| Wedge-shaped(main) bone (ossphenoidale). Back view. 1-visual channel; |
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Wedge-shaped(main) bone (os sphenoidale). Front view. 1-sphenoid sinus aperture; |
Sphenoid bone(main bone) (Latin os sphenoidale) is an unpaired bone that forms the central section of the skull base. One of the most anatomically complex bones of the human skeleton. Consists of a body (lat.corpus ossis sphenoidalis), two pairs of wings (small wings, lat.alae minores and large wings, lat.alae majores) and pterygoid processes.
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Sphenoid bone body
On the upper surface of the body there is a depression - the Turkish saddle, containing the pituitary gland. The front border of the saddle is the tubercle of the saddle, the back is the back of the saddle. On the sides of the sella turcica are carotid grooves with cavernous sinuses, in which the internal carotid arteries and associated nerve plexuses pass. Anterior to the tubercle of the saddle there is a groove of the chiasm, on which the chiasm of the optic nerves is located. The saddle back protrudes forward in the lateral regions, forming the posterior inclined processes. The posterior surface of the dorsum of the sella turcica continues smoothly with the upper surface of the basilar part of the occipital bone, forming the slope.
In front, 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. Behind, the body of the sphenoid bone fuses with the basilar part of the occipital bone.
Most of the body of the sphenoid bone is filled with an air sphenoid sinus, divided by a septum into two halves. In front, the sinus is bounded by wedge-shaped shells located on the sides of the wedge-shaped crest. The shells form holes - apertures through which the wedge-shaped cavity communicates with the nasal cavity. The walls of the sphenoid sinus are lined with mucous membranes.
Small wings
The lesser 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 ocular arteries. The upper surfaces of the lesser wings face the cranial cavity, the lower ones - into the orbital cavity, forming the upper walls of the upper orbital fissures. The front edges of the wings are articulated 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 fossa.
The lesser wings are connected to each other by a wedge-shaped elevation located in front of the groove of the intersection.
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 large wing there are three holes: a round hole 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 cerebral surface, upper, faces the cranial cavity.
The orbital surface, anteroposterior, has a rhomboid shape. It faces into 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, has a triangular shape, small in size. From above it is limited by the orbital surface, from the side from below - by the root of the pterygoid process. The maxillary surface is involved in the formation of the posterior wall of the pterygopalatine fossa. There is a round hole in it.
The temporal surface, superior lateral, is divided by the infratemporal crest into the temporal and pterygoid surfaces. The temporal surface is involved in the formation of the temporal fossa. Oval and spinous openings open on the pterygoid surface. The pterygoid surface forms the anterior wall of the infratemporal fossa.
The edges of the large wing
The frontal edge, upper, is connected to the orbital part of the frontal bone through the wedge-frontal suture. The outer parts of the frontal edge end with a sharp parietal edge, forming a wedge-parietal suture with the parietal bone. The inner parts of the frontal edge pass into a thin free edge, limiting the superior orbital fissure from below.
The zygomatic edge, anterior, connects with the frontal process of the zygomatic bone, forming a wedge-zygomatic suture.
The scaly edge, posterior, is connected to the wedge-shaped edge of the temporal bone and forms a wedge-scaly suture. Behind and outside, the scaly edge ends with a spine of the sphenoid bone. Inwardly from the spine, the scaly edge is located in front of the stony part of the temporal bone, forming with it a wedge-stony cleft that passes medially into the ragged opening.
Pterygoid processes
The pterygoid processes (Latin 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 are the pterygoid canals, in which the nerves and vessels of the same name pass. In front, each canal opens into the pterygo-palatine fossa.
Each process consists of the medial and lateral plates, which are fused in the anterior-superior sections, limiting the pterygoid fossa in front. The free, non-fused 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 pterygoid hook directed downward and outward.
