MUSCLES

From Big Medical Encyclopedia

MUSCLES [musculi (PNA, JNA, BNA); synonym muscles] — the anatomic educations which are consisting generally of muscular tissue, carrying out motive function of an organism, its parts and separate bodies.

From 28 to 45% of the weight (weight) of a body of the adult are the share of M. (women have 28 — 32%, men have 35 — 45%, at old men to 30%, at newborns and children to 20 — 22%). At M. athletes can make St. 50% of body weight. The list of names of muscles and drawings illustrating muscles of certain areas of a body and the head are provided in the end of article.

Classification

Distinguish smooth and cross-striped M. Smooth M. are a part of a wall of blood vessels, skin and various hollow bodies — a stomach, intestines, a uterus and others (see articles devoted to separate bodies).

Fig. 1. The diagrammatic representation of muscles of various form, with an unequal arrangement of muscle bundles: 1 — spindle-shaped; 2 — wide; 3 — two-headed; 4 — biventral; 5 — multibelly; 6 — multitendinous; 7 — one-plumose; 8 — bipennate.
Fig. 1. 1 - muscle (frontal abdomen); 2 — a small malar muscle; 3 — a circular muscle of a mouth; 4 — the muscle lowering a corner of a mouth; 5 — a mental muscle; 6 — a grudinopodjyazychny muscle; 7 — lopatochno - a hypoglossal muscle; «At — a biceps of a shoulder; 9 — a humeral muscle; 10 — an outside oblique muscle of a stomach; 11 — a direct muscle of a stomach; 12 — a pyramidal muscle; 13 — a humeroradial muscle; 14 — a beam sgibatel of a wrist; 15 — a long palmar muscle; 16 — a superficial sgibatel of fingers; 17 — an elbow sgibatel of a wrist; 18 — an eminence of a thumb; 19 — a palmar aponeurosis; 20 — an eminence of a little finger; 21 — a napryagatel of a wide fascia; 22 — under-vzdoshno - a lumbar muscle; 23 — an edge muscle; 24 — a long adductor; 25 — a thin muscle; 26 — a lateral wide muscle of a hip; 27 — a sartorial muscle; 28 — a medial wide muscle of a hip; 29 — the muscle giving a thumb of foot; 30 — sinews of a long razgibatel of fingers; 31 — a long sgibatel of fingers; 32 — a long razgibatel of fingers; 33 — a front tibial muscle; 33a — a soleus muscle; 34 — a gastrocnemius muscle; 35 — a back interosseous muscle of I; 36 — a short razgibatel of a thumb of a brush; 37 — the long muscle which is taking away a thumb of a brush; 38 — an elbow razgibatel of a wrist; 39 — a short beam razgibatel of a wrist; 40 — a razgibatel of fingers; 41 — a beam sgibatel of a wrist; 42 — a long beam razgibatel of a wrist; 43 — a humeroradial muscle; 44 — a humeral muscle; 45 — a tricipital muscle of a shoulder; 46 — a biceps of a shoulder; 47 — a front gear muscle; 48 — a big pectoral muscle; 49 — a deltoid muscle; 50 — a trapezoid muscle; 51 — an average scalene; 52 — grudino - a clavicular and mastoidal muscle; 53 — the muscle raising a shovel; 53a — a belt muscle of the head; 54 — a buccal muscle; 55 — a masseter; 56 — a big malar muscle; 57 — a circular muscle of an eye; 58 — a temporal muscle.
Fig. 2. 1 — an occipitofrontal muscle (an occipital abdomen); 2 — a semi-awned muscle of the head; 3 — a belt muscle of the head; 4 — a breast - klyuchichno - a mastoidal muscle; 5 — a trapezoid muscle; 6 — a deltoid muscle; 7 — a tricipital muscle of a shoulder; 8 — a biceps of a shoulder; 9 — a humeral muscle; 9a — the round pronator; 10 — a humeroradial muscle; And — a beam sgibatel of a wrist; 12 — a long palmar muscle; 13 — a superficial sgibatel of fingers; 14 — an elbow sgibatel of a wrist; 15 — an eminence of a little finger; 16 — an eminence of a thumb; 17 — a semitendinous muscle; 18 — a biceps of a hip; 19 — a semimembranous muscle; 20 — a gastrocnemius muscle; 21 — a soleus muscle; 22 — the muscle which is taking away a little finger of foot; 23 — a long fibular muscle (sinew); 24 — a short fibular muscle; 25 — a bottom muscle; 26 — a big gluteus; 27 — an average gluteus; 28 — an elbow sgibatel of a wrist; 29 — a razgibatel of fingers; 30 — a razgibatel of a little finger; 31 — an elbow razgibatel of a wrist; 32 — an elbow muscle; 33 — a short beam razgibatel of a wrist; 34 — a long beam razgibatel of a wrist; 35 — an outside oblique muscle of a stomach; 36 — the broadest muscle of a back; 37 — a tricipital muscle of a shoulder; 38 — a big round muscle; 39 — a small round muscle; 40 — a podostny muscle; 41 — a masseter; 42 — a temporal muscle.

In cross-striped muscles allocate a cardiac muscle (see. Heart ) and skeletal M. Total quantity of skeletal M. of a body of the person makes apprx. 600. Muscles are grouped depending on their arrangement in various parts and areas of a body (tsvetn. fig. 1 and 2). On this sign allocate M. of the head, necks, spins, to a breast, a stomach, top and bottom extremities.

In a form distinguish long and short, wide and circular M.; by quantity of components — simple and difficult. Simple long M. have on one head, the abdomen and a tail difficult — various quantity of parts, depending on number to-rykh allocate two-headed, tricipital and chetyrekhglavy, and also biventral, multibelly and multitendinous muscles (fig. 1).

