muscles: unit 2 lab - HAL

upper extremity

trapezius

PA:

• medial 1/3 of superior nuchal line

• external occipital protuberance

• SP C7-T12

• nuchal ligament

DA:

• lateral 1/3 of clavicle

• spine of scapula

• acromion process of scapula

Nerve: spinal accessory (CN XI) and C3-C4 nerve roots

Action:

• elevate scapula

• depress scapula

• retract scapula

• superiorly rotates glenoid cavity

rhomboid major

PA:

• SP T2-T5

DA:

• medial border of scapula @ level of spine to inferior angle

Nerve: dorsal scapular C4-C5

Action

• retract scapula

• inferiorly rotates glenoid cavity

• fix scapula to thoracic wall

rhomboid minor

PA:

• SP C7-T1

• nuchal ligament

DA:

• smooth triangle at medial end of scapular spine

Nerve: dorsal scapular C4-C5

Action:

• retract scapula

• inferiorly rotates glenoid cavity

• fix scapula to thoracic wall

levator scapulae

PA:

• posterior tubercles of TP C1-C4

DA:

• medial border of scapular superior to spine

Nerve: dorsal scapular C4-C5 and cervical spinal nerves C3-C4

Action:

• elevates scapula

• inferiorly rotates glenoid cavity

supraspinatus

PA:

• supraspinous fossa of scapula

DA:

• superior facet of greater tubercle of humerus

Nerve: suprascapular nerve C4, C5, C6

Action:

• initiates and assists deltoid in abduction of arm

• acts with other rotator cuff mm to hold humeral head in glenoid cavity

infraspinatus

PA:

• infraspinous fossa of scapula

DA:

• middle facet of greater tubercle of humerus

Nerve: suprascapular nerve C5-C6

Action:

• laterally rotates arm

• acts with other rotator cuff mm to hold humeral head in glenoid cavity

teres minor

PA:

• middle part of lateral border of scapula

DA:

• inferior facet of greater tubercle of humerus

Nerve: axillary nerve C5-C6

Action:

• laterally rotates arm

• acts with other rotator cuff mm to hold humeral head in glenoid cavity

teres major

PA:

• posterior surface of inferior angle of scapula

DA:

• medial lip of intertubercular sulcus of humerus

Nerve: lower subscapular nerve C5-C6

Action:

• adducts arm

• medially rotates arm

pectoralis major

PA:

• clavicular head:

  • anterior surface of medial ½ of clavicle

• sternocostal head:

  • anterior surface of sternum

  • superior six costal cartilages

  • aponeurosis of external oblique muscle

DA:

• lateral lip of intertubercular sulcus of humerus

Nerve: lateral and medial pectoral nerves

• clavicular head: C5-C6

• sternocostal head: C7, C8, T1

Action:

• adducts humerus

• medially rotates humerus

• (separately, clav flexes humerus, sterno extends it from flexed position)

pectoralis minor

PA:

• 3rd-5th ribs near costal cartilages

DA:

• medial border and superior surface of coracoid process of scapula

Nerve:

• medial pectoral nerve - C8-T1

• lateral pectoral nerve - variable

Action:

• stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall

serratus anterior

PA:

• external surfaces of lateral parts of 1st-8th ribs

DA:

• anterior surface of medial border of scapula, including superior and inferior angles

Nerve: long thoracic nerve C5-C7

Action:

• protracts scapula

• holds scapula against thoracic wall

• rotates scapula

deltoid

PA:

• lateral 1/3 of clavicle

• acromion process

• spine of scapula

DA:

• deltoid tuberosity of humerus

Nerve: axillary nerve C5-C6

Action:

• clavicular part - flexes and medially rotates arm

• acromial part - abducts arm

• spinal part - extends and laterally rotates arm

subscapularis

PA:

• subscapular fossa (most of anterior surface)

DA:

• lesser tubercle of humerus

Nerve: upper and lower subscapular nerves C5-C7

Action:

• medially rotates arm

• acts with other rotator cuff mm to hold humeral head in glenoid cavity

coracobrachialis

PA:

• tip of coracoid process of scapula

DA:

• middle 1/3 of medial surface of humerus

Nerve: musculocutaneous nerve C5-C7

Action:

• helps flex and adduct arm

• resists dislocation of shoulder

biceps brachii (2 heads)

PA:

• short head - tip of coracoid process of scapula

• long head - supraglenoid tubercle of scapula

DA:

• tuberosity of radius and fascia of forearm via bicipital aponeurosis

Nerve: musculocutaneous C5-C7

Action:

• supinates forearm

• when supine, flexes forearm

• short head resists dislocation of shoulder

brachialis

PA:

• distal half of anterior surface of humerus

DA:

• coronoid process of ulna

• ulnar tuberosity

Nerve: musculocutaneous nerve C5-C6 and radial nerve C5, C7

Action:

• flexes forearm in all positions

triceps brachii (3 heads)

PA:

• lateral head - posterior surface of humerus, superior to radial groove

• long head - infraglenoid tubercle of scapula

• medial head - posterior surface of humerus, inferior to radial groove

DA:

• proximal end of olecranon of ulna and fascia of forearm

Nerve: radial nerve C6, C7, C8

Action:

• extensor of forearm

• long head resists dislocation of shoulder

  • important during adduction

anconeus

PA:

• lateral epicondyle of humerus

DA:

• lateral surface of olecranon and superior part of posterior surface of ulna

Nerve: radial nerve C7, C8, T1

Action:

• assists triceps in extending elbow

• stabilizes elbow joint

• may abduct ulna during pronation

pronator teres

PA:

• ulnar head - coronoid process

• humeral head - medial epicondyle of humerus

DA:

• middle of convexity of lateral surface of radius

Nerve: median nerve C6, C7

Action:

• pronates forearm (at elbow)

• flexes forearm (at elbow)

palmaris longus

PA:

• medial epicondyle of humerus

DA:

• distal half of flexor retinaculum

• apex of aponeurosis

Nerve: median nerve C7, C8

Action:

• flexes hand (at wrist)

• tenses palmar aponeurosis

flexor carpi radialis

PA:

• medial epicondyle of humerus

DA:

• base of 2nd metacarpal

Nerve: median nerve C7, C8

Action:

• flexes hand (at wrist)

• abducts hand (at wrist)

flexor carpi ulnaris

PA:

• humeral head - medial epicondyle of humerus

• ulnar head - olecranon and posterior border of ulna

DA:

• pisiform

• hook of hamate

• 5th metacarpal

Nerve: ulnar nerve C7, C8

Action:

• flexes hand (at wrist)

• adducts hand (at wrist)

flexor digitorum superficialis

PA:

• humero-ulnar head - medial epicondyle and coronoid process

• radial head - superior half of anterior border

DA:

• shafts of middle phalanges of medial four digits

Nerve: median nerve C7, C8, T1

Action:

• flexes middle phalanges at proximal interphalangeal joints of middle four digits

• flexes proximal phalanges at metacarpophalangeal joint

flexor digitorum profundus

PA:

• proximal three quarters of medial and anterior surfaces of ulna and interosseous membrane

DA:

• medial part - bases of distal phalanges of 4th and 5th digits

• lateral part - bases o distal phalanges of 2nd and 3rd digits

Nerve:

• medial part - ulnar never C8, T1

• lateral part - anterior interosseous nerve, from median never C8, T1

Action:

• medial part - flexes distal phalanges 4 and 5 at distal interphalangeal joints

• lateral part - flexes distal phalanges 2 and 3 at distal interphalangeal joints

flexor pollicis longus

PA:

• anterior surface of radius and adjacent interosseous membrane

DA:

• base of distal phalanx of thumb

Nerve: anterior interosseous nerve, from median never C8, T1

Action:

• flexes phalanges of 1st digit

pronator quadratus

PA:

• distal quarter of anterior surface of ulna

DA:

• distal quarter of anterior surface of radius

Nerve: anterior interosseous nerve, from median nerve C8-T1

Action:

• pronates forearm

• deep fibers bind radius and ulna together

brachioradialis

PA:

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

DA:

• lateral surface of distal end of radius proximal to styloid process

Nerve: radial nerve C5-C7

Action:

• weak in flexion of forearm

• maximal flexion when forearm is midpronated (thumbs up)

extensor carpi radialis longus

PA:

• lateral supra-epicondylar ridge of humerus

DA:

• dorsal aspect of base of 2nd metacarpal

Nerve: radial nerve C6-C7

Action:

• extend hand at wrist

• abduct hand at wrist

• active in first clenching

extensor carpi radialis brevis

PA:

• lateral epicondyle of humerus

DA:

• dorsal aspect of base of 3rd metacarpal

Nerve: deep branch of radial nerve C7-C8

Action:

• extend hand at wrist

• abduct hand at wrist

extensor digitorum

PA:

• lateral epicondyle of humerus

DA:

• extensor expansions of medial four digits

Nerve: deep branch of radial nerve C7-C8

Action:

• extends medial 4 digits at

  • primarily - metacarpophalangeal joint

  • secondarily - interphalangeal joint

extensor digiti minimi

PA:

• lateral epicondyle of humerus

DA:

• extensor expansions of 5th digit

Nerve: deep branch of radial nerve C7-C8

Action:

• extends 5th digit at

  • primarily - metacarpophalangeal joint

  • secondarily - interphalangeal joint

extensor carpi ulnaris

PA:

• lateral epicondyle of humerus

• posterior border of ulna via a shared aponeurosis

DA:

• dorsal aspect of base of 5th metacarpal

Nerve: deep branch of radial nerve C7-C8

Action:

• extends hand at wrist

• abducts hand at wrist

• active during first clenching

supinator

PA:

• lateral epicondyle of humerus

• radial collateral and annular ligaments

• supinator fossa

• crest of ulna

DA:

• lateral, posterior, and anterior surfaces of proximal third of radius

Nerve: deep branch of radial nerve C7-C8

Action:

• supinates forearm

• rotates radius to turn palm superiorly

• active during fist clenching

extensor indicis

PA:

• posterior surface of distal third of ulna

• interosseous membrane

DA:

• extensor expansion of 2nd digit

Nerve: posterior interosseous nerve C7-C8 (continuation of deep branch of radial)

Action:

• extends 2nd digit (independently)

• helps extend hand at wrist

abductor pollicis longus

PA:

• posterior surface of proximal halves of ullna, radius, and interosseous membrane

DA:

• base of 1st metacarpal

Nerve: posterior interosseous nerve C7-C8 (continuation of deep branch of radial nerve)

Action:

• abducts thumb

• extends thumb at carpometacarpal joint

extensor pollicis longus

PA:

• posterior surface of middle third of ulna

• interosseous membrane

DA:

• dorsal aspect of base of distal phalanx of thumb

Nerve: posterior interosseous nerve C7-C8 (continuation of deep branch of radial nerve)

Action:

• extends distal phalanx of thumb at interphalangeal joint

• extends metacarpophalangeal and carpometacarpal joint

extensor pollicis brevis

PA:

• posterior surface of distal third of radius

• interosseous membrane

DA:

• dorsal aspect of base of proximal phalanx of thumb

Nerve: posterior interosseous nerve C7-C8 (continuation of deep branch of radial nerve)

Action:

• extends proximal phalanx of thumb at metacarpophalangeal joint

• extends carpometacarpal joint