Sphenoid body 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 Turkish saddle, sella turcica... in the center of which is the pituitary fossa. The pituitary gland lies in it. 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 nuclei of ossification of the fossa occurs at the 8th month of intrauterine life. Hence, there is a possibility of damage to the structure of the pituitary fossa with subsequent dysfunction of the pituitary gland. The turkish saddle is bounded in front by the tubercle of the saddle, tuberculum sellae... Behind it, on the lateral surface of the saddle, there is an unstable middle tilted process, processus clinoideus medius... Anterior to the tubercle of the saddle, there is a shallow transverse groove of the intersection, sulcus chiasmatis... On it lies the intersection of the optic nerves, chiasma opticum... On the sides, the furrow passes into the visual canal, canalis opticus... In front of the furrow there is a smooth surface - a wedge-shaped elevation, 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 sphenoid-ethmoid suture, sutura sphenoethmoidalis... The perforated plate has a large number of holes (25-30), through which branches of the anterior ethmoid (olfactory) nerve and the vein accompanying the anterior ethmoid artery go from the nasal cavity into the cranial cavity (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 ratio in the wedge-ethmoid suture may occur, followed by traumatization of the olfactory bulbs.
The turkish saddle is bounded at the back by the back of the saddle, dorsum sellae which ends on each side with a small posterior oblique process, processus clinoideus posterior... On the sides of the Turkish saddle, from back to front, there is a sleepy groove, sulcus caroticus(imprint of the internal carotid artery lying here and its accompanying nerve plexus).
Rice. Sphenoid bone (according to H. Feneis, 1994): 1 - body; 2 - wedge-shaped elevation; 3 - large wing, 4 - small wing; 5 - pre-crossed groove; 6 - Turkish saddle; 7 - pituitary fossa; 8 - anterior inclined process; 9 - posterior inclined process; 10 - the back of the saddle; 11 - carotid groove; 12 - wedge-shaped ridge; 13 - wedge-shaped beak; 14 - aperture of the sphenoid sinus; 15 - visual canal; 16 - superior orbital fissure; 17 - cerebral 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 - spinous hole; 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 of spheno-basilar synchondrosis.
The posterior surface of the saddle back passes into the upper surface of the basilar part of the occipital bone, forming a slope, clivus... On the clivus are the bridge, the medulla oblongata, the basilar artery with its branches. The back surface of the body is rough. Through the cartilaginous layer, it connects to the anterior surface of the basilar part of the occipital bone, forming 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 by bone tissue and both bones grow together. However, there is still no consensus on this issue. Probably, the bones still do not heal completely.
The front and part of the lower surface of the body face the nasal cavity. In the middle of the front surface of the body, a vertically running wedge-shaped ridge protrudes, crista sphenoidalis... Its anterior edge is adjacent to the posterior edge of the perpendicular plate, lamina perpendicularis, ethmoid bone. The lower segment of the ridge is pointed, stretched downwards, and forms a wedge-shaped beak, rostrum sphenoidale that wedges between the coulter wings, 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 the 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 insignificant depressions that cover the cells of the posterior part of the ethmoid labyrinth. The outer edges of these depressions are partially connected to the orbital plate of the ethmoid bone, forming a wedge-shaped ethmoid suture, sutura sphenoethmoidalis, and the lower ones - with the orbital process, processus orbitalis, palatine bone.
Sphenoid sinus sinus sphenoidalis, the paired cavity, fulfills most of the body of the sphenoid bone and belongs to the airway paranasal sinuses. Both, right and left, sinuses are separated from one another by a septum of the sphenoid sinuses, which extends anteriorly 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 a mucous membrane.
Small wings, alae minores, the sphenoid bone with two roots extends in both directions from the anterior-upper 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 the bone canal up to 5-6 mm long - the optic canal, canalis opticus... The optic nerve lies in it, n. opticus, and the ocular artery, a. ophthalmica... The small wings have an upper surface facing the cranial cavity and a lower one directed into the orbital cavity and closing the upper orbital fissure from above, fissura orbitalis superior... The front edge of the lesser wing, thickened and serrated, is connected to the orbital part of the frontal bone. The posterior concave and smooth edge freely protrudes into the cranial cavity and is the border between the anterior and middle cranial fossa, fossae cranii anterior et media... Medially, the posterior edge ends with a protruding, well-defined, anterior inclined process, processus clinoideus anterior(a part of the dura mater is attached to it, which forms the diaphragm of the sella turcica, diaphragma sellae).