On an arrangement of muscle bundles and their relation to sinews in M. allocate parallel, plumose and triangular forms of an arrangement of muscle bundles. At a parallel form muscle bundles are located along a long axis of a muscle and their direction matches the direction of draft of M. The plumose arrangement of muscle bundles meets in one-plumose (mm. unipennati), bipennate (mm. bipennati) and multiplumose (mm. multi pennati) muscles. In one-plumose M. on the one hand at an angle to a sinew muscle bundles join. In bipennate M. parallel muscle bundles from two parties are attached at an angle to a sinew. In much plumose, napr, deltoid, M. muscle bundles are attached by many groups to the sinew which is branched out in it from all directions. In triangular, or fan-shaped, napr, temporal, muscle bundles from various directions meet and attached by M. to one sinew.

M can pass through one or several joints, involving them in the movement at reduction. Depending on it distinguish uniarticular, two-joint and multiarticular M. Have no relation to joints of a muscle mimic, M. of a soft palate, a throat, over - and hypoglossal muscles of a neck, M. of a crotch, etc.

On funkts, to M.'s sign classify proceeding from that main type of movements, to-rogo this or that M. takes part in performance.

Several M. of the unidirectional or opposite action, as a rule, participate in performance of movements. Therefore the synergistic muscles i.e. acting consensually and the muscles-anta-gonisty performing opposite operations distinguish.

On the nature of the carried-out main movements distinguish: sgibatel (mm. flexores) and razgibatel (mm. extensores), bringing (mm. adductores) and taking away (mm. abduc-tores), lifting (mm. levatores) and lowering (mm. depressores), pronators (mm. pronatores) and instep supports (mm. supinatores), constrictors (mm. constrictores), sphincters (mm. sphincteres) and dilators (mm. dilatatores), rotating (mm. rotatores), straining (mm. tensores) and straightening (mm. erectores). Allocate also mimic, chewing and respiratory M.

the Structure

muscular and connecting fabrics, a sukhoyashliya, nerves, circulatory and limf, vessels are M.'s part. In M. distinguish muscular and tendinous speak rapidly.

Cross-striped M. are formed of bunches of the muscle fibers surrounded with layers of connecting fabric. Muscle fibers of cross-striped M. can have various length, reaching, e.g., in sartorial M. length of 12 cm. Thickness of muscle fibers in cross-striped M. of the newborn makes 7 — 8 microns, at the age of 2 years — 10 — 14 microns, 4 years — 14 — 20 microns, adults have 38 — 80 microns, and at the persons who are systematically playing sports — to 100 microns.

Fig. 2. Scheme of a structure of Myonum of a cross-striped muscle: 1 — muscle fibers; 2 — kernels of muscle cells; 3 — myofibrils; 4 — a sarcolemma; 5 — endomiziya; 6 — circulatory capillaries; 7 — tendinous thread; 8 — vegetative nerve fibril; 9 — somatic (dvrkhgatel-ny) nerve fibril; 10 — an aksonomyshechny synapse.

Cross-striped muscle fiber consists of a sarcoplasm with the multiple myofibrils (sokratitelny elements of fiber) located in it and is surrounded with a thin fibrillar cover — a sarcolemma (see. Muscular tissue ). Muscle fiber with its cover, nerve terminations, circulatory and limf. capillaries call muscular unit, or Myonum (fig. 2).

Muscle fibers combine I, II and III orders in bunches. Bunches of the I order are surrounded with thin layers of connecting fabric — endomiziy (endomysium). The connecting fabric surrounding muscle bundles of the II order and located between bunches of the III order makes an internal perimysium (perimysium int.). All M. has an outside connective tissue cover — an outside perimysium (perimysium ext.). Intramuscular connecting fabric passes in sinew (see). Tendinous fibers are continuation an endomiziya and a perimysium, and endomiziya, covering muscle fibers, is strongly connected to a sarcolemma. Therefore draft, to-ruyu develops the reduced muscle fiber, is transferred at first on endomizy and a perimysium, and then to tendinous fibers. M.'s sinew is attached to a bone at the expense of an interlacing of tendinous fibers with collagenic fibers of a periosteum, their joint growing into a bone with continuation in substance of bone plates.

Options of an anatomic structure. Individual anatomic distinctions of separate M. or their groups, as well as extent of development of muscles in general, depend on age, sex, a constitution, a profession, occupations physical culture and sport. Emergence of various options of an anatomic structure of M. and their variability are connected by hl. obr. with specific features of development of M. in ontogenesis. Refer distinctions to the main options of an anatomic structure of M. in shape, the sizes, topography, M.'s attachment, and also absence or existence of additional parts, separate M.' absence, existence of additional M.

The same muscle at different people can have the oval, spindle-shaped or extended form; the wide muscle can have the form from triangular to the wrong polygonal. By the sizes mimic M., short M. of a brush and feet are most variable.

Distinctions in an anatomic structure of M. and their parts are most expressed in difficult and wide M., in to-rykh various extent of division into parts can be noted. The quantity of teeth is changeable, to-rymi begin a lobby., top and bottom back gear M., and also wide M. of a perednebokovy abdominal wall. Sometimes there is no intermediate sinew at scapular and hypoglossal and biventral M. Otsutstviye of parts can take place in deltoid, big chest M., and also in a diaphragm that can lead to its relaxation and developing of phrenic hernias. Separate M. have additional muscle bundles, heads of Pi of a sinew. At many M. fields of an attachment can extend or be narrowed, to be displaced on an extent levels of an attachment. At the same time extreme levels of such shifts at nek-ry M. can defend on considerable distance. Change that on grafo-anatomic M.'s relations with the next educations is usually caused by the shift of places of the beginning and an attachment, M.'s division into parts or presence of additional parts M. Separate M.' absence, napr, a front straight line, front ladder, scapular and hypoglossal, superficial cross M. of a crotch, a sgibatel of a little finger of a brush, a short razgibatel of a thumb of a brush and nek-ry others, is observed in rare instances. So-called non-constant M.' absence — small lumbar, pyramidal M. of a stomach, by the third fibular M., мал©й the bringing M., coccygeal in M is more often observed. In some cases additional M. are marked out: sternal, presternal, cross M. of an axillary hollow, third sural, small fibular M., intermediate razgibatel of a thumb of foot, lower M. of an auricle, etc.

