Muscle Lab Exam. Lab 2: Muscles of the back, arm & forearm

Trapezius

Origin: Occipital Bone and Thoracic vertebrae spinous processes

Insertion: Acromion and spine of scapula; lateral portion of clavicle

Action: Raise, rotate, retract and stabilize scapula

latissimus dorsi

Origin: spinous processes of thoracic and lumbar vertebrae, iliac crest, and last ribs

Insertion: intertubercular sulcus of humerus

Action: Extend arm; adducts and medially rotates arm

Infraspinatus

Origin: Infraspinous fossa

Insertion: Greater Tubercle of humerus

Action: lateral rotation of humerus

teres minor

Origin: Lateral edge of scapula

Insertion: Greater tubercle of humerus

Action: lateral rotation of humerus

teres major

Origin: Posterior surface of scapula

Insertion: Intertubercular sulcus of humerus

Action: Extend medially rotate and adduct humerus

Supraspinatus

origin: supraspinous fossa of scapula

insertion: greater tubercle of humerus

Action: Start abduction of humerus

Rhomboids

Origin: Thoracic spinous processes

Insertion: Medial border of scapula

Action: Stabilizes scapula

biceps brachii

Origin: Short head: Coracoid process of scapula - Long head: superior glenoid cavity rim

Insertion: Radial tuberosity

Action: Flex elbow/forearm; supinate forearm

Brachioradialis (on thumb side)

Origin: Lateral Ridge at Distal humerus

Insertion: Styloid process of the radius

Action: Flex forearm

Brachialis (breaks up tri- and bi-ceps)

Origin: Distal portion of anterior humerus

Insertion: Coronoid process of ulna

Action: Flex forearm

Flexor carpi radialis

Origin: Medial epicondyle of humerus

Insertion: Bases of second and third metacarpal bones

Action: Flexion and abduction at wrist

Flexor Carpi Ulnaris- (pinky side)

Origin: Medial epicondyle of humerus

Insertion: Base of metacarpal 5

Action: Flex wrist and abduct hand

flexor digitorum superficialis

Origin: Medial epicondyle of humerus

Insertion: Middle phalanges of fingers 2-5

Action: Flex wrist and middle phalanges of 2-5

flexor pollicis longus

Origin: Anterior surface of radius

Insertion: Distal phalanx of thumb

Action: Flex thumb (pollex)

flexor digitorum profundus

Origin: Anteriomedial surface of ulna, interosseous membrane and coronoid process

Insertion: Distal phalanges of fingers 2-5

Action: Flex distal phalanges

triceps brachii

Origin: Inferior margin of glenoid cavity, posterior humerus, and groove on posterior humerus

Insertion: Olecranon Process

Action: extend forearm

Antagonist to: biceps

extensor carpi radialis longus (thumb side)

Origin: Lateral ridge of humerus

Insertion: Base of metacarpal 2

Action: Extend and abduct wrist

extensor digitorum

origin: lateral epicondyle of humerus

insertion: distal phalanges of digits 2-5

action: extends fingers and wrist

extensor carpi ulnaris (pinky side)

Origin: Lateral epicondyle of humerus

Insertion: base of metacarpal 5

Action: Extend and adduct wrist