Great wings of the sphenoid bone, alae majores, depart from the lateral surfaces of the body of the sphenoid bone and are oriented outward. The large wing has five surfaces and three edges. The superior, cerebral surface, facies cerebralis, concave and facing into the cranial cavity. It forms the anterior part of the middle cranial fossa and bears furrow depressions, cerebral eminences and arterial grooves, sulci arteriosi(prints of the relief of the adjacent surface of the brain and middle meningeal arteries). There are three holes at the base of the large wing: a round hole is located inward and anteriorly, foramen rotundum(the maxillary nerve comes out through it, n. maxillaris). Outward and posterior to the round is an oval opening, foramen ovale (it passes the mandibular nerve, n. mandibularis, and the vasculature of the foramen ovale). Even outward and posterior to the foramen ovale is the spinous foramen, foramen spinosum(the middle meningeal artery, vein and nerve pass through it). Anteroposterior, orbital surface, facies orbitalis, smooth, diamond-shaped, facing into the cavity of the orbit, where it forms most of its outer wall. The lower edge of this surface is spaced from the posterior edge of the orbital surface of the upper jaw body; here the inferior orbital fissure is formed, fissura orbitalis inferior... Anterior, maxillary surface, facies maxillaris, a small area of a triangular shape, bounded from above by the orbital surface, and from the side and from 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. Superior lateral, temporal surface, facies temporalis, somewhat concave, takes part in the formation of the wall of the temporal fossa, fossa temporalis(the temporal muscle is attached to it, m. temporalis). Below this surface is limited by the infratemporal ridge, crista infratemporalis, below which is the surface where the oval hole opens, foramen ovale, and a spinous foramen. 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 wedge-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 a wedge-parietal suture ( sutura sphenoparietalis)... The inner 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... Front, zygomatic edge, margo zygomaticus, serrated, connected to the frontal process, processus frontalis, zygomatic bone, forming a wedge-zygomatic suture ( sutura sphenozygomatica)... Rear, scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, the temporal bone in the sphenoid-scaly 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 sphenoid-mandibular ligament, lig. sphenomandibulare, and bundles of muscle straining the palatine curtain, m. tensor veli palatini... Inside of the spine of the sphenoid bone, the posterior edge of the large wing lies in front of the stony part, pars petrosa, the temporal bone and limits the sphenoid-stony cleft, fissura sphenopetrosa, medially passing into a ragged hole, foramen lacerum... This gap is made by cartilaginous tissue, forming a wedge-stony synchondrosis, synchondrosis sphenopetrosa.
Pterygoid processes processus pterygoidei, depart from the junction of the large wings with the body of the sphenoid bone and go down. 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 (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. Both plates grow together with their anterior edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea(this is where the medial pterygoid muscle begins, m. pterygoideus medialis). In the lower sections, both plates do not grow together 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 pterygoid hook directed downward and outward, hamulus pterygoideus, on the outer surface of which there is a groove of the pterygoid hook, sulcus hamuli pterygoidei(the tendon of the muscle straining the palatine curtain is thrown through it, m. tensor veli palatini). The posterior-superior edge of the inner plate expands at the base and forms an oblong scaphoid fossa, fossa scaphoidea(bundles of muscle begin in it, straining the palatine curtain, m. tensor veli palatini). Outwardly from the scaphoid fossa, there is a shallow groove of the auditory tube, sulcus tubae audilivae, which laterally passes to the large 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 greater wing of the sphenoid bone on the posterior wall of the pterygopalatine fossa. Under the outlet, along the front edge of the pterygoid process, there is a pterygopalatine groove. The inner 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 opener wing. As a result, the furrow of the vaginal process facing the wing is the vomer-vaginal groove, sulcus vomerovaginalis, turns into a vomer-vaginal canal, canalis vomerovaginalis... Outside the process, there is sometimes a sagittally running small palatovaginal groove, sulcus palatovaginalis... In the latter case, the sphenoid process of the palatine bone adjacent from below closes the groove into the canal of the same name (the nerve branches of the pterygopalatine node pass in both canals, and the branches of the sphenoid-palatine artery also pass in the palatine-vaginal canal). Sometimes, from the posterior edge of the outer plate, the pterygoid process is directed towards the spine of the sphenoid bone. processus pterygospinosus, which can reach the specified spine and form a hole.
