muscular system. introduction without the muscular system we would be unable to sit, stand, walk,...

MUSCULAR MUSCULAR SYSTEMSYSTEM

IntroductionIntroduction

Without the muscular system Without the muscular system we would be unable to sit, we would be unable to sit, stand, walk, speak, or grasp stand, walk, speak, or grasp objects. Blood would not objects. Blood would not circulate, because there would circulate, because there would be no heartbeat to propel it be no heartbeat to propel it through the vessels. The lungs through the vessels. The lungs could not rhythmically empty could not rhythmically empty and fill, nor could food move and fill, nor could food move through the digestive tract.through the digestive tract.

Structure and FunctionStructure and Function

The human body has The human body has more than 600 musclesmore than 600 muscles


Muscle tissue is specialized for Muscle tissue is specialized for contraction. The contraction contraction. The contraction mechanism is the same in each of mechanism is the same in each of the types of muscle tissue, but the the types of muscle tissue, but the organization of the fibers and organization of the fibers and filaments differ in each.filaments differ in each.

Muscles may be directly or Muscles may be directly or indirectly (via tendons) attached indirectly (via tendons) attached to bones. Muscles are also found to bones. Muscles are also found in and around body organs and in and around body organs and structures.structures.


MovementMovement Posture and Body PositionPosture and Body Position Support Soft TissueSupport Soft Tissue Guard Entrances and ExitsGuard Entrances and Exits Involuntary Bodily Involuntary Bodily

ProcessesProcesses ThermogenesisThermogenesis


Movement – muscle contractions Movement – muscle contractions pull on tendons and move the pull on tendons and move the bones of the skeleton.bones of the skeleton.

Posture and Body Position – Posture and Body Position – Without constant muscle tension, Without constant muscle tension, you could not sit upright without you could not sit upright without collapsing or stand without collapsing or stand without toppling over.toppling over.

Support Soft Tissue – The Support Soft Tissue – The abdominal wall and the floor of abdominal wall and the floor of the pelvic cavity consist of layers the pelvic cavity consist of layers of muscle that support the weight of muscle that support the weight of visceral organs and shield of visceral organs and shield internal tissues from injury.internal tissues from injury.


Guard Entrances and Exits – Guard Entrances and Exits – Skeletal muscles guard openings to Skeletal muscles guard openings to the digestive and urinary tracts, the digestive and urinary tracts, and provide voluntary control over and provide voluntary control over swallowing , defecation, and swallowing , defecation, and urination.urination.

Involuntary Bodily Processes – For Involuntary Bodily Processes – For example, contraction of the heart is example, contraction of the heart is an involuntary bodily process- the an involuntary bodily process- the nervous system does not provide nervous system does not provide voluntary control over the cardiac voluntary control over the cardiac muscle cells.muscle cells.


ThermogenesisThermogenesis – Muscle – Muscle contractions require contractions require energy, and whenever energy, and whenever energy is used in the body, energy is used in the body, some of its converted to some of its converted to heat. The heat lost by the heat. The heat lost by the working muscles keeps the working muscles keeps the body temperature in the body temperature in the normal range.normal range.

Characteristics of MusclesCharacteristics of Muscles

ExcitabilityExcitability ContractibilityContractibility ExtensibilityExtensibility ElasticityElasticity

ExcitabilityExcitability

Irritability, the ability to Irritability, the ability to respond to a stimulus such as respond to a stimulus such as a nerve impulsea nerve impulse

ContractibilityContractibility

Muscle fibers that are Muscle fibers that are stimulated by nerves stimulated by nerves contractcontract, , or become short and thick, or become short and thick, which causes movementwhich causes movement

ExtensibilityExtensibility

The ability to be stretchedThe ability to be stretched

ElasticityElasticity

Allows the Allows the muscle to muscle to return to its return to its original original shape after it shape after it has has contracted or contracted or stretchedstretched

Skeletal MuscleSkeletal Muscle Makes up more than 40% of Makes up more than 40% of

a person’s body weighta person’s body weight Looks striated, or banded, Looks striated, or banded,

under the microscopeunder the microscope Skeletal muscles have three Skeletal muscles have three

parts parts Origin is one end of the Origin is one end of the

muscle, attached to the less muscle, attached to the less movable part of the bone movable part of the bone

Insertion is the other end of Insertion is the other end of the muscle, attached to the the muscle, attached to the more movable part of the bone more movable part of the bone

The action, or body, is the The action, or body, is the thickthick middle part of the musclemiddle part of the muscle

Skeletal Muscles (cont.)Skeletal Muscles (cont.)

Skeletal muscles Skeletal muscles attach to bones in attach to bones in different waysdifferent ways Tendons-strong Tendons-strong

tough, fibrous tough, fibrous connective- tissue connective- tissue cordscords

Fascia- a tough Fascia- a tough sheetlike membrane sheetlike membrane that covers and that covers and protects the tissueprotects the tissue

Visceral Visceral MuscleMuscle

Lines various hollow organsLines various hollow organs Makes up the walls of blood Makes up the walls of blood

vesselsvessels Found in the tubes of the Found in the tubes of the

digestive systemdigestive system Smooth and has no striationsSmooth and has no striations Controlled by the autonomic Controlled by the autonomic

nervous system nervous system

Cardiac MuscleCardiac Muscle

Found only in the Found only in the heartheart

Striated muscle Striated muscle Under involuntary Under involuntary

controlcontrol Has specialized Has specialized

cells that provide cells that provide a stimulus for a stimulus for contractioncontraction

Naming Skeletal MusclesNaming Skeletal Muscles

The names assigned to The names assigned to muscles provide clues to their muscles provide clues to their identification.identification. Orientation of muscle fibersOrientation of muscle fibers Regional locationRegional location Structural featuresStructural features Shape, length, size, superficial Shape, length, size, superficial

or deepor deep Origin and insertionOrigin and insertion Primary functionPrimary function


Some muscles, often with Greek Some muscles, often with Greek or Latin roots, refer to the or Latin roots, refer to the orientation of muscle fibersorientation of muscle fibers. For . For example “rectus” means straight example “rectus” means straight and rectus muscle fibers generally and rectus muscle fibers generally run along the long axis of the run along the long axis of the body.body.

In a few cases, a muscle is such a In a few cases, a muscle is such a prominent feature that the prominent feature that the regionalregional name alone can identify name alone can identify it, such asit, such as the temporalis muscle the temporalis muscle of the head.of the head.