Blood supply carry out muscular branches of the main arteries and their branchings. As a rule, several feeding arteries branching on layers of a perimysium and directed preferential on the course of muscle bundles get into M. At muscle bundles of the I order of an arteriole are divided into a large number of circulatory capillaries, to-rye braid muscle fibers and extend in an endomiziya. On 1 mm3 of M. it is returned to normal apprx. 2000 capillaries. From intramuscular venous network veins form, to-rye accompany arteries. On the course of branchings of blood vessels pass limf, vessels.

Innervation. Together with arteries one or several nerves which are carrying out a motive and sensitive innervation enter M. The motor neuron with the group of muscle fibers innervated by it is called neuromotor unit. In muscle bundles of the I order motive nerve fibrils are divided into the bombways which are coming to an end with trailer motor plates. In different M. one nerve fibril can innervate different amount of muscle fibers, napr, in a lateral direct muscle of an eye one nerve fibril innervates on average 3 — 6 muscle fibers, and in tricipital M. of a shin — 120 — 160.

Auxiliary devices. Carry to auxiliary devices M. fascia (see), fibrous and synovial vaginas of sinews (see. Synovial vaginas ), synovial bags (see), blocks of muscles and sesamoids (SEE).

All M., except mimic, are surrounded with fastion, to-rye form for them muscular vaginas. Own a fascia create fascial, or osteofibrous, beds for functionally and topographical homogeneous groups M. A fascia perform basic function, being places of the beginning and an attachment of many M. They show side resistance to the reduced M., promoting performance of motive function by them. Existence around M. and neurovascular bunches of fascial beds and vaginas defines a so-called futlyarny structure of extremities that has important a wedge, value for diagnosis of the extending suppurative processes.

Vaginas of sinews of M. can be fibrous and synovial. Fibrous, or osteofibrous, vaginas of sinews (vaginae fibrosae tendiimm) meet in distal departments of extremities around the most mobile sites of long sinews, e.g. M. of razgibatel of fingers of a brush. Fibrous vaginas promote deduction of sinews about bones and joints, and also to the movement of sinews in strictly certain directions. Synovial vaginas of sinews (vaginae synoviales ten-dinum) as well as fibrous, surround sinews in places of their largest shift and a prileganiye to bones and the capsule of joints.

Synovial bags (bursae synoviales) are located under M. and sinews on the surface of bones, sometimes between a bone and skin, in places of the greatest mobility of M. and sinews.

Blocks M. meet in those places where M., changing the direction, are transferred through bone or fibrous educations. Between M.'s sinews and blocks of muscles synovial bags are located.

Sesamoids (ossa sesamoi-dea) meet in nek-ry sinews of M. near their attachment to bones.

Fig. 3. Microdrug of a cross-striped muscle at senile age: muscle fibers (1) have various tolshchuna, kernels (2) muscle cells are located unevenly; coloring hematoxylin-eosine, x 320.

Changes in muscles in the course of aging

in the course of aging reduction of perimeter of M. is noted: its abdomen becomes less, and a tendinous part increases and makes sometimes 2/3 all lengths of M. Uprugost and elasticity of muscle bundles considerably decrease, the content of connecting and fatty fabrics increases. Muscle fibers are reduced in the diameter and quite often deprived of cross striation. Kernels of muscle cells are located unevenly (fig. 3). Separate muscle fibers of a vakuolizi-rovana, sharply of an izvita or are thickened by places. There is a quantitative and high-quality reorganization argentofit ny fibers. M.'s vascularization decreases; e.g., at the age of St. 60 years in them twice less blood vessels, than at mature age are found on average. Fibrous bunches of sinews of M. are homogenized, their crimpiness is lost, the ratio of neutral mucopolysaccharides and hondroitinsulfat is broken. In places of an attachment of M. the bone becomes more dense and hilly. On the course of vessels, nerves and in M.'s sinews kaltsinata to dia, to 0,4 mm, and in some cases — the centers of bone and cartilaginous fabrics sometimes come to light.

The ultrastructure of muscular tissue changes: the quantity of mitochondrions decreases, there are hypertrophied mitochondrions which are losing cristas and accumulating granular material in a matrix that demonstrates deep disturbance of breath of a cell. In myofibrils find symptoms of dystrophy and destruction (gaps, abnormal contacts of threads) of akti-new and miozinovy threads.

The structural changes of M. arising in the course of aging are followed by a row funkts, disturbances. So, skeletal M.' force considerably decreases (to 25% in elderly and 37% at senile age), changes funkts, the condition of neuromotor unit (electric potentials and frequency of an impulsation decrease, duration of action currents increases), occurs increase in a threshold of excitement and duration of stage of latency, the current testimonial of M.'s tension at rest increases. As a result of these changes activity of all motive system is broken with age. Especially the condition of M. bending a shin and foot therefore rate of walking decreases goes down funkts. The cordial M.'s changes arising in the course of aging — see. Heart .

