The bones of the skull are a type of flat bone. Between the plates of the frontal and maxillary bones there are large sinuses filled with air that penetrates them from the nasal cavity.
Thanks to this, the bones of the skull are very light. The bones of the skull are connected to each other by sutures, which are clearly visible in young animals. The bones of the skull grow due to the sutures. After ossification of the sutures, the growth of the skull stops.
The overall shape of the skull varies among domestic animals. The massiveness of the large skull cattle depends on the size and shape of the frontal bones, which in animals of this species occupy the entire top part, pushing back and to the sides the occipital, interparietal, parietal and temporal bones.
Bones of the brain skull. The brain skull is formed by the occipital, sphenoid, ethmoid, interparietal, parietal, frontal and temporal bones.
The occipital bone limits the cranial cavity posteriorly. It distinguishes a body, scales, 2 articular condyles and 2 jugular processes. Between these parts in the middle of the bone is the foramen magnum, through which the cranial cavity communicates with the spinal canal. The occipital bone articulates with the atlas by two articular condyles.
The sphenoid bone limits the cranial cavity from below. It consists of a body, two temporal wings, two orbital wings, and two pterygoid processes. It has several openings for the passage of nerves and blood vessels.
The ethmoid bone forms the anterior wall of the cranial cavity. It has many holes (hence the name) for the passage of branches of the olfactory nerve.
The interparietal bone is located between the occipital and parietal bones. Parietal bones on inner surface have elevations and depressions from the convolutions of the brain.
The frontal bones are located in front of the parietal bones and form the upper wall of the cranial cavity; they belong only partially to the brain skull.
The temporal bones form the lateral walls of the cranial cavity. The temporal bone consists of two bones: one - the petrous bone - contains parts of the outer, middle and inner ear, and the other - the scales of the temporal bone - forms a very strong zygomatic process, on which the articular ridge is located. The articular process of the mandible is attached to the articular ridge, forming the mandibular joint.
Bones of the facial skull. They form 2 cavities - the nasal and oral, as well as the eye sockets, or orbits. The bones of the facial skull include the following 12 bones: 1) mandibular, 2) maxillary, 3) incisive, 4) nasal, 5) lacrimal, 6) zygomatic, 7) palatine, 8) pterygoid, 9) vomer, 10) hyoid, 11 ) top turbinate and 12) inferior turbinate.
All these bones are paired, only the vomer is an unpaired bone. The cartilaginous nasal septum is located in the vomer groove.
The nasal cavity is limited by the following bones: from below - the maxillary and palatine, from the sides - the maxillary, lacrimal and zygomatic. The posterior border of the nasal cavity is the ethmoid bone, the superior border is the nasal and frontal bones, and the anterior border is the incisive bone.
The superior and inferior turbinates form the basis of large folds of the nasal mucosa. Between the outer and inner plates of the frontal bone, the frontal sinus is formed, and between the plates of the maxillary bones - the maxillary sinus, which communicates with the nasal cavity and the frontal sinus. The nasal cavity communicates with the pharynx through large openings - choanae. The walls of the choanae are the palatine, pterygoid bones and the vomer.
The oral cavity is located between the jaws. Its upper wall is formed by the incisive, maxillary and palatine bones. The lateral walls of the oral cavity are formed by the maxillary and mandibular bones, along the edges of which there are recesses for the teeth. The hyoid bone, with its branches, joins petrous bone, and the root of the tongue is attached to its body and lingual process.
The socket, or orbit, is used to house the eyeballs. It is formed by the frontal, lacrimal and zygomatic bones.
If you compare the skulls of animals, you will find that the differences between them come down primarily to the size of the back of the head, the parietal region and the frontal region. And this, of course, affects the configuration of the head. When comparing domestic animals with each other, this sign is difficult to detect, but there are others character traits and features that give the skull relatively sharp differences. They depend mainly on the neck muscles, masticatory muscles, the presence of horns, their location and other features. At the cow's brain section The skull, compared to a horse’s, is very wide on the forehead side due to the increased development of the frontal bones and the presence of a frontal crest. A rough ridge - a crown - rises above it, and horns grow on the sides. The occipital region greatly expands towards the horns, turning into a massive quadrangular volume. Consequently, the presence of horns - a weapon of defense - modifies the structure of the skull of cattle. The upper jaw of a cow is shorter than that of a horse, but wider. At the level of the third molar, the facial tuber protrudes prominently. The incisive bones have the appearance of a plate with a thickened edge - a roller.
STRUCTURE OF THE SKELETON OF THE SECOND LIMIT LIMBS - ZEIGOPODIA
On the thoracic limb, the zeigopodium bones form the skeleton of the forearm - skeleton antebrachii, on the pelvic limb - the skeleton of the lower leg - skeleton cruris. The skeleton of these areas includes two bones. On the forearm (Fig. 62) radial - radius and ulnar - ulna, on the tibia - tibia and peroneal fibula (perone). In domestic animals, the main supporting column of the limb in this link includes only one of two bones: on the thoracic limb, the main bone is the radius, on the pelvic limb, the tibia. The second bones (ulna and fibula) are significantly reduced, especially on the lower leg, where in ruminants they look like small processes.
The radius and tibia are less massive compared to the humerus and femur. They are thinner in the diaphysis, longer, especially the tibia. At the proximal ends, slightly expanding the area of their articular surface, they do not have a spherical head. On the radius this is a somewhat elongated (transverse) depression along the segmental plane - an imprint of the block humerus. On the tibia, the proximal end, unlike the radius, has two flat condyles, in the center between which protrudes a significant intercondylar eminence - eminentia intercondylaris. On the cranial side of the proximal end of the tibia there is a significant thickening, from which the anterior edge - margo cranialis of the tibia - descends down to the middle of the diaphysis. It bends slightly to the lateral side and forms a groove with the body in which muscles are located that slide in it when moving.