Other muscles are named after Other muscles are named after structural featuresstructural features. For example, a . For example, a biceps muscle has two tendons of biceps muscle has two tendons of origin, whereas the triceps has origin, whereas the triceps has three.three.

Muscle names can reflect shape, Muscle names can reflect shape, lengthlength, , sizesize, and whether a muscle , and whether a muscle is is visible at the surface or lying visible at the surface or lying beneathbeneath.. Maximus means large.Maximus means large. Minimus means small.Minimus means small. Longus means long.Longus means long. Brevis means short.Brevis means short.


The first part of some names The first part of some names indicate the indicate the originorigin and the second and the second part the part the insertioninsertion, such as the , such as the brachioradialis.brachioradialis.

Other names may indicate theOther names may indicate the primary functionprimary function of the muscle, of the muscle, such as the such as the flexor digitorumflexor digitorum..

Some muscles are named Some muscles are named according to their shape, such as according to their shape, such as the deltoid (triangular), the the deltoid (triangular), the trapezius (trapezoid), or the trapezius (trapezoid), or the rhomboids (diamond shape).rhomboids (diamond shape).

Temporomandibular JointTemporomandibular Joint

The principle muscles The principle muscles opening the mouth are the opening the mouth are the external pterygoidsexternal pterygoids

Closing the mouth are the Closing the mouth are the massetermasseter, the , the temporalistemporalis, , and the and the internal pterygoidsinternal pterygoids..

The The Scapulohumeral GroupScapulohumeral Group

This group extends from the This group extends from the scapula to the humerus and scapula to the humerus and includes the muscles includes the muscles inserting directly on the inserting directly on the humerushumerus

Rotates the shoulder laterally, Rotates the shoulder laterally, and depresses and rotates the and depresses and rotates the head of the humerus.head of the humerus.

The Scapulohumeral GroupThe Scapulohumeral Group

SupraspinatusSupraspinatus – runs above – runs above the glenohumeral joint; the glenohumeral joint; inserts on to the greater inserts on to the greater tubercletubercle

InfraspinatusInfraspinatus and and Teres minorTeres minor – cross the glenohumeral – cross the glenohumeral joint posteriorly; insert above joint posteriorly; insert above the greater tuberclethe greater tubercle

The Scapulohumeral GroupThe Scapulohumeral Group

SubscapularisSubscapularis – originates on – originates on the anterior surface of the the anterior surface of the scapula and crosses the joint scapula and crosses the joint anteriorly; iniserts on the anteriorly; iniserts on the lesser tubercle.lesser tubercle.

The The Axioscapular GroupAxioscapular Group

This group attaches the trunk This group attaches the trunk to the scapula and includes to the scapula and includes the trapezius, rhomboids, the trapezius, rhomboids, serratus anterior and levator serratus anterior and levator scapulae. These muscles scapulae. These muscles rotate the scapula.rotate the scapula.

The The Axiohumeral GroupAxiohumeral Group

This group attaches the trunk This group attaches the trunk to the humerus and the to the humerus and the pectoralis major and minor pectoralis major and minor and the latissimus dorsi. The and the latissimus dorsi. The muscle produce internal muscle produce internal rotation of the shoulder.rotation of the shoulder.

The ElbowThe Elbow

The muscles traversing the The muscles traversing the elbow include the biceps and elbow include the biceps and brachioradialisbrachioradialis (flexion), the (flexion), the triceps (extension), the triceps (extension), the pronator terespronator teres (pronation), (pronation), and the and the supinatorsupinator (supination).(supination).

The Wrist and HandsThe Wrist and Hands

Wrist flexion arises from the Wrist flexion arises from the two carpal muscles, located two carpal muscles, located on the radial and ulnar on the radial and ulnar surfaces.surfaces.

Two radial and one ulnar Two radial and one ulnar muscle provide wrist muscle provide wrist extension.extension.

Supination and pronation Supination and pronation result from muscle result from muscle contraction of the forearm.contraction of the forearm.


The thumb is powered by The thumb is powered by three muscles that form the three muscles that form the thenar eminencethenar eminence and provide and provide flexion, abduction, and flexion, abduction, and oppositionopposition

The muscles of extension are The muscles of extension are at the base of the thumb at the base of the thumb along the radial margin along the radial margin


Movement in the digits depends Movement in the digits depends on the action of the flexor and on the action of the flexor and extensor tendons of muscles in extensor tendons of muscles in the forearm and wrist.the forearm and wrist.

The instrinsic muscles of the hand The instrinsic muscles of the hand attaching to the metacarpal bones attaching to the metacarpal bones are involved in flexion are involved in flexion ((lumbricalslumbricals), abduction (), abduction (dorsal dorsal interosseiinterossei), and adduction (), and adduction (palmar palmar interosseiinterossei) of the fingers) of the fingers


Holding the tendons and Holding the tendons and tendon sheath in place is a tendon sheath in place is a transverse ligament, the transverse ligament, the flexor retinaculumflexor retinaculum

The SpineThe Spine

The trapezius and latissimus dorsi The trapezius and latissimus dorsi form the outer layer of muscles form the outer layer of muscles attaching to each side of the attaching to each side of the spine.spine.

They overlie two deeper muscle They overlie two deeper muscle layers – a layer attaching the layers – a layer attaching the head, neck, and spinous head, neck, and spinous processes (processes (splenius capitissplenius capitis, , splenius cervicissplenius cervicis, and , and sacrospinalissacrospinalis) and a smaller layer ) and a smaller layer of instrinsic muscles between of instrinsic muscles between vertebrae.vertebrae.

The SpineThe Spine

Muscles attaching to the Muscles attaching to the anterior surface of the anterior surface of the vertebrae, including the vertebrae, including the psoas psoas musclesmuscles and the muscles of and the muscles of the abdominal wall, assist the abdominal wall, assist with flexion.with flexion.