The physiology

Fiziol, cross-striped M.' role is diverse: they participate in movement of parts of a skeleton, fixing of joints, maintenance of balance. The cross-striped M. located around natural an opening bear functions of sphincters. In a gullet and a throat they provide the deglutitory movements, and in a throat participate in sound education.

Thanks to smooth M.' work sokratitelny activity is carried out went. - kish. a path, edge creates optimal conditions for process of digestion, supports at the ABP certain level. In nek-ry the site:: circulatory system and internals smooth M. perform function of sphincters.

A structural basis of activity of cross-striped M. is the extended muscle cell (fiber). Cross-striped M. of mammals and the person consist of extrafusal and intrafusal muscle fibers. Extrafusal fibers subdivide into bystry phase and slow phase fibers. Bystry phase fibers make bystry M.' basis, napr, razgibatel of extremities; slow fibers — slow, napr, kambalovidny and lumbar M. Bolshinstvo M. contain both bystry, and slow phase fibers. Slow phase fibers have bigger viscosity, have more developed network of capillaries, their metabolism in more considerable degree, than at bystry phase fibers, depends on oxygen. Sokratitelny properties of slow phase and bystry phase fibers differ on a number of indicators. Slow phase fibers give a conjoint tetanus with more rare frequency of irritation and more slowly come out an active state (see. Muscular contraction ). In addition to slow and bystry phase fibers, in M. there are tonic fibers. Unlike the phase fibers having the arranged intracellular membranes in tonic fibers intracellular membranes are located chaotically.

The innervation of phase muscle fibers is carried out by axons to dia, to 20 microns and the speed of carrying out an impulse from 60 to 120 m/s, their membrane potential reaches 90 mV. Tonic muscle fibers are innervated thin, to dia, to 10 microns, by the axons with a speed of carrying out an impulse to 30 m/s forming the multiple uviform motor terminations. Tonic muscle fibers can remain in a condition of reduction under the influence of, e.g., direct current, acetylcholine and potassium ions within several minutes.

Smooth M. subdivide on unitary and multiunitary. M. of digestive organs, and also a uterus, an ureter, multiunitary — M. of an iris, a ciliary body, a blink membrane, hair follicles are unitary. Nek-rye M. M. of a deferent duct, a bladder, nek-ry arteries have of both unitary, and multiunitary smooth M.' properties, e.g. Unitary M. possess a spontaneous rhythm of excitement, between their cells there is an intercellular electric carrying out combining separate cells in funkts, a sincytium. Unitary M.' stretching leads to depolarization of membranes of smooth muscle cells and causes muscular contraction. The irritation of sympathetic and parasympathetic nerves influences unitary M., causing strengthening or oppression of spontaneous reductions. Multiunitary M. are normal reduced in response to nervous impulse, excitement from a muscle cell to a cell is transferred only on nerve terminations, multiunitary M.' stretching is not followed by depolarization of a membrane of smooth muscle cells.

Smooth M. have unequal sensitivity to effect of physiologically active agents. Membrane potential of smooth M. fluctuates from 30 to 70 mV and arises in the form of pikopodobny and platopodobny action potentials and slow spontaneous waves. The size of action potentials is defined by concentration in the environment of ions of Ca 2+ . Slow spontaneous waves result from periodic activity of the membrane ionic pumps providing transport through a cell membrane of potassium ions, sodium and chlorine. The membrane of muscle cells has muskarinovy and nicotinic receptors for acetylcholine, alpha and beta adrenoceptors — for noradrenaline. The mechanism of momentum transfer in multiunitary M. is essentially similar to that in cross-striped M. In response to irritation in smooth muscle cells there are postsynaptic exciting or brake potentials. Reduction and smooth M.' relaxation has small speed that is explained with character of an innervation, the disorder arrangement of threads of actin and a myosin, low activity of miozinovy ATP-ase, weak expressiveness from an arkoplazmatichesky reticulum. Each phase cross-striped muscle fiber is supplied with the separate nerve termination forming a so-called neyromuskulyarny plaque (a trailer plate, a motor plate) on a superficial membrane, in a cut there are holinoretseptor and cholinesterase. Under the influence of nervous impulse from nerve terminations the mediator — acetylcholine is released, to-ry, interacting with a holinoretseptor of a postsynaptic membrane, causes postsynaptic potential neuro muskulyarnoy plaques. The size of this potential depends on quantity of the allocated acetylcholine, to-ry increases sodium and potassium conductivity of a membrane. Having reached critical size, postsynaptic potential causes action potential with an amplitude up to 120 mV, lasting 2 — 3 ms, extending under the law « everything or nothing » (see).

The irritation of nerve fibril causes the local center of depolarization in tonic muscle fiber, to-ry directly causes local reduction. Rhythmic stimulation leads to summation of local potentials and the general local reduction increasing with increase in frequency of irritation. Muscle fibers, as a rule, are not reduced separately since the axon, entering a muscle, plentifully branches and innervates group of muscle fibers.

Under the influence of various influences — chemical, mechanical, actions of electric current, etc. — the membrane potential and ion permeability of M. changes, as a result to-rykh they come to a state excitement (see). M.'s ability to answer irritation with excitement is called excitability (see). As an exponent of excitability serves the excitation threshold on electric irritation, for to-ry accept force of electric current or size of its tension, sufficient to cause excitement. Such force or size of tension of electric current call threshold. Between the threshold current and duration of its action there is a dependence, edges is expressed by a formula of Hoorvega — Weiss: i = Q/t + b, where i — the threshold force of electric current, t — duration of its action, Q and b — coefficients. Excitation thresholds for influence of various duration describe in the form of a curve «force — duration», identical character for various M. has edges and differs only in degree of an inclination. In a wedge, practice defined only two points of this curve earlier — rheobase and a chronaxia (see. Hronaksimetriya ). Understand the threshold current of big duration as rheobase. A chronaxia — the minimum duration of influence of an irritant by force in two rheobases causing excitement. During the definition of a chronaxia, as a rule, did not consider complexity of a structure of muscular tissue, from to-rogo distortions in character of a curve force — duration depend. H. E. Vvedensky offered an indicator funkts, mobility or labilities (see), characterizing the speed of emergence of excitement.

