Анатомия домашних животных миология = Anatomy of domestic animals Myology. Учебно-методическое пособие

On the border between thoracic and abdominal cavities there is a diaphragm, that is incurved in thoracic cavity. Central part of the diaphragm is tendinous, and peripheral is muscular and attaches to vertebrates, ribs and sternum. During contraction its cupula retracts caudally and aids inspiration.

Table 13

Diaphragm

2.2.4 The muscles of abdominal wall

Muscles effecting abdominal wall form 3-4 layers, which muscular bundles are mutually transverse and attach cranially on thethorax.Themusclesofabdominalwallholdinternalorgansand together with the diaphragm form abdominal tension (prelum abdominale), which contractions narrows abdominal cavity and aid expiration. Thus muscles of abdominal wall are expirators.

Table 14

External abdominal oblique

The muscles of the abdominal wall Internal abdominal oblique Transversus abdominis

Rectus abdominis

It should be mentioned, that in males there is an inguinal canal: it goes between external and internal abdominal oblique muscles, through abdominal wall and opens in abdominal cavity.

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Through this canal testicles sink in scrotum at the end of fetal period in males, and the spermatic cord lies in it lifelong.

The inguinal canal (canalis inguinalis) is a hiatus, lined up by serosa, that opens under the skin from one side, forming superficial inguinal ring, on the other side it opens in abdominal cavity forming profound inguinal ring. The superficial inguinal ring (anulus inguinalis superficialis) is formed by most external abdominal muscle and its abdominal and pelvic plates. The profound inguinal ring (anulus nguinalis profundus) is formed by free caudal margin of internal abdominal oblique muscle and free margin of external abdominal oblique muscle. Tendinous margin of the latter is called inguinal ligament (ligamentum inguinale). In females the inguinal ligament is poorly developed, but uterine ligament, vessels and nerves goes through it.

Table 15

The inguinal canal

2.3 The muscles of the limbs

All muscles are divided by provided function into extensors, flexors, abductors, adductors, supinators and pronators. For better understanding of this material all muscles of the limbs are grouped by their effect on particular joint. But you should remember that one muscle can have several functions. For instance, triceps being extensor of elbow joint simultaneously aids flexion of shoulder joint. Thus all muscles can be divided into mono-, biand multiarticular.

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Monoarticular muscle effects only on one joint (subscapular, anconeus, gracilis), biarticular – on 2 joints (tricepts, quadricepts), multiarticular – on several joints (bicepts, semitendinosus).

General rules of muscle positioning on the limbs

1.Commonly muscles are situated above the joint, on that they are effecting during dynamic work of the limb (during locomotion of the animal). For instance, in forelimb muscles effecting the shoulder joint are situated in scapula area.

2.Muscles-extensors, extending the joint, are always go through the angular point of the joint; muscles-flexors, bending the joint, are always situated inside the angle of the joint.

3.Muscles-abductors always lie on lateral surface of the joint; muscles-adductors always lie on the medial surface of the joint.

4.Muscles-supinators, rotating the joint clockwise (outside), are situated closer to lateral surface; musclespronators, rotating the joint contra clockwise (inside), are situate closer to medial surface.

5.The bones of zygopodium are connected to the muscles that effect not only carpal(tarsal) joint,but also onthe digital joints.

6.The muscles of the hindlimb are better developed than in the forelimb, because during locomotion most of the work is provided by the hindlimbs.

2.3.1 The muscles of the forelimb

The muscles of the forelimb are divided into following groups according to topography and provided function.

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Table 16

Muscles of the forelimb

Muscles, that are situated in scapular area, effect the shoulder joint. On the cranial margin of the scapula there are extensors of the shoulder joint, and inside the angle of this joint there are flexors. But you should concern, that greater teres muscle isnotonlytheflexoroftheshoulderjointbutalsoitspronator.And deltoid and small teres muscle provide not only flexion, but also supination.

Table 17

Muscles acting on the shoulder joint

Muscles acting on the elbow joint are situated in brachium area. Cranially to brachiumthere are flexors of theelbow joint,and caudally – extensors. Rotators are well developed only in dogs and pigs.

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Table 18

Muscles acting on the elbow joint

There are muscles helping the work of the shoulder joint among muscles acting on the elbow joint. For instance, triceps brachii and tensor fasciae antebrachia help to flex the shoulder joint, and biceps brachii – to extend it.

Table 19

Muscles acting on the carpal and digital joints

Muscles situated in antebrachium area is acting on the carpal and digital joints. On cranio-lateral surface of the antebrachium there are extensors of the carpal and digital joints, on caudo-medial surface – flexors. Flexors of thecarpal jointcover flexors of digital joints, that are situated deeper underneath them on the palmar surface of radius.

Muscles attached in carpal area in ungulates became static and greatly reduced. In dogs and cats they are poorly developed and present as intercostal and lumbrical muscles, that act only on digital joints.

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Table 22

There are muscles helping the work of the stifle joint among musclesactingonthehipjoint.Forinstance,biceps femoris and semitendinosus help to flex the stifle joint, and Sartorius and tensor fascia latae – to extend it. And quadriceps femoris, that is exyensor of the stifle joint, helps to flex hip joint.

Muscles situated in tibia area is acting on the tarsal and digitaljoints.Oncranio-medialsurfaceofthetibiathereareflexors of the tarsal (hock) and digital joints, on caudo-lateral surface – extensors.

Table 23

Muscles acting on the tarsal and digital joints

Musclesattached intarsal area act only on digital joints. On dorsal surface of tarsal bones there is short digital extensor, and on plantar – interosseous muscles. Short abductor of the 5th finger and plantar quadrate muscle are present only in dogs.

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Bibliography

1.Akaevskii A.I., Udichev U.F., Seleznev S.B. The anatomy of the domestic animals. – Moscow: Akvarium, 2009.

2.Hrustaleva I.V. et.al. The anatomy of the domestic animals. - Moscow: Koloss, 2000.

3.König H.E., Liebich H. G. Veterinary anatomy of domestic mammals. -Schattaeur, 2007.

4.Sisson S. The anatomy of the domestic animals. – Philadelphia: Saunders Company, 2014.

5.Dyce K.M., Sack W.O., Wensing C.J.G. Textbook of Veterinary anatomy 4th ed. – Saunders, 2010.

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