Muscular System

Human Anatomy and Physiology I

Oklahoma City Community College

Dennis Anderson

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Muscles

• Movement• Posture• Stabilize joints• Generate heat• Protect

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Flexion

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Extension

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Hyperextension

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Dorsiflexion & Plantar Flexion

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Abduction, Adduction & Circumduction

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Rotation

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Gliding

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Terminology

• Prime mover (Agonist)– Muscle that is the main force for a given

movement• Biceps—prime mover for elbow flexioin

• Antagonist– Muscle that oppose a given movement

• Triceps

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Terminology Continued

• Synergist– Muscle that works with another muscle for a

given movement

• Belly– Thickest part of muscle– Biceps belly near the middle of the humerus

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Muscle Attachments

Origin

Insertion

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Origin• Muscle attachment that moves the least

Insertion• Muscle attachment that moves the most

SternocleidomastoideusFlexes and Rotates Head

O: Sternum Manubrium & ClavicleI: Mastoid process

MasseterElevate Mandible

O: Zygomatic ArchI: Mandible

TemporalisElevate & Retract Mandible

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Orbicularis orisCloses & Protrudes Lips

O: Maxilla & MandibleI: Mouth

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BuccinatorSucking & Whistling

TrapeziusExtend Head, Adduct, Elevate or

Depress Scapula

Trapezius

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Rhomboid MajorAdduct Scapula

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Teres MajorAdduct Humerus

O: ScapulaI: Humerus

Latissimus DorsiExtend, Adduct & Rotate Arm

Medially

Latissimus

dorsi

O: Vertebrae, Ilium, Ribs, ScapulaI: Humerus

DeltoidAbduct, Flex & Extend Arm

O: Clavicle and ScapulaI: Deltoid Tuberosity of Humerus

SupraspinatusAbduct arm

InfraspinatusRotates Humerus Laterally

Pectoralis MajorFlexes, adducts & rotates arm

medially

O: Clavicle and SternumI: Greater Tubercle of Humerus

Biceps BrachiiFlexes Elbow Joint

O: Coracoid Process & Glenoid Cavity

I: Radial Tuberosity

Triceps BrachiiExtend Elbow Joint

O: Humerus & Scapula

I: Olecranon

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BrachialisFlex forearm

O: Humerus

I: Ulna

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BrachioradialisFlex Forearm

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Flexor Carpi RadialisFlex Wrist

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Flexor Digitorum Superficialis

Flex Fingers

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Pronator TeresPronates forearm

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Supinator

Supinates forearm

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Estensor Carpi Radialis Longus

Extend Wrist

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Estensor Digitorum

Extend Fingers

Rectus AbdominusFlexes Abdomen

O: Pubis

I: Xiphoid Process & Cartilage of Ribs

External ObliqueCompress Abdomen

Internal ObliqueCompress Abdomen

External IntercostalsElevate ribs

Internal IntercostalsDepress ribs

DiaphragmInspiration

Gluteus Maximus

O: Ilium, Sacrum & Coccyx

I: Gluteal Tuberosity

Extends & Rotates Thigh Laterally

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Rectus Femoris

O: Ilium

I: Patella & Tibial Tuberosity

Flexes Thigh, Extends Lower Leg

Vastus LateralisExtends Lower Leg

Vastus MedialisExtends Lower Leg

Adductor LongusAdduct, Rotate & Flex Thigh

Laterally

GracilisAdducts and Flexes Thigh

O: Ischium and Pubis

I: Tibia

Sartorius

O: Anterior Superior Iliac Spine

I: Medial Side of Tibia

Flexes Thigh, & Rotates Thigh Laterally

Biceps Femoris

O: Ischial Tuberosity

I: Tibia & Fibula

Extends Thigh & Flexes Lower Leg

SemitendinosusExtends Thigh & Flexes Lower Leg

SemimembranosusExtends Thigh & Flexes Lower Leg

Gastrocnemius

O: Femur

I: Calcaneus of Foot

Plantar Flexes Foot & Flex Lower Leg

SoleusPlantar Flexes Foot

Tibialis AnteriorDorsiflexes and Inverts Foot

O: Lateral Condyle of Tibia

I: Ankle

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THE END