The most part of cross-striped M. is connected with bones of a skeleton or skin. During M.'s reduction are shortened; return to initial length after reduction is connected with activity of antagonistic muscles. In nek-ry M., napr, chewing and mimic, the role of antagonists is carried out by elastic sheaves. As a rule, even several M. which are Synergists and antagonists participate in the elementary motive acts. During reduction of synergists there comes reflex inhibition of antagonists. Synergism and M.'s antagonism are very conditional; e.g., during deduction of a load on an outstretched arm the biceps of a shoulder is strained, and tricipital — is relaxed; at a support the free brush on a surface strained tricipital and the biceps is relaxed; at completely unbent (a full ekstenziya) and the fixed upper extremity both

M. Sil M. with a longitudinal arrangement of muscle fibers, napr, spindle-shaped are strained, is defined by the area of its anatomic diameter, i.e. its thickness; M of plumose and triangular shape — the area of physiological diameter, i.e. the imagined plane, on a cut are cross sections of all muscle fibers making M. Sil M. makes from 4 to 17 kg on 1 cm 2 its diameter.

The size of reduction (tension) of M. depends on the frequency of nervous impulses, number of the excited neuromotor units, a ratio between amount of the bystry and slow phase and tonic fibers participating in reduction, and also on mechanical characteristics of connecting fabric and sokratitelny fibers. The accruing M.'s reduction is provided with asynchronous excitement of separate neuromotor units. Speed of reduction and M.'s relaxation is connected with amount of the bystry and slow fibers making neuromotor unit. Quicker M. incorporating neuromotor units with a small number of fibers are reduced and relax. M.'s ability to mechanical activity estimated on force, the speed of reduction and relaxation and others funkts, to indicators, define as its contractility.

Motive function of muscles is connected with their shortening as a result of reduction of muscle fibers and rapprochement of points, to the Crimea they are attached. The bones moving in joints under the influence of M. form levers of the motive device. As a point of support of such lever serves the joint, in Krom there is a movement, a point of application of force — the place of an attachment of M. which is carrying out the movement and a point of resistance — the scene of action on a bone of the gravity (load). Depending on an arrangement of points of resistance and application of force of weight concerning a point of support distinguish levers of the first, second and third sort. The lever of the first sort, or the lever of balance, is a dvuplechy lever, in Krom of a point of resistance and application of force are on the opposite sides from a point of support (e.g., levers around a lateral axis of atlantozatylochny and coxofemoral joints). The lever of the second sort, or the lever of force — the odnoplechy lever, in Krom a point of resistance is between a point of support and a point of application of force. Such lever is formed, e.g., in an ankle joint during the walking. In the lever of the third sort, or the lever of speed, the point of application of force is between a point of support and a point of resistance (e.g., in an elbow joint during the bending of a forearm). Functions M. study by means of dynamometry, tonometriya, ergografiya, registration of the caused reflexes, total bioelectric activity, etc. (see. Muscular work , Electromyography ). Use registration of reductions of the isolated sarcomere, membrane potential by means of a microelectrode method of a research, etc.

Pathological anatomy

Fig. 4. Microdrug of a cross-striped muscle (cross section) at vacuolar dystrophy: in muscle fibers numerous vacuoles are visible (are specified by shooters); coloring hematoxylin-eosine, x 200.

At a macroscopic research M. pay attention to their color, a consistence, a look on a section, existence of atrophic or hypertrophic changes, sites of a necrosis, hemorrhages, etc. At gistol, a research in a sarcoplasm, kernels, myofibrils or in all components of muscle fiber various dystrophic changes can be at the same time found. Different types meet more often proteinaceous dystrophy (see). At the granular dystrophy which is observed at inf. diseases and various intoxications, M. increase in volume and have a dim appearance on a section. Accumulation in a sarcoplasm of proteinaceous and fatty granules, relative safety of the myofibrillar device is histologically noted. Electronic microscopically note destructive changes in mitochondrions with destruction of their lipoprotein membranes. Vacuolar dystrophy (see) meets at a system lupus erythematosus, gipokaliyemichesky paroxysmal paralysis, thyrocardiac periodic paralysis, glycogenoses and it is characterized by emergence in muscle fibers of round or oval cavities (fig. 4) containing transparent liquid and which are formed as a result of merge of longitudinal and cross elements of sarkotubulyarny system.

At a myogelosis (hardening) in M. dense sites appear. Gistol, a research in these cases sometimes allows to find a coagulative necrosis of separate fibers. The myogelosis is connected with change of colloids of M. and their transition to a phase of gel.

At amyloidosis (see) diffusion or focal adjournment of amyloid masses in endo-and a perim-ziya, a muscular coat of arteries is noted. Amyloid can squeeze muscle fibers, causing their atrophy.

Disturbance of a lipometabolism in M. has character fatty dystrophy (see) or lipomatoza (see). The fatty dystrophy which is expressed emergence in muscle fibers of lipidic inclusions usually accompanies granular dystrophy. Lipomatoz arises at an atrophy of muscles and the general obesity and consists in growth of fatty tissue in endo-and perimysiums.

