MyologyChapter 3effect by means of the tendons, aponeuroses, andfascia. Skeletal muscles are also called voluntarySection 1Introduc-muscles, since their contraction is controlled by thetionconsciouness (Fig.I-3-1, 2) . Muscle tssue accountsfor approximately 40% of the body weights. As eachIn this chapter the skeletal muscles will be dis-skeletal muscle possesses a definite shape, structure,cussed. The skeletal muscles are the muscles attachedlocation and accessory apparatus, and is supplied byto the bone, fascia or skin. Motor ability provides or-abundant blood vessels, lymphatics and nerves, it canganisms with a means of reacting to the environment.be regarded as an organ.The contraction of skeletal muscles is a mechanicalFrontal bellyofoccipitofrontalisOrbicularis oculiocleidomastoidGreatersupraclaClavicleDeltoidPectoralis majorDeltoidBicepsbrachiiBiceps brachiiObliquus extemusabdominisCubital fossaBrachioradialisInguinal canalRectusabdominisTendonof palmaris longuSartoriusThenuadricepsfemorisHypothenarPatellaPatellaPatellar lig.PatellarligTibialis anteriorAnteriorborderof tibiaExtensordigitorumlongusFig. I-3-1 Surface anatomy and muscles of the body (anterior view). 82:扫描全能王创建
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MFChapter3Myology·83·OccipitalbellyofoccipitofrontalisSpineof scapulaTrapeziusDeltoidAcromioneresmajorTriceps brachiiTriceps brachiiOlecraLatissimus dorsiExtensorcarpiradialislongusIliaccreExtensordigitorumGluteus maximtGluteusmaximusHead of ulnaBicGluteal sulclliotibialtractSemitendinosusPopliteal fossaSemimembranosusI港可GastrocnemiusendocalcaneusLateral malleolusFig.I-3-2 Surface anatomy and muscles of thebody (posterior view)vary extremely in their shape. It may be long, short,broad or circular-band-like (sphincter).Some mus-I . Morphology of Skeletalcles have more than one belly or one origin.Some shape is related to the fibers and long axisMuscleof the muscles.The fibers are oblique to the long axisof the muscle.When muscle fbers resembling half aThe muscle fibers or cells are the smallest struc-feather and have a linear or narrow origin, they aretural unit of a muscle. The connective tissue thatcalled the unipennate muscle and when the fiberswraps the muscle fibers,bundle of muscle fibers andarise from a broad surface resembling a whole featherthe muscle is called the endomysium, perimysiumthey are called the bipennate muscles and when septaand epimysium, respectively. The fleshy part of aextending into the attachments of the muscles and di-muscle is often called the belly. At each end of theviding them into several featherlike portions they aremuscle, the connective tissue blends with the strongcalled the multipennate muscles (Fig.1-3-3).collagen bundles to form the tendon. The muscles可口扫描全能王创建
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·84PARTILOCOMOTORSYSTEMTendon of muscleBellyEInterBellmediateBtendonTUNOrbicularmuscleTendon Short muscleDigastric muscleFlate muscleLongmuscleTendonTriceps muscleBipennatemuscleBiceps muscleMultipennatemuscleUnipennatemuscleFig.I-3-3 The yarious shapes of muscleimal parts of a limb while movements are occurringin distal parts.Amuscle may act as a prime mover,I.Oriqin,Insertion and Ac-antagonist, synergist orfixatorunder different condi-tionof Skeletal Musclestions.Each skeletal muscle has at least two attachmentsII. Nomenclature of Musclesto some part of the skeleton, mucous membrane orskin.For purposes of description,most of musclesThe muscles have been named by their shape, lo-are commonly described as having an origin and ancation, action, attachments, direction, number of partsinsertion.The origin is usually a fixed attachment and so on. The trapezius and rhomboid muscle areof the muscles, while the insertion may be movable.However, some muscles may act in both directions innamed for their shapes. The levator scapulae is nameddifferent circumstances. Therfore, in most cases, it isfor its action in lifing the scapula. The gluteus maxi-best to use the terms proximal attachment and distalmus, gluteus medius and gluteus minimus are namedattachment, instead oforigin and insertion.because of theirlocation in the gluteal region and forControlled by nervous system, the skeletal mus-their contrast in size. The sternocleidomastoid musclecular cells (fbers) and tssues work together to movehas attachments to the sternum, the clavicle, and theparts of the