The diaphysis of the radius is flattened from front to back; on the tibia it is more rounded. The distal ends - the block of the radius - trochlea radii and the block of the tibia - trochlea tibiae are very different from each other in shape. On the radius it is a rather flat area with an uneven articular surface in the form of a transverse oval. On the sides of it, on the lateral and medial sides, small thickenings are visible; they are called styloid processes. On the tibia, on the contrary, the distal end has deep grooves on the articular surface and high ridges between them. The distal epiphysis of the tibia is much smaller than the proximal one. On the lateral and medial sides of the articular surfaces there are thickenings, which are called medial and lateral ankles - malleoli medialis et lateralis. The lateral malleolus is formed by an adherent rudiment of the fibula. The second bones - the ulna and fibula - in various stages reduction.
The ulna - ulna, unlike the fibula, has at its proximal end a large olecranon process - olecranon with a significant tubercle of the olecranon - tuber olecrani. This olecranon process projects strongly above the proximal end of the adjacent radius and is the site of attachment of the powerful extensor muscles of the elbow joint. The body of the ulna and its distal end undergo significant reduction, especially in horses and ruminants.
Rice. 62. Cow forearm bones
The fibula - fibula - is reduced to a much greater extent. A rudiment of its distal end forms the lateral malleolus.
Features of the structure of zeigopodium bones.
In ruminants radius always fused with the rudimentary ulna, and only the proximal and distal interosseous spaces remain between them - spatium interosseum antebrachii proximale et distale (Fig. 63).
The tibia is slightly curved at the proximal end (Fig. 64). A downward directed bone plate, narrowed downward, grows to its lateral condyle. This is a rudiment of the fibula. At the distal end, the articular groove is placed in the sagittal plane. On the lateral side it bears a small articular surface for connection with the ankle bone (fibular rudiment).
In horses (Fig. 65), the radius is flattened from front to back and fused with ulna only in the proximal part, forming one interosseous space. The ulnar tubercle is massive and shorter than that of ruminants. The body of the ulna is expressed only in the upper third.
A characteristic feature of the tibia is the obliquely placed trochlear grooves on its distal epiphysis. On the outer surface of the lateral condyle of the proximal epiphysis there is a small rough surface for connection with the rudiment of the fibula, which resembles a stick with an expanded flat head at the proximal end. Its length is equal to half the length of the tibia.
In pigs, the radius is massive, flattened, and rather short. On the caudal side it bears a rough surface to which a triangular shape is attached elbow bone with a large ulnar tubercle. Inferiorly, the radius widens.
The tibia is massive, with a powerful crest leading edge. Proximally and distally on the lateral surface there are roughnesses - the attachment points of the fibula, which has the shape of a flat bone, slightly widened at the ends in the form of a spatula. The groove of the distal tibial trochlea is placed straight.
In dogs, the radius bone is flat, slightly thickened at the ends. On the caudal side of the proximal end it bears a small articular surface for connection with the ulna. The ulna has a groove on the ulnar tubercle. Towards the distal end it narrows and does not fuse with the radius.
Rice. 63. Bones of the forearm of a cow (I), horse (II), pig (III), dog (IV)
Rice. 64. Tibia bones of a cow (I), horse (II), pig (III), dog (IV)
Rice. 65. Horse shin bones
The tibia is also curved. On the lateral condyle it has a facet for connection with the thin flat fibula, which at its distal end often fuses with the tibia.
Thus, the ulna and fibula are expressed along their entire length only in pigs and dogs, i.e., in animals in which the autopodium is multirayed (4-5 rays). In ruminants and horses, which have only 1-2 rays in the autopodium, the ulna and fibula have undergone significant reduction. In ruminants, the ulna, although expressed along its entire length, is thin and has lost its “independence” - it has fused with the radius. They don’t have a fibula. In horses, the ulna and fibula are expressed only in the proximal part and have very small sizes.
The pelvic limb includes the bones of the pelvic girdle and the bones of the free limb.
PELVIC GIRDLE
Pelvic girdle - cingulum membri pelvini - consists of two symmetrical halves, called pelvic or innominate bones - ossa coxae, s. innominata. The right and left innominate bones, fused together, form the pelvic suture - symphysis pelvis (26), and connecting with the sacral bone form the pelvis - pelvis. The pelvis, together with the sacral and first caudal vertebrae, limits the pelvic cavity. Each of the innominate bones, in turn, is formed by three fused bones: the ilium, pubis and ischium. At the site of fusion, an articular cavity is formed - acetabulum (1), in the depth of which a fossa of the cavity is visible - fossa acetabuli (2), for the round ligament, and a notch of the cavity - incisura acetabuli (3) - for the transverse ligament. In relation to the pelvic cavity, the ilium is located craniodorsally, the pubis medially, and the ischium caudally.
Ilium (I) - os ilium - consists of a wing - alla ossis ilii (4) and a body - corpus ossis ilii (5) - column-shaped.
There are two surfaces on the wing: the outer or gluteal - facies gluteae (6) and the inner or pelvic - facies pelvina (7). The pelvic surface is divided by an arcuate line into a rough ear-shaped surface - facies auricularis (25) - for articulation with the wing of the sacral bone and a smooth iliac surface - facies iliaca. The cranial edge of the wing is called the iliac crest - crista iliaca (8), the crest medially passes into the sacral tubercle - tuber sacrale (9), and laterally - into the iliac tubercle or macloque - tuber coxae (10). The latter in a horse has the appearance of an obliquely located crest with a thickened and forked edge. The caudal edge of the wing, when transitioning to the body, forms a large sciatic notch - incisura ischiadica major (11), which continues along the body to the ischial spine - spina ischiadica (12), the latter is located dorsally from glenoid cavity. On the body above the pelvic cavity there are pits for the straight head of the quadriceps femoris muscle.
Rice. 10. Horse pelvic bones
I – ilium; II – ischium; III – pubic bone; 1 – glenoid cavity; 2 – pit of the depression; 3 – notch of the cavity; 4 – wing of the ilium; 5 – body of the ilium; 6 – gluteal surface; 7 – pelvic surface; 8 – iliac crest; 9 – sacral tubercle; 10 – maklok; 11 – greater sciatic notch; 12 – ischial spine; 13 – fossa for the straight head of the quadriceps muscle; 14 – iliac crest; 15 – lumbar tubercle; 16 – body of the pubic bone; 17 – locked hole; 18 – pubic ridge; 19 – body of the ischium; 20 – lesser sciatic notch; 21 – plate of the ischium; 22 – ischial tuberosity; 23 – ischial arch; 24 – gluteal crest (in a pig); 25 – ear-shaped surface; 26 – pelvic suture.
