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Chapter 11The Muscular SystemAppendicular Musculature

2015 Pearson Education, Inc.Introduction Appendicular Musculature Appendicular muscles are responsible for:Stabilizing the pectoral and pelvic girdlesMoving the upper and lower limbs Absorbing shocks and jolts as you walk, run, or jumpAiding in strengthening the joint area

2015 Pearson Education, Inc.IntroductionTwo Major Groups of Appendicular MusclesThe muscles of the pectoral girdle and upper limbsThe muscles of the pelvic girdle and lower limbs

2015 Pearson Education, Inc.Factors Affecting Appendicular Muscle FunctionAction Lines of the MuscleFlexion and extension at the shoulder jointAdduction and abduction at the shoulder jointMedial and lateral rotation at the shoulder jointAction lines at the hip jointSpurt and Shunt Muscles

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Figure 11.2 Factors Affecting Appendicular Muscle Function (7 of 7)

Action Lines at the Hip JointThe hip joint, like the shoulder joint, is a multiaxial synovial joint that permits flexion/extension,adduction/abduction, and medial/lateral rotation. Determining the action of a muscle on the hipis identical to the process utilized for the shoulder, in that the action of a muscle on the hip isdetermined by the structure of the joint and the location of the insertion of the muscle on thefemur (not shown) relative to the permitted axes of motion at the joint.AdductormagnusIliopsoas: flexionGluteus medius andminimus: abductionObturator externus: lateral rotationTensor fasciae latae: medial rotationAdductor longus: adductionHamstring group: extension andlateral rotationAction lines of the adductor magnusGluteal GroupExtensionExtension andabductionFlexion,abduction, andmedial rotationLateral Rotator GroupAdductor GroupExtension andlateral rotationAdductionANTERIORPOSTERIORGluteusmaximusGluteus mediusGluteus minimusTensorfasciaelataeAcetabulumHamstringgroupAdductorlongusAdductor magnus

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Figure 11.2 Factors Affecting Appendicular Muscle Function (6 of 7)

Spurt and Shunt MusclesDetermining the location of the insertion of a musclerelative to the axis of the joint will provide additionaldetails about the functions of the muscle at that joint.The primary action of a muscle whose insertion isclose to the joint will be the production of movementat that joint. Such a muscle is termed a spurtmuscle, and spurt muscles are prime movers.However, a muscle whose insertion is considerablyfarther from the joint will generally help to stabilizethat joint in addition to producing motion at thatjoint. This type of muscle, a synergist, is termeda shunt muscle.Biceps brachii:movementand torque(spurt muscle)Triceps brachii:movementand torque(spurt muscle)Brachioradialis:stability andmovement(shunt muscle)ExtensorsFlexorsElbow joint(monaxial)

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles associated with the pectoral girdle and upper limbs can be divided into four groupsMuscles that position the pectoral girdleMuscles that move the armMuscles that move the forearm and handMuscles that move the hand and fingers

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Position the Pectoral GirdleThese muscles also coordinate with the muscles that move the armLevator scapulaeElevates the scapulaPectoralis minorProtracts the shoulder

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Figure 11.6 Muscles That Position the Pectoral Girdle, Part II

Muscles ThatPosition thePectoral GirdleLevator scapulaeTrapeziusSubclaviusPectoralis minorSerratus anteriorInternalintercostalsExternalintercostalsT12Short headLong headBicepsbrachiiSerratus anteriorCoracobrachialisPectoralis minor (cut)Serratusanterior(insertion)Serratusanterior(origin)PectoralisminorTrapeziusPectoralismajorSubclaviusPectoralismajor (cutand reflected)OriginInsertion

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Position the Pectoral GirdleThese muscles also coordinate with the muscles that move the armRhomboid majorAdducts the scapulaRhomboid minorAdducts the scapula

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Figure 11.5 Muscles That Position the Pectoral Girdle, Part I

Superficial DissectionDeep DissectionMuscles ThatPosition thePectoral GirdleMuscles ThatPosition thePectoral GirdleLevator scapulaeRhomboid minorRhomboid majorSerratus anteriorTriceps brachiiScapulaC1C7TrapeziusDeltoidInfraspinatusTeres minorTeres majorSerratus anteriorT12

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Position the Pectoral GirdleThese muscles also coordinate with the muscles that move the armSerratus anteriorProtracts the scapulaSubclaviusProtracts the scapulaTrapeziusRotate scapula and extend the neck

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Figure 11.6 Muscles That Position the Pectoral Girdle, Part II

