The skull (Fig. 16) is the skeleton of the head. It houses the brain, organs of vision, organs of hearing and balance, nasal cavity, and organs of the oral cavity. Powerful chewing muscles, facial muscles and muscles coming from the torso are attached to the skull.

All of these organs influence the shape and structure of the skull.

The brain and facial parts of the skull are examined. The border between them passes approximately through the posterior edge of the eye sockets. The medulla of the skull contains the brain and is connected to the atlas.

The facial part of the skull contains the nasal cavity and oral organs.

The skull consists of 13 paired and 7 unpaired bones. The unpaired bones of the brain part of the skull include: occipital, sphenoid and other bones; to the paired ones - parietal, temporal and frontal. The unpaired bones of the facial part of the skull are: ethmoid, vomer, hyoid and proboscis (in pigs), paired - the upper jaw, premaxillary, nasal, lacrimal, zygomatic, palatine, pterygoid, lower jaw, nasal turbinates (upper and lower).

Rice. 16. Cow Skull:

A - on the left side; B - longitudinal cut; 1 - occipital bone; 2 - facial tubercle; 3 - parietal bone; 4 - temporal bone; 5 - frontal bone; 6 - maxillary bone; 7 - premaxillary bone; 8 - nasal bone; 9 - lacrimal bone; 10 - zygomatic bone; 11 - lower jaw; 12 - eye socket; 13 - angle of the lower jaw; 14 - sphenoid bone; 15 - ethmoid bone; 16 - opener; 17 - palatine bone; 18— pterygoid bone; 19—upper and 2 0—lower shell; 21—sinus of the frontal bone in the region of the frontal crest,

The shape of the skull changes dramatically during ontogenesis. In fetuses and newborns, the skull is more rounded, since its cerebral part is more developed. As teeth grow, the facial part of the skull begins to develop more strongly, especially in herbivores. With age, the shape of the cerebral part of the skull also changes, as the masticatory muscles are attached to it.

Side functions are also reflected in the shape of the skull. In pigs, the ability to dig the ground determines the powerful development of jugular processes and scales occipital bone, as a result, the skull as a whole takes the shape of a tetrahedral pyramid. In cattle, due to the development of horns, which serve for protection, the frontal bone is greatly enlarged, which forms the frontal crest between the base of the horns. This ridge forms the posterior upper edge of the skull. In small cattle and other species of animals there is no frontal crest, and the posterior upper edge of the skull is formed by the occipital crest of the occipital bone.

The powerful development of teeth causes the growth of the upper jaws and the formation of maxillary sinuses (cavities) in them, communicating with the nasal cavity. Sinuses increase bone strength. Such sinuses are also present in some other bones of the skull, for example in the frontal bones, especially in horned cows.

The strong development of the masticatory muscles causes: 1) the formation of the zygomatic arches, to which the masticatory muscles and lower jaws are attached; 2) the formation of sometimes more or less deep temporal fossae in the cerebral part of the skull; 3) the formation of zygomatic ridges in horses or facial ridges in cattle; 4) closing the eye sockets behind by connecting the frontal bones with the zygomatic arches in herbivores, which increases the strength of the jaw joints; 5) strong development of the branches and angles of the lower jaw.

There are many holes and canals in the skull where blood vessels, feeding the organs of the cranial and nasal cavities, and for the cranial nerves emerging from the brain.

(neurocranium) - formed by unpaired (occipital, sphenoid, interparietal, ethmoid) and paired (parietal, temporal and frontal) bones, which form the cranial cavity to house the brain, and therefore their internal (cerebral) surface is smooth. But at the same time, it bears imprints of all the irregularities of the brain: the cerebral convolutions - in the form of finger impressions (impression digitalis), the grooves between the convolutions - in the form of brain ridges - juga cerebralia, individual areas of the brain - in the form of pits, brain vessels and nerves emerging from it - in the form of vascular and nerve grooves, channels and openings.

Occipital bone - os occipitale

Unpaired, lies in occipital region skull and is characterized by the presence of a large occipital foramen - for. occipitale magnum, through which the spinal canal communicates with the cranial cavity. The occipital bone is divided into: body, lateral parts and scales

Body of the occipital bone - pars basilaris, is located ventral to the foramen magnum and fuses nasally with the body of the sphenoid bone. At the place of their fusion on the ventral side there is a paired muscular tubercle - tuberculum musculare, on which the long muscles of the head are attached. On the dorsal or medullary surface of the body of the occipital bone there are two flat fossae:

• 1) behind - fossa for the medulla oblongata - fossa medullae oblongatae,
• 2) and in front of it there is a transverse fossa for the brain bridge - fossa pontis.

The body of the occipital bone forms the medial edges of the ragged foramina - for. lacerum, through which vessels pass into the cranial cavity, and nerves emerge from it.

Side parts - pars. lateralis - represented by condyles and jugular processes. Occipital condyles - condylus occipitalis - located on both sides of the foramen magnum and serve for articulation with the atlas to form the occipito-atlas joint. Jugular processes - processus jugularis - lie lateral to the condyles and the muscles going to the neck are attached to them. Between the condyles and jugular processes there is a hyoid foramen - for. n. hypoglossi, through which the XII pair of cranial nerves (hypoglossal nerve) exits. The lateral parts of the occipital bone are connected to the temporal bones.