Rice. 11. Pelvic bones.
Along the medial surface of the body runs the ilioponic crest - crista iliopectinae (14), passing to the cranial edge of the pubic bone. In the middle of this ridge protrudes the lumbar tubercle - tuberculum psoadicum (15), for the psoas minor muscle.
pubic bone (III) - os pubis – consists of a body, corpus osis pubis (16) and a branch, ramus ossis pubis. The body participates in the formation of the glenoid cavity, the branch - in the formation of the pelvic fusion, and the body and branch together - in the formation of the locked opening - foramen obturatum (17). The cranial edge of the pubic bone forms the pubic ridge - pectin ossis pubis (18), which laterally passes into the iliopubic eminence - eminentia iliopubica. In the area of the pelvic fusion, the pubic bones form the pubic tubercle - tuberculum pubicum, which is more prominent in males.
Ischium (II) - os ischii – consists of a body, a blade and a branch. The body - corpus ossis ischii (19) - participates in the formation of the glenoid cavity and the lesser sciatic notch (20), running from the ischial spine to the ischial tuberosity. The plate - tubula ossis ischii (21) - caudolaterally passes into the powerful ischial tubercle - tuber ischiadicum (22). Between the ischial tuberosities of the right and left bones there is an ischial arch - arcus ischiadicus (23). The branch - ramus ossis ischii grows together with that of the other side and participates in the formation of a locked hole.
Peculiarities:
In cattle the macloque is oval, the ventral surface of the pelvis is convex, the ischial tuberosity is three-processed, the ischial arch is deep.
At the pig's The iliac crest is convex. The gluteal crest (24) is pronounced on the gluteal surface, the ischial spine is high, and the ischial tuberosity is rounded.
In a dog the iliac crest is convex, the gluteal surface is pitted, the macular and sacral tuberosities are weakly expressed, the ischial spine is low.
SKELETON OF THE FREE PELVIC LIMB
The skeleton of the free pelvic limb includes the femur with kneecap, bones of the leg and foot.
FEMUR
Femur – os femoris – like any tubular bone, has three parts: a body and two ends – proximal and distal.
At the proximal end there is a pronounced head - caput femoris (1) with a fossa of the head - fovea capitis (2) - for securing the round and accessory ligaments. The fossa is displaced medially and has a triangular shape. Under the head there is a neck - collum femoris (3). Laterally from the head protrudes the large trochanter - trochanter major (4), from which the middle trochanter - trochanter medius (5) is separated by a notch. Both trochanters serve to strengthen the gluteal muscles.
Rice. 12. Horse femur
A – lateral surface; B – caudal surface;
1 – head; 2 – fossa of the head; 3 – neck; 4 – greater trochanter; 5 – middle trochanter; 6 – acetabulum; 7 – body femur; 8 – lesser trochanter; 9 – third trochanter; 10 – lateral lip; 11 – medial lip; 12 – nutrient opening; 13 – supracondylar fossa; 14 – lateral and medial condyles; 15 – intercondylar fossa; 16 – fossa for the popliteal muscle; 17 – extensor fossa; 18 – block for the popliteal cup; 19 – interacetabular ridge; 20 – supracondylar roughness; 21 – supracondylar tubercle; 22 – facets for sesamoid bones.
Rice. 13. Femur
A – cattle; B – pigs; B – dogs.
Medial to the greater trochanter is the acetabulum fossa - fossa trochanterericca (6).
On the body of the femur - corpus ossis femoris (7) - the lesser trochanter - trochanter minor (8) protrudes from the medial surface, and the third - trochanter tertius (9) from the lateral surface. From them, along the caudal surface of the body, rough lines go to the corresponding condyles, called the lateral and medial lips - labium laterale et mediale (10, 11). In this case, the medial lip has a vascular opening in the middle - for. nutricium (12), and the lateral lip goes around the deep supracondylar fossa - fossa supracondylaris (13).
At the distal end of the femur there are two articular condyles: lateral and medial - condylus lateralis et medualis (14), separated by an intercondylar fossa - fossa intercondylaris (15). The lateral thickened surfaces of the condyles are called epicondyles and have ligamentous tubercles and fossae. The lateral condyle, in addition, has a fossa for the popliteal muscle - fossa musculi poplitea (16) and an extensor fossa - fossa extensoria (17). On the distal epiphysis, a block for the popliteal cup (trochlea patellaris) is located cranially (18). It has the appearance of a sagittal groove, bounded by two trochlear ridges - lateral and medial.
Peculiarities:
In cattle the femur has an almost cylindrical body. Greater skewer strongly developed, it is connected to the lesser trochanter by the interacetabular ridge (19), which limits the deep acetabulum fossa. The ligamentous fossa on the head is shallow and lies in the center. The supracondylar fossa is poorly defined. The medial trochlear ridge for the kneecap is thicker and higher than the lateral one.
At the pig's The femur is short, massive, the neck is clearly separated, the greater trochanter does not protrude above the head. On the body, instead of the supracondylar fossa, supracondylar roughness is expressed (20). The block ridges for the kneecap are the same in height.
In a dog the femur is long, thin, its body is slightly convex forward. Head with a shallow pit. The neck is clearly separated, the greater trochanter does not protrude above the head. The body has a pronounced supracondylar tubercle (21). The trochlear ridges of the kneecap are identical. On the proximal surface of the condyles there are facets for the sesamoid ossicles (22).
Knee cap – patella It distinguishes between the base - basis patellae (1), the apex - apex patellae (2), the articular and cranial surfaces - facies articularis et cranialis (a).
At the horse patella is quadrangular in shape, cattle and pigs it is triangular and laterally compressed, and dogs - bean-shaped.
Rice. 14. Kneecap.
A – horses; B – cattle; B – pigs; G – dogs.
1 – base; 2 – apex; a – cranial (skin) surface.
