- Sphenoid bone, os sphenoidale. Located between the frontal, occipital and temporal bones. Rice. A B C.
- Body, corpus. Located between the large wings. Rice. A, B.
- Wedge-shaped eminence, jugum sphenoidale. Connects the lesser wings of the sphenoid bone. Rice. A.
- (Pre)cross groove, sulcus prechiasmaticus. Located between the right and left visual channels. Rice. A.
- Turkish saddle, sella turcica. A fossa located above the sphenoid sinus. Contains the pituitary gland. Rice. A.
- Tubercle sellae, tuberculum sellae. Elevation anterior to the pituitary fossa. Rice. A.
- [Middle inclined process, processus clinoideus medius]. Located on the side of the pituitary fossa. Not constantly present. Rice. A.
- Pituitary fossa, fossa hypophysialis. Filled with the pituitary gland. Rice. A.
- The back of the saddle, dorsum sellae. Located posterior to the pituitary fossa. Rice. A, V.
- Posterior inclined process, processus clinoideus posterior. Bilaterally located projections of the back of the saddle. Rice. A, V.
- Carotid groove, sulcus caroticus. It starts from the middle of the torn hole and goes forward. The internal carotid artery passes through it. Rice. A.
- Wedge-shaped tongue, lingula sphenoidalis. Located lateral to the entry point of the internal carotid artery into the skull. Rice. A.
- Wedge-shaped crest, crista sphenoidalis. Located in the midline on the anterior surface of the body and serves as the attachment point for the perpendicular plate of the ethmoid bone. Rice. IN.
- Wedge-shaped beak, rostrum sphenoidale. It is a continuation of the wedge-shaped ridge downwards. Connects to the opener. Rice. IN.
- Sphenoid sinus, sinus sphenoidalis. Paired air cavity of the skull. Rice. IN.
- The septum of the sphenoid sinuses, septum intersinuale sphenoidale. Separates the right sphenoid sinus from the left. Rice. IN.
- Aperture of the sphenoid sinus, apertura sinus sphenoidalis. Opens into a wedge-ethmoid recess. Rice. IN.
- Wedge-shaped shell, concha sphenoidalis. Usually a paired concave plate fused with the body of the sphenoid bone. Forms the anterior and lower walls of her sinus. Rice. IN.
- Small wing, ala minor. Rice. A B C.
- Optic canal, canalis opticus. Contains the optic nerve and ophthalmic artery. Rice. A.
- Anterior inclined process, processus clinoideus anterior. Paired conical projection of the lesser wings in front of the pituitary fossa. Rice. A.
- Superior orbital fissure, fissura orbitals superior. Located between the large and small wings. Nerves and veins pass through it. Rice. A B C.
- Large wing, ala major. Rice. A B C.
- Brain surface, fades cerebralis. Facing the brain. Rice. A.
- Temporal surface, fades temporalis. Facing outwards. Rice. B, V.
- Maxillary surface, fades maxillaris. Directed towards the upper jaw. There is a round hole on it. Rice. IN.
- Orbital surface, fades orbitalis. Facing inside the eye socket. Rice. IN.
- Zygomatic margin, margo zygomaticus. Connects to the zygomatic bone. Rice. IN.
- Frontal edge, margo frontalis. Articulates with the frontal bone. Rice. A.
- Parietal edge, margo parietalis. Connects to the parietal bone. Rice. IN.
- Scaly margin, margo squamosus. The scaly suture articulates with the temporal bone. Rice. A.
- Infratemporal crest, crista infratemporalis. It is located between the vertically oriented temporal and horizontally oriented inferior surfaces of the greater wing. Rice. B, V.
- Round hole, foramen rotundum. Opens into the pterygopalatine fossa. Contains the maxillary nerve. Rice. A B C.
- Oval hole, foramen ovale. Located medially and anterior to the foramen spinosum. The mandibular nerve passes through it. Rice. A, B.
- [Venous opening, foramen venosum]. Located medial to the foramen ovale. Contains an emissary vein originating from the cavernous sinus. Rice. A, B.
