Lab Activity 11: Group II Muscles Martini Chapter 11 Portland Community College BI 231.

Lab Activity 11: Group II

Muscles

Martini Chapter 11

Portland Community CollegeBI 231

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Origin and Insertion

• Origin: The place where the fixed end attaches to a bone, cartilage, or connective tissue.

• Insertion: The site where the movable end attaches to another structure.

MUSCLES OF THE SHOULDER AND ARM

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• Origin: Anterior surface, lateral clavicle, acromion process and spine of scapula

• Insertion: Deltoid tubercle of humerus

• Action: Abducts humerus; aids in flexion, extension, and internal and external rotation

Deltoid

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• Origin: Supraspinous fossa

• Insertion: Greater tubercle of humerus

• Action: Abducts humerus

Supraspinatus

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• Origin: Infraspinous fossa

• Insertion: Greater tubercle of humerus

• Action: Rotates humerus laterally

Infraspinatus

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• Origin: Axillary border of scapula

• Insertion: Greater tubercle of humerus

• Action: Rotates humerus laterally

Teres Minor

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• Origin: Axillary border at inferior angle of scapula

• Insertion: Intertubular groove of humerus

• Action: Extends, adduction and medial rotates humerus.

Teres Major

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• Origin: Subscapular fossa

• Insertion: Lesser tubercle of humerus

• Action: Rotates humerus medially

Subscapularis

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• Origin: Long head, supraglenoid tubercle;Short head, coracoid process scapula

• Insertion: Radial tuberosity of the radius

• Action: Flexes radius and humerus, and supinates forearm

Biceps BrachiiShort Head Long

Head

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• Origin: Coracoid process of scapula

• Insertion: Middle third of humerus

• Action: Flexes and adducts humerus

Coracobrachialis

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• Origin: Long head, infraglenoid tubercle; Lateral head, proximal portion of posterior humerus; Medial head, distal half of posterior humerus

• Insertion: Olecranon process of ulna

• Action: Extends humerus and ulna

Triceps Brachii Long Head

Lateral Head

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• Origin: Anterior distal two-thirds of humerus

• Insertion: Coronoid process of ulna

• Action: Flexes ulna

Brachialis

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• Origin: Lateral epicondyle of humerus

• Insertion: Olecranon process, posterior surface of ulna

• Action: Weak extensor of ulna, stabilizes elbow joint in extension

Anconeus

MUSCLES OF THE PALM

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• Origin: Scaphoid and trapezium

• Insertion: Proximal phalanx of thumb

• Action: Abducts thumb and aids in flexion

Palm

Abductor Pollicis Brevis

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• Origin: Trapezium • Insertion: Proximal

phalanx of thumb • Action: Flexes thumb

PalmPalm

Flexor Pollicis Brevis

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• Origin: Hook of hamate

• Insertion: Proximal phalanx of fifth digit

• Action: Flexes fifth digit

PalmPalm

Flexor Digiti Minimi

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• Origin: Pisiform and tendon of flexor carpi ulnaris

• Insertion: Proximal phalanx of fifth digit

• Action: Abducts fifth digit

PalmPalm

Abductor Digiti Minimi

MUSCLES OF ANTERIOR FOREARM

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• Origin: Medial epicondyle of humerus and coronoid process of ulna

• Insertion: Middle portion of radius

• Action: Pronates and flexes forearm

Pronator Teres

Anterior, Superficial Layer

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• Origin: Medial epicondyle of humerus

• Insertion: Base of second metacarpal

• Action: Flexes wrist and elbow and abducts wrist

Flexor Carpi Radialis

Anterior, Superficial Layer

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• Origin: Medial epicondyle of the humerus

• Insertion: Palmar aponeurosis

• Action: Weak flexion of wrist, tenses skin of palm

Palmaris Longus

Anterior, Superficial Layer

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• Origin: Medial epicondyle of humerus, olecranon process, & posterior ulna

• Insertion: Pisiform, hamate, and fifth metacarpal

• Action: Flexes and adducts wrist

Flexor Carpi Ulnaris

Anterior, Superficial Layer

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• Origin: Medial epicondyle of humerus and coronoid process of ulna

• Insertion: Middle phalanges of fingers

• Action: Flexes fingers and wrist

Flexor Digitorum Superficialis

Anterior, Middle Layer

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• Origin: Anterior and medial surfaces of ulna and interosseous membrane

• Insertion: Distal phalanges of fingers

• Action: Flexes fingers and wrist

Flexor Digitorum Profundus

Anterior, Deepest Layer

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• Origin: Middle half of radius, interosseous membrane, coronoid process of ulna

• Insertion: Distal phalanx of thumb

• Action: Flexes thumb and wrist

Flexor Pollicis Longus

Anterior, Deepest Layer

MUSCLES OF POSTEROLATERAL FOREARM

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• Origin: Lateral supracondylar ridge

• Insertion: Styloid process of radius

• Action: Flexes forearm

Brachioradialis

Posterior, Superficial Layer

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• Origin: Lateral supracondylar ridge of humerus

• Insertion: Second metacarpal

• Action: Extends and abducts hand

Extensor Carpi Radialis Longus

Posterior, Superficial Layer

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• Origin: Lateral epicondyle of humerus

• Insertion: Third metacarpal

• Action: Extends and abducts hand

Extensor Carpi Radialis Brevis

Posterior, Superficial Layer

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• Origin: Lateral epicondyle of humerus

• Insertion: Into distal phalanx by 4 tendons

• Action: Extends fingers and hand

Extensor Digitorum

Posterior, Superficial Layer

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• Origin: Lateral epicondyle of humerus and posterior border of ulna

• Insertion: Fifth metacarpal

• Action: Extends and adducts hand

Extensor Carpi Ulnaris

Posterior, Superficial Layer

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• Origin: Lateral epicondyle of humerus

• Insertion: Extensor expansion of little finger

• Action: Extends 5th digit and hand

Extensor Digiti Minimi

Posterior, Middle Layer

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• Origin: Lateral epicondyle of humerus, supinator crest of ulna

• Insertion: Lateral surface and posterior border of radius

• Action: Supinates forearm

Supinator

Posterior, Deepest Layer

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• Origin: Posterior surface of ulna and radius, and interosseous membrane

• Insertion: First metacarpal

• Action: Abducts thumb and hand

Abductor Pollicis Longus

Posterior, Deepest Layer

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• Origin: Middle third of radius and interosseous membrane

• Insertion: Base of proximal phalanx of thumb

• Action: Extends thumb

Extensor Pollicis Brevis

Posterior, Deepest Layer

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• Origin: Middle third of ulna and interosseous membrane

• Insertion: Base of distal phalanx of thumb

• Action: Extends thumb

Extensor Pollicis Longus

Posterior, Deepest Layer

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The End