SHIN BONES
The bones of the lower leg - ossa cruris - consist of the tibia and fibula.
Tibia – tibia is a long, tubular bone, with a widened proximal end and a thinner distal end. At the proximal end, there are lateral and medial condyles - condylis lateralis et medialis (1, 2), separated by an intercondylar groove - sulcus intercondyloideus (3) with pits for the cruciate ligaments; the groove is limited on the sides by the lateral and medial tubercles (4). Between the condyles on the caudal side there is a popliteal notch - incisura poplitea - for the popliteal muscle. On the lateral edge of the proximal end of the tibia there is an articular surface for the fibula (5). Along the anterior surface of the tibia, a ridge descends from the epiphysis to the diaphysis - crista tibiae (6), bending to the lateral side. Between the ridge and the lateral condyle there runs a muscular or extensor groove – sulcus extensoria (7). On the caudal surface there is a line of the popliteal muscle - linea poplitea (11) and there is a nutrient opening - for. nutricium.
The distal epiphysis is slightly expanded and bears a block - trochlea (cochlea) tibiae (8) - with two obliquely placed grooves. On the sides of the block are the lateral and medial ankles - maleolus lateralis et medialis (9) - to secure the ligaments.
fibula – fibula. Its proximal end is expanded and called the head - caput fibula (10), through which the bone connects to the lateral condyle of the tibia.
The body, gradually thinning, reaches only the middle of the tibia. The distal end is completely reduced.
Peculiarities:
In cattle on the lateral condyle of the tibia, a small tubercle protrudes - a rudiment of the head of the fibula (12). At the distal end there is a block with three straight grooves. Of these, the lateral groove serves as a facet for the ankle bone - facies articularis malleoli (13).
The fibula in cattle is almost completely reduced. The proximal epiphysis has fused with the lateral condyle of the tibia, the diaphysis has been reduced, and the distal epiphysis has become the ankle bone - os malleolare.
At the pig's The tibia is short, massive, the crest is powerful. The intercondylar lateral tubercle is better developed. The proximal and distal epiphyses have roughness for connection with the fibula.
The tibia of a pig is lamellar and long. Its proximal half is wider than the distal half. The distal end forms the lateral malleolus - malleolus laterali (14), on which there are articular surfaces for the tibia, calcaneus and talus.
Rice. 15. Shin bones
A – horses; B – cattle;
1 – lateral condyle; 2 – medial condyle; 3 – intercondylar groove; 4 – lateral and medial tubercles; 5 – articular surface for the fibula; 6 – crest of the tibia; 7 – extensor groove; 8 – block; 9 – lateral and medial ankles; 10 – head; 11 – lines of the popliteal muscle; 12 – rudiment of the head of the fibula; 13 – ankle bone; 14 – lateral malleolus.
Rice. 16. Shin bones
B – pigs; G – dogs.
In a dog The tibia is long, thin, cylindrical in the distal half, the ridge is well developed, the intercondylar tubercles are equal in height. On the lateral condyle there is a noticeable facet for the head of the fibula, and on the lateral surface of the distal half of the body there is a roughness for the fibula. The ankle is expressed only medially.
The fibula of a dog is in the form of a thin long ribbon with thickened ends, the proximal half with a medial groove, the distal half with a roughness for the tibia.
SKELETON OF THE FOOT
The skeleton of the foot - skeleton pedis - is represented by the bones of the tarsus, metatarsus and toes.
tarsus bones
Tarsal bones- ossa tarsi – represented by short bones arranged in three rows: proximal, middle and distal.
In the proximal row there are two bones: the talus and the calcaneus (Fig. 18).
Talus - talus, s. os tarsi tibiale - at the proximal end it carries a block with obliquely set ridges (1) for articulation with the tibia. The distal end has a flat articular surface for the central tarsal bone (2). On the medial surface there is a clearly defined ligamentous tubercle (3).
Calcaneus - calcaneus, s. os tarsi fibulare – located lateroplantar in relation to the talus. It is connected by a series of articular facets to the talus and IV + V tarsal bones. It distinguishes the calcaneal process (4) with the calcaneal tuber - tuber calcanei (5) - for securing the Achilles, the coracoid process - proc. Coracoideus (6), connecting in a horse only to the talus, and the holder of the talus - sustentaculum tali (7). A groove for the deep flexor digitorum tendon (8) runs along its posterior surface.
In the middle row lies one central tarsal bone - os tarsi centrale. It is located between the talus, I, II and III tarsal bones, medial from the IV + V tarsal bones. It has the shape of a rounded quadrangular plate.
There are three bones in the distal row: I and II tarsal bones - os tarsi primum et secundum - are fused, III - os tarsi tertium is placed under it, IV + V - os tarsi guartum et guintum - lie between the calcaneus and metatarsal bones. Between the central, III and IV + V bones of the tarsus it goes from the dorsal side to the plantar tarsal canal - canalis tersi - for the perforating tarsal artery.
Rice. 17. Skeleton of the foot of a dog, pig, cattle, horse
Talus, 4th metatarsal;
Calcaneus, III tarsal bone, 3rd metatarsal bone;
Central tarsal bone;
IV + V tarsal bones, 1 metatarsal bone;
I tarsal bone, 5th metatarsal bone;
II tarsal bone, 2nd metatarsal bone.
Rice. 18. Bones of the proximal row of the horse's tarsus
A – calcaneus; B – talus;
1 – ridges of the trochlea, 2 – articular surface for the central tarsal bone; 3 – ligamentous tubercle; 4 – calcaneal process; 5 – calcaneal tubercle; 6 – coracoid process; 7 – holder of the talus; 8 – groove for the deep flexor digitorum tendon.
Peculiarities:
In cattle The talus has two blocks - a proximal one with a deep groove and a distal one with a shallower one. The ridges of the blocks are located in the sagittal plane. The calcaneus is relatively thin and long, and the coracoid process provides the articular surface for the ankle bone. The central bone is fused with the IV + V tarsal bones of the distal row. In the latter, I and II + III remained independent for metatarsals.