Occipital bone scales - squama occipitalis - rises dorsally above the foramen magnum and lateral parts. The dorsal edge of the scales forms the occipital crest - crista occipitalis, which on the right and left continues into the temporal crest of the zygomatic arch. On the outer or nuchal surface of the scales - pars nuchalis, near the occipital crest, there is an external occipital protuberance - protuberantia occipitalis externa for attachment of the nuchal ligament. Imprints of the cerebellum are visible on the inner or cerebral surface. The squama of the occipital bone is connected to parietal bones.

Peculiarities:

U dogs jugular processes are short and straight. The scales are powerful; the occipital crest separates its parietal part, on which the outer sagittal crest protrudes. At the base of the jugular process there is a hyoid foramen, and posterior to it, on the medullary surface of the occipital bone there is an entrance to the condylar canal - canalis condylaris.

U pigs the jugular processes are very long, straight and directed ventrally. The scales of the occipital bone in old animals contain a cavity - sinus occipitalis, which communicates with the parietal sinuses. The hyoid foramen is located at the base of the jugular process.

U cattle the jugular processes are short and curved ventrally, the hyoid foramen is often double, there is a condylar canal, and the nuchal crest is absent.

U horses jugular processes are straight, the occipital crest is well defined, which separates parietal part. Below the occipital protuberance is the nuchal fossa - fossa nuchalis.

Sphenoid bone - os sphenoidale

Lies at the base of the skull, nasal to the body of the occipital bone. Dorsally and laterally it borders with the temporal and frontal, and nasally with the ethmoid, palatine, pterygoid bones and vomer. The sphenoid bone is divided into: a body, two pairs of wings (orbital and temporal) and paired pterygoid processes (Fig. 14, 15, 16).

Body of the sphenoid bone - The corpus sphenoidale in young animals consists of two parts:

• 1) nasal - presphenoid (os praesphenoidale)
• 2) caudal - basisphenoid (os basissphenoidale).

The orbital wings, ala orbitalis, extend dorsolaterally from the presphenoid, which participate in the formation of the sphenopalatine fossa and partially the orbit. From the basisphenoid, also dorsolaterally, extend the temporal wings - ala temporalis, connecting with the temporal bones. Paired pterygoid processes - processus pterygoideus - extend nasoventrally from the basisphenoid and temporal wings, which connect to the palatine (lateral) and pterygoid bones (medially). The nasal edge of the pterygoid process forms a wing crest - crista pterygoidea, which caudally frames the sphenopalatine fossa - fossa sphenopalatina and the floor of the orbit. Dorsally, the alar crest passes into the orbital-temporal crest - crista orbitotemporalis.

A series of openings open in front of the alar crest in the sphenopalatine fossa: ethmoidal for. ethmoidae - belongs to the ethmoid bone and through it, together with the artery of the same name, the ethmoid nerve passes into the nasal cavity. Optical opening for. opticum leads into the cranial cavity and serves to pass optic nerve from the eyeball to the brain. Ventral to the optic foramen is the orbital fissure fissura orbitalis, and even more ventral is the foramen rotundum. rotundum, which can merge into one - orbital round for. orbitorotundum. Through these openings, vessels and nerves pass from the cranial cavity into the sphenopalatine fossa. So, through the orbital fissure, the ophthalmic nerve exits (n. ophtalmicus, branch of the V pair, trigeminal nerve), The maxillary nerve (n. maxillaris, branch of the V pair - the trigeminal nerve) exits into the orbit through the round foramen.

From the sphenopalatine fossa, the vessels of both the infraorbital and sphenopalatine nerves go to three holes:

• 1. through the maxillary foramen. maxillare, the infraorbital nerve with the artery of the same name goes into the infraorbital canal, which opens with the infraorbital foramen on the maxillary bone.
• 2. sphenopalatine foramen - for. sphenopalatinum - leads into the nasal cavity; one of the branches of the sphenopalatine nerve passes through it into the nasal cavity.
• 3. posterior palatine foramen. palatinum caudale - into the palatine canal, which opens with a large palatine foramen along the edge of the palatine bone.

On brain surface The presphenoid, which is elevated dorsally from the basisphenoid, has a groove of the optic chiasm - sulcus chiasmatus - running behind it. On the cerebral surface of the basisphenoid there is a pituitary fossa fossa hypophysialis, or sella turcica sela turcica, behind which there is a transverse plate - the back of the sella turcica dorsum sellae.

Peculiarities:

U dogs The dorsum of the sella turcica is strongly developed, the groove of the optic chiasm is absent. The orbital fissure and foramen rotundum lead into the sphenopalatine fossa. Behind the round foramen, at the base of the temporal wing, the caudal alar foramen opens - for. alare caudale, even more posteriorly - foramen ovale - for. ovale, and between the temporal wings and the tympanic part of the temporal bone - the carotid foramen - for. caroticum, which leads to sleepy channel temporal bone.

U pigs The wing processes are well defined, on the caudal surfaces of which there are wing fossa fossa pterygoidea. Orbital fissure merges with the round and forms an extensive orbital round.

U cattle at the base of the temporal wing there is an oval foramen.

U horses At the base of the pterygoid process there passes the wing canal - canalis alaris, which begins with the caudal wing opening for. alare caudale, and opens nasally into a round opening.

