye; at the zygomatic process - pit of the lacrimal gland, fossa gldndulae lacrimdlis, near the incisura supraorbitalis - fovea trochledris and a small spine, spina trochledris, where a cartilaginous block (trochlea) is attached to the tendon of one of the muscles of the eye. Both orbital parts are separated from each other by a notch, incisura ethmoidlis, filled on the entire skull with ethmoid bone.

4. Bow, pars nasalis, occupies the anterior part of the ethmoidal notch along the midline; a comb is noticeable here, which ends in a sharp process - spina nasalis, which takes part in the formation of the nasal septum. On the sides of the scallop there are pits that serve as the upper wall for the cells of the ethmoid bone; in front of them there is a hole leading to frontal sinus, sinus frontalis, - a cavity that is located in the thickness of the bone behind the brow ridges and the size of which varies greatly. The frontal sinus, containing air, is usually divided by a septum, septum sinuum frontdlium. In some cases, additional frontal sinuses are found behind or between the main ones (Jovanovic, 1961). The frontal bone is the most characteristic of all the bones of the skull for humans. In the most ancient hominids (like apes), it was sharply tilted back, forming a sloping, “running back” forehead. Behind the orbital narrowing it is sharply divided into scales and orbital parts. Along the edge of the eye sockets, from one zygomatic process to the other, there was a continuous thick ridge. In modern humans, the ridge has sharply decreased, so that only the brow ridges remain. According to the development of the brain, the scales straightened and took a vertical position, at the same time the frontal tubercles developed, as a result of which the forehead became convex from sloping, giving the skull a characteristic appearance.

Ethmoid bone

Ethmoid bone, os ethmoidale, unpaired, usually described among bones brain skull, although for the most part it participates in the formation of the facial skull. Located centrally between the bones of the face, it comes into contact with most of them, participating in the formation of the nasal cavity and eye sockets, and is covered by them on the entire skull. It develops in connection with the nasal capsule, based on cartilage, and is built from thin bone plates surrounding the air cavities (Fig. 28). The bony plates of the ethmoid bone are arranged in the shape of the letter “T”, in which the vertical line is perpendicular plate, lamina perpendicularis, and horizontal - cribriform plate, lamina cribrosa. From the latter on the sides lamina perpendicularis hang lattice labyrinths, labyrfnthi ethmoidales. As a result, the ethmoid bone can be divided into 4 parts:

1. Lamina cribrosa- a rectangular plate that performs the incisura ethmoidalis of the frontal bone. It is pierced, like a sieve, with small holes (hence its name), through which branches of the olfactory nerve pass (about 30). Along its midline rises cockscomb, crista gdlli(place of attachment of the dura mater).

2. Lamina perpendicularis is part of the nasal septum.

3 and 4. Labyrfnthi ethmoidales They represent a paired complex of bony air cells, cellulae ethmoidales, covered from the outside by a thin orbital plate, lamina orbitlis, forming the medial wall of the orbit (Fig. 29). The upper edge of the orbital plate connects with the orbital part of the frontal bone, anteriorly - with the lacrimal ossicle, posteriorly - with the sphenoid and orbital process of the palatine, inferiorly - with upper jaw; all these bones cover the marginal cellulae ethmoidales. On the medial side of the labyrinths there are two turbinates - conchae nasdles superior et media, although sometimes there is a third one - concha nasalis suprema.

Sinks They are curved bone plates, due to which the surface of the nasal mucosa covering them increases.