At the pig's The talus resembles that of cattle, but the blocks are slightly displaced in relation to the other, while the lateral ridge is better defined on the distal block. The calcaneus has a calcaneal process with a rounded tubercle; on the coracoid process there is an articular surface for the fibula. The central bone on the plantar side has a distally curved process. There are 4 bones in the distal row: I, II, III, IV + V.
In a dog The talus, like that of a horse, has one - a proximal block, but with ridges located sagittally, and a head. The calcaneus on the calcaneal tuberosity bears a groove facing proximally. Central bone with proximal fossa-shaped facet for the head of the talus. There are 4 bones in the distal row: I, II, III, IV + V.
Metatarsus bones
Metatarsus bones- ossa metatarsi – similar to the calf ones, but differ in greater length and massiveness. In the horse, the main bone is the third metatarsal bone - os metatarsi tertium, II and IV are rudimentary. The third metatarsal bone in cross section is not oval, like the third metacarpal, but rounded.
Peculiarities:
In cattle three metatarsal bones (II, III IV). III and IV of them have fused into one massive bone with a tetrahedral cross-sectional shape and with an articular surface for the second rudimentary metatarsal bone, button-shaped.
At the pig's 4 metatarsal bones II, III, IV and V. At the proximal end, from the plantar side of the III and IV bones, processes with facets for the tarsal bones protrude.
In a dog the metatarsus, unlike the metacarpus, most often consists of four bones (II, III, IV V). In the presence of the first vestigial finger, the metatarsal bone merges with the first phalanx.
TOE BONES
Toe bones- ossa digitorium. The phalanges of the fingers and their sesamoid bones are generally similar to those of the thoracic limbs. However, in the horse, the 1st and 2nd phalanges are narrower and shorter, the dorsal wall of the 3rd phalanx is steeper, and its plantar surface is laterally compressed.
LITERATURE
Main:
1. Anatomy of domestic animals / A.I. Akaevsky, Yu.F. Yudichev, N.V. Mikhailov and others; Ed. A.I. Akaevsky. - 4th ed., revised. and additional - M.: Kolos, 1984.-543 p.
2. Anatomy of domestic animals / I.V. Khrustaleva, N.V. Mikhailov, Ya.I. Schneiberg et al.; Ed. I.V. Khrustaleva.- M.: Kolos, 1994.-704 p.
3. Anatomy of domestic animals / I.V. Khrustaleva, N.V. Mikhailov, Ya.I. Schneiberg et al.; Ed. I.V. Khrustaleva.- 3rd ed. rev. - M.: Kolos, 2000.-704 p.
4. Klimov A.F. Anatomy of domestic animals. - 4th ed. reworked prof. A.I. Akaevsky.-M.: 1955, volume 1.- 576 p.
5. Popesco P. Atlas of topographic anatomy of farm animals. Ed. 2nd. ČSSR, Bratislava: Priroda, 1978, volume 1.- 211 p. with ill.
6. Popesco P. Atlas of topographic anatomy of farm animals. Ed. 2nd. ČSSR, Bratislava: Priroda, 1978, volume 2.- 194 p. with ill.
7. Popesco P. Atlas of topographic anatomy of farm animals. Ed. 2nd. ČSSR, Bratislava: Priroda, 1978, volume 3.- 205 p. with ill.
8. Udovin G.M. International veterinary anatomical nomenclature in Latin and Russian. [ Tutorial for students of veterinary universities and faculties]. - M.: 1979, volume 1. - 262 p.
Additional:
1. Akaevsky A.I. Anatomy of domestic animals. Ed. 3rd, rev. and additional M.: Kolos, 1975.- 592 p. with ill.
2. Akaevsky A.I., Lebedev M.I. Anatomy of domestic animals. - M.: Vyssh. school, 1971, part 3.- 376 p.
3. Vokken G.G., Glagolev P.A., Bogolyubsky S.N. Anatomy of domestic animals. - M.: Vyssh. school, 1961, part 1.- 391 p.
4. Gatje V., Pashteya E., Riga I. Atlas of anatomy. volume 1. Osteology. Myology. Bucharest, 1954.- 771 p. (Romanian).
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6. Lebedev M.I. Workshop on the anatomy of farm animals. L.: Kolos, 1973.- 288 p. with ill.
7. Malashko V.V. Anatomy of meat-producing animals. - Mn.: Urajai, 1998.
8. Osipov I.P. Atlas of anatomy of domestic animals. - M.: Kolos, 1977.
Brain department The skull, compared to that of horses, is very wide on the forehead side due to the strong development of the frontal bones with a pair of horns located on the border with the occipital and temporal regions. The temporal fossa lies completely to the side. In accordance with this, the occipital, parietal, interparietal and temporal bones have their own characteristics that are not characteristic of other domestic animals.
Occipital bone. The body, or main part (Fig. 89-a), is relatively short and wide, as if flattened in the dorso-ventral direction. The right and left ruptured foramina adjacent to its lateral edges are narrow and insignificant. On the outer (pharyngeal) surface of the body, muscle tubercles clearly protrude. They are located at the very border of the junction of the occipital and sphenoid bones so that both bones participate in their formation. The lateral parts (Fig. 88-h, i) of the occipital bone, covering the foramen magnum with their condyles, have relatively short, wide and inwardly curved jugular processes (i).
The sublingual opening (Fig. 90-13) is often double, has some extent, as a result of which it takes on the character of a canal. Near its internal (cerebral) mouth there is an entrance (sometimes even double) into the condylar canal - canalis condyloideus (12) - for the passage of the vein. It leads towards the opening of the temporal canal at the apex of the petrous bone. The scales of the occipital bone merge early with the parietal bone.
Parietal, interparietal bones and squama of the occipital bone(Fig. 71-D). In the embryo (C) they are clearly separated from each other, the scales extending to the dorsal surface of the skull and having the nuchal crest where it is usually found in horses and dogs. Thus, in the embryo, the parietal bones also serve as the upper roof of the cranial cavity. Shortly before birth, all these bones fuse with each other into one flat U-shaped arch. After birth, as the growth of the frontal bones intensifies, all the fused bones of this arch recede. With its middle, most voluminous behind the occipital plate - lamina occipitalis (Fig. 71-1) - the fused arch is located entirely in the occipital region, and the right and left lateral plates - laminae temporales (Fig. 88-6) - take part in the formation of the right and left temporal fossae, which lie laterally on the skull. On the outer surface of the occipital plate, mainly the area corresponding to the occipital protuberance (or tubercle) and the weak external occipital crest along the midsagittal line remain more pronounced (Fig. 71-8, 9).