Parietal bone - os parietale

Paired lamellar bone. Wedged between the scales of the occipital bone, frontal and temporal bones. Its outer surface is involved in the formation of the temporal fossa. On its cerebral surface there are noticeable finger impressions impressions digitalae, cerebral ridges - juga cerebralia and vascular grooves. (Fig. 15)

Peculiarities:

U dogs The parietal bone is separated from the other side of the same name by the external sagittal crest.

At the pig's The parietal bone is massive and is divided by the temporal crest linea temporalis into the parietal planum parietale and the temporal platform planum temporale. In adult animals, the parietal bone contains the sinus parietalis, which communicates with the occipital and frontal sinuses.

U cattle The parietal bone lies in the occipital and temporal regions and has, respectively, occipital and temporal parts, separated by temporal crests.

U horses The external sagittal crest of the parietal bone passes nasally into the external frontal crest.

Interparietal bone - os interparietale

Unpaired, noticeable in fetuses and newborns. In adult animals, it fuses with the occipital and parietal bones, between which it lies (Fig. 13).

Peculiarities:

In a dog interparietal bone heart-shaped. The bony cerebellar tentorium protrudes on its cerebral surface - tentorium cerebelli osseum.

U pigs she's not there.

U cattle The interparietal bone is triangular in shape.

U horses the bone is quadrangular, and the bony cerebellar tentorium protrudes on its medullary surface.

Temporal bone - os temporale

The steam room lies in the temporal region and consists of scales and petrous bone. (Fig. 12,15, 16, 17)

Temporal bone scales- pars squamosa - together with the parietal bone forms the temporal fossa fossa temporalis for attaching the temporal muscle. Laterally, the zygomatic process processus zygomaticus protrudes on the scales, which connects nasally with the zygomatic bone and forms the zygomatic arch arcus zygomaticus. Ventrally at the base of the zygomatic process there is an articular tubercle tuberculum articulare for articulation with the articular process of the lower jaw to form the temporomandibular, complex, biaxial joint.

Petrous bone- pars petrosa serves as a container for the middle and inner ear. In the horse it occurs as an independent bone, while in other animals it fuses with the scales of the temporal bone. The petrous bone consists of three parts: mastoid, tympanic and rocky.

Mastoid part- pars mastoidea - fuses with the occipital bone and protrudes in the form of the mastoid process processus mastoideus nasally from the base of the jugular process. The cleidomastoid part of the brachiocephalic muscle is attached to the mastoid part. An external opening opens between the mastoid process and the tympanic part. facial canal canalis facialis, through which it exits facial nerve.

The mastoid part of the temporal bone forms the lateral edge of the foramen lacerum. lacerum.

Drum part- pars tympanica - located nasally from the mastoid bone and consists of the external auditory canal meatus acusticus externus and the tympanic bulla bulla tympanica with the tympanic cavity. The muscular process processus musculare extends nasoventrally from the tympanic bladder to attach the muscles of the velum palatine, medially from which there is the bony auditory tube tuba auditiva ossea, connecting the tympanic cavity with the pharyngeal cavity. IN tympanic cavity The organs of the middle ear are located: the chain of auditory ossicles with their ligaments and muscles.

rocky part- pars petrosa - located in the naso-medial part of the petrosal bone. In the rocky part there is a labyrinth of the inner ear, as a result of which three openings leading into the labyrinth are visible on its surface: the largest of them is the internal auditory canal meatus acusticus internus, through which two nerves pass: the equilibrium-auditory (VIII pair), and at the back - facial nerve (VII). Dorso-caudally from the internal auditory canal there is an opening of the aqueduct of the vestibule apertura externa aquaeductus vestibuli, and caudally between both openings there is a third - the entrance to the aqueduct of the cochlea apertura externa aquaeductus cochlea.

Peculiarities:

U dogs The external auditory canal is very short, the tympanic bulla is extensive and round. The mastoid process lies dorsal to the external auditory canal. The opening of the bony auditory tube is located between the foramen ovale and the carotid foramen. The ragged opening is only noticeable behind the bulla tympanum.

U pigs the external auditory canal is long, the tympanic bulla is extended nasoventrally. The mastoid process lies lateral to the tympanic bulla, anterior to the jugular process.

U cattle the external auditory canal is long, directed laterally, the tympanic bulla is large and flattened laterally. It contains the hyoid process processus hyoideus, to which the hyoid bone is attached with its proximal segment. Eustachian tube passes laterally from the foramen ovale. The ragged opening is slit-like.

U horses petrous bone fuses with scales only in old age. The external auditory canal is relatively short, caudal to it lies a well-developed mastoid process, which gives off a powerful hyoid process. Dorsally from the external auditory canal there is a groove, which, together with the scales, forms the temporal passage meatus temporalis, which opens outward with three openings: 1) into the temporal fossa; 2) in front of the external auditory canal; 3) behind the mastoid process. The muscular process is well developed. The torn hole is extensive.

Frontal bone - os frontale

The steam room borders medially on the other side of the same name, caudally on the parietal bone, nasally on the nasal and lacrimal bones, lateroventrally on the palatine, sphenoid and temporal, and medioventrally on the ethmoid bone (Fig. 12,19).

