Human Anatomy UE Muscles

trapezius (descending/upper, middle, ascending/lower) action

descending: scapular elevation, ascending: scapular depression, middle/all: scapular retraction, descending & ascending: superiorly rotate glenoid cavity

trapezius (descending/upper, middle, ascending/lower) PA

medial 1/3 of superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7-T12

trapezius (descending/upper, middle, ascending/lower) DA

lateral 1/3 of clavicle, acromion, spine of scapula

trapezius (descending/upper, middle, ascending/lower) innervation

spinal accessory nerve CN XI (motor fibers) & spinal nerves C3, C4 (pain & proprioceptive fibers)

rhomboid major action

retract scapula, rotate glenoid cavity inferiorly, fix scapula to thoracic wall

rhomboid major PA

spinous processes of T2-T5

rhomboid major DA

medial border of scapula from level of spine to inferior angle

rhomboid major innervation

dorsal scapular nerve C4, C5

rhomboid minor action

retract scapula, rotate glenoid cavity inferiorly, fix scapula to thoracic wall

rhomboid minor PA

nuchal ligament, spinous processes of C7 & T1

rhomboid minor DA

smooth triangular area at medial end of scapular spine

rhomboid minor innervation

dorsal scapular nerve C4, C5

levator scapulae action

scapular elevation, rotates glenoid cavity inferiorly by rotating scapula

levator scapulae PA

posterior tubercles of transverse processes of C1-C4

levator scapulae DA

medial border of scapula superior to root of scapular spine

levator scapulae innervation

dorsal scapular nerve C4, C5 & cervical nerves C3, C4

supraspinatus action

initiates & assists deltoid in abduction of arm, acts with other rotator cuff muscles

supraspinatus PA

supraspinous fossa of scapula

supraspinatus DA

superior facet of greater tubercle of humerus

supraspinatus innervation

suprascapular nerve C4-C6

infraspinatus action

laterally rotates arm, acts with other rotator cuff muscles

infraspinatus PA

infraspinous fossa of scapula

infraspinatus DA

middle facet of greater tubercle of humerus

infraspinatus innervation

suprascapular nerve C5, C6

teres major action

adducts & medially rotates arm

teres major PA

posterior surface of inferior angle of scapula

teres major DA

medial lip of intertubercular sulcus of humerus

teres major innervation

lower subscapular nerve C5, C6

teres minor action

laterally rotates arm, acts with other rotator cuff muscles

teres minor PA

middle part of lateral border of scapula

teres minor DA

inferior facet of greater tubercle of humerus

teres minor innervation

axillary nerve C5, C6

subscapularis action

medially rotates arm. as part of rotator cuff, helps hold head of humerus in glenoid cavity

subscapularis PA

subscapular fossa - most of anterior surface of scapula

subscapularis DA

lesser tubercle of humerus

subscapularis innervation

upper & lower subscapular nerves C5-C7

pectoralis major action

adducts & medially rotates humerus, draws scapula anteriorly & inferiorly, clavicular head: flexes humerus, sternocostal head: extends humerus from flexed position

pectoralis major PA

clavicular head: anterior surface of medial half of clavicle. sternocostal head: anterior surface of sternum, superior 6 costal cartilages, aponeurosis of external oblique muscle

pectoralis major DA

lateral lip of intertubercular sulcus of humerus

pectoralis major innervation

lateral & medial pectoral nerves. clavicular head C5, C6. sternocostal head C7, C8, T1

pectoralis minor action

stabilizes scapula by drawing it inferiorly & anteriorly against thoracic wall

pectoralis minor PA

3rd-5th ribs near their costal cartilages

pectoralis minor DA

medial border & superior surface of coracoid process of scapula

pectoralis minor innervation

medial pectoral nerve C8, T1, lateral pectoral nerve (variable)

serratus anterior action

protracts scapula & holds it against thoracic wall, rotates scapula

serratus anterior PA

external surface of lateral parts of 1st-8th ribs

serratus anterior DA

anterior surface of medial border of scapula, including superior & inferior angles

serratus anterior innervation

long thoracic nerve C5-C7

deltoid action

clavicular (anterior) part: flexes & medially rotates arm, acromial (middle) part: abducts arm, spinal (posterior) part: extends & laterally rotates arm