On the brain surface of the same plate, imprints of the cerebellum are visible.
Sphenoid bone has a short body compared to that of horses.
Sella turcica on the brain surface - with a clearly visible bipartite back. Small temporal and highly developed orbital wings are adjacent to the body, and the latter do not take part in the formation of the ethmoidal opening, as is the case in horses. The wings are wedged into the orbit between the frontal and palatine bones. At the border of the body and wings lies the groove of the optic chiasm (Fig. 90-4). On the cerebral surface of the temporal wings, to the right and left of the body, it runs along the neural (not subdivided) groove. Each of them has a fairly large oval opening - foramen ovale. Instead of an independent orbital fissure and foramen rotundum, there is one canal-shaped round orbital foramen - foramen orbitorotundum (18), - to which the indicated neural groove approaches. The pterygoid processes are of considerable size, but without a wing canal.
Frontal bones(Fig. 88-5) are extremely developed, especially towards the occipital region. Each of them has frontonasal and orbital-temporal parts. The first is especially extensive and thick, with the frontal sinus extending posteriorly into the parietal bones. On the outer (frontal) surface, the supraorbital groove stretches along the skull, at the bottom of which, near the base of the zygomatic process, there is the supraorbital foramen. The latter leads through the supraorbital canal into the orbit (d). Amorally, the frontal bone reaches the border with the occipital region, forming the posterior frontal crest - crista frontalis aboralis - which in its position is similar (not homologous) to the occipital crest of other domestic animals. It represents a roller-shaped edge of the frontal bone, differently curved in different races (Fig. 71-D, b). At the lateral ends of this ridge there are horny processes (7) with a part narrowed at the base - the neck - and a rough ring-shaped ridge rising directly above it - the crown. The outer surface of the processes is rough, porous and penetrated by many vascular grooves. The size and shape of horns vary greatly among different races, and some have no horns at all. The horny processes enclose a complex cavity inside, connected to the frontal sinus.
Horny processes develop as follows. On the frontal bone, at the site of their formation, the periosteum gives exostosis, and on the surface adjacent to the exostosis, i.e. in the skin, small bony horny processes are formed; At first, exostosis and the rudiment of the horny processes are separated from each other by the periosteum, and then grow together. At the same time, a small cavity appears in the exostosis of the frontal bone - a sinus, connecting to the sinus of the frontal bone itself, and then this sinus gradually continues into an enlarging horny process. The bony horny processes are therefore of cutaneous origin.
The nasal end of the frontal bone is connected loosely with the nasal bone and somewhat more firmly with the lacrimal bone.
At the border of the orbital and temporal regions, a short zygomatic process departs from the frontal bone with a wide base (Fig. 88); it does not reach the zygomatic arch, but connects with the frontal process of the zygomatic bone going towards it (9). The orbital-temporal part of the frontal bone is separated from the frontal-nasal part by an edge, and its section bordering the temporal fossa located very laterally corresponds to the external frontal crest of other animals. It is slightly concave and in front passes into the zygomatic process, and behind it adjoins the base of the corneal process.
The orbital plate of the frontal bone bears the ethmoidal foramen.
The internal (cerebral), with digital impressions, surface of the frontal bone (Fig. 90) is very extensive and creates the entire dorsal covering of the cranial cavity. The frontal sinus (1), with a series of bridges from the inner to the outer plate, extends throughout the entire thickness of the frontal bone, connects with the cavities of the horny processes and parietal bone, as well as with the nasal cavity (with the middle nasal meatus).
Temporal bones(Fig. 88-7). The scales and petrous bone early merge into one. The scales, with their relatively small cranial plate, overlap the parietal and occipital bone. On its outer concave surface several holes are visible that lead into the temporal canal. The temporal crest is located on it, heading towards the zygomatic process and delimiting the temporal fossa. The short zygomatic process of the bone connects directly to the zygomatic bone. At its base, a weakly convex articular tubercle protrudes on the ventral surface.
The laterally compressed tympanic part of the petrous bone (k) is highly developed and has a long, narrow outer ear canal(g), which rises slightly above the surface. The tympanic part consists of numerous oblong bony chambers; the latter are connected to the tympanic cavity through narrow openings.
Lacrimal bones(Fig. 88-4) are very developed. Their facial, slightly concave part is connected by sutures to the dorsal jaw, frontal and zygomatic bones, and is separated from the nasal bone by a small gap. The fossa of the lacrimal sac is located at the very orbital edge and leads into tear duct(c), faintly visible from the medial surface. In adult animals, after the eruption of the last molar, a thin-walled bony lacrimal vesicle is formed in the lacrimal bone (Fig. 89-p). It enlarges the lacrimal sinus, which communicates with the maxillary sinus.
Zygomatic bones(Fig. 88-9) are significant in size. Each of them gives rise to two processes: the temporal, connected to the scales of the temporal bone, and the frontal, which takes part in the formation of the orbit and fuses with the process of the frontal bone.
Facial part of the skull(the skeleton of the muzzle) of ruminants, in addition to its characteristic shape, has a peculiarity on the incisor bones, which are original in the sense that they are completely devoid of incisor teeth.
Dorsal jaws(Fig. 88-3) shorter than those of horses, but wider, especially their palatine processes (Fig. 89-h). Behind the last tooth lies a slight maxillary tubercle, narrowed laterally, on which a special wing process protrudes. The edentulous margin does not have an alveolus for the canine.
The maxillary sinus is extensive. The palatine processes also contain the palatine sinus, which communicates with the cavity of the palatine bone. The right and left palatine sinuses are separated from each other along the midsagittal plane by a bone plate. There is no zygomatic (facial) ridge on the facial surface of the jaw, and at the level of the 3rd molar, a significant facial tuber protrudes strongly - tuber malare (Fig. 88-o). The infraorbital canal opens at the level of the 1st molar with the infraorbital foramen (b).