body. During movements of the body,mastoid process of the temporal bone. The numberofthe main muscles are called prime movers or ago-heads of the origin is indicated by the terms, for ex-nists. They contract actively to produce the desiredample the quadriceps femoris.movement. The muscle that opposes the action of aprime mover is called antagonist. As a prime moverIV . Supplementary Struc-contracts, the antagonist progressively relaxes, so thetures of Musclesmovement is produced smoothly.The antagonistsmay protect the joint from injury. The muscles whichThey include the fascia, the synovial bursa, thecooperate in performing an action are called syner-gists. Other muscles, called fixators, steady the proxsynovial sheath oftendon and sesamoid bones.A2R扫描全能王创建口
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Chapter3Myology ·85.insulation and a store of energy for metabolic useFasciaSubcutaneous nerves,vessels,lymphatics and skin店muscles arefound in the superficial fascia.It is formed by the connective tissue. There are(2) Deep fasciasuperficial and deep groups of fascia in the body (Fig.1-3-4) .They are also composed of collagenous fibers,but dense and inelastic,and arranged to regular fiber(1)Superficial fasciamembrane. The deep fascia may form a strong sep-arate sheath surronding muscles or the vessels andIt is found immediately under the skin and cov-nerves. In the limbs they give off septa which separateers almost the entire body. It is a layer of variablethe functional groups of muscle by attaching alongthickness which contains fat. In the scalp, the palmthe longitudinal axis of a bone. These fascia sheetsof hand and the sole of foot, the superficial fascia isare called intermuscular septa. In certain situationsvery dense, and it is so thick that superficial fascia isthe deep fascia affords attachment for muscles. It iscapable of being subdivied into several laminae in thethickened at the wrist and ankle to form the retinacu-groin. It provides for increased mobility of skin, andlum that maintains its underlying tendon.the adipose component, which contributes to thermalSkinSuperficialfasciaSheath of fasciaDeepfasciaSheathfor vesselsand nerveHumeruMuscular septumFig.I-3-4 The fascia of the musclesurrounding a tendon, which is usually found in thehand and foot.It consists of twoparts.Theouterfi-Synovial bursabrous sheath is formed by thickened deep fascia thatrestricts the tendon to the surface ofabone.The innerThe synovial bursa is a sac containing synovialsynovial sheath is formed by double-layered synovialfluid. It is often found between a tendon and a bonemembrane. The outer parietal layer lines the inneror a ligament, or between two tendons. This is a spe-surface of the fibrous sheath and the inner visceralcialized structure that functions to reduce friction,layer surrounds the tendon. The two layers are con-allowing an effcient freedom of motion between con-tinuous at the bottom of the sheath, thus forming themesotendon to allow vessels and nerves to reach thetiguous connective tissue surfaces.tendon. The parietal and visceral layers of the syno-vial sheath is lubricated by a film of synovial fluid to.Tendinous sheathreduce friction while the tendon moving in the sheath.(Fig. I-3-5).The tendinous sheath is a connective tissue sheath扫描全能王创建
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Chapter3Myology.87.extends it, and rotates it medially.traction of this muscle pulls the arm posteriorly, orSemispinalis capitisStemocleidomastoidSplenius capitis-Levator seapulaeSupraspinatusTrapeziuRhomboidasisDeltoidInfraspinatusTeresminorTeres majorTriangle of ausculationSerratus anteriorSerratus posterior inferiorLatissimus dorsiSuperficial layer of thoraco lumbarfasciErrector spinaeObliquus extermus abdominisObliquusinternusabdominisSublumbar triangleGluteusmediusGluteus maximusFig.I-3-6 Themuscles of back3.Levator scapulae4.Rhomboid musclesThis narrow elongated muscle is situated at theThis muscle may be divided into rhomboide-dorsal and lateral part of the neck (Fig.I-3-6). It aris-us major and rhomboideus minor (Fig.I-3-6).Thees by tendinous slips from the transverse processesrhomboideus major arises tendinous fibers from theof the atlas and axis and from the posterior tuberclesspinous processes of the second to fifth thoracic ver-of the transverse processes of the third and fourthtebrae. The fibers course inferolaterally