The HipThe Hip

Four powerful muscle groups Four powerful muscle groups move the hip:move the hip:

Flexor groupFlexor group Extensor groupExtensor group Adductor groupAdductor group Abductor groupAbductor group

Flexor GroupFlexor Group

This group lies anteriorly and This group lies anteriorly and flexes the thighflexes the thigh

The primary hip flexor is the The primary hip flexor is the iliopsoasiliopsoas, extending from , extending from above the iliac crest to the above the iliac crest to the lesser lesser trochantertrochanter

The Extensor GroupThe Extensor Group

Lies posteriorly and extend to Lies posteriorly and extend to the thighthe thigh

The gluteus maximus is the The gluteus maximus is the primary extensor of the hipprimary extensor of the hip

It forms a band crossing from It forms a band crossing from its origin along the medial its origin along the medial pelvis to its insertion below pelvis to its insertion below the trochanterthe trochanter

The Adductor GroupThe Adductor Group

Is medial and swings the Is medial and swings the thigh toward the bodythigh toward the body

The muscles in this group The muscles in this group arise from the arise from the rami of the rami of the pubispubis and ischium and insert and ischium and insert on the posteromedial aspect on the posteromedial aspect of the femur.of the femur.

The Abductor GroupThe Abductor Group

Lateral, extending from the Lateral, extending from the iliac crest to the head of the iliac crest to the head of the femur, and moves the thigh femur, and moves the thigh away from the bodyaway from the body

This group includes the This group includes the gluteus medius and minusgluteus medius and minus

These muscles help stabilize These muscles help stabilize the pelvis during the stance the pelvis during the stance phase of gaitphase of gait

The KneeThe Knee

Powerful muscles move and Powerful muscles move and support the knee.support the knee.

The quadriceps femoris The quadriceps femoris extends the leg, covering the extends the leg, covering the anterior, medial, and later anterior, medial, and later aspects of the thighaspects of the thigh

The hamstring muscles lie on The hamstring muscles lie on the posterior aspect of the the posterior aspect of the thigh and flex the knee.thigh and flex the knee.

The KneeThe Knee

The The meninscimeninsci and two and two important pairs of ligaments, important pairs of ligaments, the collaterals and the the collaterals and the cruciatescruciates, are crucial to , are crucial to stability of the kneestability of the knee

The MenensciThe Menensci

The medial and lateral The medial and lateral menisci cushion the action of menisci cushion the action of the femur on the tibiathe femur on the tibia

These crescent shaped These crescent shaped fibrocartilaginous discs add a fibrocartilaginous discs add a cup like surface to the cup like surface to the otherwise flat tibial plateauotherwise flat tibial plateau

Collateral LigamentsCollateral Ligaments

The The medial collateral ligamentmedial collateral ligament (MCL), not easily palpable, is (MCL), not easily palpable, is a broad, flat ligament a broad, flat ligament connecting the connecting the medial medial fermoral epiccondylefermoral epiccondyle to the to the medial condyle of the tibiamedial condyle of the tibia

The medial portion of the MCL The medial portion of the MCL also attaches to the medial also attaches to the medial meniscusmeniscus

Collateral LigamentsCollateral Ligaments

The The lateral collateral ligamentlateral collateral ligament (LCL) connects the (LCL) connects the lateral lateral femoral epicondylefemoral epicondyle and the and the head of the fibula. head of the fibula.

The MCL and LCL provide The MCL and LCL provide medial and lateral stability to medial and lateral stability to the knee jointthe knee joint

Cruciate LigamentsCruciate Ligaments

The The anterior cruciate ligamentanterior cruciate ligament (ACL) crosses obliquely from (ACL) crosses obliquely from the anterior medial tibia to the the anterior medial tibia to the lateral femoral condyle, lateral femoral condyle, preventing the tibia from preventing the tibia from sliding forward on the femursliding forward on the femur

Cruciate LiagmentsCruciate Liagments

The The posterior cruciate ligamentposterior cruciate ligament (PCL) crosses from the posterior (PCL) crosses from the posterior tibia and lateral meniscus to the tibia and lateral meniscus to the medial femoral condylemedial femoral condyle, , preventing the tibia from slipping preventing the tibia from slipping backward on the femurbackward on the femur

Because these ligaments lie within Because these ligaments lie within the knee joint, they are not the knee joint, they are not palpablepalpable

The Ankle and FootThe Ankle and Foot

Movement at the ankle joint is Movement at the ankle joint is limited to dorsiflexion and limited to dorsiflexion and plantar flexionplantar flexion

Plantar flexion is powered by Plantar flexion is powered by the gastrocnemius, the the gastrocnemius, the posterior tibial muscle, and posterior tibial muscle, and the toe flexorsthe toe flexors

Their tendons run behind the Their tendons run behind the malleolimalleoli


The dorsiflexors include the The dorsiflexors include the anterior tibia muscle and the anterior tibia muscle and the toe extensorstoe extensors

They lie prominently on the They lie prominently on the anterior surface, or dorsum, anterior surface, or dorsum, of the ankle, anterior to the of the ankle, anterior to the malleolimalleoli


Ligaments extend from each Ligaments extend from each malleolus onto the footmalleolus onto the foot

Medially, the triangular shaped Medially, the triangular shaped deltoid ligament fans out from the deltoid ligament fans out from the inferior surface of the medial inferior surface of the medial malleolus to the malleolus to the talustalus and and proximal tarsal bones, protecting proximal tarsal bones, protecting against stress from eversion against stress from eversion (ankle bows inward)(ankle bows inward)


Laterally, the three ligaments are Laterally, the three ligaments are less substantial, with higher risk less substantial, with higher risk for injury:for injury:

The The anterior talofibular ligamentanterior talofibular ligament – – most at risk for injury from most at risk for injury from inversion (ankle bows outward) inversion (ankle bows outward) injuries;injuries;

The The calcaneofibular ligamentcalcaneofibular ligament; and ; and the the posterior talofibular ligamentposterior talofibular ligament


The strong Achilles tendon The strong Achilles tendon attaches the gastronemius attaches the gastronemius and and soleussoleus muscles to the muscles to the posterior calcaneusposterior calcaneus

The The plantar fasciaplantar fascia inserts on inserts on the the medial tuberclemedial tubercle of the of the calcaneuscalcaneus

Additional Muscle GroupsAdditional Muscle Groups

SternocleidomastoidSternocleidomastoid

Location: Location: Side of neckSide of neck

Function: Function: Turns and Turns and flexes headflexes head

TrapeziusTrapezius

Location: Location: Upper back Upper back and neckand neck

Function: Function: Extends Extends head, moves head, moves shouldershoulder

DeltoidDeltoid

Location: Location: ShoulderShoulder

Function: Function: Abducts Abducts arm, arm, injection siteinjection site

Biceps brachiiBiceps brachii

Location: Location: Upper armUpper arm

Function: Function: Flexes lower Flexes lower arm and arm and supinates supinates handhand