The frontal bone is divided into the frontotemporal and nasoorbital parts, which respectively participate in the formation of the roof of the cranial cavity (frontotemporal), as well as in the formation of the dorsal and lateral walls of the nasal cavity. The frontal and temporal surfaces are separated from each other by the external frontal crest - crista frontalis externa, and the nasal surface from the orbital surface - by the orbital edge - margo supraorbitalis, and the orbital surface from the temporal surface - by the orbital-temporal crest - crista orbitotemporalis. At the border between the orbit and the temporal fossa, the zygomatic process extends laterally - proc. zygomaticus. The frontal bone has a sinus - sinus frontalis, which communicates with the nasal cavity. Frontal sinuses of the left and right side separated by a longitudinal partition. The supraorbital foramen opens on the frontonasal surface - for. supraorbitale.

Peculiarities:

U dogs The zygomatic process is poorly developed and is connected to the zygomatic arch by the orbital ligament - liq. orbitale. There is no supraorbital foramen.

U pigs The frontonasal surface of the bone is flat in some breeds, while in others it is curved. The supraorbital foramen opens at the level of the anterior edge of the orbit, from which the supraorbital groove - sulcus supraorbitalis - is directed onto the nasal bone. The zygomatic process is short and is connected to the zygomatic arch by the orbital ligament. The frontal sinuses are extensive, connecting with the sinuses of the parietal and occipital bones.

U cattle The frontal bones are highly developed and serve as the vault of the cranial cavity - calvaria, and with their posterior edge they reach the occipital-parietal region, where they form the posterior frontal ridge - crista frontalis caudalis, or interhorn ridge. Its position corresponds to the occipital crest of other animals. Powerful horn-like processes - processus cornualis - extend from the posterior frontal crest on the sides, on which they distinguish: a neck - collum, and above the neck - a rough ridge - corona. The outer surface of the horn-shaped processes is rough and penetrated by vascular processes and grooves. The zygomatic process of the frontal bone connects with the frontal process zygomatic bone and the orbit turns out to be closed. Nasally and caudally from the zygomatic process, at the base of which is the supraorbital foramen, the supraorbital groove passes.

U horses The zygomatic process of the frontal bone connects with the zygomatic process of the temporal bone; at the base of the process there is a supraorbital foramen. The frontal sinuses are well defined.

Ethmoid bone - os ethmoidale

Unpaired, lies in posterior section The nasal cavity, between the frontal and sphenoid bones, separates the cranial cavity from the nasal cavity. It distinguishes a paired labyrinth and three plates - lattice, perpendicular and paper.

Ethmoid labyrinth- labyrinthus ethmoidalis consists of large quantity turbinalia, bone porous plates rolled into spindle-shaped tubes, each of which is attached laterally to a paper plate, and at the posterior end to a ethmoid plate (Fig. 18). The medial turbinalia - endoturbinalia - are larger, their number is small, and are equipped with additional curls. Lateral turbinalia - ectoturbinalia - are small, but their number is greater. Between the turbinalia there are narrow slits communicating with the nasal cavity. Turbinalia support the folds of the olfactory part of the nasal mucosa.

Lattice plate - lamina cribrosa - forms the anterior wall of the cranial cavity. It is pierced by openings for the passage of the olfactory filaments into the olfactory bulbs of the brain, which are located in the olfactory pits - fossa olfactoria, located on the cribriform plate from the side of the cranial cavity. The olfactory pits are divided into midline cock's comb - crista galli. At the lateral edges of the olfactory fossae there are ethmoidal openings - for. ethmoidae, opening into the orbit.

Perpendicular plate - lamina perpendicularis - lies in the median plane and anteriorly passes into the cartilaginous nasal septum, and posteriorly it is attached to the cribriform plate in the region of the cock's crest.

Paper or side plate- steam room - lamina tectoria papyracea, very thin, forms the lateral wall of each labyrinth; its dorsal and ventral edges are fused with the ethmoidal and perpendicular plates, respectively. It can be seen from the side of the frontal sinus.

Peculiarities:

U dogs the labyrinth consists of 4 endo- and 6 ectoturbinals.

U pigs in the labyrinth there are 7 endo- and 18 ectoturbinals. The curl plates are thick.

U cattle the perpendicular plate is highly developed, and the labyrinth consists of 5 endo- and 18 ectoturbinals, the largest of which forms the middle turbinate- concha media.

U horses in the labyrinth there are 6 endo- and 25 ectoturbinals.

Facial skull: structure, development, specific features.

The shape of the skull changes dramatically during ontogenesis. In fetuses and newborns, the skull is more rounded, since its cerebral part is more developed. As teeth grow, the facial part of the skull begins to develop more strongly, especially in herbivores. With age, the shape of the cerebral part of the skull also changes, as the masticatory muscles are attached to it. Side functions are also reflected in the shape of the skull. In pigs, the ability to dig the ground determines the powerful development of the jugular processes and the scales of the occipital bone, as a result of which the skull as a whole takes the shape of a tetrahedral pyramid. In cattle, due to the development of horns, which serve for protection, the frontal bone is greatly enlarged, which forms the frontal crest between the base of the horns.

BONES OF THE FACIAL SKULL

Lower jaw

The lower jaw, mandlbula, is an unpaired bone and is the only movable bone of the skull, which forms the temporomandibular joints with the temporal bones. There is a body of the lower jaw, located horizontally, and two vertically directed branches.