Incisive bones ruminants are especially characteristic (Fig. 88-1). Their body has the appearance of a plate with a ridge-like thickened edge and does not bear alveoli for either incisive teeth or canines, since both are completely absent.
Palatines(Fig. 89-r) are highly developed. The horizontal (palatal) plate of each bone occupies more than a quarter of the hard palate. The palatine canal with the posterior and greater palatine (often double) foramina is located entirely in this bone (g). Several small palatine foramina are visible near the latter. The horizontal plate has a cavity that connects with the cavity of the palatine process of the dorsal jaw into one palatine sinus. The vertical plate, together with the paper plate of the ethmoid bone, forms a relatively narrow oval sphenopalatine foramen.
Pterygoid bones(Fig. 89) represent wide plates involved in the formation of the choanae.
Nasal bones(Fig. 88-2) are quite strongly curved across and shorter than those of horses. The dorsal shell ridge protrudes on their inner surface.
Opener(Fig. 90-27) is directed posteriorly between the choanae, bypassing the palatine bones. Its wings in cattle are very developed.
The dorsal concha (Fig. 90-7) is not spirally wrapped, as in horses, but is a simple cavity communicating with the middle nasal passage and labyrinth; it does not form a direct connection with the maxillary and frontal sinuses.
The ventral shell (9) is shorter, much wider and more complex than the dorsal one. The main bony plate extending from the dorsal jaw is divided into two whorls: the upper whorl makes 1 1/4-1 1/2 turns dorsally and laterally, and the lower whorl makes 1-1 1/4 turns ventrally and laterally. Thus, two cavities are obtained, which are separated by partitions into a number of secondary cavities. The cavities of the upper helix are in connection with the middle nasal meatus, and the cavities of the lower helix are connected with the lower nasal meatus.
The ethmoid bone (6) has a rather strongly developed perpendicular plate. The right and left labyrinths consist of 5 endo- and 18 ectoturbinals each. Ectoturbinals have 6-7 whorls.
Ventral jaw(Fig. 88-10). The bodies of each half of it in the incisal part (p) do not fuse with each other along the midsagittal line, even in adult animals, but remain connected through cartilage. The alveolar edge of both incisal parts is expanded fan-shaped and contains 8 sockets for the incisor teeth.
The root parts (q) diverge from each other more than in a horse. On their concave dorsal edge they bear 6 sockets for molars, and the sockets become larger in the aboral direction. The mental foramen (n) is clearly defined. The ventral convex edge with a very flat vascular notch (m) passes almost at a right angle into the slightly concave edge of the maxillary ramus. The latter ends in a long coronoid process (e) with a pointed, bent back apex.
Hyoid bone(Fig. 87-B). From the body (7) of the hyoid bone, a short blunt lingual process (7) extends forward, and large horns, or laryngeal branches (3), extend back. Small horns (2) are directed upward to the skull from the body. A long branch descends to the small horns from the hyoid process of the tympanic part of the petrous bone, breaking up, as in other animals, into segments: a) the short proximal segment remains cartilaginous; b) the long, flat middle segment (5) has a pronounced muscular angle (5") at the upper end; c) the distal segment (4), compared with that of horses, is highly developed and articulates with the upper end of the small horn.
The cow is one of the most important domestic animals - meat and dairy products from it are on our table almost every day.
Let's take a closer look at the anatomy and physiological characteristics of this animal.
Head
The largest domestic animal is distinguished by a large head, which is on the same axis with the spine. Pronounced facial features are the main characteristics of this representative of cattle. 
Scull
Large skull connected by cervical region spine with the skeleton of an animal is one of the methods of protection. The cow, unlike other large ungulates, does not shed its horns. The structure of the skull is divided into the brain and facial parts.
The strong bones of this part of the skeleton can withstand strong impact. Besides strong bones, the animal’s head has powerful occipital muscles, which help it to spend a long time grazing with its head down.
Important! The calf's skull has equally developed facial and brain parts. With age, the facial region develops much more prominently and the face becomes larger than the rest of the skull.
Eyes
The eyes of a cow are very expressive, because this organ consists of three membranes at once - reticular, vascular and fibrous. The pupil is located in the iris, which belongs to the choroid.
Cows have long and stiff eyelashes, which is why they are called “cows.” They help the animal distinguish the length of the blades of grass and avoid injury to the eyes from various tall plants. 
The structure of the eye does not allow these pets to see colors - they only normally distinguish White color, and green and red are the worst to see. Cows also see images on a larger scale, which makes their movements awkward.
Teeth
This pet has complex system teeth, which changes as he grows. Initially, the calf has 20 milk teeth, which are replaced by molars within a year and a half. An adult cow has 32 teeth, including no upper incisors.
Due to their absence, the animal plucks grass in a special way - it grabs a bunch of grass with its lips and tongue and presses it to lower teeth. After this, the grass is pulled out with a sharp movement of the head.
Important! Thus, unlike sheep or goats, cows do not injure the roots of plants, so the grass is always green on their pastures.
An adult has 24 molars with a flat structure and 8 incisors. The animal has no fangs, but the jaw muscles are very strong. The immobility of the upper jaw is compensated by the activity of the lower jaw, which is capable of making circular grinding movements. 
Ears
A cow's hearing is simply unique, since this animal remembers pieces of music and is able to respond to a remembered melody.
The cow's hearing aid consists of three parts:
- internal;
- middle - contains the eardrum;
- external - consists of a large amount of cartilage, which gives the organ mobility.
Skeleton
The skeleton of this representative of cattle is an example for research by novice doctors. It has large, strong bones, and examining them helps in understanding the body structure and musculoskeletal system of animals. 
Spine
The cow's spine is divided into five sections:
- cervical - 7 vertebrae from the skull to the chest;
- thoracic - 13 vertebrae, which are consistent with the ribs and are movable in the lower part near the lungs;
- lumbar - 6 vertebrae;
- sacral - 5 vertebrae;
- caudal - up to 20 vertebrae.