- Spinous foramen, foramen spinosum. Located lateral and posterior to the foramen ovale. Designed for the middle meningeal artery. Rice. A, B.
- [Rocky hole, foramen petrosum, []. Located between the foramen ovale and the foramen spinosum. Contains n.petrosus major. Rice. A, B.
- Spine of the sphenoid bone, spina ossis sphenoidalis. Departs from the large wing and is directed downward. Rice. A, B.
- The groove of the auditory tube, sulcus tubae auditoriae (auditivae). Located on the lower surface of the greater wing, lateral to the base of the pterygoid process. Contains the cartilaginous part of the auditory tube. Rice. B.
Located in the center of the base of the skull. It participates in the formation of the lateral walls of the cranial vault, as well as the cavities and fossae of the cerebral and facial parts of the skull. The sphenoid bone has a complex shape and consists of a body from which 3 pairs of processes extend: large wings, small wings and pterygoid processes.
Body of the sphenoid bone has the shape of an irregular cube. Inside it there is a cavity - the sphenoid sinus. There are 6 surfaces in the body: the upper, or cerebral, posterior, fused in adults with the basilar (main) part of the occipital bone; the front one, which passes without sharp boundaries into the lower one, and two lateral ones.
On the upper (cerebral) surface there is a noticeable depression - the sella turcica. In its center there is a pituitary fossa in which the pituitary gland is located. In front of the recess there is a transversely lying tubercle of the sella. The saddle has a fairly high backrest. The lateral parts of the dorsum sella protrude forward, forming posterior inclined processes. At the base of the back of the saddle on the right and left there is a groove for the internal carotid artery - the carotid groove. Outside and somewhat posterior to the carotid sulcus there is a wedge-shaped tongue, which turns the carotid sulcus into a deep groove. This groove, together with the apex of the pyramid of the temporal bone, limits the internal carotid foramen, through which the internal carotid artery emerges from the carotid canal into the cranial cavity.
The anterior surface of the body of the sphenoid bone is elongated into a small wedge-shaped ridge. The latter continues to the lower surface in the form of a sharp wedge-shaped beak (keel); the wedge-shaped ridge, with its anterior edge, is connected to the perpendicular plate of the ethmoid bone. On the sides of the ridge there are irregularly shaped bone plates - wedge-shaped shells, limiting the opening - the aperture of the sphenoid sinus, leading into the air-bearing sphenoid sinus, most often divided by a septum into two parts.
The lateral surfaces of the body of the sphenoid bone continue anteriorly and inferiorly into the lesser and greater wings.
Small wing It is a paired plate extending from each side of the body of the sphenoid bone with two roots. Between the latter there is the optic canal, for the passage of the optic nerve from the orbit. The anterior edges of the lesser wings are serrated; the orbital parts of the frontal bone and the cribriform plate of the ethmoid bone are connected to them. The posterior edges of the small wings are free and smooth. On the medial side, each wing has an anterior inclined process. The dura mater of the brain grows to the anterior as well as to the posterior inclined processes.
The lesser wing has an upper surface facing the cranial cavity, and a lower one, participating in the formation of the upper wall of the orbit. The space between the lesser and greater wings is the superior orbital fissure. Through it, the oculomotor, lateral and abducens nerves (3, 4, 6 pairs of cranial nerves) and the optic nerve - 1 branch of the trigeminal nerve (5 pair) pass from the cranial cavity into the orbit.
Big wing paired, begins with a wide base from the lateral surface of the body of the sphenoid bone. At the very base, each wing has three holes. Above the others and anteriorly there is a round hole through which the 2nd branch of the trigeminal nerve passes, in the middle of the wing there is an oval hole for the 3rd branch of the trigeminal nerve. The foramen spinosum is smaller in size and is located in the region of the posterior corner of the large wing. Through this hole, the middle meningeal artery penetrates into the cranial cavity. The large wing has four surfaces: medullary, orbital, maxillary and temporal. The cerebral surface has well-defined finger-like impressions and arterial grooves. The orbital surface is a quadrangular smooth plate; part of the lateral wall of the orbit. The maxillary surface occupies a triangular area between the orbital surface above and the base of the pterygoid process below. On this surface, facing the pterygopalatine fossa, a round opening opens. The temporal surface is the most extensive. The infratemporal crest divides it into two parts. The upper part is larger, located almost vertically, and is part of the wall of the temporal fossa. The lower part is located almost horizontally and forms the upper wall of the infratemporal fossa.