Triceps brachiiTriceps brachii

Location: Location: Upper armUpper arm

Function: Function: Extends and Extends and adducts lower adducts lower armarm

Pectoralis majorPectoralis major

Location: Location: Upper chestUpper chest

Function: Function: Adducts and Adducts and flexes upper flexes upper armarm

IntercostalsIntercostals

Location: Location: Between ribsBetween ribs

Function: Function: Moves ribs Moves ribs for breathingfor breathing

Rectus abdominusRectus abdominus

Location: Location: Ribs to pubis Ribs to pubis (pelvis)(pelvis)

Function: Function: Compresses Compresses abdomen abdomen and flexes and flexes vertebral vertebral columncolumn

Latissimus dorsiLatissimus dorsi

Location: Location: Spine Spine around to around to chestchest

Function: Function: Extends and Extends and adducts adducts upper armupper arm

Gluteus maximusGluteus maximus

Location: Location: ButtocksButtocks

Function: Function: Extends and Extends and rotates thigh, rotates thigh, injection siteinjection site

SartoriusSartorius

Location: Location: Front of thighFront of thigh

Function: Function: Abducts thigh, Abducts thigh, flexes legflexes leg

Quadriceps femorisQuadriceps femoris

Location: Location: Front of Front of thighthigh

Function: Function: Extends leg, Extends leg, injection siteinjection site

Tibialis anteriorTibialis anterior

Location: Location: Front of Front of lower leglower leg

Function: Function: Flexes and Flexes and inverts footinverts foot

GastrocnemiusGastrocnemius

Location: Location: Back of lower Back of lower legleg

Function: Function: Flexes and Flexes and supinates supinates sole of the sole of the footfoot

Basic Types of Muscle Basic Types of Muscle MovementMovement AdductionAdduction AbductionAbduction FlexionFlexion ExtensionExtension RotationRotation

AdductionAdduction

Moving a body Moving a body part toward the part toward the midlinemidline

AbductionAbduction

Moving a body Moving a body part away from part away from the midlinethe midline

FlexionFlexion

Decreasing the Decreasing the angle between angle between two bones, or two bones, or bending a bending a body partbody part

ExtensionExtension

Increasing the Increasing the angle between angle between two bones, or two bones, or straightening a straightening a body partbody part

RotationRotation

Turning a body Turning a body part around its part around its own axis; for own axis; for example, example, turning the turning the head from side head from side to side.to side.

CircumductionCircumduction

Moving in a Moving in a circle at a joint, circle at a joint, or moving one or moving one end of a body end of a body part in a circle part in a circle while the other while the other end remains end remains stationary, such stationary, such as swinging a as swinging a arm in a circlearm in a circle

Body MechanicsBody Mechanics

Body Mechanics is the way in Body Mechanics is the way in which the body moves and which the body moves and maintains balance while maintains balance while making the most efficient use making the most efficient use of all its body parts.of all its body parts. To prevent injury to yourself To prevent injury to yourself

and others while working in the and others while working in the health field, it is important to health field, it is important to observe good body mechanicsobserve good body mechanics

Four Main Reasons for Using Four Main Reasons for Using Good Body MechanicsGood Body Mechanics

Muscles work best when used Muscles work best when used correctly.correctly.

Correct use of muscles makes Correct use of muscles makes lifting, pulling and pushing lifting, pulling and pushing easiereasier

Prevents unnecessary fatigue, Prevents unnecessary fatigue, strain and saves energystrain and saves energy

Prevents injury to self and Prevents injury to self and othersothers

Eight Basic Rules of Good Eight Basic Rules of Good Body MechanicsBody Mechanics

1)Maintain a broad base of support 1)Maintain a broad base of support by keeping the feet 8-10 inches by keeping the feet 8-10 inches apartapart

2)Bend from the hips and knees to 2)Bend from the hips and knees to get close to an object, and keep get close to an object, and keep your back straightyour back straight

3)Use the strongest muscles to do 3)Use the strongest muscles to do the job (shoulders, upper arms, the job (shoulders, upper arms, hips and thighs)hips and thighs)

4)Use the weight of your body to 4)Use the weight of your body to help push or pull an object. help push or pull an object. Whenever possible, push, slide, or Whenever possible, push, slide, or pull rather than liftpull rather than lift

Eight Basic Rules of Good Eight Basic Rules of Good Body MechanicsBody Mechanics

5)Carry heavy objects close to the 5)Carry heavy objects close to the bodybody

6)Avoid twisting your body as you 6)Avoid twisting your body as you work. Turn with your feet and work. Turn with your feet and entire body when you change entire body when you change direction of movementdirection of movement

7)Avoid bending for long periods7)Avoid bending for long periods

8)If a patient or object is too heavy 8)If a patient or object is too heavy for you to lift alone, always get for you to lift alone, always get help help

Diseases and Abnormal Diseases and Abnormal ConditionsConditions

Muscular DystrophyMuscular Dystrophy

Muscular dystrophy is a Muscular dystrophy is a group of disorders that group of disorders that involve involve muscle weaknessmuscle weakness and and loss of muscle tissue that get loss of muscle tissue that get worse over timeworse over time..

SymptomsSymptoms

Symptoms vary with the different Symptoms vary with the different types of muscular dystrophy.types of muscular dystrophy.

All of the muscles may be All of the muscles may be affected. Or, only specific groups affected. Or, only specific groups of muscles may be affected, such of muscles may be affected, such as those around the pelvis, as those around the pelvis, shoulder, or face. Muscular shoulder, or face. Muscular dystrophy can affect adults, but dystrophy can affect adults, but the more severe forms tend to the more severe forms tend to occur in early childhood.occur in early childhood.