Muscles ThatPosition thePectoral GirdleLevator scapulaeTrapeziusSubclaviusPectoralis minorSerratus anteriorInternalintercostalsExternalintercostalsT12Short headLong headBicepsbrachiiSerratus anteriorCoracobrachialisPectoralis minor (cut)Serratusanterior(insertion)Serratusanterior(origin)PectoralisminorTrapeziusPectoralismajorSubclaviusPectoralismajor (cutand reflected)OriginInsertion

2015 Pearson Education, Inc.Muscles of the Pectoral Girdleand Upper Limbs

2015 Pearson Education, Inc.A&P Flix: Muscles of the Pectoral Girdle (a)

2015 Pearson Education, Inc.A&P Flix: Muscles of the Pectoral Girdle (b)

2015 Pearson Education, Inc.A&P Flix: Muscles of the Pectoral Girdle (c)

2015 Pearson Education, Inc.A&P Flix: Movement of the Pectoral Girdle

2015 Pearson Education, Inc.A&P Flix: Trapezius Muscle

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Move the ArmAnterior viewDeltoidAbducts the armPectoralis majorAdducts and medially rotates the arm

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Figure 11.7a Muscles That Move the Arm

Superficial DissectionDeep DissectionMuscles ThatMove the ArmMuscles ThatMove the ArmRibs (cut)ClavicleDeltoidPectoralismajorSternumSubscapularisCoracobrachialisTeres majorBiceps brachii,short headBiceps brachii,long headAnterior view.T12a

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Move the ArmAnterior viewCoracobrachialisAdduction at the shoulderBiceps brachii (short head and long head)Flexes the lower armTeres majorExtension and medial rotation at shoulderSubscapularisMedial rotation at shoulder

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Figure 11.7a Muscles That Move the Arm

Superficial DissectionDeep DissectionMuscles ThatMove the ArmMuscles ThatMove the ArmRibs (cut)ClavicleDeltoidPectoralismajorSternumSubscapularisCoracobrachialisTeres majorBiceps brachii,short headBiceps brachii,long headAnterior view.T12a

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Move the ArmPosterior viewSupraspinatusAbduction at the shoulderDeltoidAbduction at the shoulderLatissimus dorsiAdduction and medial rotation at the shoulder

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Figure 11.7b Muscles That Move the Arm

Superficial DissectionDeep DissectionMuscles ThatMove the ArmMuscles ThatMove the ArmbPosterior view.Triceps brachii,lateral headTriceps brachii,long headTeres majorTeres minorInfraspinatusSupraspinatusVertebra T1SupraspinatusDeltoidLatissimusdorsiThoraco-lumbarfascia

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsMuscles That Move the ArmPosterior viewSupraspinatusAbduction at the shoulderInfraspinatusLateral rotation at the shoulderTeres majorExtension and medial rotation at the shoulderTeres minorAdduction and lateral rotation at the shoulderTriceps brachiiExtension of the lower arm

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Figure 11.7b Muscles That Move the Arm

Superficial DissectionDeep DissectionMuscles ThatMove the ArmMuscles ThatMove the ArmbPosterior view.Triceps brachii,lateral headTriceps brachii,long headTeres majorTeres minorInfraspinatusSupraspinatusVertebra T1SupraspinatusDeltoidLatissimusdorsiThoraco-lumbarfascia

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper Limbs Action Line of MusclesWhen a muscle contracts, it develops tensionThe direction the muscle moves upon developing tension is known as the action line

2015 Pearson Education, Inc.Muscles of the Pectoral Girdle and Upper LimbsAction Line of Muscles (continued)Action lines that cross:The anterior aspect of a joint are flexorsThe posterior aspect of a joint are extensorsThe medial aspect of a joint are adductors or sometimes called medial rotatorsThe lateral aspect of a joint are abductors or sometimes called lateral rotators

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Figure 11.2 Factors Affecting Appendicular Muscle Function (5 of 7)

Action Lines at the Shoulder JointHere is a superficial lateral view showing the actionlines of the deltoid, biceps brachii, and tricepsbrachii muscles. As you have seen, analyzing howthose action lines cross the shoulder joint enablesone to determine the actions of these muscles onthe humerus.AcromionClavicleClavicular deltoid:flexion andmedial rotationEntire deltoid:abduction atthe shoulderScapular deltoid:extension and lateral rotationTriceps brachii:extension andadductionBiceps brachii:flexionHumerusPOSTERIORANTERIOR