The body of the lower jaw, corpus mandibulae, is horseshoe-shaped and has outer and inner surfaces. The lower edge of the body - the base of the lower jaw, basis mandibulae, is rounded and thickened, the upper edge forms the alveolar part, pars alueoldris. The latter contains dental alveoli, alveoli dentdles (for 16 teeth), separated by interalveolar septa, septa interalveoldria. On outer surface The alveolar arch has alveolar elevations, jiiga alveoldria, corresponding to the alveoli. In the anterior part of the body of the lower jaw, along the midline, there is a mental protuberance, protuberdntia mentdlis, which gradually widens from below and ends with a paired mental tubercle, tuberculum mentdle. -Posterior to the mental tubercle at the level of the second small molar there is a mental foramen, foramen mentdle. serving for the exit of the artery and nerve of the same name. Behind the mental foramen, an oblique line begins, iinea obliqua, heading backward and upward and ending at the base of the coronoid process.

In the middle of the inner surface of the body of the lower jaw, the mental spine, spina mendlis, protrudes. On the sides of it, at the base of the jaw on the right and left, there is an oblong abdominal fossa, fossa digastrica, the place of attachment of the muscles of the same name. At the upper edge of the spine, closer to the dental alveoli, there is also a sublingual fossa on both sides, /ossa sublingualis, for the ossa sublingualis salivary gland. Below it begins and goes obliquely upward, ending at the posterior end of the body of the lower jaw, a weakly defined mylohyoid line, linea mylohyoidea. Under this line, at the level of the molars, there is a submandibular fossa, fovea submandibularis, the location of the submandibular salivary gland.

The branch of the lower jaw, ramus mandibulae, paired, extends from the body at an obtuse upward angle, has anterior and posterior edges and two surfaces, external and internal. When the body passes into the posterior edge of the branch, the angle of the lower jaw, angulus mandibulae, is formed, on the outer surface of which there is a chewing tuberosity, tuberositas masseterica, and on the inner surface there is a pterygoid tuberosity, tuberositas pterygoidea. Somewhat above the latter, on the inner surface of the branch, a rather large opening of the lower jaw, foramen mandibulae, is visible, facing upward and backward, which is limited on the medial side by the tongue of the lower jaw, llngula mandibulae. This hole leads into the canal of the lower jaw, candlis mandibulae, which runs inside the body of the lower jaw and ends on its outer surface with the mental foramen. On the inner surface of the branch of the lower jaw, somewhat posterior to the uvula, the mylohyoid groove, slilcus mylohyoideus, descends obliquely down and forward, to which the nerve and vessels of the same name are adjacent.

The branch of the lower jaw is completed by two processes directed upward: the anterior coronoid process, processus coronoideus. and the posterior condylar (articular) process, processus condylaris. Between these processes there is a notch of the lower jaw, incisura mandibulae. The coronoid process has a pointed apex. From its base, on the inside, a buccal ridge, crista buccinatoria, is directed to the last large molar. The condylar process ends with a well-defined head of the lower jaw, caput mandibulae, which continues into the neck of the lower jaw, collum mandibulae. On the anterior surface of the neck is visible the pterygoid fossa, fovea pterygoidea, the attachment site of the lateral pterygoid muscle.

Hyoid bone

The hyoid bone, os hyoideum, is located in the neck, between lower jaw and larynx. It consists of a body and two pairs of processes: small and large horns. The body of the hyoid bone, corpus ossis hyoldei, has the appearance of a curved plate; back surface concave, anterior convex. Thickened at the ends extend from the body on the right and left big horns, cornua majora, directed slightly upward and posteriorly. Small horns, cornua minora, extend from the body upward, backward and laterally in the same place as the large ones; they are significantly shorter than the large horns. The hyoid bone, with the help of muscles and ligaments, is suspended from the bones of the skull and connected to the larynx.

Brain section of the skull

The brain section of the head, or skull - cranium - is based on four unpaired (occipital, sphenoid, interparietal, ethmoid) and four paired (temporal, parietal, frontal, pterygoid) bones. All of these bones participate in the formation of the cranial cavity (cavum cranii) and the orbit (orbita).

Occipital, parietal, interparietal bones.

Target

Study the structure and specific features of the occipital, parietal, interparietal bones.

Educational visual aids

1. Tables – skeletons and skulls of domestic animals and birds.

2. Skeletons of domestic animals and birds.

3. Skulls of dogs, pigs, cattle, horses.

4. Sagittal section of the skull of a horse and cattle.

Teaching Methodology

1. There are four sets of study materials on the students’ tables.

2. On the teacher’s table there are demonstration preparations and a set of training preparations.

3. Tables are posted on the board and a record of Latin terms is made.

4. The teacher explains the content of the lesson (25 min).

5. Independent work students (40 min).

6. Checking the quality of assimilation of the studied material (20 min).

7. Answers to questions and homework (5 min).

1. Familiarize yourself with the general structure of the skull.

2. Study the structure of the occipital, parietal and interparietal bones and the species characteristics of various types domestic animals and birds.

Occipital bone – os occipitale(unpaired)

I. Body of the occipital bone – pars basilaris.

1. Deepening of the medulla oblongata - impressionis medullae oblongatae.

2. Deepening of the medullary pons – impressionis pontis.

3. Muscular processes – tuberculum muscularis.

II. The lateral parts are pars lateralis.

1. Condyles – condylus occipitals.

2. Jugular processes – processus jugulars.

3. Jugular notches - incessura jugulars.

4. Canal of the hypoglossal nerve – canalis nervi hypoglossi.

5. Condylar foramen – foramen condylaris.

6. Foramen magnum – foramen occipitale magnum.

III. The scales of the occipital bone are squama occipitalis.

1. Nuchal ridge – crista nuchae.

2. Nuchal line – linia nuchae.

3. Nuchal crest – crista occipitalis.

4. Nuchal fossa – fossa nuchalis.

5. Nuchal tubercles – tuberculum nuchale.

6. External and internal occipital protrusion – protuberantia occipitalis externa et interna.

7. External sagittal ridge – crista sagittalis externa.

Species features:

Dog. The jugular processes are short and wide. There is a condylar foramen, an external sagittal ridge, and nuchal fossae.