SymptomsSymptoms

Mental retardationMental retardation (only present in some (only present in some types of the condition) types of the condition)

Muscle weakness that slowly gets Muscle weakness that slowly gets worse worse

Delayed development of muscle motor Delayed development of muscle motor skills skills

Difficulty using one or more muscle Difficulty using one or more muscle groups groups

DroolingDrooling Eyelid droopingEyelid drooping ( (ptosisptosis) ) Frequent falls Frequent falls Problems walkingProblems walking (delayed walking (delayed walking

Causes and Risk FactorsCauses and Risk Factors

Many diseases called muscular Many diseases called muscular dystrophies (MD) are inherited dystrophies (MD) are inherited disorders, such as:disorders, such as:

Becker's muscular dystrophyBecker's muscular dystrophy DuchenneDuchenne muscular dystrophy muscular dystrophy Emery-Dreifuss muscular Emery-Dreifuss muscular

dystrophy dystrophy FacioscapulohumeralFacioscapulohumeral

muscular dystrophy muscular dystrophy Limb-girdle muscular dystrophyLimb-girdle muscular dystrophy MyotoniaMyotonia congenitacongenita Myotonic dystrophyMyotonic dystrophy

Tests and DiagnosisTests and Diagnosis

A physical examination and A physical examination and your medical history will help your medical history will help the doctor determine the type the doctor determine the type of muscular dystrophy. of muscular dystrophy. Specific muscle groups are Specific muscle groups are affected by different types of affected by different types of muscular dystrophy.muscular dystrophy.


A A muscle biopsymuscle biopsy may be used to may be used to confirm the confirm the diagnosis. In diagnosis. In some cases, a some cases, a DNA blood test DNA blood test may be all that may be all that is needed.is needed.

Other tests Other tests may include:may include:

ElectrocardiograElectrocardiographyphy ( (ECGECG) )

ElectromyograpElectromyographyhy ( (EMGEMG) )

Serum CPKSerum CPK


This disease may also alter This disease may also alter the results of the following the results of the following tests:tests:

AldolaseAldolase ASTAST CreatinineCreatinine LDHLDH MyoglobinMyoglobin - urine/ serum - urine/ serum

TreatmentsTreatments

There are no known cures for the There are no known cures for the various muscular dystrophies. various muscular dystrophies. The goal of treatment is to control The goal of treatment is to control symptoms.symptoms.

Physical therapy may help Physical therapy may help patients maintain muscle strength patients maintain muscle strength and function. Orthopedic and function. Orthopedic appliances such as braces and appliances such as braces and wheelchairs can improve mobility wheelchairs can improve mobility and self-care abilities. In some and self-care abilities. In some cases, surgery on the spine or cases, surgery on the spine or legs may help improve function.legs may help improve function.


CorticosteroidsCorticosteroids taken by mouth taken by mouth are sometimes prescribed to are sometimes prescribed to children to keep them walking children to keep them walking for as along as possible.for as along as possible.

The person should be as The person should be as active as possible. Complete active as possible. Complete inactivity (such as bedrest) inactivity (such as bedrest) can make the disease worse.can make the disease worse.

ComplicationsComplications

CardiomyopathyCardiomyopathy Decreased ability to care for Decreased ability to care for

self self Decreased mobility Decreased mobility Joint contracturesJoint contractures Mental impairment (varies) Mental impairment (varies) RespiratoryRespiratory failurefailure ScoliosisScoliosis

PreventionPrevention

Genetic counseling is advised Genetic counseling is advised when there is a family history of when there is a family history of muscular dystrophy. Women may muscular dystrophy. Women may have no symptoms but still carry have no symptoms but still carry the gene for the disorder. the gene for the disorder. Duchenne muscular dystrophy Duchenne muscular dystrophy can be detected with about 95% can be detected with about 95% accuracy by genetic studies accuracy by genetic studies performed during pregnancy.performed during pregnancy.

FibromyalgiaFibromyalgia

Fibromyalgia is a common Fibromyalgia is a common condition characterized by long-condition characterized by long-term, body-wide pain and tender term, body-wide pain and tender points in joints, muscles, tendons, points in joints, muscles, tendons, and other soft tissues. and other soft tissues. Fibromyalgia has also been linked Fibromyalgia has also been linked to fatigue, morning stiffness, to fatigue, morning stiffness, sleep problems, headaches, sleep problems, headaches, numbness in hands and feet, numbness in hands and feet, depression, and anxiety.depression, and anxiety.

Fibromyalgia can develop on its Fibromyalgia can develop on its own or along with other own or along with other musculoskeletal conditions such musculoskeletal conditions such as rheumatoid arthritis or lupus.as rheumatoid arthritis or lupus.

SymptomsSymptoms

The overwhelming characteristic The overwhelming characteristic of fibromyalgia is long-standing, of fibromyalgia is long-standing, body-wide pain with defined body-wide pain with defined tender points. Tender points are tender points. Tender points are distinct from trigger points seen in distinct from trigger points seen in other pain syndromes. Unlike other pain syndromes. Unlike tender points, trigger points can tender points, trigger points can occur in isolation and represent a occur in isolation and represent a source of radiating pain, even in source of radiating pain, even in the absence of direct pressure.the absence of direct pressure.

SymptomsSymptoms

Fibromyalgia pain can mimic Fibromyalgia pain can mimic the pain that occurs with the pain that occurs with various types of arthritis. various types of arthritis. However, the significant However, the significant swelling, destruction, and swelling, destruction, and deformity of joints seen in deformity of joints seen in diseases such as rheumatoid diseases such as rheumatoid arthritis does not occur with arthritis does not occur with fibromyalgia syndrome alone.fibromyalgia syndrome alone.

SymptomsSymptoms

The soft-tissue pain of The soft-tissue pain of fibromyalgia is described as fibromyalgia is described as deep-aching, radiating, deep-aching, radiating, gnawing, shooting or burning, gnawing, shooting or burning, and ranges from mild to and ranges from mild to severe. Fibromyalgia severe. Fibromyalgia sufferers tend to wake up with sufferers tend to wake up with body aches and stiffness.body aches and stiffness.

SymptomsSymptoms

For some patients, pain For some patients, pain improves during the day and improves during the day and increases again during the increases again during the evening, though many evening, though many patients with fibromyalgia patients with fibromyalgia have day-long, unrelenting have day-long, unrelenting pain. Pain can increase with pain. Pain can increase with activity, cold or damp activity, cold or damp weather, anxiety and stress.weather, anxiety and stress.

Specific SymptomsSpecific Symptoms

Body aches Body aches Chronic facial muscle pain or Chronic facial muscle pain or

aching aching Fatigue Fatigue Irritable bowel syndrome Irritable bowel syndrome Memory difficulties and cognitive Memory difficulties and cognitive

difficulties difficulties Multiple tender areas (muscle and Multiple tender areas (muscle and

joint pain) on the back of the neck, joint pain) on the back of the neck, shoulders, sternum, lower back, shoulders, sternum, lower back, hips, shins, elbows, knees hips, shins, elbows, knees

Specific SymptomsSpecific Symptoms

Numbness and tingling Numbness and tingling Palpitations Palpitations Reduced exercise tolerance Reduced exercise tolerance Sleep disturbances Sleep disturbances Tension or migraine Tension or migraine

headaches headaches


The cause of this disorder is The cause of this disorder is unknown. Physical or unknown. Physical or emotional trauma may play a emotional trauma may play a role in development of the role in development of the syndrome. Some evidence syndrome. Some evidence suggests that fibromyalgia suggests that fibromyalgia patients have abnormal pain patients have abnormal pain transmission responses.transmission responses.