Pterygoid process paired, departs from the body of the sphenoid bone at the beginning of the large wing and is directed vertically downward. The medial plate of the process faces the nasal cavity, the lateral plate faces the infratemporal fossa. The base of the process is pierced from front to back by a narrow pterygoid canal through which vessels and nerves pass. The anterior opening of this canal opens into the pterygopalatine fossa, the posterior opening - on the outer base of the skull near the spine of the sphenoid bone. The plates of the pterygoid process are distinguished: medial and lateral. The anterior plates are fused. Posteriorly, the plates of the pterygoid process diverge, forming the pterygoid fossa. Below, both plates are separated by a pterygoid notch. The medial plate of the pterygoid process is somewhat narrower and longer than the lateral one and below passes into the pterygoid hook.
The bones of the skull, located on the outside, play an important protective role. In the very center of the facial part is the sphenoid bone, which plays an important role in the structure of the skull. It is represented by many different grooves and openings that distribute nerve and blood branches. In addition, it borders many cranial regions on different sides.
The sphenoid bone of the skull is shaped like a butterfly, which suggests that it is symmetrical, as if it were made of two identical parts, but this is an erroneous guess. This element is integral, and its upper edges are pointed. Almost all important vessels and nerve branches pass through this part of the skull, so it has an important purpose.
Like all elements of the human skeleton, the sphenoid bone can be subject to various pathological disorders, which provokes the development of diseases of the internal branches. Moreover, this segment is involved in the production of pituitary hormonal substances. Thus, the sphenoid bone performs three main functions.
- Protects important branches of the central nervous system, as well as blood vessels supplying the brain, from damage.
- Connects the superficial parts of the skull, ensuring their strength.
- Synthesizes pituitary hormones.
Structural features
The structure of the sphenoid bone distinguishes several parts, which completely grow together during the formation of the body, representing the formation of paired and individual elements. At birth, it consists of only three segments, but in a fully formed person, the main bone formation consists of four sections.
- Bodies.
- Large and small wings.
- Pterygoid processes.
Primary fragments of ossification appear in the first two months of fetal development, directly on the large wings; the remaining fragments appear a month later. At birth they appear in wedge-shaped concave plates. The small ones fuse together in the womb in the third trimester of pregnancy, and the rest by the age of two years. Complete formation of the sinus begins after six months, and the fusion of the body with the occipital region is completely transformed by the age of twenty.
Body of bone
The department in question is the central part. It is presented in the form of a cube, and includes many smaller segments. At the top there is a plane directed into the inside of the skull. It has a peculiar notch called the sella turcica. In the middle of this element is the pituitary recess, the depth of which directly depends on the size of the pituitary gland.
The anterior part of the body is expressed by the crest of the saddle, and on the posterior side of the lateral plane of this element, the middle inclined process is localized. On the front side of the tuberous segment there is a transverse cross groove, the rear part of which is expressed by a plexus of nerve ganglia responsible for visual functions. Laterally, this canal becomes the orbital groove. The front side of the upper plane has a jagged surface. It unites with the dorsal edge of the plate of the ethmoid bone, forming a wedge-ethmoid suture.
The dorsal part of the body is expressed by the back of the saddle-shaped protrusion, which ends on both sides with inclined processes. To the right and left of the sella is the carotid canal, which is an intracranial groove of the carotid artery and nerve branches. A wedge-shaped tongue is observed on the outer part of the canal. Considering the localization of the dorsum sella on the dorsal side, one can observe a smooth transition of this element to the upper segment of the basilar region of the occipital part.