Pig. The jugular processes are long and curved along the longitudinal axis. The scales are smooth, concave, triangular in shape. There is no condylar foramen.

Cattle. The jugular processes are long and directed medially. There is a condylar foramen, a nuchal line. The scales are narrow.

Horse. The jugular processes are long and somewhat spaced apart. There is a nuchal and external sagittal ridge, a nuchal fossa.

Parietal bone – os parietale(steam room)

I. Temporal line – linea temporalis.

1. Parietal plate – planum parietale.

2. Temporal plate – planum temporale.

3. Nuchal plate – planum nuchale.

4. Temporal fossa – fossa temporale.

II. The brain surface is facies medularis.

1. Brain crests – juggi medulare.

2. Finger impressions – impressionis digitale.

Species features:

Dog. The bone is convex. It is not divided into plates, because the outer sagittal ridge bifurcates into left and right temporal lines on the frontal bone.

Pig. The bone is flat. The temporal line extends rostrally from the lateral edges of the external nuchal crest.

Cattle. The temporal line is located ventral to the corneal process and divides into the temporal and nuchal plates. The temporal plate is longitudinally concave. The nuchal plate is displaced onto the nuchal surface by the interhornal prominence.

Horse. The temporal line is a continuation of the external sagittal ridge. The parietal plate is small. The temporal plate is large and convex.

Interparietal bone – os interparietale(unpaired)

Dogs and horses have:

1. External sagittal ridge – crista sagittalis externa.

2. Brain surface – facies medularis.

The tentorium process is processus tentoricus.

The groove of the transverse sinus is sulcus sinus transversae (losh.).

Canal of the transverse sinus – canalis sinus transversae (sob.).

Species features:

Dog. Heart-shaped.

Pig. The bone is missing.

Cattle. Triangular shape.

Horse. Quadrangular shape.

Questions to reinforce learned material

1. What are the main parts of the occipital bone?

2. Name the specific features of the occipital bone in a dog, pig, cattle, horse.

3. Which animal does not have a nuchal ridge and why, what is this ridge called.

4. Name the canals and openings of the occipital bone.

5. Name the components: body, lateral parts, and squama of the occipital bone.

6. What main parts does the parietal bone include?

7. Name the specific features of the parietal bone in a dog, pig, cattle, horse.

8. Name the specific features of the interparietal bone in dogs, pigs, cattle, and horses.

9. Name the structure of the interparietal bone in dogs and horses.

10. To which part of the skull do the occipital, parietal and interparietal bones belong?

11. Paired or unpaired bones include the occipital, parietal, and interparietal bones.

12. Name the boundaries of the occipital, parietal, interparietal bones.

Literature

Akaevsky A.I. “Anatomy of Domestic Animals” M. 1975. pp. 57-77.

Klimov A.F. "Anatomy of Pets", 2005. Part 1. S 117-144.

Khrustaleva I.V., Mikhailov N.V. and others. “Anatomy of Domestic Animals” M. Kolos. 1994. S 93-118

Popesco P. “Atlas of topographic anatomy of agriculture. animals." "Bratislava". 1961 T. 1.

Yudichev Yu.F. "Comparative Anatomy of Domestic Animals". Volume 1. Orenburg-Omsk. 1997. pp. 85-122.

Yudichev Yu.F., Efimov S.I. “Anatomy of Domestic Animals” Omsk. 2003. pp. 87, 97-98.

Appendix, Fig. 11 - 15.

The shape of the skull changes dramatically during ontogenesis. In fetuses and newborns, the skull is more rounded, since its cerebral part is more developed. As teeth grow, the facial part of the skull begins to develop more strongly, especially in herbivores. With age, the shape of the cerebral part of the skull also changes, as the masticatory muscles are attached to it. Side functions are also reflected in the shape of the skull. In pigs, the ability to dig the ground determines the powerful development of the jugular processes and squama of the occipital bone, as a result of which the skull as a whole takes the shape of a tetrahedral pyramid. In cattle, due to the development of horns, which serve for protection, the frontal bone is greatly enlarged, which forms the frontal crest between the base of the horns.

Release occurs in response to the onset of electrical impulses in the nerve fibers. After this event, the contents of the vesicles are poured into the extracellular interstitium, from which it is removed from the circulating blood. As a result of this "action, loss of water through" urine can be controlled, and in emergency conditions, reduced to a minimum. During lactation, oxytocin acts on the muscular epithelium of the mammary glands, stimulating contraction, followed by the release of milk. During labor, "oxytocin stimulates massive contraction of the uterine myometrium, favoring" expulsion of the fetus. reticular formation and wakefulness-sleep Cycle change general level brain activity occurs with states of consciousness that can be very different from each other, for example. wakefulness and sleep.