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(os sphenoidale), unpaired, airy, located in the middle of the base of the skull (Fig. 1, 2). It connects with many bones of the skull and takes part in the formation of a number of bone cavities, pits, and partially in the formation of the cranial vault. 4 parts are distinguished in the bone: the body and 3 pairs of processes, of which 2 pairs are directed laterally and are called small and large wings. The third pair of processes (pterygoid) is directed downward.
Body (corpus) makes up the middle part of the bone and contains the sphenoid sinus (sinus sphenoidalis), which is divided by a septum into 2 halves. The posterior surface of the body grows together with the basilar part of the occipital bone in children through cartilage, in adults with the help of bone tissue.
Front surface the body is facing the nasal cavity, adjacent to the posterior cells of the ethmoid bone, closing them behind wedge-shaped shells (conchae sphenoidales)... Along the midline of the front surface is wedge-shaped crest (crista sphenoidalis) on both sides of which there are sphenoid sinus aperture (aperturae sinus sphenoidalis)... Through them, the sinus communicates with the nasal cavity. The perpendicular plate of the ethmoid bone is adjacent to the wedge-shaped crest in front. Downward, the wedge-shaped ridge passes into wedge-shaped beak (rostrum sphenoidale).
Rice. one.
a - topography of the sphenoid bone;
b - front view: 1 - body of the sphenoid bone; 2 - wedge-shaped shell; 3 - small wing; 4 - upper orbital fissure; 5 - the temporal surface of the large wing; 6 - spine of the sphenoid bone; 7 - maxillary surface; 8 - wedge-shaped ridge; 9 - pterygoid canal; 10 — round hole; 11 - infratemporal crest; 12 - orbital surface of the large wing; 13 - aperture of the sphenoid sinus;
c - rear view: 1 - back of the Turkish saddle; 2 - pituitary fossa; 3 - anterior inclined process; 4 - upper orbital fissure; 5 - large wing of the sphenoid bone; 6 - pterygoid canal; 7 - spine of the sphenoid bone; 8 - scaphoid fossa; 9 - lateral plate of the pterygoid process; 10 - pterygoid fossa; 11 - pterygoid notch; 12 - pterygoid hook groove; 13 - processus vaginalis; 14 - pterygoid hook; 15 - pterygoid process; 16 - carotid groove: 17 - auditory tube groove; 18 - wedge-shaped tongue; 19 - round hole; 20 - the cerebral surface of the large wing; 21 - parietal edge of the large wing; 22 - small wing; 23 - visual canal; 24 - the back surface of the body of the sphenoid bone;
d - bottom view: 1 - wedge-shaped beak; 2 - opener; 3 - pterygoid fossa; 4 - lateral plate of the pterygoid process; 5 - oval hole; 6 - spinous hole; 7 - medial plate of the pterygoid process; 8 - opener wing; 9 - the body of the sphenoid bone; 10 - scaphoid fossa; 11 - groove of the auditory tube; 12 - spine of the sphenoid bone; 13 - infratemporal surface of the large wing; 14 - infratemporal crest; 15 - the temporal surface of the large wing; 16 - small wing; 17 - wedge-shaped shells
Rice. 2. Sphenoid bone and occipital bone, rear, right and top view: 1 - spine of the sphenoid bone; 2 - spinous opening; 3 - oval hole; 4 - large wing of the sphenoid bone; 5 - small wing; 6 - anterior inclined process; 7 - visual canal; 8 - pre-crossed groove; 9 - upper orbital fissure; 10 - round hole; 11 - saddle tubercle; 12 - sleepy groove; 13 - pituitary fossa; 14 - posterior inclined process; 15 - saddle back; 16 - slope; 17 - large hole; 18 - occipital scales; 19 - lateral part of the occipital bone
On lateral surface there is a body on each side sleep sulcus (sulcus caroticus), to which the internal carotid artery is adjacent. Posteriorly and laterally, the edge of the groove forms a protrusion - wedge-shaped tongue (lingula sphenoidalis).