The frontal plane of the wedge-shaped bone with some part of its lower element rushes towards the nasal cavity. In the middle of this plane a vertical wedge-shaped ridge is formed, the lower spine of which has a pointed shape, thereby forming a wedge-shaped beak. It directly combines with the wings of the vomer, forming a kind of beak-shaped groove. On the side of this ridge are curved plates.
The shells form the outer part of the lower septum of the sphenoid sinus - the cavity that occupies its main area. Each of these shells has a small round passage. On the outer plane of this segment there are recesses that cover the cells of the rear section of the lattice fragment. The outer ends of these elements combine with the ocular plates of the ethmoid bone, forming a wedge-shaped ethmoid suture.
The body is a communication center of nerve and blood fibers, so any damage can cause serious complications. This once again proves the features and importance of the cranial elements, since their condition affects the health of the whole organism. In addition, this segment performs the following functions:
- Protects almost all important vessels and nerves of the human brain passing through it;
- Participates in the formation of the wedge-shaped nasal cavity;
- Reduces the weight of the skull due to the large number of cavities and holes;
- The body of the central bone of the skull has special receptors that help support the body in its impulse response to changes in pressure from the interaction of external factors;
- Promotes the secretion of the pituitary gland.
Small wings
They are paired elements that extend from two opposite sides. They have the shape of horizontal plates, at the beginning of which there are holes. Their upper planes are directed to the cranial roof, and the lower ones are directed into the cavity of the orbit, forming the upper eye opening. Their ends have thickening and jagged edges. The back part has a smooth surface and a concave shape.
Due to these elements, the wedge-shaped bone has articulation with the bony segments of the nose and frontal region. The bases of both fragments have a canal through which orbital blood vessels and optic nerve fibers pass. This factor determines the main functions of the wing-shaped formations.
Big wings
This element is also paired and originates from the lateral part of the body, rushing upward. Both fragments have 4 planes:
- brain;
- orbital;
- maxillary;
- temporal
However, there is an opinion according to which there is a fifth surface formed as a result of the division of the infratemporal crest into the temporal and pterygoid.
The brain plane is directed towards the inside of the skull and is located at the top. At the bases of the large wings there are also oval holes that perform certain functions. In addition, the segments have other openings, which indicate their complex anatomical structure:
- Round. Intended for nerve branches emanating from the maxilla;
- Oval. It is a channel for the passage of mandibular nerve fibers;
- Spinous. Forms a groove through which the aforementioned nerve, together with the meningeal arteries, exits into the cranial cavity.
As for the front part, it has a jagged end. The dorsal squamosal portion articulates with the wedge-shaped edge, forming a wedge-shaped squamosal end. The process of the wedge-shaped bone is the point of fixation of the mandibular ligament with the muscles responsible for the functions of the soft palate. If you look deeper, you can see the dorsal portion, meaning the large wing of the sphenoid bone, which is adjacent to the petrous part of the temporal part, thus separating the wedge-shaped petrosal cleft.
Pterygoid processes
The pterygoid process of the sphenoid bone originates at the point of articulation of the previously considered elements with the body, and then descends below. They are formed by the lateral and median plates. When they are connected by their anterior ends, a pterygoid fossa is formed. Unlike them, the lower segments do not have common formations. Thus, the medial sphenoid bone ends with peculiar hooks.
The dorsal upper section of the medial plate has a wide base, where the scaphoid recess is localized, next to which the ear canal is located. Then it smoothly flows into the lower plane of the dorsal part of the large wing, and the sphenoid bone, the anatomy of which is determined by the location of the segments under consideration, determines their main functions. They consist in facilitating the activity of a group of muscles responsible for the normal functionality of the soft palate and eardrums.
Fracture of the sphenoid bone
Mechanical injuries to the wedge-shaped segment are a dangerous phenomenon from which anything can be expected. The cause may be a fall or a strong direct blow from a hard, heavy object. Fractures of the skull often have serious consequences, which cause disruption of brain activity, and therefore the entire body. First of all, the nerve or blood branches that supply the brain center are affected, which can cause a severe headache. Without a clinical atlas, it is difficult to determine what complications may cause such injuries.