BONES OF THE FACIAL SKULL

Lower jaw

The lower jaw, mandlbula, is an unpaired bone, and is the only movable bone of the skull, which forms the temporomandibular joints with the temporal bones. There is a body of the lower jaw, located horizontally, and two vertically directed branches.

The body of the lower jaw, corpus mandibulae, is horseshoe-shaped and has outer and inner surfaces. The lower edge of the body - the base of the lower jaw, basis mandibulae, is rounded and thickened, the upper edge forms the alveolar part, pars alueoldris. The latter contains dental alveoli, alveoli dentdles (for 16 teeth), separated by interalveolar septa, septa interalveoldria. On the outer surface of the alveolar arch there are alveolar elevations, jiiga alveoldria, corresponding to the alveoli. In the anterior part of the body of the lower jaw, along the midline, there is a mental protuberance, protuberdntia mentdlis, which gradually widens from below and ends with a paired mental tubercle, tuberculum mentdle. -Posterior to the mental tubercle at the level of the second small molar there is a mental foramen, foramen mentdle. serving for the exit of the artery and nerve of the same name. Behind the mental foramen, an oblique line begins, iinea obliqua, heading backward and upward and ending at the base of the coronoid process.

Such changes are closely related to the activation or inhibitory effect of specific neuronal systems included in the reticular formation. As mentioned earlier, this is the region of gray matter, extending from the bulbar to the midbrain, which, in addition to containing some important centers for the regulation of autonomic functions and movement, also includes neuronal aggregates capable of determining the level of brain activity, and therefore controlling state. The neural systems of the reticular formation involved in the state of consciousness control are different in the reticular systems of reticular activation and deactivation.

In the middle of the inner surface of the body of the lower jaw, the mental spine, spina mendlis, protrudes. On the sides of it, at the base of the jaw on the right and left, there is an oblong abdominal fossa, fossa digastrica, the place of attachment of the muscles of the same name. At the upper edge of the spine, closer to the dental alveoli, there is also a sublingual fossa on both sides, /ossa sublingualis, for the salivary gland of the same name. Below it begins and goes obliquely upward, ending at the posterior end of the body of the lower jaw, a weakly defined mylohyoid line, linea mylohyoidea. Under this line, at the level of the molars, there is a submandibular fossa, fovea submandibularis, the location of the submandibular salivary gland.

Therefore, the influence of the reticular formation in almost all areas nervous system and depends on them. the state of wakefulness or sleep is associated with the predominance of activation or deactivation of the system. Wakefulness is determined by the state of excitement of the activating system: “sudden excitement produces awakening, then” prolonged excitement maintains wakefulness. Sleep may depend on both the inactivation of the reticular activating system and how activation is deactivated. The modification of “general brain activity is accompanied by specific changes” in the electrical activity of the cerebral cortex.

The branch of the lower jaw, ramus mandibulae, paired, extends from the body at an obtuse upward angle, has anterior and posterior edges and two surfaces, external and internal. When the body passes into the posterior edge of the branch, the angle of the lower jaw, angulus mandibulae, is formed, on the outer surface of which there is a chewing tuberosity, tuberositas masseterica, and on the inner surface there is a pterygoid tuberosity, tuberositas pterygoidea. Somewhat above the latter, on the inner surface of the branch, a rather large opening of the lower jaw, foramen mandibulae, is visible, facing upward and backward, which is limited on the medial side by the tongue of the lower jaw, llngula mandibulae. This hole leads into the canal of the lower jaw, candlis mandibulae, which runs inside the body of the lower jaw and ends on its outer surface with the mental foramen. On the inner surface of the branch of the lower jaw, somewhat posterior to the uvula, the mylohyoid groove, slilcus mylohyoideus, descends obliquely down and forward, to which the nerve and vessels of the same name are adjacent.

This has optical system, designed to form images on the retina. Light stimuli, converted into electrical impulses from the retina's visual receptors, pass through the optic tract and reach the cerebral cortex, where image processing takes place. Tear fluid is produced by a small gland, weighing approximately 2 g, located in the upper part and laterally into the orbital cavity. The lacrimal gland deposits its product into the conjunctival sac through a series of excretory ducts.

Tear fluid, after being moistened to the eyeball, collects in the lacrimal lake, located in close proximity to the “medial corner” of the eyes. In order to maintain the "visual image on the fovea, the external eye muscles" the impression of movement of the eyeballs under the control of certain nerve centers. Since most of the visual field is examined by both eyes simultaneously, we need perfect coordination of eye movements so that images can be formed at the corresponding points of the two retinas. “Changing this process causes a double vision” of the object.

The branch of the lower jaw is completed by two processes directed upward: the anterior coronoid process, processus coronoideus. and the posterior condylar (articular) process, processus condylaris. Between these processes there is a notch of the lower jaw, incisura mandibulae. The coronoid process has a pointed apex. From its base, on the inside, a buccal ridge, crista buccinatoria, is directed to the last large molar. The condylar process ends with a well-defined head of the lower jaw, caput mandibulae, which continues into the neck of the lower jaw, collum mandibulae. On the anterior surface of the neck is visible the pterygoid fossa, fovea pterygoidea, the attachment site of the lateral pterygoid muscle.

The eye muscles determine four main types of movements: saccadic movement, very quickly, which occurs when the eye suddenly moves from one object to another; motion tracking, which allows you to follow with your eyes an object that crosses your field of view; compensatory movements, which keep "the image on the retina even when moving the head; and finally, convergence movements, which rotate the eyes towards" the interior when viewing close objects.

