Actions, insertions, origins, innervations of arm muscles

Deltoid origin

lateral third of clavicle;acromion and spine of scapula

Deltoid insertion

deltoid tuberosity of humerus

Deltoid action

prime mover of arm abduction when its fibers contract simultaneous, active during rhythmic arm-swinging, can flex and rotate medially, extend and laterally rotate

Antagonist of pectoralis major and latissimus dorsi

deltoid

Synergist of pectoralis major when anterior fibers only

deltoid

Biceps brachii short head origin

coracoid process

biceps brachii long head origin

supraglenoid tubercle and lip of glenoid cavity

Insertion of biceps brachii

radial tuberosity

Biceps brachii action

flexes and supinates forearm

Biceps brachii innervation

musculocutaneous nerve (C5 and C6)

Deltoid innervation

axillary nerve (C5 and C6)

Triceps brachii long head origin

infraglenoid tubercle of scapula

Triceps brachii lateral head origin

posterior shaft of humerus

Triceps brachii medial head origin

posterior humeral shaft distal to radial groove

Triceps brachii insertion

by common tendon into olecranon of ulna

triceps brachii action

powerful forearm extensor, may help stabilize shoulder joint and assist in adduction

triceps brachii nerve supply

radial nerve (C6-C8)

Flexor digitorium superficials origin

medial epicondyle of hymerus, coronoid process of ulna, shafr of radius

flexor digitorum superficialis insertion

middle phalanges of 2nd-5th fingers

flexor digitorum superficialis action

flexes hand and middle phalanges of 2nd-5th finger- finger flexor for speed

Innervation of flexor digitorum superficialis

median nerve (C7, C8, T1)

Flexor digitorum profundus origin

coronoid process, anteromedial surface of ulna, and interosseous membrane

flexor digitorum profundus insertion

distal phalanges of 2nd-5th fingers

flexor digitorum profundus action

flexes distal interphalangeal joints- slow acting flexor of al fingers, helps flex wrist

Flexor digitorum profundus innervation

medial half by ulnar nerve; lateral half by median nerve

Brachioradialis origin

lateral supracondylar ridge at distal end of humerus

brachioradialis insertion

base of radial styloid process

brachioradialis action

synergist in flexing forearm, stabilizes elbow during rapid flexion and extension

brachioradialis innervation

radial nerve

extensor carpi radialis longus origin

lateral supracondylar ridge of humerus

extensor carpi radialis longus insertion

base of second metacarpal

extensor carpi radialis longus action

extends hand in conjunctio w/ extensor carpi ulnaris and abducts hand in conjunction with flexor carpi radialis

extensor carpi radialis longue innervation

radial nerve (C6 and C7)

Extensor carpi ulnaris origin

lateral epicondyle of humerus and posterior border of ulna

extensor carpi ulnaris insertion

base of 5th metacarpal

extensor carpi ulnaris action

extends hand in conjunction w/ extensor carpi radialis and adducts hand in conjunction w/ flexor carpi ulnaris

Pronator teres origin

medial epicondyle of humerus; coronoid process of ulna

pronator teres insertion

lateral radius, midshaftr

pronator teres action

pronates forearm, weak flexor

pronator teres innervation

median nerve

pronator quadratus origin

anterior surface of distal ¼ of ulna

pronator quadratus insertion

anterior surface of distal ¼ of radius

pronator quadratus action

forearm pronation

pronator quadratus innervation

medial nerve; anterior interosseous nerve

extensor pollicus brevis origin

posterior surface of the radius and ulna and the interosseous membrane

extensor pollicus brevis insertion

base of 1st metacarpal and trapezium

extensor pollicus brevis action

abducts and extens thumb

extensor pollicus brevis innervation

posterior interosseous nerve