Content
This element occupies a central position at the base of the skull and performs a number of important functions. The sphenoid bone consists of many canals and holes, and also has boundary surfaces with the occipital, frontal, parietal, and temporal regions. Learn more about the anatomy of this unique formation, which, like a cache, stores precious structures.
What is the sphenoid bone
This part of the skull is an unpaired element, shaped like a butterfly, which explains the name of its components. The sphenoid bone (SC), or os sphenoidale, plays an important role in craniosacral therapy. Many nerve fibers related to the central nervous system pass through this part of the skull, which directly affects their functioning.
Thus, vision problems and pain in the facial area in most cases arise due to irritation of these structures due to pathology of the sphenoid (main) bone. In addition, this segment of the skull is directly involved in the process of synthesizing pituitary hormones. With all this, the CC performs two other very important functions:
- protects nerves, brain, blood vessels;
- forms the cranial vault.
Anatomy
The main bone is the result of the fusion of several structures that independently exist in mammals. For this reason, it develops as a mixed formation, consisting of several paired and single points of ossification (ossification). The latter at the time of birth include three parts, which subsequently grow together into a single segment. A fully formed main bone consists of the following parts:
- body (corpus);
- large wings (alae majores);
- small wings (alae minores);
- pterygoid processes (processus pterygoidei).
Body of the sphenoid bone
This segment forms the middle section of the main bone. The body (corpus) of the CC has a cubic shape and consists of many other smaller elements. On its upper surface, which faces the cavity of the cranium, there is a specific depression - the sella turcica (sella turcica). In the center of this formation there is a so-called pituitary fossa, the size of which is determined by the size of the pituitary gland itself.
Anteriorly, the border of the sella turcica is marked by the tubercle sella. Behind it, on the lateral surface of this formation with an unusual name, is the middle inclined process. Anterior to the tubercle sella there is a transverse cross groove. The posterior part of the latter is represented by the optic chiasm. Laterally, the groove passes into the optic canal. The anterior edge of the upper surface of the body of the CC is serrated and connects with the posterior end of the cribriform plate of the ethmoid bone, resulting in a sphenoethmoidal suture.
The posterior border of the sella turcica is the dorsum sella, which ends on both sides with small inclined processes. On the sides of the saddle there is a carotid groove. The latter is an internal trace of the carotid artery and the accompanying plexus of nerve fibers. A wedge-shaped tongue protrudes from the outside of the furrow. Analyzing the location of the dorsum sella (posterior view), one can notice the transition of this formation to the upper surface of the basilar part of the occipital bone.
The anterior surface of the main bone and a certain proportion of its lower segment are directed into the nasal cavity. In the middle of the frontal plane of the CC, a wedge-shaped ridge protrudes vertically. The lower process of this formation is pointed and forms a wedge-shaped beak. The latter connects with the wings of the vomer and forms the vomer-coracoid canal. Lateral to the crest there are curved plates (shells).
The latter form the anterior and partially lower walls of the sphenoid sinus, a paired cavity that occupies most of the main bone. Each shell contains the aperture of the sphenoid sinus (a small round hole). Outside this formation there are depressions that cover the cells of the posterior part of the labyrinth of the ethmoid bone. The outer edges of these “gaps” are partly connected to the orbital plate of the ethmoid bone, forming a sphenoethmoidal suture.
It must be said that any even minor damage to the latter can lead to persistent impairment of the sense of smell, which once again emphasizes the special importance of the body of the main bone for the normal functioning of the whole organism. In addition, the middle section of the CC is involved in the process of synthesizing pituitary hormones and protects this endocrine organ from trauma. Along with these, the body of the main bone performs the following important functions:
- protects the carotid artery and other smaller vessels of the brain;
- forms the sphenoid sinus;
- due to the large number of round, oval holes and channels, it reduces the mass of the skull;
- The sinuses present in the body of the main bone help the body respond to changes in environmental pressure.