At carbohydrate dystrophy (see) excess adjournment in muscle fibers of a glycogen is noted, especially at glycogenoses and thyrocardiac periodic paralysis. Electronic microscopically granules of a glycogen come to light preferential in expanded subsarcolemmic and interfibrillar spaces.

Adjournment in M. of salts of calcium is manifestation local or the general calcification (see).

Patol, M.'s pigmentation is more often observed at their atrophy. Due to the massive adjournment lipofuscin (see) M. can gain brown color. Their green coloring is noted at the miositis accompanying sarcosporidiosis (see).

Fig. 5. Microdrug of a cross-striped muscle at a necrosis: in muscle fibers with a diskoidny necrosis (1) strengthening of cross striation is noted, unstructured glybk (2) of a coagulative necrosis are visible; coloring toluidine blue, x 100.

As a result of necrotic changes muscular tissue takes a clay form, becomes dry, dim or edematous, gelatinous. Distinguish a diskoidny and coagulative necrosis of M., and also a myolysis. Damages of structure of muscle fibers at a necrosis have focal, diffusion character is more rare. Different types of a necrosis can arise at the same time both in different muscle fibers, and in one fiber. At a diskoidny necrosis in muscle fibers define easing of an eosinophilia of a sarcoplasm, disappearance of a glycogen, the expressed cross striation (fig. 5). Electronic disintegration at first of aktino-vy myofilaments and partitions of T in isotropic disks with the subsequent destruction of myofibrils and intracellular organellas is microscopically noted. Feature of a tsiskoidny necrosis consists in almost total absence of lysosomes. The Diskoidny necrosis can come to the end with a coagulative necrosis and a myolysis. At a coagulative necrosis muscle fibers homogeneous, eosinophilic coloring with piknotichny kernels, places break up to glybk of different size and a form (fig. 5). At the ultrastruk-turny level osmiofilny conglomerates from homogeneous myofibrils are defined, to-rye gradually resolve. A part of muscle fibers can obyzvestvlyatsya. At a myolysis the sarcoplasm of muscle fibers becomes bulked up with badly distinguishable cross striation, contains gidropichesky and fatty inclusions; kernels of a liziro-vana. At electronic microscopic examination define a lysis of myofilaments, destruction of mitochondrions, fragmentation of a sarcoplasmic reticulum, increase in quantity of lysosomes. In the outcome of a myolysis destruction of a sarcolemma and loss of a detritis in intercellular space is observed.

Thanks to electronic and microscopic and gistofermentokhimichesky researches special forms of damage of structure of muscle fibers, identification to-rykh quite often are described has crucial diagnostic importance. Carry threadlike structures, sarcoplasmic little bodies, sarcoplasmic masses, ring-shaped fibrilla, fibers targets, cores to them. Threadlike structures have the form of peculiar threads and meet in subsar-kolemmalny zones of muscle fibers at a threadlike myopathy. In them ribonucleoproteins and high activity of a tyrosinase are found. Sarcoplasmic little bodies — irregular shape the sites of cytoplasm deprived of mitochondrions. They are observed in M. at a neyrotrofi-chesky atrophy, myopathies and a dystrophic myatonia. Sarcoplasmic masses — a wide rim of regional cytoplasm, in a cut is noted high activity of oxidation-reduction enzymes and phosphorylase, and also a large number of a glycogen is found. Often in the same fibers ring-shaped fibrilla comes to light, to-rye is located perpendicular to a long axis of muscle fiber and clearly is visible at statement CHIC reaction. The sarcoplasmic masses and ring-shaped fibrilla meet in M. at a dystrophic myatonia and myopathies. Fibers targets are characterized by lack of oxidation-reduction enzymes, a glycogen, phosphorylase, adenozintri-phosphatase in the central area of fiber and the increased enzymatic activity in adjacent sites; are defined in M. at-nervatsionnoy atrophies. Cores represent sites of fiber, roundish on cross section, to-rye are painted by eosine more intensively, than other sarcoplasm; are deprived of a glycogen and enzymatic activity. They are found in M. at the inborn not progressing myopathy (a disease of the central core). Electronic microscopically in a core define the amorphous and incorrectly located fragments of myofilaments and partitions of T, mitochondrions are absent.

Skeletal muscles have the developed vascular network therefore at ischemia heart attacks very seldom develop in them. At acute ischemia in muscle fibers the phenomena of a myolysis prevail. After recovery of a blood-groove in the damaged sites of muscle fibers they become impregnated with a blood plasma and the coagulative necrosis develops. Hron, M.'s ischemia is marked out at atherosclerosis of arteries, an obliterating endarteritis, rheumatism, etc. It is characterized by hypostasis and a sclerosis an endo-miziya, walls of vessels, atrophic and dystrophic changes of muscle fibers.

M.'s inflammation, and also fungal and their parasitic infections are characterized by alterativny, exudative and productive processes in muscular tissue (see. Miositis ).

Fig. 6. Microdrugs of a cross-striped muscle at a neurotrophic atrophy (a) and a myopathy: 1 — atrophied muscle fibers; 2 — normal and hypertrophied muscle fibers; coloring hematoxylin-eosine; x 200.

At M.'s atrophy are usually reduced, condensed, brown color. Diameter of muscle fiber decreases to 20 — 30 microns. Dedifferentiation of types of muscle fibers with lack of distinctions between them in enzymatic activity is characteristic of early stages of an atrophy. In atrophied muscle fibers the quantity of a glycogen is reduced, low activity of enzymes, kernels small, hyperchromic is noted. Electronic microscopically reduction of quantity of myofibrils and accumulation of granules of lipopigment is noted. In endo-and perimysiums growth of connecting and fatty tissue is observed. The Neyrotrofi-chesky atrophy of muscle fibers (fig. 6, a) usually has focal character. The atrophy at myopathies is characterized by mixed Stew of muscle fibers with chaotic distribution of atrophied fibers among normal and hypertrophied (fig., b).