Top surface body, facing the cranial cavity, forms the so-called Turkish saddle (sella turcica)(see fig. 2). At its bottom is pituitary fossa (fossa hypophysial), which houses the pituitary gland. In front and behind the fossa is limited by protrusions, the front of which is represented saddle tubercle (tuberculum sellae), and the back - a high ridge, called saddle back (dorsum sellae)... The angles of the back of the Turkish saddle are stretched down and back in the form posterior inclined processes (processus clinoidei posteriors)... On each side of the saddle tubercle is middle tilted process (processus clinoideus medius).
In front of the tubercle of the saddle, on wedge-shaped elevation (jugum sphenoidalis) there is a transverse shallow pre-cross furrow (sulcus prehiasmatis), behind which is the intersection of the optic nerves.
Human anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
Sphenoid bone, os sphenoidale , unpaired, forms the central section of the skull base.
The middle part of the sphenoid bone is the body, corpus, cubic in shape, has six surfaces. On the upper surface, facing the cranial cavity, there is a depression - the Turkish saddle, sella turcica, in the center of which is the pituitary fossa, fossa hypophysialis. It contains the pituitary gland, hypophysis. The size of the fossa depends on the size of the pituitary gland. The border of the Turkish saddle in front is the tubercle of the saddle, tuberculum sellae. Behind it, on the lateral surface of the saddle, there is an unstable middle tilted process, processus clinoideus medius.
Sphenoid bone body–Corpussphenoidalis
Pituitary fossa–Fossahypophysialis
Saddle tubercle–Tuberculumsellae
Posterior inclined processes- processus clinoidei posterioris
Anterior inclined process–Processusclinoideusanterior
Sleep groove–Sulcuscaroticum
Wedge-shaped tongue- lingual sphenoidalis
Wedge-shaped beak–Rostrum sphenoidale
Wedge-shaped shell- conchae sphenoidalis
Sphenoid sinus aperture- aperture sinus sphenoidalis
Sphenoid sinus- sinus sphenoidalis
Small wing- ala minor
Large wing–Ala major
Visual channel–Canalisopticus
Superior orbital fissure- fissura orbitalis superior
Round hole–Foramen rotundum
Oval hole–Foramenovale
Spinous hole–Foramenspinosus
Brain surface–Faciescerebralis
Finger-shaped impressions–Impressionsdigitales
Arterial sulcus–Sulcusarteriosi
Orbital surface–Faciesorbitales
Maxillary surface–Faciesmaxillaries
Temporal surface–Faciestemporalis
Infratemporal ridge–Cristainfratemporalis
Pterygoid process–Processuspterygoideus
Pterygoid canal–Canalispterygoideus
Sphenoid bone–Spinaossissphenoidalis
Medial plate–Laminamedialis
Lateral plate–Laminalateralis
Pterygoid fossa–Fossapterygoidea
Pterygoid notch–Incisurapterygoidea
Wing hook–Hamulus pterygoideas
Sphenoid bone body
On the upper surface of the body there is a depression - the Turkish saddle, containing the pituitary gland. The front border of the saddle is the tubercle of the saddle, the back is the back of the saddle. On the sides of the sella turcica are carotid grooves with cavernous sinuses, in which the internal carotid arteries and associated nerve plexuses pass. Anterior to the tubercle of the saddle there is a groove of the chiasm, on which the chiasm of the optic nerves is located. The saddle back protrudes forward in the lateral regions, forming the posterior inclined processes. The posterior surface of the dorsum of the sella turcica continues smoothly with the upper surface of the basilar part of the occipital bone, forming the slope.