It has been suggested that sleep It has been suggested that sleep disturbances, which are common disturbances, which are common in fibromyalgia patients, may in fibromyalgia patients, may actually cause the condition. actually cause the condition. Another theory suggests that the Another theory suggests that the disorder may be associated with disorder may be associated with changes in skeletal muscle changes in skeletal muscle metabolism, possibly caused by metabolism, possibly caused by decreased blood flow, which decreased blood flow, which could cause chronic fatigue and could cause chronic fatigue and weakness.weakness.


Others have suggested that an Others have suggested that an infectious microbe, such as a infectious microbe, such as a virus, triggers the illness. At this virus, triggers the illness. At this point, no such virus or microbe point, no such virus or microbe has been identified.has been identified.

Pilot studies have shown a Pilot studies have shown a possible inherited tendency possible inherited tendency toward the disease, though toward the disease, though evidence is very preliminary.evidence is very preliminary.

Men and women of all ages get Men and women of all ages get fibromyalgia, but the disorder is fibromyalgia, but the disorder is most common among women most common among women aged 20 to 50.aged 20 to 50.


Diagnosis of fibromyalgia Diagnosis of fibromyalgia requires a history of a least 3 requires a history of a least 3 months of widespread pain, months of widespread pain, and pain and tenderness in at and pain and tenderness in at least 11 of 18 tender-point least 11 of 18 tender-point sites. These tender-point sites sites. These tender-point sites include fibrous tissue or include fibrous tissue or muscles of the:muscles of the:

These tender-point sites These tender-point sites include fibrous tissue or include fibrous tissue or muscles of the:muscles of the:

Arms (elbows) Arms (elbows) Buttocks Buttocks Chest Chest Knees Knees Lower back Lower back

Neck Neck Rib cage Rib cage Shoulders Shoulders Thighs Thighs


In mild cases, symptoms may go In mild cases, symptoms may go away when stress is decreased or away when stress is decreased or lifestyle changes are lifestyle changes are implemented. A combination of implemented. A combination of treatments including medications, treatments including medications, patient education, physical patient education, physical therapy, and counseling are therapy, and counseling are usually recommended. Many usually recommended. Many fibromyalgia sufferers have found fibromyalgia sufferers have found support groups helpful.support groups helpful.


In 2007, the Food and Drug In 2007, the Food and Drug Administration approved Administration approved Pregabalin (Lyrica) as the first Pregabalin (Lyrica) as the first drug for the treatment of drug for the treatment of fibromyalgia. In June 2008, a fibromyalgia. In June 2008, a second drug, Cymbalta, which second drug, Cymbalta, which was previously approved for was previously approved for treating depression, was FDA treating depression, was FDA approved for treating fibromyalgia approved for treating fibromyalgia as well. In 2009 the FDA approved as well. In 2009 the FDA approved milnacipran (Savella) for the milnacipran (Savella) for the treatment of fibromyalgia.treatment of fibromyalgia.


Studies show that antidepressants Studies show that antidepressants in low doses can decrease in low doses can decrease depression, relax craniofacial and depression, relax craniofacial and skeletal muscles, improve sleep skeletal muscles, improve sleep quality, and release pain-killing quality, and release pain-killing endorphins. Other medications endorphins. Other medications that are used include anti-that are used include anti-inflammatory pain medications inflammatory pain medications and medications that work on pain and medications that work on pain transmission pathways, such as transmission pathways, such as Gabapentin. Gabapentin.


Eating a well-balanced diet Eating a well-balanced diet and avoiding caffeine may and avoiding caffeine may help with problems sleeping, help with problems sleeping, and may help reduce the and may help reduce the severity of the symptoms. severity of the symptoms. Lifestyle measures to improve Lifestyle measures to improve the quality of sleep can be the quality of sleep can be effective for fibromyalgia.effective for fibromyalgia.


Some reports indicate that Some reports indicate that fish oil, magnesium/malic acid fish oil, magnesium/malic acid combinations, or vitamins combinations, or vitamins may be effective. Reducing may be effective. Reducing stress and improving coping stress and improving coping skills may also help reduce skills may also help reduce painful symptoms. painful symptoms.


Studies have shown that Studies have shown that fibromyalgia symptoms can fibromyalgia symptoms can be relieved by aerobic be relieved by aerobic exerccise. The best way to exerccise. The best way to begin a fitness program is to begin a fitness program is to start with short sessions of start with short sessions of just a few minutes of gentle, just a few minutes of gentle, low-impact exercises such as low-impact exercises such as walking and swimming.walking and swimming.

Compartment SyndromeCompartment Syndrome

Compartment syndrome Compartment syndrome occurs when too much occurs when too much pressure builds up in and pressure builds up in and around the muscles. It can around the muscles. It can result from crushing injuries, result from crushing injuries, extended pressure on a blood extended pressure on a blood vessel, swelling inside a cast, vessel, swelling inside a cast, or complications from or complications from surgery.surgery.

Compartment SyndromeCompartment Syndrome

Symptoms - include severe pain, a Symptoms - include severe pain, a feeling of fullness or tightness in feeling of fullness or tightness in the muscle, and a tingling the muscle, and a tingling sensation. Numbness indicates sensation. Numbness indicates cellular death, and it may be cellular death, and it may be difficult to restore full function difficult to restore full function once it reaches that point.once it reaches that point.

Treatment - Surgery to relieve the Treatment - Surgery to relieve the pressure is usually required.pressure is usually required.

RhabdomyolosisRhabdomyolosis

Damages both the muscles and Damages both the muscles and the kidneys by causing the muscle the kidneys by causing the muscle fibers to breakdown and be fibers to breakdown and be released into the blood stream. released into the blood stream. The fibers erode into a substance The fibers erode into a substance called myoglobin, which blocks called myoglobin, which blocks the kidney structures and can lead the kidney structures and can lead to kidney failure. to kidney failure.