Small wings
These paired CC segments extend in both directions from the anterior corners of the body in the form of two horizontal plates, at the base of each of which there is a round hole. The upper surface of the small wings faces the inside of the skull, while the lower surface is directed into the cavity of the orbit and forms the superior orbital fissure. The anterior edge of the small wing is serrated and thickened, while the posterior edge is smooth and has a concave shape.
It is important to note that through these segments (alae minores) the main bone connects to the structures of the nose and the frontal area. At the base of each small wing there is a kind of canal that carries the optic nerve and ophthalmic artery into the orbit, which generally determines the functions of these structural elements of the unique wedge-shaped formation of the skull.
Big wings
Alae majores extend from the lateral planes of the body laterally and upward. Each large wing of the sphenoid bone has 4 surfaces: medullary, orbital, maxillary, temporal. It is worth saying that some experts identify 5 planes characteristic of alae majores. This fact is due to the fact that the infratemporal crest of the sphenoid bone divides the latter into the pterygoid and, in fact, the temporal part itself.
The upper cerebral part of the large wing is concave and faces the inside of the skull. At the bases of alae majores there are specific openings, each of which has a strictly defined functional load. The anatomical features of the latter, in fact, determine the “job responsibilities” of alae majores to the body. So, in each of the large wings there are the following holes:
- round - serves for the passage of the maxillary branch of the trigeminal nerve;
- oval - forms the path for the lower part of the trigeminal nerve;
- spinous - forms a canal through which the meningeal arteries and maxillary nerve enter the skull.
At the same time, it is important to mention that the anterior zygomatic margin of the large wing is serrated. The posterior scaly region, connecting with the wedge-shaped end, forms the wedge-squamoid edge. In this case, the spine of the sphenoid bone is the site of attachment of the sphenomandibular ligament with the tensor palatine muscle. Somewhat deeper from this formation, the posterior edge of the greater wing lies in front of the so-called petrous part of the temporal bone, thereby limiting the sphenoid-petrosal fissure.
Pterygoid processes
The indicated components of the CC extend from the junction of the alae majores with the body and rush down. The pterygoid process of the sphenoid bone is formed by the lateral (lamina lateralis) and medial (lamina medialis) plates, which, fused with the anterior edges, limit the pterygoid fossa. It is important to note that the lower sections of these formations are not connected. Thus, the free end of the medial plate is completed by the pterygoid hook.
The posterosuperior edge of the lamina medialis, expanding at the base, forms a scaphoid fossa, near which there is a groove of the auditory tube, which laterally passes to the lower surface of the posterior edge of the greater wing. As you can see, the pterygoid processes form many vital structures. The main functions of the processus pterygoidei are associated with ensuring the proper functioning of the muscles that strain the velum palatine and the tympanic membrane.
The sphenoid bone (os sphenoidale) is unpaired, located in the center of the base of the skull, and has four parts (Fig. 46).
46.A. Sphenoid bone (os sphenoidale), front view.
1 - corpus ossis sphenoidalis; 2 - dorsum sellae; 3 - ala minor; 4 - fissura orbitalis superior!; 5 - ala major; 6 - far. rotundum; 7 - canalis pterygoideus; 8 - processus pterygoideus
46.B. Sphenoid bone (posterior view).
1 - ala minor; 2 - ala major; 3 - facies orbitalis; 4 - facies temporalis; 5 - apertura sinus sphenoidalis; 6 - lamina lateralis; 7 - lamina medialis; 8 - processus pterygoideus.
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 (sella 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 sphenoidalis) 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 the 8th week of embryonic development, bone points appear in the cartilaginous primordia of the large wings, 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) .
47. Scheme of age-related changes in the volume of the air sinus of the sphenoid bone (no Torigiani)
1 - superior nasal concha;
2 - middle turbinate;
3 - inferior nasal concha;
4 - border of the sinus in a newborn;
5 - at 3 years;
6 - at 5 years old;
7 - at 7 years old;
8 - at 12 years old;
9 - in an adult;
10 - sella turcica.
Anomalies. Between the front and back parts of the body of the bone there may be a hole (the remnant of a 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.