In front, 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. Behind, the body of the sphenoid bone fuses with the basilar part of the occipital bone.
Most of the body of the sphenoid bone is filled with an air sphenoid sinus, divided by a septum into two halves. In front, the sinus is bounded by wedge-shaped shells located on the sides of the wedge-shaped crest. The shells form holes - apertures through which the wedge-shaped cavity communicates with the nasal cavity. The walls of the sphenoid sinus are lined with mucous membranes.
Small wings
The lesser 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 ocular arteries. The upper surfaces of the lesser wings face the cranial cavity, the lower ones - into the orbital cavity, forming the upper walls of the upper orbital fissures. The front edges of the wings are articulated 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 fossa.
The lesser wings are connected to each other by a wedge-shaped elevation located in front of the groove of the intersection.
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 large wing there are three holes: a round hole 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 cerebral surface, upper, faces the cranial cavity.
The orbital surface, anteroposterior, has a rhomboid shape. It faces into 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, has a triangular shape, small in size. From above it is limited by the orbital surface, from the side from below - by the root of the pterygoid process. The maxillary surface is involved in the formation of the posterior wall of the pterygopalatine fossa. There is a round hole in it.
The temporal surface, superior lateral, is divided by the infratemporal crest into the temporal and pterygoid surfaces. The temporal surface is involved in the formation of the temporal fossa. Oval and spinous openings open on the pterygoid surface. The pterygoid surface forms the anterior wall of the infratemporal fossa.
The edges of the large wing
The frontal edge, upper, is connected to the orbital part of the frontal bone through the wedge-frontal suture. The outer parts of the frontal edge end with a sharp parietal edge, forming a wedge-parietal suture with the parietal bone. The inner parts of the frontal edge pass into a thin free edge, limiting the superior orbital fissure from below.
The zygomatic edge, anterior, connects with the frontal process of the zygomatic bone, forming a wedge-zygomatic suture.
The scaly edge, posterior, is connected to the wedge-shaped edge of the temporal bone and forms a wedge-scaly suture. Behind and outside, the scaly edge ends with a spine of the sphenoid bone. Inwardly from the spine, the scaly edge is located in front of the stony part of the temporal bone, forming with it a wedge-stony cleft that passes medially into the ragged opening.
Pterygoid processes
The pterygoid processes (Latin 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 are the pterygoid canals, in which the nerves and vessels of the same name pass. In front, each canal opens into the pterygo-palatine fossa.
Each process consists of the medial and lateral plates, which are fused in the anterior-superior sections, limiting the pterygoid fossa in front. The free, non-fused 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 pterygoid hook directed downward and outward.
Sphenoid body 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 Turkish saddle, sella turcica... in the center of which is the pituitary fossa. The pituitary gland lies in it. 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 nuclei of ossification of the fossa occurs at the 8th month of intrauterine life. Hence, there is a possibility of damage to the structure of the pituitary fossa with subsequent dysfunction of the pituitary gland. The turkish saddle is bounded in front by the tubercle of the saddle, tuberculum sellae... Behind it, on the lateral surface of the saddle, there is an unstable middle tilted process, processus clinoideus medius... Anterior to the tubercle of the saddle, there is a shallow transverse groove of the intersection, sulcus chiasmatis... On it lies the intersection of the optic nerves, chiasma opticum... On the sides, the furrow passes into the visual canal, canalis opticus... In front of the furrow there is a smooth surface - a wedge-shaped elevation, 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 sphenoid-ethmoid suture, sutura sphenoethmoidalis... The perforated plate has a large number of holes (25-30), through which branches of the anterior ethmoid (olfactory) nerve and the vein accompanying the anterior ethmoid artery go from the nasal cavity into the cranial cavity (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 ratio in the wedge-ethmoid suture may occur, followed by traumatization of the olfactory bulbs.