Limbs
The forelimbs rest on thoracic region spine, which is why they are called accordingly - thoracic. Hind limbs are called pelvic. There are also auxiliary bones through which the limbs are connected to the skeleton.
For the front bones, these are the shoulder blades, shoulders, forearms, hands, and for the rear bones, these are the hip bone system, thigh, lower leg and foot.
Did you know? When cows are happy, they run and jump with excitement.
All four limbs of the cow end in hooves - two cloven toes with the rudiments of two more that hang behind.
Video: cattle foot skeleton
Internal organs and systems
A large and powerful animal must be strong and resilient. A cow is just like that, but that's all internal organs and systems help her with this.
Muscular
The musculoskeletal system of an animal at birth makes up almost 80% of its mass. When growing up, this figure drops to 60–70% - this means that such a powerful skeleton needs to be moved with serious force. muscle mass, which makes up almost 50% of the weight of an adult.
The musculature of a large bull consists of almost 250 different muscles, which often work with opposing forces - translational or abductive, flexor or extension. Thanks to quality work the entire complex - the external skeletal muscles and the internal smooth muscle system - all organs and systems of the body function without interruption. 
Nervous
Nervous system animal includes the sense organs through which the cow sees, hears and feels the world. All received data is delivered to the brain, where it is processed and conclusions are formed about the need and type of reaction to the information received. Each part of the brain is responsible for a specific reaction, controlled by fibers of the spinal tract.
The high-quality work of internal organs determines a healthy and productive animal, so it is worth paying close attention proper nutrition and a good psychological atmosphere when raising adults.
Respiratory
Large volume of internal cavities in chest occupied by the respiratory system, through which gas exchange is carried out in the body. Due to the size of the animal, its respiratory system is very large and developed.
Did you know? The right lung in cattle is larger than the left due to the placement of the large heart in the chest. The left organ can be practically divided by the location of the heart into two parts.
The weight of the lung in a cow reaches 3.55 kg, in a bull - 4.8 kg, and the respiratory rate is an important factor for diagnosing various diseases. 
Cardiovascular
The heart of a healthy cow is capable of pumping several tons of blood per day. This is enough to ensure the continuous movement of the main fluid in the body.
IN circulatory system There is a constant movement of blood and lymph, which has a positive effect on hormonal regulation and the functioning of the immune system.
High-quality heart function helps transport antibodies and hormones, and also helps provide the body's cells with water, oxygen, and nutrients.The four-chambered bovine heart is divided into two parts, each of which contains an atrium and a ventricle. The thin-walled atria receive blood from the lungs and deliver fluid to the left atrium, where it is squeezed out of the chambers of the heart. 
Digestive
The cow's digestive system has a complex structure that allows it to obtain the necessary nutrients even from poor and hard feed. Food eaten “quickly” is regurgitated from the stomach into the oral cavity for further chewing, after which it is swallowed again in a digestible form.
Oral cavity. The lips, teeth and tongue capture plant matter, which is further crushed with the help of teeth and a dental plate located above the lower incisors. The size of the upper jaw is larger than the lower jaw, and the animal benefits from this by moving food from one side of the mouth to the other.
IN oral cavity located a large number of salivary glands, which help in grinding the feed, significantly moistening it. Through the esophagus, the mass of food moves to the stomach, which has a unique structure, from where, after a while, it is regurgitated for “chewing.”
The stomach of a cow has a complex structure and functionality - this organ consists of several sections:- mesh section (consists of mesh and scar);
- book;
- abomasum.
Actually, the abomasum is a real stomach with secretion gastric juice, and the previous parts are considered only an extension of the esophagus.
Food enters the small intestine from the abomasum in portioned form. Bile and pancreatic juice digest food, and the produced substances are absorbed into the blood. The small intestine of an adult cow is about 45 m long, and many receptors create a huge area for the absorption of nutrients.
- cecum - here the fermentation of food that has undergone splitting in the abomasum takes place;
- colon - serves for the formation of excrement;
- anal hole.
The structure of the stomach of ruminant animals: video
Urinary
The cow's urinary system consists of the following organs:
- kidneys - filter blood and produce urine;
- ureters - conduct urine into the bladder;
- bladder - stores urine and directs it into the urethra;
- urethra - serves to remove processed fluid from the body.
Genitals
The genital organs of animals of different sexes, like those of humans, differ significantly. Let us consider the structure of the reproductive system of the female and the male separately. 
Structure of the genital organs of a cow
- In the ovaries, eggs grow and develop, which flow out from the bursting of a mature follicle.
- IN fallopian tube fertilization of the egg occurs, from there it is sent to the uterus.
- The uterus is necessary for the development of the fetus, which during childbirth is pushed out from there by muscle contractions.
- The vagina is intended for copulation and is located between the cervix and the urethra.
- The clitoris performs the functions of additional stimulation, increasing contractions of the uterus, which has a beneficial effect on the likelihood of fertilization.
- The vulva contains the opening of the urethra and is located under the opening of the anus.
- The pudendal lips are the entrance to the vagina and, when deepened inside, they change their structure from the folds of the skin to the mucous membrane.
Video: anatomy of the cow's reproductive system
Structure of the genital organs of a bull
The genital organs of a bull produce up to 6 ml of sperm during one ejaculation.
- The formation and subsequent growth of sperm occurs in the testis. Another purpose of the organ is the production of male sex hormones.
- The scrotum, the repository of the testis, is a massive fold of skin between the thighs of a bull. The temperature in this cavity is lower than in the peritoneum, and this helps in the development of sperm.
- The vas deferens, true to its name, carries sperm to the site of fertilization of the cow's egg through the ejaculatory duct.
- The spermatic cord is a fold in abdominal cavity, which encloses nerve fibers, blood and lymphatic vessels, as well as the vas deferens.
- The urogenital canal (also called the male urethra) carries urine out and ejects semen. The organ starts from the bladder and ends at the head of the penis.
- The penis introduces sperm into the cow's vagina and also serves for urination.
- The prepuce is an analogue of the male foreskin, which covers the head of the penis in a relaxed state and is pulled off the erect penis.
The structure of the male genital organs: video
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