Lecture 2.02 - Appendicular Skeleton 1 - Attachments and Actions

trapezius (superior fibers) action

elevates and superiorly rotates scapula

trapezius (middle fibers) action

retracts scapula

trapezius (inferior fibers) action

depresses scapula

trapezius medial attachment (origin)

occipital bone and superior nuchal line; ligamentum nuchae; spinous processes of C7-T12

trapezius lateral attachment (insertion)

clavicle; acromion process and spine of scapula

levator scapulae action

elevates scapula, inferiorly rotates scapula

levator scapulae superior attachment (origin)

transverse processes of C1-C4

levator scapulae inferior attachment (insertion)

superior part of medial border of scapula

rhomboid minor action

elevates and retracts (adducts) scapula; inferiorly rotates scapula

rhomboid minor medial attachment (origin)

spinous processes of C7-T1

rhomboid minor lateral attachment (insertion)

medial border of scapula superior to spine

rhomboid major action

elevates and retracts (adducts) scapula; inferiorly rotates scapula

rhomboid major medial attachment (origin)

spinous processes of T2-T5

rhomboid major lateral attachment (insertion)

medial border of scapula from spine to inferior angle

pectoralis minor action

protracts and depresses scapula

pectoralis minor inferior attachment (origin)

ribs 3 to 5

pectoralis minor superior attachment (insertion)

coracoid process of scapula

serratus anterior action

prime mover of scapular protraction (boxer’s muscle), stabilizes scapula against posterior side of ribcage, superiorly rotates scapula

serratus anterior inferior attachment (origin)

ribs 1-8; anterior and superior margins

serratus anterior superior attachment (insertion)

medial border of scapula, anterior surface

subclavius actions

stabilizes and depresses the clavicle

subclavius inferior attachment (origin)

rib 1

subclavius superior attachment (insertion)

inferior surface of clavicle

latissimus dorsi actions

agonist of arm extension; adducts and medially rotates arm (swimmer’s muscle)

lattissimus dorsi proximal attachment (origin)

spinous processes of T7-T12; ribs 8 to 12; iliac crest; throacolumbar fascia

latissimus dorsi distal attachment (insertion)

floor of intertubercular sulcus of humerus

pectoralis major actions

agonist of arm flexion; adducts and medially rotates arm

pectoralis major proximal attachment (origin)

medial clavicle; costal cartilages of ribs 2-6; body of sternum

pectoralis major distal attachment (insertion)

lateral part of intertubercular sulcus of humerus

teres major actions

extends, adducts, and medially rotates arm

teres major proximal attachment (origin)

inferior lateral border and inferior angle of scapula

teres major distal attachment (insertion)

lesser tubercle and medial part of intertubercular groove of humerus

deltoid anterior fibers: clavicular part actions

flex and medially rotate arm

deltoid middle fibers: acromial part actions

agonist of arm abduction

deltoid posterior fibers: scapular part actions

extend and laterally rotate arm

deltoid proximal attachment (origin)

acromial end of clavicle; acromion and spine of scapula

deltoid distal attachment (insertion)

deltoid tuberosity of humerus

coracobrachialis actions

adducts and flexed arm

coracobrachialis proximal attachment (origin)

coracoid process of scapula

coracobrachialis distal attachment (insertion)

middle medial shaft of humerus

subscapularis actions

medially rotates arm

subscapularis proximal attachment (origin)

subscapular fossa of scapula

subscapularis distal attachment (insertion)

lesser tubercle of humerus

supraspinatus actions

abducts arm

supraspinatus proximal attachment (origin)

supraspinous fossa of scapula

supraspinatus distal attachment (insertion)

greater tubercle of humerus

infraspinatus actions

adducts and laterally rotates arm

infraspinatus proximal attachment (origin)

infraspinous fossa of scapula

infraspinatus distal attachment (insertion)

greater tubercle of humerus

teres minor actions

adducts and laterally rotates arm

teres minor proximal attachment (origin)

upper dorsal lateral border of scapula

teres minor distal attachment (insertion)

greater tubercle of humerus

biceps brachii (long and short heads) actions

flexes forearm, powerful supinator of forearm, long head flexes arm

biceps brachii long head proximal attachment (origin)

supraglenoid tubercle of scapula

biceps brachii short head proximal attachment (origin)

coracoid process of scapula

biceps brachii distal attachment (insertion)

radial tuberosity and bicipital aponeurosis

brachialis actions

primary flexor of forearm

brachialis proximal attachment (origin)

distal anterior surface of humerus

brachialis distal attachment (insertion)

tuberosity and coronoid process of ulna

triceps brachii (long, lateral, and medial heads) actions

primary extensor of forearm; long head of triceps also extends and adducts arm

triceps brachii long head origin

infraglenoid tubercle of scapula

triceps brachii lateral head origin

posterior humerus proximal to radial groove

triceps brachii medial head origin

posterior humerus distal to radial groove

triceps brachii insertion

olecranon of ulna

anconeus actions

extends forearm

anconeus origin

lateral epicondyle of humerus

anconeus insertion

olecranon of ulna

brachioradialis actions

flexes forearm (especially when forearm is semi-pronated)

brachioradialis origin

lateral supracondylar ridge of humerus

brachioradialis insertion

styloid process of radius

pronator teres actions

pronates forearm

pronator teres origin

medial epicondyle of humerus and coronoid process of ulna

pronator teres insertion

lateral surface of radius

pronator quadratus actions

pronates forearm

pronator quadratus origin

anterior surface of distal one-fourth of ulna

pronator quadratus insertion

anterior surface of distal one-forth of radius

supinator actions

supinates forearm

supinator origin

lateral epicondyle of humerus and ulna distal to radial notch

supinator insertion

anterolateral surface of radius distal to radial tuberosity

superficial layer of anterior forearm muscles

pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris

superficial layer of anterior forearm muscles common flexor origin

medial epicondyle of humerus

golfer’s elbow

medial epicondylitis

superficial layer of posterior forearm muscles

extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris

deep layer of posterior forearm muscles

abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis, supinator

posterior forearm muscles common extensor origin

lateral epicondyle of humerus

tennis elbow

lateral epicondylitis

extrinsic muscles

muscles bellies outside of wrist or hand

carpal tunnel

space between carpal bones and flexor retinaculum