to be insertedcervical vertebrae. It descends deep to the sternoclei-by a narrow tendinous arch to medial border of thedomastoid muscle, along the floor of the posteriorscapula to the inferior angle of the scapula below.Thetriangle of the neck, and then under cover of the tra-rhomboideus minor arises from the inferior part of thepezius to be inserted into the vertebral border of theligamentum nuchae and from the spinous processesscapula, between the superior angle and the triangularof the seventh cervical and first thoracic vertebrae.smooth surface at the root of the spine. The muscleIts fibers course inferolaterally just superior to thecan elevate the superior angle of the scapula,tends torhomboideus major to be inserted into the base of thedraw the scapula medially, and rotates it so as to low-root of the spine edge of the scapula. They adduct theer the lateral angle. With the scapula fixed, the levatorscapula by pulling it medially toward the vertebralScapulae bends the neck laterally and rotates it slight-column and also support the scapula by elevating it.lytoward the same side.口R扫描全能王创建口
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.88·PART1LOCOMOTORSYSTEMI . Muscles of Thorax5.Erector spinae (sacrospinalis)They are divided into the thoracico-upper-limbProlongations in the thoracic and cervical regionsmuscles, including the pectoralismajor, thepectoralslay the groove on the side of the vertebral column.minor and the serratus anterior, and the thoracicoiThey are covered in the lumbar by the thoracolumbartrinsic muscles, including the external intercostalfascia. This large muscular and tendinous mass arisesmuscles and the internal intercostal muscles.from the anterior surface of a broad and thick tendon,which is attached to median sacral crest, to the spi-1.Pectoralis majornous processes of the lumbar and lower tow thoracicvertebrae and their supraspinal ligaments, and to thelateral crests of thesacrum.ThemuscularfibersformThe clavicular portion of the pectoralis majora large fleshy mass which, in the upper lumbar re-arisesfrom medial halfof the clavicle, the costostergion, splits into three columns: the lateral, called thenal portion from the anterior surface of the stermumiliocostalis; the intermediate, called the longissimus;and costal cartilages of the upper six ribs, and theand the medial, called the spinalis. They are insertedabdominal portion from theaponeurotic tendon of theseparately into ribs and vertebrae. From these bonesextermal abdominis oblique muscle.The insertion isit runs continuously upward to insert into the mas-on the crest of the greater tubercle of the humerus, thetoid process of the temporal bone. When acting onclavicular portion overriding the costosternal part Isone side,it bends the spinal column toward the samemain action is to flex, adduct, and medially rotate atside. When acting on both sides, it extends the spinal the shoulder joint, an act that brings the arm acrosscolumn(Fig.I-3-6).the chest (Fig.I-3-7) .DeltoidPectoralisminPectoralis majorPectoralis majorSerratus anteriorLatissimus dorsiFig.I-3-7 Muscles of thorax扫描全能王创建
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Chapter3Myology .89.MEIficial muscle in the intercostal spaces (Fig.I-3-8).Themajority of its fasciculi arises from the rib above andPectoralis minorinsert on the rib below. It reaches as far as the tuber-cles of the ribs posteriorly and to the costochondralThis muscle lies deep to the pectoralis major andjoint anteriorly, from this point on to the sternum.arises from the external surface of three ribs—usuallyThe muscle has disappeared gradually and a fibrousthe third, fourth and fifh, and converges superiorlysheet-the external intercostal membrane--is all thatand laterally to insert on the coracoid process of theremains. Its main action is to elevate the ribs in inspi-scapula. The pectoralis minor draws the scapula for-ration.ward and downward and also rotates the scapula so asto lower the lateral angle during adduction of the armInternal intercostal muscles(Fig.I-3-7) .The Internal Intercostal Muscles occupy the same3.Serratus anteriorarea as just mentioned for the external intercostalmuscle but at a deeper level. It arises from the rib be-The muscle is a thin muscular sheet that is situatlow and course superiorly to insert on the rib above,ed between the ribs and the scapula, spreading overand ends posteriorly