At M.'s hypertrophy increase in volume generally at the expense of muscle fibers, diameter to-rykh quite often exceeds 65 microns. At the same time puzyrkovidny kernels of muscle fibers move to the center, contain large kernels and proliferate, creating chains. Electronic microscopically in such fibers find a hyperplasia of a lamellar complex and sarcoplasmic reticulum, a large number of polyribosomes and mitochondrions. The regenerating muscle fibers have large kernels with one or several kernels, basphilic cytoplasm without the expressed cross striation. In them high activity glyu-kozo-6-fosfatdegidrogenazy, NADF-diaphorases, low activity of a succinatedehydrogenase and phosphorylase is observed that testifies to dominance of glycolysis, a large number of a glycogen. Electronic microscopically randomly located myofilaments decide on irregular sarcomeres and a large number of ribosomes.

Postmortem changes of M. are characterized by disintegration of proteins of muscular tissue under the influence of specific cellular enzymes (see. Autolysis ).

Pathology

Malformations

Fig. 1. Microdrug of a muscle at an ossifying miositis: 1 — the single remained muscle cells, 2 — growths of fibrous fabric with fibroblastopodobny cells, 3 — neogenic bone crossbeams; coloring hematoxylin-eosine; X 80. Fig. 2. Microdrug of a muscle at an ossifying miositis: in fibrous fabric bone crossbeams (are specified by shooters) with deposits of lime are visible; coloring hematoxylin-eosine; x 100. Fig. 3. Microdrug of a leiomyoma of skin: in a derma randomly located bunches of smooth muscle fibers and narrow layers of connecting fabric between them are visible; coloring hematoxylin-eosine; X 80. Fig. 4. Microdrug of a leiomyosarcoma: all field of vision is filled with the intertwining bunches of smooth muscle fibers with polymorphism of cells; triple coloring according to Masson; x 160. Fig. 5. Microdrug of a rhabdomyoma: are visible a polygonal form of a cell with the granular cytoplasm containing small vacuoles; triple coloring according to Masson; X 600. Fig. 6. Microdrug of a rhabdomyosarcoma: sharply expressed polymorphism with existence of multinucleate colossal cells; coloring hematoxylin-eosine; x 200.

Most often meet the inborn malformation of grudinoklyuchichno-mastoidal M. bringing to to a wryneck (see), and also underdevelopment of a part diaphragms (see) that creates conditions for formation of phrenic hernia. Absence or big chest or deltoid M.'s underdevelopment causes deformation of a shoulder girdle and considerably affects its function. However even at total absence of a muscle the wedge, manifestations can not be and the malformation remains unnoticed during all life, napr, lack of m. palmaris longus.

Damages

divide Damages on closed, or hypodermic, and open.

Carry bruises, hemorrhages, complete and incomplete (partial) separations of M. and their sinews, formation of muscular hernias to the closed M.'s damages. The closed M.'s damages most often result from direct mechanical influence, napr, at blow, stretching of the reduced M., or can accompany dislocations and fractures. Gaps are described, and M.'s separations and their sinews are more often at reduction, excessive on force, napr, at tetanus, sharp exercise stresses, etc. However in the majority of similar cases the closed damages changed M. Izredka, napr are damaged patholologically, hemorrhages, can be observed in M. and without considerable mechanical influence (at atherosclerosis, disturbance of permeability of vessels, patol, changes of coagulant system of blood, etc.).

M.'s bruise is followed by education in its thickness of infiltrate, painful without clear boundary. During the first hours M. can lose ability to reduction that sometimes forms the basis for the wrong diagnosis of a complete separation of M. or its sinew. Further relaxation is replaced by reduction and shortening hurt by M. The movements of an extremity causing stretching and M.'s reduction become sharply painful (to a full painful contracture). The bruise can be resulted sacculated hematoma (see), cicatricial substitution of M., its calcification and ossification in the field of damage (see. Miositis, ossifying ), etc. Treatment: in the first 24 hours — rest, cold and a compressing bandage; since second day if the hematoma does not accrue, appoint thermal procedures, with 4 — the 8th day — to lay down. gymnastics. In 10 — 20 days, as a rule, there comes the rassasyvaniye of infiltrate and recovery of function M.

The complete separation of M. is clinically shown by developing of pains in the place of damage, in some cases deformation in the form of two hillocks of the reduced parts M. remote from each other on nek-rum distance, decrease in a muscle strength or total absence of sokratitelny function. In the first days after emergence of a gap at a palpation painful defect of M is defined. On skin in the field of a gap bruise as a result of an imbibition blood of the fabrics surrounding the damaged M. can develop. At a complete separation of M. operational treatment with suture on edges damaged by M is shown. Optimum results are observed during the carrying out operation during 24 — 48 hours after an injury.

The incomplete rupture of M. clinically reminds a bruise, but the wedge, manifestations differs from it in bigger expressiveness and duration. Treatment at an incomplete rupture of M. (without essential dysfunctions), as a rule, conservative: an immobilization of an extremity in the provision of the maximum relaxation by the damaged M. by means of a plaster bandage for 12 — 15 days. In the subsequent appoint physical therapy, LFK with gradual expansion of an exercise stress.

Muscular hernias result from defect of a fascial muscular vagina at an injury, and also inborn or patol, its inferiority. Through this defect there is M.'s protrusion at its reduction disappearing at relaxation of M. At the same time pains and dysfunction are possible. Treatment operational — plastics of a wall of a fascial muscular vagina.