The turkish saddle is bounded at the back by the back of the saddle, dorsum sellae which ends on each side with a small posterior oblique process, processus clinoideus posterior... On the sides of the Turkish saddle, from back to front, there is a sleepy groove, sulcus caroticus(imprint of the internal carotid artery lying here and its accompanying nerve plexus).
Rice. Sphenoid bone (according to H. Feneis, 1994): 1 - body; 2 - wedge-shaped elevation; 3 - large wing, 4 - small wing; 5 - pre-crossed groove; 6 - Turkish saddle; 7 - pituitary fossa; 8 - anterior inclined process; 9 - posterior inclined process; 10 - the back of the saddle; 11 - carotid groove; 12 - wedge-shaped ridge; 13 - wedge-shaped beak; 14 - aperture of the sphenoid sinus; 15 - visual canal; 16 - superior orbital fissure; 17 - cerebral 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 - spinous hole; 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 of spheno-basilar synchondrosis.
The posterior surface of the saddle back passes into the upper surface of the basilar part of the occipital bone, forming a slope, clivus... On the clivus are the bridge, the medulla oblongata, the basilar artery with its branches. The back surface of the body is rough. Through the cartilaginous layer, it connects to the anterior surface of the basilar part of the occipital bone, forming 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 by bone tissue and both bones grow together. However, there is still no consensus on this issue. Probably, the bones still do not heal completely.
The front and part of the lower surface of the body face the nasal cavity. In the middle of the front surface of the body, a vertically running wedge-shaped ridge protrudes, crista sphenoidalis... Its anterior edge is adjacent to the posterior edge of the perpendicular plate, lamina perpendicularis, ethmoid bone. The lower segment of the ridge is pointed, stretched downwards, and forms a wedge-shaped beak, rostrum sphenoidale that wedges between the coulter wings, 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 the 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 insignificant depressions that cover the cells of the posterior part of the ethmoid labyrinth. The outer edges of these depressions are partially connected to the orbital plate of the ethmoid bone, forming a wedge-shaped ethmoid suture, sutura sphenoethmoidalis, and the lower ones - with the orbital process, processus orbitalis, palatine bone.
Sphenoid sinus sinus sphenoidalis, the paired cavity, fulfills most of the body of the sphenoid bone and belongs to the airway paranasal sinuses. Both, right and left, sinuses are separated from one another by a septum of the sphenoid sinuses, which extends anteriorly 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 a mucous membrane.
Small wings, alae minores, the sphenoid bone with two roots extends in both directions from the anterior-upper 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 the bone canal up to 5-6 mm long - the optic canal, canalis opticus... The optic nerve lies in it, n. opticus, and the ocular artery, a. ophthalmica... The small wings have an upper surface facing the cranial cavity and a lower one directed into the orbital cavity and closing the upper orbital fissure from above, fissura orbitalis superior... The front edge of the lesser wing, thickened and serrated, is connected to the orbital part of the frontal bone. The posterior concave and smooth edge freely protrudes into the cranial cavity and is the border between the anterior and middle cranial fossa, fossae cranii anterior et media... Medially, the posterior edge ends with a protruding, well-defined, anterior inclined process, processus clinoideus anterior(a part of the dura mater is attached to it, which forms the diaphragm of the sella turcica, diaphragma sellae).