The ear consists of external formations and formations included in the neurocranial bones, more precisely in the Petrosa Buri rocks. In the ear there are receptors for the states of the acoustic apparatus, i.e. structures capable of perceiving sounds and providing the object with balance in space. From a physiological point of view, the organ of hearing can be distinguished: a conducting device formed by a speaker and an external auditory wire; a transmitting device consisting of the tympanic membrane, the chain of ossicles and the middle ear as a whole, a perceptual mechanism contained in the anterior part of the labyrinth and represented by the organ of Corti and its nerve centers.

Hyoid bone

The hyoid bone, os hyoideum, is located in the neck, between the lower jaw and larynx. It consists of a body and two pairs of processes: small and large horns. The body of the hyoid bone, corpus ossis hyoldei, has the appearance of a curved plate; the posterior surface is concave, the anterior convex. Large horns, cornua majora, thickened at the ends, extend slightly upward and backward from the body on the right and left. Small horns, cornua minora, extend from the body upward, backward and laterally in the same place as the large ones; they are significantly shorter than the large horns. The hyoid bone, with the help of muscles and ligaments, is suspended from the bones of the skull and connected to the larynx.

To ensure static and dynamic balance of the body, instead, with the help of the visual apparatus, the cerebellum and myocrotic and muscular sensitivity, the middle and posterior segments of the labyrinth. The nasal cavities are two large pits excavated in the facial frame, elongated in the sagittal direction. They represent the first part of the breathing apparatus, which is the main path for receiving air, which are prepared for contact with the delicate structures of the lungs by heating, humidifying and clearing of the largest wastes: functions that must be in the form of cavities Anatomical structures The nasal cavities are formed by two symmetrical canals, distinct from the left and right, separated from each other by the nasal cavity.

The appearance of the head and its skeleton was associated with the complication of the general organization of the ancestors of vertebrates, which occurred in the struggle for existence and due to the progressive development of the organism adapting to changing living conditions. At the anterior end of the bipolar body of the animal, two independent sections of the head skeleton develop (Fig. 32). One - protective device for the developing brain - the skull - cranium, the second (facial section) - in connection with the improvement of devices for better, greater capture of food and its primary processing. Thus, at the anterior end of the body of lower vertebrates, two parts of the head skeleton arose: the skull, which forms the cranial cavity for the brain, and the visceral region, which later forms the face - fades. These two sections were united by the commonality of their location and the fact that the movable jaw apparatus of the facial section found support for its muscles on the skull.

They communicate with appearance through the nostrils while they open into the pharynx through the coals or internal nostrils. They consist of two parts: the front, vestibule and back, the nasal cavity itself. The antechamber is bounded by the outer nose or nasal pyramid, supported by the nasal cartilage, vermis and accessory, and posteriorly by a small relief called the lymphatic nasal cavity. It is covered with very thin skin with large and stiff hairs called vibris, which constitute the first defense against the penetration of corpuscular material into the respiratory canal.

Each section developed from different elements located in this area: cartilages formed on the sides of the notochord and in front of it (skull), and from the first visceral arches (face). Bones originating from these areas undergo three stages of ossification during ontogenesis and are secondary. Subsequently, individual parts of the exoskeleton participate in the formation of the skull, forming the integumentary bones of the skull. The integumentary bones of the skull are primary and in ontogenesis they undergo only two stages of ossification - membranous and bone (Fig. 33).

Some vibrations are also associated with large sebaceous glands and small sweat glands. The medial wall consists of the nasal septum, which is formed by the posterior part of the vertical plate of the ethmoid, posterior to the vomra and septal cartilage. The lateral wall is irregular in the presence of three bony reliefs called croissants or whorls, divided into superior, middle and inferior; from the latter, the bone segment should be counted independently. Three croissants, which protrude as concave segments in the lower and lateral areas, define spaces called meats, distinct also in the upper, middle and lower.

The skull was formed from many bones that formed separate parts of the skull and face. There are sutures between the bones, which at a young age are filled with dense connective tissue. Between some bones in ontogenesis, significant connective tissue spaces called fontanelles are formed; in old age they ossify. Thus, in mammals, such fontanelles are located between the occipital and parietal bones of the skull or between the occipital, parietal and temporal.
During the process of phylogenesis, some bones that build the skeleton of the head of lower vertebrates subsequently change their functions. Thus, the primitive jaws of fish are replaced by integumentary bones, but the jaw bones do not disappear at all, they change their function and turn out to be the auditory ossicles of the middle ear in higher vertebrates (Fig. 34).

In terrestrial animals, due to the change from gill to pulmonary respiration, a nasal cavity develops on the basis of the olfactory pits on the face, communicating in its anterior part with the oral cavity through a narrow opening between the incisive, maxillary bones and the vomer. These openings were called primary choanae. In animals with primary choanae, food cannot pass through oral cavity when air passes through the nasal cavity. In this regard, the structure of the nasal cavity is improved and complicated. The location of the choanae gradually changes, and already in reptiles they open behind the nasal cavity into the pharynx and are called secondary choanae.
The skull is connected to the first cervical vertebra (atlas) and forms the cranial cavity in which the brain is located. This cranial cavity - cavum cranii has a roof, back, front, side walls and bottom of the cranial cavity.