Open damages of M. arise hl. obr. as a result of wounds (see. Wounds, wounds ). At full crossing of M. usually there occurs the reduction of its parts leading to the fact that in a wound it is possible not to notice edges of M. At partial crossing of M. reduction of its damaged parts leads to the fact that the wound widely gapes. In the hurt and avulsive wounds which are followed by M.'s crush, their reduction can be insignificant. The diagnosis of a rupture of M. is established at survey and primary surgical treatment of a wound, in time a cut the crossed M. sew a catgut (M. hearts — not resolving suture material or a chrome-plated catgut). Treatment in the postoperative period same as at the closed M.'s rupture

Diseases

Inflammatory, dystrophic and some other diseases of M. can have independent value (e.g., a miositis and Myunkhmeyer's disease) or to be a complication of any disease (e.g., metastatic abscesses in M. at sepsis, a wax-like necrosis of M. at a typhoid). In the latter case treatment of diseases of M. is, as a rule, connected with treatment of a basic disease.

Separate options of pathology of M. — see. Amyotrophy , Atrophy muscular , Myasthenia , Myatonia , Myopathy , Miotoniya .

Tumors

Tumours in M. meet rather seldom. From smooth muscular tissue can develop leiomyoma (see) and leiomyosarcoma (see), from cross-striped muscular tissue — rhabdomyoma (see) and rhabdomyosarcoma (see), and from endo-and a perimysium — fibroma (see. Fibroma, fibromatosis ), lipoma (see), etc. In M. tumors, coming from other fabrics can burgeon; occasionally in M. metastasises of malignant tumors — a breast cancer, a uterus, a rectum, etc.

Klin are observed, displays of tumors of M. depend on their localization, the sizes and degree of a zlokachestvennost. Their treatment is based on the principles and methods accepted in oncology. The forecast at benign tumors of M., as a rule, favorable.

M.'s tumors of separate bodies (e.g., stomach, intestines, uterus, etc.) — see articles devoted to these bodies.

Operations on M. are performed for the purpose of removal patol, the center, a tumor, opening of an abscess, emptying of a hematoma or for sewing together of a gap, plastics at a contracture, etc. M.'s crossing — the myotomy or its full removal are applied to elimination of the contractures caused by irreversible shortening of M. when the tenotomy cannot be carried out. In some cases M. use as plastic material for closing of defects of fabrics, napr, for filling of bone cavities at osteomyelitis, etc.

For suture on M. use, as a rule, resolving suture material (see). Stitches on M. are put without big tension not to cause disturbance of their food (see. Seams surgical ).

See also THE LIST OF NAMES OF MUSCLES ON PNA, JNA, BNA


Bibliography: Vishnevsky A. A. and Schreiber M. I. Field surgery, M., 1975; V.P's Sparrows. Anthropotomy, t. 1, M., 1932; And at with - manova-Petrusevich And. Muscular diseases, the lane with polsk., Warsaw, 1971; At to about in E. K. Sketches on neuromuscular physiology, JI., 1969; Ivanitsky M. F. Anthropotomy, t. 1, page 1 91, M., 1965; To and p l and A. V N. Injuries of bones and joints, M., 1979; To l and a seam A. A. Gistogenez, regeneration and tumoral growth of skeletal muscular tissue. L., 1971, bibliogr.; Materials of the 9th scientific conference on age morphology, physiology and biochemistry, t. 1 — 2, M., 1969; Myopathies, under the editorship of S. Bo-zhinov and G. Gylabov, lane with bolg., Sofia, 1977; Molecular and physiological mechanisms of age development, under the editorship of V. N. Nikitin, etc., page 342, Kiev, 1975; R. S. Fiziologiya's Eagles of smooth muscles, M., 1967, bibliogr.; The guide to gerontology, under the editorship of D. F. Chebotaryova, etc., page 143, M., 1978; With e to and m of the island of S. M., Kopyev T. N. and Zhvaniya M. A. Ultrastructure of skeletal muscles at a dermatomyositis at children, Arkh. patol., t. 40, century 2, page 56, 1978, bibliogr.; Xie Kamova S. M., Kopyev of T. H. and T r about y N I to about in N. K. Dinamik of necrotic changes of skeletal muscles at a syndrome of long crush, in the same place, t. 38, century 7, page 25, 1976; Sinelnikov R. D. Atlas of anthropotomy, t. 1, M., 1967; Comparative zoophysiology, under the editorship of JI. Prosser, the lane with English, t. 3, page 164, M., 1978; F v - del - Osipova S. I. Aging of neuromuscular system, Kiev, 1968, bibliogr.; Yumashev G. S. Traumatology and orthopedics, page 152, M., 1977; In e t h-1 e m J. Muscle pathology, Amsterdam — L., 1970: Carlson F., D. a. W i 1 k i e D. R. Muscle physiology, Englewood Cliffs, 1974; D u b o w i t z V. a. Brooke of M. of H. Muscle biopsy, L., 1973; D z i a k A. i i. Traumatologia sportowa, Warszawa, 1976; J o n e s J. G. a. B e with k C. H. Motor potentials and the timing of muscular activity, Electroenceph. clin. Neurophysiol., v. 38, p. 273, 1975; MairW.G. P. a. T o m e e F. M. S. Atlas of the ultrastructure of diseased human muscle, Edinburgh — L., 1972; Wilson P. D. a. Franks L. M. The effect of age on mitochondrial ultrastructure, Gerontologia (Basel), v. 21, p. 81, 1975.


I. I. Kagan; T. H. Kopyeva (stalemate. An.), R. S. Orlov (physical.), E. P. Podrushnyak (mister.), V. A. Sakharov (hir.), author of the list I. I. Kagan.

Яндекс.Метрика