Etiology - Alcoholism, heatstroke, Etiology - Alcoholism, heatstroke, cocaine and heroin overdoses, cocaine and heroin overdoses, seizures, and severeseizures, and severe exertion are exertion are possible causes. possible causes.

RhabdomyolysisRhabdomyolysis

Treatment - If the condition is Treatment - If the condition is caught early, intravenous fluids caught early, intravenous fluids are given to restore hydration. are given to restore hydration. Once kidney damage occurs, Once kidney damage occurs, treatment focuses on restoring treatment focuses on restoring renal functions and preventing renal functions and preventing further damage. further damage.

Signs of rhabdomyolysis include Signs of rhabdomyolysis include weakness, muscle stiffness and weakness, muscle stiffness and pain, joint pain and weight gain.pain, joint pain and weight gain.

Myasthenia GravisMyasthenia Gravis

A neuromuscular disorder A neuromuscular disorder characterized by variable characterized by variable weakness of voluntary weakness of voluntary muscles, which often muscles, which often improves with rest and improves with rest and worsens with activity. The worsens with activity. The condition is caused by an condition is caused by an abnormal immune response.abnormal immune response.

Myasthenia GravisMyasthenia Gravis

Myasthenia gravis affects Myasthenia gravis affects about 3 of every 10,000 about 3 of every 10,000 people and can affect people people and can affect people at any age. It is most common at any age. It is most common in young women and older in young women and older men.men.

Signs and SymptomsSigns and Symptoms

Muscle Muscle weakness, weakness, including: including:

Difficulty Difficulty swallowing, swallowing, frequent gagging, frequent gagging, or choking or choking

Paralysis Paralysis Muscles that Muscles that

function best function best after rest after rest

Drooping head Drooping head

Difficulty Difficulty climbing stairs climbing stairs

Difficulty lifting Difficulty lifting objects objects

Need to use Need to use hands to rise hands to rise from sitting from sitting positionspositions

Difficulty talkingDifficulty talking Difficulty Difficulty

chewingchewing

Signs and SymptomsSigns and Symptoms

Vision problems: Vision problems: Double visionDouble vision Difficulty Difficulty

maintaining maintaining steady gaze steady gaze

Eyelid droopingEyelid drooping

Additional Additional symptoms that symptoms that may be may be associated with associated with this disease:this disease:

Hoarseness or Hoarseness or changing voicechanging voice

Fatigue Fatigue Facial paralysis Facial paralysis Drooling Drooling Breathing Breathing

difficultydifficulty


Weakness occurs when the Weakness occurs when the nerve impulse to initiate or nerve impulse to initiate or sustain movement does not sustain movement does not adequately reach the muscle adequately reach the muscle cells. This is caused when cells. This is caused when immune cells target and immune cells target and attack the body's own cells attack the body's own cells (an autoimmune response). (an autoimmune response).


This immune response This immune response produces produces antibodiesantibodies that attach that attach to affected areas, preventing to affected areas, preventing muscle cells from receiving muscle cells from receiving chemical messages chemical messages (neurotransmitters) from the (neurotransmitters) from the nerve cell.nerve cell.


The cause of The cause of autoimmune disordersautoimmune disorders such as such as myasthenia gravis is unknown. myasthenia gravis is unknown. In some cases, myasthenia In some cases, myasthenia gravis may be associated with gravis may be associated with tumors of the thymus (an organ tumors of the thymus (an organ of the immune system). of the immune system).


Patients with myasthenia Patients with myasthenia gravis have a higher risk of gravis have a higher risk of having other autoimmune having other autoimmune disorders like disorders like thyrotoxicosisthyrotoxicosis, , rheumatoid arthritisrheumatoid arthritis, and , and systemic lupus systemic lupus erythematosuserythematosus..

Test and Diagnosis Test and Diagnosis

Examination may be normal Examination may be normal or may show muscle or may show muscle weakness that progressively weakness that progressively worsens as the muscle is worsens as the muscle is used. In many patients the used. In many patients the eye muscles are affected first. eye muscles are affected first. Reflexes and sensation are Reflexes and sensation are normal. Weakness may affect normal. Weakness may affect the arms, legs, breathing or the arms, legs, breathing or swallowing muscles, and any swallowing muscles, and any other muscle group.other muscle group.

Repetitive stimulation (type of Repetitive stimulation (type of nerve conduction studynerve conduction study) is more ) is more sensitive. sensitive.

Single-fiber Single-fiber EMGEMG can be very sensitive. can be very sensitive. Acetylcholine receptor antibodiesAcetylcholine receptor antibodies may be may be

present in the blood. present in the blood. A A TensilonTensilon test test is positive in some cases is positive in some cases

but must be interpreted carefully by an but must be interpreted carefully by an experienced doctor. Baseline muscle experienced doctor. Baseline muscle strength is evaluated. After Tensilon (strength is evaluated. After Tensilon (edrophoniumedrophonium, a medication that blocks , a medication that blocks the action of the the action of the enzymeenzyme that breaks that breaks down the transmitter acetylcholine) is down the transmitter acetylcholine) is given, muscle function may improve. given, muscle function may improve.

The patient may need a The patient may need a CTCT or or MRIMRI scan scan of the chest to look for a possible of the chest to look for a possible tumortumor in the thyroid.in the thyroid.

TreatmentTreatment

There is no known cure for There is no known cure for myasthenia gravis. However, myasthenia gravis. However, treatment may result in prolonged treatment may result in prolonged periods of remission.periods of remission.

Lifestyle adjustments may enable Lifestyle adjustments may enable continuation of many activities. continuation of many activities. Activity should be planned to Activity should be planned to allow scheduled rest periods. An allow scheduled rest periods. An eye patch may be recommended if eye patch may be recommended if double visiondouble vision is bothersome. Stress is bothersome. Stress and excessive heat exposure should and excessive heat exposure should be avoided because they can be avoided because they can worsen symptoms.worsen symptoms.

TreatmentTreatment

Some medications, such as Some medications, such as neostigmineneostigmine or or pyridostigminepyridostigmine, , improve the communication between improve the communication between the nerve and the muscle. the nerve and the muscle. PrednisonePrednisone and other medications and other medications that suppress the immune response that suppress the immune response (such as (such as azathioprineazathioprine, , cyclosporinecyclosporine, , or or mycophenolatemycophenolate mofetilmofetil) may be ) may be used if symptoms are severe and used if symptoms are severe and there is inadequate response to there is inadequate response to other medications.other medications.