deltoid PA

lateral 1/3 of clavicle, acromion, spine of scapula

deltoid DA

deltoid tuberosity of humerus

deltoid innervation

axillary nerve C5, C6

coracobrachialis action

helps flex & adduct arm, resists dislocation of shoulder

coracobrachialis PA

tip of coracoid process of scapula

coracobrachialis DA

middle 1/3 of medial surface of humerus

coracobrachialis innervation

musculocutaneous nerve C5-C7

biceps brachii action

supinates forearm. when supine, flexes forearm. short head: resists dislocation of shoulder

biceps brachii PA

short head: tip of coracoid process of scapula, long head: supraglenoid tubercle of scapula

biceps brachii DA

tuberosity of radius & fascia of forearm via bicipital aponeurosis

biceps brachii innervation

musculocutaneous nerve C5-C7

brachialis action

flexes forearm in all positions

brachialis PA

distal half of anterior surface of humerus

brachialis DA

coronoid process & tuberosity of ulna

brachialis innervation

musculocutaneous nerve C5, C6 & radial nerve C5, C7

brachioradialis action

relatively weak flexion of forearm, maximal flexion when forearm is in midpronated position

brachioradialis PA

proximal 2/3 of lateral supra-epicondylar ridge of humerus

brachioradialis DA

lateral surface of distal end of radius proximal to styloid process

brachioradialis innervation

radial nerve C5-C7

triceps brachii action

chief extensor of forearm, long head: resists dislocation of humerus, especially important during adduction

triceps brachii PA

long head: infraglenoid tubercle of scapula, lateral head: posterior surface of humerus superior to radial groove, medial head: posterior surface of humerus inferior to radial groove

triceps brachii DA

proximal end of olecranon process of ulna & fascia of forearm

triceps brachii innervation

radial nerve C6-C8

pronator teres action

pronates & flexes forearm at elbow

pronator teres PA

ulnar head: coronoid process, humeral head: medial epicondyle of humerus

pronator teres DA

middle of convexity of lateral surface of radius

pronator teres innervation

median nerve C6, C7

palmaris longus action

flexes hand at wrist, tenses palmar aponeurosis

palmaris longus PA

medial epicondyle of humerus

palmaris longus DA

distal half of flexor retinaculum, apex of palmar aponeurosis

palmaris longus innervation

median nerve C7, C8

flexor carpi radialis action

flexes & abducts hand at wrist

flexor carpi radialis PA

medial epicondyle of humerus

flexor carpi radialis DA

base of 2nd metacarpal

flexor carpi radialis innervation

median nerve C6, C7

flexor carpi ulnaris action

flexes & adducts hand at wrist

flexor carpi ulnaris PA

humeral head: medial epicondyle of humerus, ulnar head: olecranon & posterior border of ulna via aponeurosis

flexor carpi ulnaris DA

pisiform, hook of hamate, 5th metacarpal

flexor carpi ulnaris innervation

ulnar nerve C7, C8

flexor digitorum superficialis action

flexes middle phalanges at proximal interphalangeal joints of middle 4 digits. acting more strongly, also flexes proximal phalanges at metacarpophalangeal joints

flexor digitorum superficialis PA

humero-ulnar head: medial epicondyle & coronoid process, radial head: superior half of anterior border

flexor digitorum superficialis DA

shafts of middle phalanges of medial 4 digits

flexor digitorum superficialis innervation

median nerve C7, C8, T1

flexor digitorum profundus action

medial part: flexes distal phalanges 4 & 5 at distal interphalangeal joints, lateral part: flexes distal phalanges 2 & 3 at distal interphalangeal joints

flexor digitorum profundus PA

proximal 3/4 of medial & anterior surfaces of ulna & interosseous membrane

flexor digitorum profundus DA

medial part: bases of distal phalanges of 4th & 5th digits, lateral part: bases of distal phalanges of 2nd & 3rd digits

flexor digitorum profundus innervation

medial part: ulnar nerve C8, T1. lateral part: anterior interosseous nerve, from median nerve C8, T1

flexor pollicis longus action

flexes phalanges of 1st digit (thumb)

flexor pollicis longus PA

anterior surface of radius & adjacent interosseous membrane

flexor pollicis longus DA

base of distal phalanx of thumb

flexor pollicis longus innervation

anterior interosseous nerve, from median nerve C8, T1