toform theinternal intercostalthe lateral part of the chest. It arises by fleshy digi-membrane. Its main action is problematical, but mosttations from the outer surfaces and superior bordersfeel that the interchondral portion aids in inspirationof the eight or nine ribs, and from the aponeurosesand the interosseous portion involved with expiration.covering the intervening intercostal muscles (Fig.I-3-8).It is inserted to the entire anterior surface of medialII. Diaphragmborder of the scapula.This muscle draws the medialborder of the scapula, anteriorly close to the thoracicIt is a dome-shaped musclofibrous septum thatwall, thereby preventing the bone from protrudingseparates the thoracic from the abdominal cavity.Itsbackward in reaching and pushing movements. Itsconvex upper surface forms the floor of the thorax,lower fiber helps to rotate glenoid cavity of scapulaand its concave inferior surface forms the roof of theupward when the arm is raised above the head. Byabdomen.Its peripheral part consists of muscularfixing the scapula, it helps the inspiration.fibers that take origin from the circumference of thethoracic outlet and converge to be inserted into a cen-tral tendon of diaphragm (Fig.I-3-9, 10) .Serratus anteiorThe muscular portion is divided into three partsaccording to the origin of its fibers.The sternal partarises from the posterior aspect of the.xiphoid pro-Scapulacess. The costal part arises from the internal surfaceIntercostales extermiof the lower six ribs and costal cartilages.The lumbarIntercostales interni(vertebral) part arises by two crura from the upper 2-3lumbar vertebrae and the arcuate ligaments on the sur-face of the psoas major and the quadratus lumborum.Between the three original parts of the diaphragm, i. e.between the origins of the sternal part and the costalpart and between the costal part and the lumbar part,there are usually triangular spaces without muscularfibers, called the lumbocostal triangle and the ster-Fig.1-3-8 Serratus anteriornocostal triangle respectively.These triangles are thecommon site for a diaphramatic hernia and an even-tration of the diaphragm.External intercostal musclesThe central tendon of the diaphragm is a thin butstrong aponeurosis situated near the center of theThe external intercostal muscle is the most super-口口扫描全能王创建
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90·PARTI LOCOMOTORSYSTEMdian plane. It is the highest opening in the diaphragm.muscle. There are three openings in the diaphragm.The inferior vena cava and some branches of the rightThe aortic hiatus lies in front of the 12th thoracicphrenic nerve and lymph vessels pass through the fo.vertebra and is formed by the two crura of diaphragmramen.and the vertebral body of the 12th thoracic vertebra.The diaphragm is the principal muscle of inspi-It transmits the abdominal aorta, the thoracic ductration. When it contracts, the muscle descends andand often the azygos vein. The esophageal hiatus isdraws the central tendon downward with it, so in.located in the right crus of the diaphragm at the levelcreases the vertical diameter of the thoracic cavity,of the 10th thoracic vertebra, 2-3cm to the left andresulting in air being taken into the lungs. Diaphrag.upward of the aortic hiatus. It transmits the esopha-matic movements are also important in the bloodgus, the branches of the left gastric artery and vein,circulation because the increased abdominal pressureand the anterior and posterior vagal trunks. The venaand decreased thoracic pressure accompanying con-caval foramen is located in the central tendon of thetraction of the diaphragm help to return blood to thediaphragm at the level of thedisc between the 8th and9th thoracic vertebrae, 2-3cm to the right of the me-heart.Vena caval foramenCentraltendonEsophageal hiatusCostal part of diaphragLumbarpartofdiaphragmAortichiatusMedial hiatusPsoasminorLateral aceuate ligSAQuadratuslumboruCrura of diaphragmIntertransversarii810PsoasmajorIliacusIliacusInquinal lig.PiriformisPsoas majorFig. I-3-9 The diaphragm and the muscles of posterior abdominal wall扫描全能王创建