TreatmentTreatment

PlasmapheresisPlasmapheresis, a technique in , a technique in which blood plasma containing which blood plasma containing antibodiesantibodies against the body is against the body is removed from the body and removed from the body and replaced with fluids (donated replaced with fluids (donated antibody-free plasma or other antibody-free plasma or other intravenous fluids), may reduce intravenous fluids), may reduce symptoms for up to 4 - 6 weeks symptoms for up to 4 - 6 weeks and is often used to optimize and is often used to optimize conditions before surgery conditions before surgery

TreatmentTreatment

When other treatments do not When other treatments do not improve systems, patients may improve systems, patients may receive intravenous receive intravenous immunoglobulin.immunoglobulin.

Surgical removal of the thymus Surgical removal of the thymus (thymectomy) may result in (thymectomy) may result in permanent remission or less need permanent remission or less need for medicines.for medicines.

Patients with eye problems may Patients with eye problems may try lens prisms to improve vision. try lens prisms to improve vision. Surgery may also be performed on Surgery may also be performed on the eye muscles.the eye muscles.

ComplicationsComplications

Restrictions on lifestyle Restrictions on lifestyle (possible) (possible)

Side effects of medications Side effects of medications (see the specific medication) (see the specific medication)

Complications of surgery Complications of surgery Myasthenic crisis (breathing Myasthenic crisis (breathing

difficulty), may be life difficulty), may be life threateningthreatening

Diseases and Abnormal Diseases and Abnormal Conditions (cont.)Conditions (cont.)

Muscle sprain Muscle sprain A traumatic injury to the A traumatic injury to the

tendons, muscles, or tendons, muscles, or ligaments of a jointligaments of a joint

Muscle strainMuscle strainTorn or stretched tendons Torn or stretched tendons

and muscles, causing painand muscles, causing pain

PharmacologyPharmacology

Complete a Medication Complete a Medication Worksheet for the following Worksheet for the following drugs:drugs:

LyricaLyrica SavellaSavella CymbaltaCymbalta GabapentinGabapentin Fish OilFish Oil PrednisonePrednisone NeostigmineNeostigmine PyridostigminePyridostigmine AzathioprineAzathioprine

CyclosporineCyclosporine Mycophenolate Mycophenolate

mofetilmofetil SomaSoma FlexerilFlexeril ValiumValium SkelaxinSkelaxin MyforticMyfortic RobaxinRobaxin ZanaflexZanaflex

Medication Sheet should Medication Sheet should include:include: Drug Generic and Drug Generic and

Brand NameBrand Name ClassificationClassification PreparationPreparation Route availableRoute available Dosage availableDosage available Frequency Frequency

administeredadministered

Drug ActionDrug Action Side EffectsSide Effects IncompatibilitiesIncompatibilities Administered Administered

TimesTimes ContraindicationsContraindications TeachingTeaching Health Care Health Care

Provider Provider ImplicationsImplications

Related Health CareersRelated Health Careers

Athletic TrainerAthletic Trainer ChiropractorChiropractor Doctor of Doctor of

Osteopathic Osteopathic MedicineMedicine

Massage Massage TherapistTherapist

MyologistMyologist NeurologistNeurologist OrthopedistOrthopedist

PhysiatristPhysiatrist Physical Physical

Therapist Therapist PodiatristPodiatrist ProsthetistProsthetist RheumatologistRheumatologist Sports Medicine Sports Medicine

Physician Physician

Medical TerminologyMedical Terminology

Root Word(s):Root Word(s): My(o)My(o)- a word element denoting - a word element denoting

musclemuscle MyMyasastheniathenia- muscular weakness- muscular weakness MyoMyocardicardialal- pertaining to the heart of the - pertaining to the heart of the

musclemuscle MyoMyokinesiskinesis- movement of the muscle- movement of the muscle MyoMyodyniadynia- pain of the muscle- pain of the muscle MyoMyomalaciamalacia- abnormal muscle softening- abnormal muscle softening ElectroElectromyomyographygraphy- electrical recording of - electrical recording of

muscle activitymuscle activity MyosMyositisitis- inflammation of muscle- inflammation of muscle MyoMyopathypathy- any disease of muscle- any disease of muscle


Root Word(s):Root Word(s): Rhabdomy(o)Rhabdomy(o)- denotes skeletal - denotes skeletal

musclemuscle RhabdomyRhabdomyomaoma- a benign tumor of - a benign tumor of

the skeletal musclethe skeletal muscle RhabdomyoRhabdomyosarcsarcomaoma- a malignant - a malignant

tumor of the skeletal muscletumor of the skeletal muscle


Root Word(s):Root Word(s): Leiomy(o)Leiomy(o)- denotes smooth - denotes smooth

musclemuscle LeiomyLeiomyomaoma- benign tumor of the - benign tumor of the

smooth musclesmooth muscle LeiomyoLeiomyosarcsarcomaoma- malignant - malignant

tumor of the smooth muscletumor of the smooth muscle

Abbreviations (D)Abbreviations (D)

d- dayd- day D&C- Dilatation and CutterageD&C- Dilatation and Cutterage DA- Dental AssistantDA- Dental Assistant DC- Doctor of ChiropracticDC- Doctor of Chiropractic DDS- Doctor of Dental SurgeryDDS- Doctor of Dental Surgery DEA- Drug Enforcement AgencyDEA- Drug Enforcement Agency del- Deliverydel- Delivery Dept- DepartmentDept- Department


DH- Dental HygenistDH- Dental Hygenist DHHS- Department of Health and DHHS- Department of Health and

Human Services Human Services Diff- Differential White Blood Cell Diff- Differential White Blood Cell

Count Count DDM- Doctor of Dental MedicineDDM- Doctor of Dental Medicine DNR- Do Not ResuscitateDNR- Do Not Resuscitate DO- Doctor of OsteopathyDO- Doctor of Osteopathy DOA- Dead on ArrivalDOA- Dead on Arrival DOB- Date of BirthDOB- Date of Birth


DPM- Doctor of Pediatric MedicineDPM- Doctor of Pediatric Medicine DPT- Diptheria, Pertussis, TetanusDPT- Diptheria, Pertussis, Tetanus DW- Distilled WaterDW- Distilled Water Dx- DiagnosisDx- Diagnosis

muscular system. introduction without the muscular system we would be unable to sit, stand, walk,...

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