Great wings of the sphenoid bone, alae majores, depart from the lateral surfaces of the body of the sphenoid bone and are oriented outward. The large wing has five surfaces and three edges. The superior, cerebral surface, facies cerebralis, concave and facing into the cranial cavity. It forms the anterior part of the middle cranial fossa and bears furrow depressions, cerebral eminences and arterial grooves, sulci arteriosi(prints of the relief of the adjacent surface of the brain and middle meningeal arteries). There are three holes at the base of the large wing: a round hole is located inward and anteriorly, foramen rotundum(the maxillary nerve comes out through it, n. maxillaris). Outward and posterior to the round is an oval opening, foramen ovale (it passes the mandibular nerve, n. mandibularis, and the vasculature of the foramen ovale). Even outward and posterior to the foramen ovale is the spinous foramen, foramen spinosum(the middle meningeal artery, vein and nerve pass through it). Anteroposterior, orbital surface, facies orbitalis, smooth, diamond-shaped, facing into the cavity of the orbit, where it forms most of its outer wall. The lower edge of this surface is spaced from the posterior edge of the orbital surface of the upper jaw body; here the inferior orbital fissure is formed, fissura orbitalis inferior... Anterior, maxillary surface, facies maxillaris, a small area of a triangular shape, bounded from above by the orbital surface, and from the side and from 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. Superior lateral, temporal surface, facies temporalis, somewhat concave, takes part in the formation of the wall of the temporal fossa, fossa temporalis(the temporal muscle is attached to it, m. temporalis). Below this surface is limited by the infratemporal ridge, crista infratemporalis, below which is the surface where the oval hole opens, foramen ovale, and a spinous foramen. 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 wedge-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 a wedge-parietal suture ( sutura sphenoparietalis)... The inner 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... Front, zygomatic edge, margo zygomaticus, serrated, connected to the frontal process, processus frontalis, zygomatic bone, forming a wedge-zygomatic suture ( sutura sphenozygomatica)... Rear, scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, the temporal bone in the sphenoid-scaly 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 sphenoid-mandibular ligament, lig. sphenomandibulare, and bundles of muscle straining the palatine curtain, m. tensor veli palatini... Inside of the spine of the sphenoid bone, the posterior edge of the large wing lies in front of the stony part, pars petrosa, the temporal bone and limits the sphenoid-stony cleft, fissura sphenopetrosa, medially passing into a ragged hole, foramen lacerum... This gap is made by cartilaginous tissue, forming a wedge-stony synchondrosis, synchondrosis sphenopetrosa.
Pterygoid processes processus pterygoidei, depart from the junction of the large wings with the body of the sphenoid bone and go down. 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 (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. Both plates grow together with their anterior edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea(this is where the medial pterygoid muscle begins, m. pterygoideus medialis). In the lower sections, both plates do not grow together 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 pterygoid hook directed downward and outward, hamulus pterygoideus, on the outer surface of which there is a groove of the pterygoid hook, sulcus hamuli pterygoidei(the tendon of the muscle straining the palatine curtain is thrown through it, m. tensor veli palatini). The posterior-superior edge of the inner plate expands at the base and forms an oblong scaphoid fossa, fossa scaphoidea(bundles of muscle begin in it, straining the palatine curtain, m. tensor veli palatini). Outwardly from the scaphoid fossa, there is a shallow groove of the auditory tube, sulcus tubae audilivae, which laterally passes to the large 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 greater wing of the sphenoid bone on the posterior wall of the pterygopalatine fossa. Under the outlet, along the front edge of the pterygoid process, there is a pterygopalatine groove. The inner 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 opener wing. As a result, the furrow of the vaginal process facing the wing is the vomer-vaginal groove, sulcus vomerovaginalis, turns into a vomer-vaginal canal, canalis vomerovaginalis... Outside the process, there is sometimes a sagittally running small palatovaginal groove, sulcus palatovaginalis... In the latter case, the sphenoid process of the palatine bone adjacent from below closes the groove into the canal of the same name (the nerve branches of the pterygopalatine node pass in both canals, and the branches of the sphenoid-palatine artery also pass in the palatine-vaginal canal). Sometimes, from the posterior edge of the outer plate, the pterygoid process is directed towards the spine of the sphenoid bone. processus pterygospinosus, which can reach the specified spine and form a hole.
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