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Chapter 3Myology · 91 .intermediate of the three flat abdominal muscles (Fig.I-3-11). It arises from the thoracolumbar fascia (Fig.InferionEsophagusenacavsI-3-12), anterior two-thirds of iliac crest, and lateralernumhalf of inguinal ligament. The fibers run superoanteri-orly,and also become aponeurotic and the aponeuro-sis splitstoform sheathfortherectus abdominismus-cle. The muscle inserts into inferiorborders of 1Othto 12th ribs, linea alba,and the pubis via the conjointtendon.Aorta(3) Transversus abdominisThis is the innermost of the three fat abdominalFig. I-3-10 The opening in the diaphragmmuscles (Fig.1-3-1l,12).It arises from the intermnalsurfacesof 7thto12th costal cartilages,thoracolum-bar fascia, iliac crest, and lateral third of inguinalIV .Muscles of Abdomenligament and inserts into linea alba withaponeurosisand Fasciaeof intemal oblique,pubic crest, and pecten pubis viaconjoint tendon.Its fibers run more or less horizontal-ly and end in an aponeurosis which contributes to theMuscles of abdomen include the anterior groupformation of the sheath of rectus abdominisand posterior group.There are four important pairedThe three flat abdominal muscles and their exten-muscles in the anterior abdominal wall:three flatsive aponeurosis form a strong expandable support tomuscles, external oblique muscle of abdomen,in-theanterolateral abdominal wall,whichprotectstheternal oblique muscle of abdomen, and transversusabdominal viscrea.They can increase theintraabdom-abdominis muscle and one rectus abdominis muscle.inal pressure for defecation, micturition and parturi-The flat muscles cross each other that strengthen thetion.abdominal wall and afford considerable protection tothe abdominal viscera.(4) Rectus abdominisL. Anteriolateral group of abdominalThis is a long, broad, strap muscle and the princi-musclespal vertical one in the anterior abdominal wall (Fig.I-3-11).It arises from pubic symphysis and pubiccrest, and inserts into xiphoid process and 5th to(1) External oblique muscle of abdo-7th costal cartilages.The two muscles are separatedmenby the linea alba and enclosed in the rectus sheathformed by the aponeurosis of three flat abdominalThis is the largest and the most superficial musclemuscles. The anterior layer of the rectus sheath isof abdomen (Fig.I-3-11). It is located in the antero-firmly attached to the rectus muscle at three or morelateral part of the abdominal wall. The muscle arisestendinous intersections.The muscle forms the ante-from the external surface of 5th to 12th ribs, and itsrior abdominal wall and prevents tilting of the pelvisfibers run inferoanteriorly and medially in the sameby the weight ofthe lower limbs.direction as do the extended digits. As the fibers passActions: The anterolateral group of abdominalmedially, they become aponeurotic that ends mediallymuscles support and protect the viscera. The abdomi-in the linea alba. The muscles insert into linea alba,nal muscles compress the abdomen to maintain and topubic tubercle and anterior half ofiliac crest.increase the intraabominal pressure.The muscles aretherefore important in respiration, defecation, mictu-(2) Internal oblique muscle of abdo-rition,parturition, cough and vomiting.Acting sepa-rately, they can move the vertebral column in flexion,menrotation and maintain posture.The internal oblique muscle of abdomen is the扫描全能王创建D5
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·92·PARTILOCOMOTORSYSTEMfat. At lower part of abdominal wall, t may be divi.edinowolayers,afatty supeciallayer (Campr(5)Fasciaeofabdomen?fascia) and a membranous deep layer (Scarpa's fas.cia) containing elastic fibers.1) Superficial fasciaeOver the greater part of2)DepfasciaItis several layers covering septhe anterolateral abdominal wall.The superficial fas-arately the surface of the muscles.cia consists of layers containing a variable amount ofIntercastalesintemiIntercostalesextermiAnterior layer of sheathofrectus abdominisCostal cartilageRectus abdominisLinea albaTendinous intersectionTransversus abdominisSemilunar linePosterior layer ofsheath of rectus abdominisObliquusextermusabdominisAponeurosis of obliquusextemus abdominisObliquus intemus abdominisArcuate lineTransverse fasciaInquinal ligSpermaticcordFig. I-3-11The muscles of anterolateral abdominal wallPsoas majorTransverse fasciaAETransversus abdominisPDeep layerofObliquus internus abdominisEAthoracolumbarObliquus extemus abdominis恩NfasciaSerratus posterior inferiorLatissimus dorsiQuadrat lumborumMiddle layer of thoracolubar fasciSuperficial layer of thoracolumbarfeErrectorspinaoFig.I-3-12 ThoracolumbarfasciaD扫描全能王创建
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